본 연구에서는 해산 규조류(Skeletonema cosatatum)의 개체군성장률(r)을 사용하여 중금속 3종 (As, Cr, Pb)의 독성영향 평가를 실시하였다. S. costatum을 As (0, 0.32, 0.63, 1.25, 2.50 및 5.00 mg L-1), Cr (0, 0.16, 0.32, 0.63, 1.25 및 2.50 mg L-1) 및 Pb (0, 1.25, 2.50, 5.00, 10.00 및 20.00 mg L-1)에 96시간 노출한 이후에 r 값을 측정하였다. 대조구에서 r 은 0.04보다 높았으며 As 농 도 0.63, Cr 농도 0.63 및 Pb 농도 10.00 mg L-1 이상에서 r 이 대조구 대비 유의하게 감소하였고 중금속 농도가 증가할수록 농도 의존적으로 감소되는 경향을 나타냈다. EC50(반수영향농도)을 이용한 중금속의 독성세기는 Cr>As>Pb 순서를 나타냈으며, EC50 각각 0.80, 2.57 및 13.88 mg L-1으로 나타났으며, 최소영향농도(LOEC)는 각각 0.63, 0.63 및 10.00 mg L-1으로 나타났다. LOEC 를 기준으로 해양환경에서 Cr, As, Pb 농도가 0.63, 0.63 및 10.00 mg L-1 이상이 되었을 때, S. costatum에게 독성 영향이 나타날 수 있을 것으로 판단된다. 또한, 본 연구를 통해 S. costatum 의 r 은 해양생태계 내에서 생산자 역할을 하는 생물에 대한 중금속의 독성평가를 위하여 유용 하게 사용될 수 있을 것으로 판단된다.

Effect of heavy metals (Cd, Cu, Zn) on the survival and population growth rates (PGR) of marine rotifer, Brachionus plicatilis were examined. B. plicatilis were exposed to Cd, Cu and Zn for 24 h to determine their survival and 72 h to determine their PGR. Survival rates in the control groups were greater than 90%. They were decreased with increasing concentrations of Cd, Cu and Zn. Survival rates were reduced in a concentration-dependent manner. Significant reduction in survival rates after exposure to Cd, Cu and Zn at concentration greater than 40.00, 0.13 and 10.00 mg L-1, respectively. PGR in the control groups were greater than 0.50. They were decreased with increasing concentrations of heavy metals. PGR were reduced in a concentrationdependent manner. Significant reduction in PGR after exposure to Cd, Cu and Zn occurred at concentration greater than 12.5, 0.06 and 1.00 mg L-1, respectively. The order of heavy metal toxicity based on PGR was Cu>Zn>Cd, with EC50 (50% Effective Concentration) values of 0.12, 6.15 and 21.41 mg L-1, respectively. The lowest-observed-effective-concentrations (LOEC) of PGR after exposure to Cd, Cu and Zn were 12.50, 0.06 and 1.00 mg L-1, respectively. The No-observedeffective- concentrations (NOEC) of PGR after exposure to Cd, Cu and Zn were 6.25, 0.03 and 0.01 mg L-1, respectively, in marine ecosystems have toxic effects on PGR of B. plicatilis. These results suggest that the PGR of B. plicatilis are useful tool to assess the effect of heavy metals on primary consumers in marine natural ecosystems.

Toxicity assessment of heavy metals (As, Cr and Pb) has been investigated by using the rate of survival and population growth(r) of marine rotifer, Brachionus plicatilis. The survival rate was determined after 24 hours of exposure to As, Cr and Pb. As and Cr reduced survival rate in dose-dependent manner and a significant reduction were occurred at concentration of greater than 30 and 150 mg L-1, but Pb had no effect on survival rate. The r was determined after 72 hours of exposure to As, Cr and Pb. As, Cr and Pb reduced r in dose-dependent manner and a significant reduction were occurred at concentration of greater than 5, 25 and 50 mg L-1. The toxicity of heavy metals were ranked As>Cr>Pb, with EC50 values of 12.98, 82.34 and 110.14 mg L-1, respectively. The no-observed-effect-concentration (NOEC) of r in As, Cr and Pb exposure were 1, 12.5 and 50 mg L-1, respectively. The lowest-observed-effect-concentration (LOEC) of r in As, Cr and Pb exposure were 5, 25, and 50 mg L-1, respectively. From the results, the concentration of As, Cr and Pb (greater than 5, 25 and 50 mg L-1, respectively) have toxic effect on the r of B. plicatilis in natural ecosystems. These results (including NOEC and EC50) might be useful for the mixing toxicity assessment and toxic guide line of heavy metals in marine ecosystems.

