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Effects of the Atmosphere on the Comparative Solderability of Lead-Tin and Lead-Free Solders

  • Bin, Jeong-Uk;S.M.Adams;P.F.Stratton
    • Proceedings of the International Microelectronics And Packaging Society Conference
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    • 2001.04a
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    • pp.45-47
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    • 2001
  • Due to pressure from threatened legislation in Europe, consumer and governmental pressure in Japan, and glob머 market considerations in the US, there is a rapidly growing interest in lead-free solderinger, Although the move to lead free soldering seems inevitable, many problems will arise in production assembly. It is generally acknowledged that the lead-free solders available offer a much s smaller process window than lead/tin, related mainly to the higher soldering temperatures which naturally result from increases of liquidus temperatures of at least 300 C. However, raising reflow temperatures from the current 220-2300 C to 250 2600 C will lead to problems with the boards and components as well as i increasing oxidation effects. There is a need to keep reflow temperatures low without reducing solderablity. Some results on benefits of inert atmospheres are discussed in this paper. For example, testing in a nitrogen atmosphere, with 300 ppm oxygen, by the N National Physical Laboratory (NPU has revealed clear benefits for ine$\pi$mg lead-free alloys, by restoring the solderability to lead/tin levels, by enabling lower soldering temperatures. However, there has been little testing over a range of oxygen levels in nitrogen and this is an important issue in determining n nitrogen supply and oven costs. Some results are reported here from work by NPL conducted for BOC in w which solderability was evaluated for tin기ead and tin/silver/copper eutectic a alloys in a wetting balance over a range of oxygen levels form 10 ppm to 21% ( (air). The studies confirm that acceptable wetting times occur in inert atmospheres a at soldering temperatures 20 to 300 C lower than are possible in air.

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Litholohical and Mechanical Characteristics of Crushed Limestone Aggregates (쇄석 골재용 석회암의 암석학적 및 역학적 특성)

  • 진호일;민경원;백환조;연규석
    • Magazine of the Korea Concrete Institute
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    • v.9 no.3
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    • pp.119-126
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    • 1997
  • Recently, duc to highly increased consumption of' ngg~.egatc>s f o ~ . construction. studies have focused on the effective utilization of rock wastes abandoned so far. This study was designed, firstly, to determine t,hc petrological, g'ochemical and mechanical cha~,acte~istics of' crushed limestone aggregates in thc Samhwa district for suitable construction aggregates and, secondly, to offer basic data for cff'ective utilization of low grade limestones. Results of' the petrographic st,udy indicates that the crushed limestone aggregates in the Samhwa district can bo separate4 into two groups, namely f'inc-grained and cowlxcgrained limestones. Dominantly distributed fine-grained limestone containing some dolomite has higher Mgo and $SiO_2$ contents compared to the coarse-graincd limestonr. It, can be classified as medium strength rock by the physical and mcxhanical pi.opertics. I3ased on the size of' mineral grains and chemical compositions, it is suggested that the crushed limestone aggregates in t,his study area would bctkr be u s ~ i for asphalt concr.ctt., road pavement, or railroad ballast materials than for cement concrete.

Anti-oxidant Effects of Samultang-Gami on MEF Cells (사물탕가미방(四物湯加味方)의 항산화 활성에 대한 실험적 연구)

  • Jung, Jae-Joong;Goo, Sun-Young;Go, Eun-Bi;Sung, Jung-Suk;Kim, Dong-Il
    • The Journal of Korean Obstetrics and Gynecology
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    • v.23 no.3
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    • pp.26-37
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    • 2010
  • Purpose: This experiment is designed to find out anti-oxidant effects of Samultang-Gami which was composed of Rehmanniae Radix(RR), Angelicae Gigantis Radix, Cnidii Rhizoma(CR), Paeoniae Radix(PR), Cortex Moutan Radicis, Hedyotis Diffusa(HD) and Caesalpinia Sappan on MEF cells. Methods: In vitro antioxidant effects were measured by MTT assay, DPPH assay, cell cycle analysis, AnnexinV-FITC/PI assay and DAPI staining using MEF cells treated with various concentrations of 70% ethanol extract of Samultang-Gami. Results: 1. In the scavenging for DPPH radical, the each treated groups of PR, CR and HD showed positive effects. RR and CR increased the viability of oxidative damaged MEF cells in a dose-dependent manner. 2. 70% ethanol extract of Samultang-Gami was shown best antioxidative effect in the concentration of $0.5mg/m{\ell}$. 3. The treatment of Samultang-Gami in oxidative damaged MEF cells didn't have any effect on cell cycle restoration. but it could lower late apoptosis rate a little and be observed the protection of nucleus. Conclusion: It can be concluded that Samultang-Gami, RR and CR have antioxidant effects on MEF cells.

