Sohyun Park

A formulated red ginseng extract rescues PC12 cells from PCB-induced oxidative cell death through Nrf2-mediated upregulation of heme oxygenase-1 and glutamate cysteine ligase

Polychlorinated biphenyls (PCBs) are ubiquitous environmental contaminants that display a broad spectrum of biological and toxicological properties. There has been compelling evidence supporting that PCB-induced cytotoxicity is mediated through generation of reactive oxygen species (ROS). Considerable attention has been focused on identifying naturally occurring phytochemicals that are able to scavenge excess ROS, thereby protecting against oxidative cell death. Red ginseng, which has a variety of biological and pharmacological activities including antioxidant, anti-inflammatory, antimutagenic and anticarcinogenic effects, has been used for thousands of years as a general tonic in traditional oriental medicine. In this study, we have investigated the effect of red ginseng extract (RGE) on PCB126-induced oxidative cell death in cultured rat pheochromocytoma (PC12) cells. PC12 cells treated with PCB126 exhibited increased accumulation of intracellular ROS and underwent apoptosis as determined by positive in situ terminal end-labeling (TUNEL staining) and the perturbation of the mitochondrial membrane potential (ΔΨ(m)). RGE treatment attenuated PCB126-induced cytotoxicity, apoptotic features and intracellular ROS accumulation. RGE treatment upregulated heme oxygenase-1 (HO-1) and glutamate cysteine ligase (GCLC) that are key antioxidant enzymes essential for cellular defense against oxidative stress. To elucidate the molecular mechanisms underlying RGE-mediated HO-1 and GCLC induction, we have examined the possible involvement of NF-E2-related factor 2 (Nrf2), a redox-sensitive transcription factor, that plays an important role in the transcriptional regulation of diverse antioxidative genes via interaction with the antioxidant response element (ARE). Treatment of PC12 cells with RGE increased the nuclear translocation, ARE-binding and transcriptional activity of Nrf2. Moreover, U0126 and LY294002, pharmacological inhibitors of MEK1/2 and phosphatidylinositol 3-kinase which are upstream of ERK1/2 and Akt/protein kinase B, respectively attenuated HO-1 and GCLC expression as well as the ARE-driven transcriptional activation of Nrf2. These findings, taken together, suggest that HO-1 and GCLC induction via Nrf2 activation may contribute to cytoprotection exerted by RGE against PCB126-induced oxidative stress.

Design elements to improve pleasantness, vitality, safety, and complexity of the pedestrian environment: evidence from a Korean neighbourhood walkability case study

The relationship between walking and the built environment has attracted the attention of many researchers. It is commonly recognized that a more walkable environment enhances walking activities. Although numerous empirical studies have supported that certain design elements have statistically significant effects on walking, many have methodological limitations due to the assumption that the relationship between walking and the built environment is a one-to-one, direct correspondence. To supplement these limitations, this paper embraces a ‘perception’ step in the decision-making process of walking, where perception is not determined by one design element, but by the integration of several elements. Acknowledging four perceptional factors, this paper draws certain design elements of ‘pleasantness’, ‘vitality’, ‘unsafety’, and ‘complexity’ in residential neighbourhoods. Residents in four neighbourhoods completed a questionnaire, from which the following five additional design factors were extracted using factor analysis: sidewalk difficulty, crosswalk difficulty, well-ordered street furniture, poor building design and management, and various walking destinations. The regression analysis indicated that the design factors had statistically significant effects on the four perception factors, which substantiated this papers hypothesis that walking activities are generated by the combination of several environmental elements, rather than a single attribute. The key study finding is that appropriate design factors are necessary to enhance a certain perception factor: designing and managing street furniture and street buildings induce a high level of pleasantness and vitality. The feeling of unsafety and complexity is mainly driven from the sidewalk and crosswalk difficulty. We expect that the results of this paper will contribute to formulating future guidelines in planning for more walkable neighbourhoods.

Analysis of the wetting state of super-repellent fabrics with liquids of varying surface tension

In designing a super-repellent surface that is not wet to liquids with a lower surface tension than water, micro and nano-scale surface roughness have a great impact in addition to low surface energy. In this study, a super-repellent fabric was fabricated using oxygen plasma etching and plasma enhanced chemical vapor deposition (PECVD) with hexamethyldisiloxane (HMDSO). The influence of dual roughness on wettability in micro and nano-scale structures was analyzed using the contact angles of test reagents whose surface tension ranges from 33–72 dyn cm−1. The treated fabrics produced dual scale roughness, and exhibited contact angles greater than 160° against the test liquid whose surface tension was greater than 42 dyn cm−1. The Cassie–Cassie theoretical model, which is based on the non-wetting assumption of either micro-scale or nano-scale roughness, explained well the actual water contact angles on the treated fabrics. For the liquid with 42 dyn cm−1 surface tension, the wetting behavior followed behavior between the Cassie–Wenzel state and Cassie–Cassie state depending on the aspect ratio of the nano-scale roughness. With an increased etching time of 7 min or longer, the actual contact angles were measured to be larger than those predicted using the Cassie–Cassie model, which may be a result of the formation of partial re-entrant structures at the tips of the nano-pillars. Self-cleaning effects were demonstrated for solid particles adhered on the treated fabrics such as silicon carbide and Sudan Black B. Water was more effective in adhering to both particle types and rolling off the surface than isopropyl alcohol solution.