For the development of a low-melting point filler metal for brazing aluminum alloy, we analyzed change of melting point and wettability with addition of Sn into Al-20Cu-10Si filler metal. DSC results showed that the addition of 5 wt% Sn into the Al-20Cu-10Si filler metal caused its liquidus temperature to decrease by about 30 oC. In the wettability test, spread area of melted Al-Cu-Si-Sn alloy is increased through the addition of Sn from 1 to 5 wt%. For the measuring of the mechanical properties of the joint region, Al 3003 plate is brazed by Al-20Cu-10Si-5Sn filler metal and the mechanical property is measured by tensile test. The results showed that the tensile strength of the joint region is higher than the tensile strength of Al 3003. Thus, failure occurred in the Al 3003 plate.

Heavy metals have been analyzed on the non-woven from the 24 kinds of wet wipes and 8 kinds of mask packs. The following materials used in the non-woven according to each product are: rayon+polyester for the 12 wet wipe products, rayon+PET for the 5 wet wipe products, and rayon, cotton, rayon+polyester+cotton, pulp+polypropylene for the rest of the wet wipe products. No further information on the materials was found on the 3 wet wipes and 8 mask packs. However, polyester may be applied for the non-woven in wet wipes, because PET is part of the polyester group. The heavy metals analysis in the 24 kinds of wet wipes and 8 kinds of mask packs revealed the following: arsenic was found from 47.14±1.13 to 71.75±1.64 ㎍/L on the 3 products, the amount of nickel in the 2 products were 261.26±5.14 and 1,242.63±43.71 ㎍ /L, 53.69±1.45 and 103.52±2.02 ㎍/L on the 2 mask packs. It was also revealed that lead was detected from 7.23±0.32 to 55.67±1.46 ㎍/L on the 6 wet wipes, antimony was ranged from 187.86±5.24 to 19,558.35±3,537.30 ㎍/L on the 12 wet wipes, and 5.25±0.25 and 8,936±55.22 ㎍/L on the 2 mask packs. No cadmium, mercury, or thallium were detected from all the products. A high concentration of antimony might come from antimony trioxide, which was used as a catalyst when manufacturing the polyester. Therefore, it is strongly recommended that a non-woven used for cosmetic purposes should not use heavy metals as a catalyst when manufacturing, and it’s important to clarify which materials are used in non-woven.

In recent years, consumers have become more interested in convenient lifestyles, leading to increased use of salted cabbages for preparation of kimchi. This study aimed to investigate the safety of heavy metals, pesticide residues, and foodborne pathogens in commercial salted cabbages in Seoul from August to November, 2014. The survey, which was conducted to determine whether or not salted cabbages were prepared under the highest sanitary conditions, showed that Seoulites are interested in purchasing hygienic and safe salted cabbages. The average amounts (range) of Pb and Cd found in 30 salted cabbage samples were 0.007 (0.000~0.063) mg/kg and 0.004 (0.000~0.012) mg/kg, respectively. The cabbages were analyzed for residues from 285 types of pesticides using the multiresidue method. Residues for pesticides were not detected. Major foodborne pathogens, specifically Escherichia coli, Salmonella spp., Listeria monocytogenes, Campylobacter jejuni, Staphylococcus aureus, Vibrio parahaemolyticus, Enterohemorrhagic Escherichia coli, Bacillus cereus, Clostridium perfringens and Norovirus, were also not detected.