Expression and Purification of Biologically Active Human Bone Morphogenetic Protein-4 in Recombinant Chinese Hamster Ovary Cells

  • Cha, Minyub;Han, Nara;Pi, Jia;Jeong, Yongsu;Baek, Kwanghee;Yoon, Jaeseung
    • Journal of Microbiology and Biotechnology
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    • v.27 no.7
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    • pp.1281-1287
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    • 2017
  • Bone morphogenetic protein-4 (BMP-4) is considered to have therapeutic potential for various diseases, including cancers; however, the high expression of biologically active recombinant human BMP-4 (rhBMP-4) needed for its manufacture for therapeutic purposes has yet to be established. In the current study, we established a recombinant Chinese hamster ovary (rCHO) cell line overexpressing rhBMP-4 as well as a production process using 7.5-l bioreactor (5 L working volume). The expression of the mature rhBMP-4 was significantly enhanced by recombinant furin expression. The combination of a chemically defined medium and a nutrient supplement solution for high expression of rhBMP-4 was selected and used for bioreactor cultures. The 11-day fed-batch cultures of the established rhBMP-4-expressing rCHO cells in the 7.5-L bioreactor produced approximately 32 mg/l of rhBMP-4. The mature rhBMP-4 was purified to homogeneity from the culture supernatant using a two-step chromatographic procedure, resulting in a recovery rate of approximately 55% and a protein purity greater than 95%. The N-terminal amino acid sequences and N-linked glycosylation of the purified rhBMP-4 were confirmed by N-terminal sequencing and de-N-glycosylation analysis, respectively. The mature purified rhBMP-4 has been proved to be functionally active, with an effective dose concentration of $EC_{50}$ of 2.93 ng/ml.

A study on Korean medicine methodology for active postpartum care by examining San-Hu-Byung cases (산후병 치험례로 살펴본 적극적 산후관리를 위한 한의학적 방법론 연구)

  • Pi, Chien Mei;Bae, Jae Ryong;Jang, Sang Chul;Roh, Ju Hee;Park, Seo Hee
    • Journal of Korean Medical Ki-Gong Academy
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    • v.15 no.1
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    • pp.23-43
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    • 2015
  • Objects : The purpose of this study is to evaluate Korean medicine treatment as an active postpartum care for women with San-Hu-Byung. Methods : We examined 35 patients(39 cases) with San-Hu-Byung who had hospitalized at the M Korean medicine hospital in Gyeonggi Province between January 1st, 2006 and March 31th, 2015. Based on medical records and questionnaires, we analyzed the general characteristics, main symptoms, duration of hospitalization, treatment satisfaction, etc. We also reviewed and analyzed the results using multifaceted questions. Results : 1. The patients were divided into four age groups; 30-34 years old(46%), 35-39 years old(33%), 27-29 years old(13%), more than 40 years old(5%) and less than 26 years old(3%) in the order. 2. Patients appealed musculoskeletal symptoms(44.05%), reproductive and breast symptoms(21.43%), circulatory symptoms(10.12%), neuropsychiatric symptoms(8.33%), digestive symptoms(7.14%), the other symptoms(5.95%), urinary symptoms(1.79%) and respiratory symptoms(1.19%) in the order. 3. Duration of hospitalization were; within 2 months(33.33%), more than 3 months(25.64%), within 1 month(17.95%), within 3 weeks(12.82%), within 3 months(5.13%) in the order. 4. The improvement of musculoskeletal symptoms including back pain was measured by VAS. After 6 weeks, the pain fell to less than half. After 12 weeks, the pain fell to less than 1. 5. Average satisfaction with Korean medicine treatment is a 4.51 out of 5. Conclusions : As an active postpartum care, Korean medical treatment had significant effect on San-Hu-Byung and patients found the treatment satisfying.

Study on Explosion Behavior of Air-born Rice Bran Dusts according to Ignition Energy (점화에너지 변화에 따른 쌀겨분진의 폭발 거동에 관한 연구)

  • 김정환;김현우;현성호;백동현
    • Fire Science and Engineering
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    • v.13 no.2
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    • pp.26-32
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    • 1999
  • We had investigated combustion pro야$\pi$ies of rice bran dusts. Decomposition of rice bran d dusts with temperature were investigated using DSC and the weight loss according to t temperature using TGA in order to find the thermal hazard of rice bran dusts, and the p properties of dust explosion in variation of their dust with the same particle size. Using H Hartman's dust explosion apparatus which estimate dust explosion by electric ignition after m making dust disperse by compressed air, dust explosion experiments have been conducted by v varying concen$\sigma$ation and size of rice br뻐 dust. According to the results for thermodynamic stability of rice bran dust, there are little change of initiation temperature of heat generation 때d heating value for used particle size. But i initiation temperature of heat generation decreased with high heating rate whereas d decomposition heat increased with particle size. Also, the explosion pressure was increased as t the ignition energy increased and average maximum explosion pressure was 13.5 kgv'cnt for 5 BJ/60 mesh and 1.5 뼈Ie미 dust concentration.