The Source and Credibility of Colorectal Cancer Information on Twitter

AbstractDespite the rapid penetration of social media in modern life, there has been limited research conducted on whether social media serves as a credible source of health information. In this study, we propose to identify colorectal cancer information on Twitter and assess its informational credibility.We collected Twitter messages containing colorectal cancer-related keywords, over a 3-month period. A review of sample tweets yielded content and user categorization schemes. The results of the sample analysis were applied to classify all collected tweets and users, using a machine learning technique. The credibility of the information in the sampled tweets was evaluated.A total of 76,119 tweets were analyzed. Individual users authored the majority of tweets (n = 68,982, 90.6%). They mostly tweeted about news articles/research (n = 16,761, 22.0%) and risk/prevention (n = 14,767, 19.4%). Medical professional users generated only 2.0% of total tweets (n = 1509), and medical institutions rarely tweeted (n = 417, 0.6%). Organizations tended to tweet more about information than did individuals (85.2% vs 63.1%; P < 0.001). Credibility analysis of medically relevant sample tweets revealed that most were medically correct (n = 1763, 84.5%). Among those, more frequently retweeted tweets contained more medically correct information than randomly selected tweets (90.7% vs 83.2%; P < 0.01).Our results demonstrate an interest in and an engagement with colorectal cancer information from a large number and variety of users. Coupled with the Internets potential to increase social support, Twitter may contribute to enhancing public health and empowering users, when used with proper caution.

Influence of micro and nano-scale roughness on hydrophobicity of a plasma-treated woven fabric

A superhydrophobic fabric surface was fabricated by forming a dual roughness structure in combination with lowered surface energy. The contribution of the innate micro-scale roughness resulting from the waviness of filaments and yarns in a woven fabric on hydrophobicity was investigated in comparison with a smooth film surface. Though the micro-scale roughness coming from the multi-filaments of fabric was conducive in enhancing the hydrophobicity of the surface, the micro-scale roughness itself was not enough to create superhydrophobicity. Thus a nano-scale roughness was introduced by an anisotropic etching employing oxygen plasma etching followed by plasma enhanced chemical vapor deposition. As for the nano-scale roughness, however, it was possible to achieve the superhydrophobicity only with nano-scale roughness, but with a very large aspect ratio of nano-pillar structure. In the presence of dual-scale roughness consisting of both micro- and nano-scale structures, the superhydrophobic characteristic was effectively achieved even at a small aspect ratio of nano-pillar. By adjusting the number of filaments in a yarn and by controlling the plasma process time, it was possible to control the dual-scale roughness of a woven fabric and its wettability. An excessive thinning and lengthening of nano-pillars may negatively affect the hydrophobicity by the collapse and aggregation of pillar tips, and an appropriate processing condition is critical to design a durable superhydrophobic surface.

Metabolic Radiomics for Pretreatment 18 F-FDG PET/CT to Characterize Locally Advanced Breast Cancer: Histopathologic Characteristics, Response to Neoadjuvant Chemotherapy, and Prognosis

Radiomics has been spotlighted as imaging biomarker for estimation of intratumoral heterogeneity (ITH) which is regarded as the main reason for resistance to tumor treatment. Although a number of studies has shown clinical evidences that separate measurement of metabolic ITH by texture features (TFs) on 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) has prognostic ability in various tumors, there has been no consensus regarding the best parameter representing ITH. Besides, it is yet uncertain that TFs are useful for estimation of histopathologic markers, prediction of response to neoadjuvant chemotherapy (NAC), or prognostic ability in breast cancer. To depart from the traditional approach, we evaluated the clinical usefulness of integrated metabolic radiomics using unsupervised clustering with 109 TFs measured from pretreatment 18F-FDG PET/CT scans of 73 patients with locally advanced breast cancer (LABC) underwent NAC before surgery. Our study shows that metabolic radiomics patterns of LABC are associated with Ki67 expression, achievement of pathologic complete response after NAC, and risk of recurrence. Integrated metabolic radiomics has potential for clinically relevant pretreatment biomarker with predictive and prognostic ability for personalized management in LABC.