2013년 8월 진해만을 대상으로 표층 퇴적물을 채취하여 미량금속(As, Cd, Co, Cr, Cu, Fe, Hg, Mn, Pb, Zn)의 분포를 살펴보고, 오염도를 분석하였다. 미량금속의 평균농도는 As 11.1 mg/kg, Cd 0.52 mg/kg, Co 14.1 mg/kg, Cr 69.8 mg/kg, Cu 57.2 mg/kg, Fe 3.7 %, Hg 0.064 mg/kg, Mn 600 mg/kg, Pb 40.1 mg/kg, Zn 167.2 mg/kg 의 범위로 조사되었다. 미량금속 중 As, Co, Cr, Fe의 농도는 만 전반적으로 균일한 분포를 보였다. 반면, Cd, Hg, Pb, Zn는 마산만을 포함한 진해만의 북쪽 해역, Cu는 진해만 남동쪽의 고현만, Mn은 거제도 북쪽과 마산만 남쪽을 잇는 만 동쪽방면의 외해로 열린 해역에서 국지적으로 높은 농도를 나타냈다. 각 미량금속의 공간적 분포, 퇴적물 입도 및 미량금속 간의 상관관계와 요인분석 결과 등을 종합적으로 검토해봤을 때, Co, Cr, Fe는 퇴적물의 입도, Mn은 퇴적물의 산화환원 상태, 그리고 As, Cd, Cu, Hg, Pb, Zn은 만 주변의 오염활동으로 인한 미량금속 공급에 따라 분포가 지배되는 것으로 파악되었다. 미량금속 중 As, Cd, Cr, Hg, Pb의 농도를 국내 해양 퇴적물 환경기준인 주의기준(TEL), 관리기준(PEL)과 비교 시, Cd, Hg, Pb의 농도가 만의 북쪽인 마산만 주변에서 주의기준을 초과하였다. 각 미량금속의 농축계수 및 농집지수를 계산한 결과, As, Cd, Cu, Hg, Mn, Pb, Zn가 일부 해역에서 인위적 오염을 보였다. 이 중 As, Mn, Zn은 우려할만한 수준의 오염을 보이진 않았으나, 마산만을 포함한 만 북쪽에서는 Cd, Hg, Pb, 만 남동쪽 가장 안쪽의 고현만에서는 Cu로 인한 오염 수준이 비교적 높게 나타나 해당 원소의 농축에 대해 주의가 필요할 것으로 판단된다.

In order to evaluate the pollution of heavy metals in offshore surface sediments around shipyards in Korea, surface sediment samples were collected at eleven stations around four major shipyards located in the southeastern coast of Korea in summer 2010 and nine kinds of heavy metals such as copper(Cu), zinc(Zn), cadmium(Cd), lead(Pb), chrome(Cr), arsenic(As), mercury(Hg), iron(Fe) and aluminum(Al) in sediments were analyzed. The concentrations of Cu at all sampling stations were in the range of 47.10 ~ 414.96 mg/kg and exceeded TEL(Threshold Effects Level) 20.6 mg-Cu/kg of Korean marine environmental standards for offshore sediments and ERL(Effect Range-Low) 34.0 mg-Cu/kg . The concentrations of Cu at seven stations around four shipyards were 65.18 ~ 414.96 mg/kg and exceeded PEL(Probable Effects Level) 64.4 mg-Cu/kg of Korean marine environmental standards for offshore sediments. The concentration of Cu at one station around B-shipyard was 414.96 mg/kg and exceeded ERM(Effect Range-Median) 270.0 mg-Cu/kg . The concentrations of Zn at all stations were in the range of 135.09 ~ 388.79 mg/kg which exceeded ERL 150.0 mg-Zn/kg . The concentrations of Zn at seven stations around four shipyards were 157.57 ~ 388.79 mg/kg and exceeded PEL 157.0 mg-Zn/kg . The concentration of Zn at one station around B-shipyard was 388.79 mg/kg and was approaching ERM 410.0 mg-Zn/kg . The concentrations of Cd at all stations were in the range of 0.11 ~ 0.54 mg/kg and were below TEL 0.75 mg-Cd/kg and ERL 1.2 mg-Cd/kg . The concentrations of Pb at all stations were in the range of 18.04 ~ 105.62 mg/kg . The concentrations of Pb at two stations around B-shipyard were 73.87 ~ 105.62 mg/kg which exceeded TEL 44.0 mg-Pb/kg and ERL 46.7 mg-Pb/kg , and were below PEL 119.0 mg-Pb/kg and ERM 218.0 mg-Pb/kg . The concentrations of Cr at all stations were in the range of 51.26 ~ 85.39 mg/kg. The concentration of Cr at one station around B-shipyard was 85.39 mg/kg and exceeded ERL 81.0 mg-Cr/kg . The concentrations of As at all stations were in the range of 8.70 ~ 22.15 mg/kg which exceeded ERL 8.2 mg-As/kg and were below ERM 70.0 mg-As/kg . The concentrations of As at eight stations around A-shipyard, B-shipyard and D-shipyard were 14.93 ~ 22.15 mg/kg which exceeded TEL 14.5 mg-As/kg and were below PEL 75.5 mg-As/kg . The concentrations of Hg at all stations were in the range of 0.02 ~ 0.35 mg/kg. The concentrations of Hg at three stations around A-shipyard were 0.11 ~ 0.13 mg/kg which were almost equal to TEL 0.11 mg-Hg/kg . Those at two stations around B-shipyard were 0.27 ~ 0.35 mg/kg which exceeded TEL 0.11 mg-Hg/kg and ERL 0.15 mg-Hg/kg, and were below PEL 0.62 mg-Hg/kg and ERM 0.71 mg-Hg/kg. The concentrations of Fe and Al at all stations were in the range of 2.90 ~ 3.66 % and 3.12 ~ 6.80 %, respectively. These results imply that heavy metals such as copper, zinc, lead, arsenic and mercury were likely to be transferred to marine environment from shipyards, especially from B-shipyard.