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Antiproliferative Evaluation and Apoptosis Induction in MCF-7 Cells by Ziziphus spina christi Leaf Extracts

  • Farmani, Fatemeh;Moein, Mahmoodreza;Amanzadeh, Amir;Kandelous, Hirsa Mostafapour;Ehsanpour, Zahra;Salimi, Mona
    • Asian Pacific Journal of Cancer Prevention
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    • v.17 no.1
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    • pp.315-321
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    • 2016
  • Background: Herbal medicine has becoming a potential source of treatment for different types of cancer including breast cancer. It has been shown that plants from the family Rhamnaceae possess anticancer activity. Objective: In this study, we determined the antiproliferative influence of Ziziphus spina christi- a species from this family- on the MCF-7 (human breast adenocarcinoma) cell line. Materials and Methods: The cytotoxicity of the total extract, ethanol, ethanol-aqueous (1:1) as well as aqueous fractions of Ziziphus spina christi leaves was evaluated through MTT assay against MCF-7 cell line. Cell cycle inhibition and apoptosis induction were assessed by flowcytometry cycle RNase/PI analysis and Annexin V-FLUOS, respectively. Apoptosis was also analyzed by immunoblotting assay. Results: Our results indicated that the ethanolic fraction had the lowest $IC_{50}$ value (0.02 mg/ml), induced cell cycle arrest at the G1/S phase as well as apoptosis after a 48h of treatment. Conclusions: This is the first report on anticancer effect of Ziziphus spina christi ethanolic fraction on breast cancer cells, providing a scientific basis for its utility in traditional medicine. However, further in-depth studies are needed to confirm the precise mechanisms.

Proapoptotic and antitumor effect of Hangbaek-Tang(HBT) in a tumor transplanted mouse model (마우스 모델에서 항백탕 투여에 의한 종양 증식의 억제 및 Apoptosis의 유도)

  • Yun, Young-Gab;Kim, Jun-Hee;Song, Eun-Jung;Hwang, Jin-Ki;Nam, Sang-Yun
    • Herbal Formula Science
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    • v.17 no.2
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    • pp.73-83
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    • 2009
  • Objective : In vitro proapoptotic effect of Hangbaek-Tang (HBT) has been documented by one of us. In the present study, we aimed to demonstrate in vivo effect of HBT on tumor growth. Methods : In vitro selective cytotoxicity of HBT was examined by enumeration of viable cell numbers using BC3A mouse leukemic cells and normal spleen cells. In vivo effect of HBT (25 and 50 mg/mouse) on tumor growth was assayed using BC3A cells innoculated subcutaneously in the flank. Annexin-V apoptosis assay and PI staining was performed to determine the effective serum factor in HBT-treated mice. Leukocyte recruitment into peritoneum were analyzed by microscopy with a stained cytosmear of peritoneal lavage fluid. Results : HBT exhibited in vitro selective cytotoxicity to leukemic cells and did not show any toxicity on immune organs. In vivo i.p. administration of HBT induced significant reduction in tumor growth but not complete regression. Sera obtained from HBT-treated mice strongly inhibited BC3A cell growth in vitro and were revealed to markedly enhance apoptosis and accompanying cell death, when compared to those from PBS-treated mice. Abundant extravasation of leukocytes, especially neutrophils, into peritoneum was observed in HBT-treated mice. Conclusions : HBT causes leukemic, BC3A cell death in vivo via apoptosis as well as in vitro, for which functional involvement of leukocytes is suggested.

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Effect of Epidermal Growth Factor (EGF) on Meiotic Maturation and Pronuclear Formation of Porcine Oocytes Produced In Vitro