B-RafV600E inhibits sodium iodide symporter expression via regulation of DNA methyltransferase 1

B-RafV600E mutant is found in 40–70% of papillary thyroid carcinoma (PTC) and has an important role in the pathogenesis of PTC. The sodium iodide symporter (NIS) is an integral plasma membrane glycoprotein that mediates active iodide transport into the thyroid follicular cells, and B-RafV600E has been known to be associated with the loss of NIS expression. In this study, we found that B-RafV600E inhibited NIS expression by the upregulation of its promoter methylation, and that specific regions of CpG islands of NIS promoter in B-RafV600E harboring PTC were highly methylated compared with surrounding normal tissue. Although DNA methyltransferase 3a and 3b (DNMT3a,3b) were not increased by B-RafV600E, DNMT1 expression was markedly upregulated in PTC and B-RafV600E expressing thyrocytes. Furthermore, DNMT1 expression was upregulated by B-RafV600E induced NF-κB activation. These results led us to conclude that NIS promoter methylation, which was induced by B-RafV600E, is one of the possible mechanisms involved in NIS downregulation in PTC.

The effect of fabric movement on washing performance in a front-loading washer

Types of fabric movement inside a front-loading washer were analyzed in order to examine their effect on washing performance. A high-speed camera was used to record and track the outlines of the fabric inside a washer, and 13 movement indexes were derived. From this observation, fabric movements were divided into four categories, and the relationship between fabric movements and washing performance were examined. It was shown that the mechanical force from the complex movement where diverse fabric movements were mixed was stronger than that from the simple movement where only single fabric movement appeared. With regard to the detergency, it was also shown that complex movement was more effective than single movement. For fabric with a lower drape coefficient, there seemed to be a greater potential to generate more flexing under similar mechanical action, therefore resulting in higher washing performance.

The effects of the fabric properties on fabric movement and the prediction of the fabric movements in a front-loading washer

The purpose of this study is to determine the effects of the fabric properties on fabric movement and to suggest a prediction model for the fabric movements in a front-loading washer. During a wash cycle, the fabric moves in many different ways depending on the mechanical and physiochemical properties of the fabric. In this study, 14 different fabrics were measured for their mechanical and physiochemical properties by the Kawabata Evaluation System (KES) and the water absorption test. From the observation of the fabric movements in the washer, 13 movement indexes were derived, and the relationships between the fabric properties and fabric movements were studied. The critical fabric properties that affected the fabric movements were determined by the analysis of variance (one-way ANOVA) and the post hoc test using the Scheffe method. The major fabric properties that affected fabric movements were found to be fabric weight, drape coefficient, water content, shear recovery, compression linearity, and energy required for compression. These fabric properties were investigated for their relation with the fabric movement indexes. The predicting models for fabric movements were suggested by the multi-linear regression equations.

Physical Activity and the Built Environment in Residential Neighborhoods of Seoul and Seattle: An Empirical Study Based on Housewives′ GPS Walking Data and Travel Diaries

This paper is based on a collaborative pilot-study to ascertain the characteristic walking patterns and neighborhood features in residential areas of Seoul, Korea and Seattle, USA. As for sample sites, four case neighborhoods were selected: two from Seoul and two from in and outside of the Seattle-Shoreline areas. As for participants, thirty Korean housewives in Seoul and thirty Korean-American housewives in the Seattle area were selected respectively, and their socio-demographic characteristics, GPS records, and travel diary data for seven days were collected and analyzed. Considering the typical rainy seasons in the two cities, data collections, including the physical activity assessment by GPS devices, were carried out from May to June and from September to October in Seoul, and from July to October in Seattle during the year 2010. Noteworthy research findings include the following: Korean participants in Seoul walk about 2.6 km on average per day, while Korean-American participants in Seattle walk about 400m on average per day. In the case sites of Seoul, 75% of grocery shopping activities happen within the neighborhood by walking, while only 17% of those activities on foot happen in the case sites of Seattle. As for the most walking activity, about 70% of total walking amounts are related to utilitarian walking in Seoul sites, while 50% of total walking are related to recreational walking in Seattle sites. Recreational walking and utilitarian walking occur separately in Seattle sites, while the two walking types are often combined in Seoul sites, which also contribute to more walking amounts and farther walking distances in Seoul sites. This paper empirically confirms the widely held assumptions in part that residents in Seoul, a relatively high-density and high mixed-use city, walk more than those in Seattle, a relatively low-density and low mixed-use city. This paper also recognizes that in the case of both cities, more walking activities occur in the neighborhood built environment, where finely-grained street networks, small lots and blocks, various pedestrian destinations, public transit access, etc are provided in close connection. The amount and frequency of walking activities, as well as the fineness of neighborhood features, however, are remarkably different in the two cities, whose implications deserve in-depth exploration in further studies.