Chironomous is aquatic insect belonging to order Diptera, family Chironomidae. Their larval stage can be found mainly in aquatic benthic environment, hence good model organism to study environmental toxicology assessments and consider as useful bio indicators of contamination of the aquatic environment. In this study, Chironomus Heat Shock Proteins, Cytochrome 450, Glutathione S-transferase, Serine-type endopeptidase gene expressions were compared between polluted field areas (Chironomus plumosus) and under laboratory conditions (Chironomus riparious) to investigate molecular indicators for environmental contaminant stress assessment. Heavy metal (Al, Fe, Mn, Cu, Cr, Zn, Se, Pb, As, Cd) concentrations in sediments collected from three study areas exceeded the reference values. Moreover, HSPs, CYP450 and GST gene expression except SP for C. plumosus showed higher expression than C. riparious gene expression. Similar gene expression pattern was observed in C. riparious that exposed environment waters up to 96 h when compared to C. plumosus exposed to waters that grown in lab conditions. In summary, this comparative gene expression analysis in Chironomous between field and laboratory condition gave useful information to select candidate molecular indicators in heavy metal contaminations in the environment.

Porous metals are called as a new material of 21th century because they show not only extremely low density, but also novel physical, thermal, mechanical, electrical, and acoustic properties. Since the late in the 1990‘s, considerable progress has been made in the production technologies of many kinds of porous metals such as aluminum, titanium, nickel, copper, stainless steel, etc. The commercial applications of porous metals have been increased in the field of light weight structures, sound absorption, mechanical damping, bio-materials, thermal management for heat exchanger and heat sink. Especially, the porous metals are promising in automotive applications for light-weighting body sheets and various structural components due to the good relation between weight and stiffness. This paper reviews the recent progress of production techniques using molten metal bubbling, metal foaming, gas expansion, hollow sphere structure, unidirectional solidification, etc, which have been commercialized or under developing, and finally introduces several case studies on the potential applications of porous metals in the area of heat sink, automotive pannel, cathod for Ni-MH battery, golf putter and medical implant.