  • Song S. H.;Kim J. G.;Song H. J.;Kumar B. Mohana;Cho S. R.;Choe C. Y.;Choi S. H.;Rho G. J.;Choe S. Y.
    • Reproductive and Developmental Biology
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    • v.29 no.2
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    • pp.127-131
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    • 2005
  • The objective of this study was to examine the effect of EGF on meiotic maturation and pronuclear (PN) formation of porcine oocytes. Prepubertal gilt cumulus-oocyte-complexes (COCs) aspirated from $2\~6mm$ follicles of abbatoir ovaries were matured in TCM199 containing 0.1mg/ml cysteine, $0.5{\mu}/ml$ FSH and LH, and EGF (0, 5, 10, 20, 40 ng/ml) for 22 hr at $39^{\circ}C$ in a humidified atmosphere of $5\%$ $CO_2$ in air. They were then cultured for an additional 22hr without hormones. In Experiment 1, to examine the nuclear maturation at 44hr of culture, the expanded cumulus cells were removed by vortexing for 1 min in 3 mg/ml hyaluronidase. The oocytes were fixed in acetic acid: methanol (1:3, v/v) at least for 48 hr and stained with $1\%$ orcein solution for 5 min. Nuclear status was classified as germinal vesicle (GV), germinal vesicle breakdown (GVBD), prophase-metaphase I (PI-MI), and PII-MII under microscope. In Experiment 2, to investigate PN formation, oocytes were fertilized with Percoll-treated freshly ejaculated sperm $(1\times10^5\; cells/ml)$ in mTBM with $0.3\%$ BSA and 2mM caffeine for 5hr, and cultured in NCSU-23 medium with $0.4\%$ BSA. At 6hr of culture, the embryos were fixed in $3.7\%$ formaldehyde for 48hr and stained with 10ug/ml propidium iodide for 30 min. PN status was classified as no or one PN (unfertilized), 2 PN (normal fertilized) and $\geq3$ PN (polyspermy). Differences between groups were analyzed using one-way ANOVA after arc-sine transformation of the proportional data. The rate of oocytes that had reached to PII-MII were significantly (P<0.05) higher in all groups added EGF than that of non-treated group $(67\%)$, but it did not differ among the all added groups $(86\%,\;85\%,\;79\%\;and\;81\%$, in 5, 10, 20 and 40 ng/ml EGF, respectively). No differences on the incidence of 2PN were observed in all treated groups $(25\%,\;30\%,\;33\%,\;29\%\;and\;29\%$, in 0, 5, 10, 20 and 40 ng/ml EGF, respectively), however, in non-treated group, polyspermy tended to be increased ($66\%\;vs\;. 58\%,\;54\%,\;52\%\;and\;55\%$, 0 vs. 5, 10, 20, 40 ng/ml EGF, respectively). These results suggest that EGF can be effectively used as an additive for enhancing oocyte maturation and reducing the incidence of polyspermy in pig.

Effects of Hyolbuchukeo-tang Extracts on Blood and liver of Hyperlipidemia Rats Induced by High Fat Diet (혈부축어탕(血府逐瘀湯) 추출물(抽出物)이 고지방식이(高脂肪食餌)로 유발(誘潑)시킨 고지혈증(高脂血症) 흰쥐의 혈액(血液) 및 간(肝) 기능(機能)에 미치는 영향(影響))

  • Pi, Chien-Mei;Chong, Myong-Soo;Kim, Hae-Ja;Cho, Hwa-Eun;Choi, Yun-Hee;Lee, Ki-Nam
    • Journal of Society of Preventive Korean Medicine
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    • v.13 no.1
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    • pp.41-58
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    • 2009
  • Objectives: The purpose of this study was to investigate the effects of Hyolbuchukeo-tang extracts on the hyperlipidemia rats induced by high fat diet. Methods and Materials: In vitro; The extracts prepared for Hyolbuchukeo-tang by hot water extraction (HH), fermentation(HF) and UMPM extraction(HU) method. The extracts were examined for levels of polyphenol compounds, antioxidant activities, and inhibitory potencies for HMG-CoA reductase. In vivo; Sprague-Dawley male rats of weighing $150{\pm}5g$ were randomly divided into six groups ; normal control diet(NC), and high fat diet(HC), high fat diet with treated lovastatin of 10mg/kg(PC), high fat diet with Hyolbuchukeo-tang extracts; HH, HF and HU treated extracts of 300mg/kg, respectively. Also, we compared the effects of the extracts of HH, HF and HU on rats fed high fat diet for four weeks. Results: 1. The content of polyphenol compounds and electron donating abilities(EDAs) was the HF higher than HH and HU. The superoxide dismutase(SOD)-like activities were proportionate in consistency and they appeared highly from all extracts. The HMG-CoA reductase inhibition activities was highest activities in the HU. 2. The activities of serum GOT and GPT were significantly lower in the HH and HF groups. The level of serum triglyceride was significantly decreased in the HF group. HH and HU groups were significantly decreased in the atherogenic index(AI). The total cholesterol concentration in liver was significantly decreased in the HF group, and HU showed more significantly decreased in the triglyceride than of the lovastatin. Also, photomicrographs of liver tissue showed higher fat accumulation in the HC group than in the HH, HF and HU groups. Conclusions: These result suggest that the hyper-lipidemia caused by a high fat diet was effectively inhibited the administration of HF and HU.

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