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Has the dominant search engine, if any, discriminated against rival websites?
( Ju Won Kwak ) 한국산업조직학회 2015 한국산업조직학회 정책세미나 논문집 Vol.2015 No.1
Some dominant horizontal search engines have recently been facing antitrust charges worldwide, based on allegations that they give preference to their own contents and discriminate against their rivals. In this short article, we use Internet tra c data to test whether the entry of a dominant search engine to certain downstream Internet service markets has a ected the out ow of Internet tra c from this search engine to its downstream rivals. We do not nd any empirical evidence of such a search bias.
The Alteration of Ganglioside GD1a Expression in Swedish Mutation-Induced Alzheimer's Disease
Won Seok Ju,Dong Hoon Kwak,Sung Youn Heo,Yu Na Seo,Hyun Gyu Lim,Seo Yi Lee,Ji-Su Kim,Kyu-Tae Chang,Young-Kug Choo 한국당과학회 2016 한국당과학회 학술대회 Vol.2016 No.07
Alzheimer's disease(AD), known as a chronic neurodegenerative disease, is the most common type of dementia with clinical symptoms. The pathogenesis of AD is highly believed to have a effect on the production and deposition of β-amyloid(Aβ) peptide. Swedish mutation or Familial Alzheimer’s disease genetic mutation is one of the most well known genetic variation that causes early onset familial AD. Gangliosides are key lipid molecules required for the regulation of cellular processes such as proliferation, differentiation and cell signaling. However the mechanism is not unclear between ganglioside and AD. This study was investigated relationship of gangliosides between ganglioside and AD. We made a cell line(WK-H4) using transformed Vector that is forced to gene over-expression of Aβ. We investigate the expression by using high performance thin-layer chromatograph(HPTLC), Western Blot(WB) and Immunofluoresence(IF). According to IF, the results show Aβ significantly increase in WK-H4. Also, HPTLC analysis shows that the expression of ganglioside GD1a is markedly diminished in WK-H4 than H4. Furthermore, β-Catenin at Wnt signal increases on WB analysis. While GSK-3β imperceptibly decrease in WK-H4. In conclusion, This study may reason out a conclusion that ganglioside is associated with AD and the selective control of ganglioside is helpful treatment of AD as a fresh bio-marker.
A Case of Significant Endobronchial Injury due to Recurrent Iron Pill Aspiration
Kwak, Joo-Hee,Koo, Gun Woo,Chung, Sung Jun,Park, Dong Won,Kwak, Hyun Jung,Moon, Ji-Yong,Kim, Sang-Heon,Sohn, Jang Won,Yoon, Ho Joo,Shin, Dong Ho,Park, Sung Soo,Pyo, Ju Yeon,Oh, Young-Ha,Kim, Tae-Hyung The Korean Academy of Tuberculosis and Respiratory 2015 Tuberculosis and Respiratory Diseases Vol.78 No.4
Gastric mucosal damage by iron pills is often reported. However, iron pill aspiration is uncommon. Oxidation of the impacted iron pill causes bronchial mucosal damage that progresses to chronic bronchial inflammation, necrosis, endobronchial stenosis and rarely, perforation. We reported a case of a 92-year-old woman with chronic productive cough and significant left-sided atelectasis. Bronchoscopy revealed substantial luminal narrowing with exudative inflammation of the left main bronchus. Bronchial washing cytology showed necroinflammatory exudate and a small amount of brown material. Mucosal biopsy showed diffuse brown pigments indicative of ferrous pigments, crystal deposition, and marked tissue degeneration. After vigorous coughing, she expectorated dark sediments and her symptoms and radiological abnormalities improved. There are a few such reports worldwide; however, this was the first case reported in Korea. Careful observation of aspiration-prone patients and early detection of iron pill aspiration may prevent iron pill-induced bronchial injury.
How Essential and Biased are Search Engines? Empirical Evidence from the Flow of Internet Traffic
( Ju Won Kwak ) 정보통신정책학회 2015 정보통신정책연구 Vol.22 No.4
Dominant horizontal search engines have recently been facing antitrust challenges around the globe based on allegations that their search results are biased. In this short article, we present empirical evidence based on Internet traffic data from Korea that weakly supports this search bias claim. In short, we show that search engines tend to herd their users back to their own content significantly more than their share of overall page views. Moreover, about a quarter of all page views originating from outside sources come from search engines, thus suggesting that search engines are fairly important to most websites. However, results of this study do not fully justify immediate antitrust intrusion. Instead, they may be used as an initial test for a more thorough scrutiny.