국내 대형 조선소 주변해역의 중금속오염 현황을 밝히기 위하여 2010년 여름에 4개의 대형 조선소 주변 11개의 채수정점과 4개의 대조 정점에서 해수 시료를 채취하여 6종의 금속(Cu, Zn, Fe, Cd, Pb, Hg)을 분석하였다. 조선소별 주변해역 수중의 금속을 분석한 결과, (1) 구리(Cu)의 평균 농도는 0.817 ~ 1.638 ㎍/L로 해역환경기준(사람의 건강보호기준 20 ㎍/L, 해양생태계 보호 단기기준 3 ㎍/L)보다 낮았지만, 대조정점에 비하여 1.64 ~ 2.75배의 높은 값을 나타냈다. (2) 아연(Zn)의 평균 농도는 0.228 !~ 0.567 ㎍/L로 해역환경기준(사람의 건강보호기준 100 ㎍/L, 해양생태계 보호 단기기준 34 ㎍/L)보다 낮았지만, 대조정점에 비하여 1.62 ~ 5.91배의 높은 값을 나타냈다. (3) 철(Fe)의 평균 농도는 3.332 ~ 7.410 ㎍/L로 대조정점에 비하여 1.30 ~ 6.75배의 높은 값을 나타냈다. (4) 카드뮴(Cd)의 평균 농도는 0.013 ~ 0.028 ㎍/L로 해역환경기준(사람의 건강보호기준 10 ㎍/L, 해양생태계 보호 단기기준 19 ㎍/L)보다 낮았지만, 대조정점에 비해 1.18 ~ 2.33배의 높은 값을 나타냈다. (5) 납(Pb)의 평균 농도는 0.007 ~ 0.126 ㎍/L로 해역환경기준(사람의 건강보호기준 50 ㎍/L, 해양생태계 보호 단기기준 7.6 ㎍/L)보다 낮았다. (6) 수은(Hg)의 평균 농도는 0.002 ~ 0.004 ㎍/L로 해역환경기준(사람의 건강보호기준 0.5 ㎍/L, 해양생태계 보호 단기기준 1.8 ㎍/L)보다 낮았다. 비록 모든 중금속의 수중 농도가 해역환경기준보다 낮다고 할지라도, 선박 건조작업에 사용되는 구리, 아연, 철과 같은 중금속의 농도가 대조해역에 비해 조선소 주변해역에서 높다는 것은 조선소의 영향에 기인하는 것을 암시한다. 따라서 조선소로부터 각종 오염물질이 해양에 유입되지 않도록 통제하고 해양오염을 방지하는 국가적 차원의 해양환경관리가 필요하다.

국내 유통 중인 총 391건의 유리제, 도자기제, 법랑, 옹기류, 폴리에틸렌제 및 폴리프로필렌제 식품용 기구 및 용 기·포장 중 이행 우려가 있는 납, 카드뮴, 비소, 안티몬, 6가크롬 및 수은에 대하여 이행량을 조사하고 안전성 평가를 실시하였다. 29건의 도자기제 및 법랑 검체에서 현행 식품용 기구 및 용기·포장 공전상의 용출규격 이하인 납, 카드뮴 및 안티몬이 이행되었다. 이행량 결과를 토대로 안전성 평가 시나리오에 적용하여 이행된 납, 카드뮴 및 안티몬의 EDI를 산출한 후 TDI와 비교하여 위해도를 평가하였다. 도자기제 기구 이행 납 및 카드뮴의 위해도는 TDI 대비 0.25%, 0.11% 수준이었고 법랑 기구 이행 납, 카드뮴 및 안티몬의 위해도는 TDI 대비 0.33%, 1.52% 및 0.13% 수준이었다. 결론적으로 검토된 평가 항목들의 위해도는 TDI 대비 최대 1.52%에 불과한 것으로 조사되어 안전한 수준인 것으로 사료되었다. 이러 한 결과들은 앞으로 기구 및 용기·포장의 안전관리를 위한 과학적인 근거자료로 이용될 수 있을 것으로 판단된다.

The potential ability of Button mushroom compost (BMC) to solubilize heavy metals was estimated with metal contaminated soils collected from abandoned mines of Boryeong area in South Korea. The bacterial strains in BMC were isolated for investigating the mobilization of metals in soil or plant by the strains and identified according to 16S rRNA gene sequence analysis. When metal solubilization potential of BMC was assessed in a batch experiment, the BMC was found to be capable of solubilizing metals in the presence of metals (Co, Pb and Zn) and the results showed that inoculation of BMC could increase the concentrations of water soluble Co, Pb and Cd by 35, 25 and 45% respectively, than those of non-inoculated soils. BMC-assisted growth promotion and metal uptake in sunflower (Helianthus annuus) was also evaluated in a pot experiment. In comparison with non-inoculated seedlings, the inoculation led to increase the growth of H. annuus by 27, 25 and 28% respectively in Co, Pb and Zn contaminated soils. Moreover, enhanced accumulation of Co, Pb and Zn in the shoot and root systems was observed in inoculated plants, where metal translocation from root to the above-ground tissues was also found to be enhanced by the BMC. The apparent results suggested that the BMC could effectively be employed in enhancing phytoextraction of Co, Pb and Zn from contaminated soils.

천수만 내 어장해역과 비어장해역의 해저퇴적물에 대한 지화학적 특성을 파악하기 위하여 입도 및 유기물오염의 특성과 중금속 오염도를 평가하였다. 천수만 퇴적물은 Sand, Silt, Clay가 혼재된 퇴적 특성을 나타내었으며, 어장해역인 만내에는 세립질이 우세하고, 비어장해역인 만외는 조립질이 우세한 것으로 나타났다. 퇴적물의 유기물(COD, TOC, I.L.) 오염정도는 양식어장해역이 비양식어장해역보다 유기물 오염도가 더 심한 것으로 나타났으며, 퇴적물 총질소 농도도 양식어장이 더 높은 것으로 나타났다. 퇴적물중의 중금속 함량을 양식어장인 내측과 비양식어장인 외측과 비교해 보면, 모든 항목에서 양식어장에서 높은 평균농도를 나타내고 있었다. 퇴적물의 입도와 이화학적 성분, 중금속과의 상관성에서 평균입도, Sand, Clay는 유기물 인자와 높은 상관성을 보였고, 유기물 지표와 중금속간의 상관성도 대체적으로 높게 나타났다. 중금속 오염도의 평가에서 농축계수는 Cu를 제외한 모든 중금속 항목에서 1 이상의 값을 보여 인위적인 영향이 있는 것으로 나타났고, 중금속 과잉량은 Cd와 Cr이 0에 가까운 값을 보였으나, 나머지 항목은 높은 값을 나타내어 중금속 과잉량이 높은 것으로 나타났다. 농집지수에 의한 평가에서는 Cu, Pb, Al은 0등급의 오염되지 않은 수준이었고, Hg, Cr은 10개 이내의 자료에서 0~1등급 이상이었고, 나머지는 0등급이었다. 그리고 Cd은 18개 자료에서 0~1등급 이상을 나타내었고, As의 경우 모든 자료에서 0~1등급 이상이었다. 미국해양대기청(NOAA) 퇴적물 기준과 비교하면 모든 중금속 항목에서 ERL 이하의 오염수준을 보였고, 한국환경정책평가연구원 퇴적물 기준과 비교에서도 목표수준 이하의 농도를 나타내었다.

산업 및 도시 개발로 오염이 심화되고 있는 진해만에서 생물을 이용한 오염도 모니터링을 위하여 부착성 이매패류인 진주담치를 이용하여 중금속 분석을 실시하였다. 중금속 농도는 원소 및 정점에 따라 차이가 있었는데 내만해역 또는 하수처리장 방류지역에 인접한 정점에서 높게 나타나는 원소가 있었다. 국내 및 국외 과거 자료와의 비교에서는 전체적으로 본 조사 결과가 낮은 값을 보였다. 특히 진해만의 소형만의 하나인 고현만의 조선소 주변해역 진주담치 중..

Cathode materials and their precursors are prepared with transition metal solutions recycled from the thewaste lithium-ion batteries containing NCM (nickel-cobalt-manganese) cathodes by a H2 and C-reduction process. Therecycled transition metal sulfate solutions are used in a co-precipitation process in a CSTR reactor to obtain the tran-sition metal hydroxide. The NCM cathode materials (Ni:Mn:Co=5:3:2) are prepared from the transition metal hydroxideby calcining with lithium carbonate. X-ray diffraction and scanning electron microscopy analyses show that the cathodematerial has a layered structure and particle size of about 10 µm. The cathode materials also exhibited a capacity ofabout 160 mAh/g with a retention rate of 93~96% after 100 cycles.

Heavy metals such as cadmium and mercury are a highly toxic metal that affects a variety of cellular events, such as cell proliferation, differentiation and survival in animals as well as in human. The exposed heavy metals significantly affected the development and health in pubertal period. However, it is not clear how the toxicity of heavy metals in pubertal affects comparing in adults. To determine the effects of heavy metals on pubertal and adults, heavy metals such as cadmium and mercury were exposed to in pubertal and adults mice for 48 and 72h. Results showed that mice exposed to heavy metals for several hours induced overall tissue and organ damage. Especially, blood vessels of the most organ were more increased in adult mice compared to pubertal mice. And for morphologic alteration, secretary organs such as salivary gland and kidney were affected the most. Taken together, exposing to heavy metal in mice altered the blood vessels. In addition, the adverse effects of cadmium and mercury were more severe in adult mouse than puberty mouse. Further study is needed to focus on endothelial cells for more precise its mechanism