Silver Nanowires: Room‐Temperature Nanosoldering of a Very Long Metal Nanowire Network by Conducting‐Polymer‐Assisted Joining for a Flexible Touch‐Panel Application (Adv. Funct. Mater. 34/2013)

Lee, Jinhwan,Lee, Phillip,Lee, Ha Beom,Hong, Sukjoon,Lee, Inhwa,Yeo, Junyeob,Lee, Seung Seob,Kim, Taek‐,Soo,Lee, Dongjin,Ko, Seung Hwan WILEY‐VCH Verlag 2013 Advanced functional materials Vol.23 No.34

<P>D. Lee, S. H. Ko, and co‐workers develop an alternative to rigid ITO transparent conductors. On page 4171, conducting polymer‐assisted nanosoldering of Ag nanowires allows them to develop nanowire percolation networks, which form highly flexible and stretchable transparent conductors. A large area transparent conductor and a flexible touch panel on a non‐flat surface are fabricated, demonstrating the possibility of cost‐effective mass production as well as the applicability of these networks to unconventional, non‐flat surfaces. </P>

Room‐Temperature Nanosoldering of a Very Long Metal Nanowire Network by Conducting‐Polymer‐Assisted Joining for a Flexible Touch‐Panel Application

Lee, Jinhwan,Lee, Phillip,Lee, Ha Beom,Hong, Sukjoon,Lee, Inhwa,Yeo, Junyeob,Lee, Seung Seob,Kim, Taek‐,Soo,Lee, Dongjin,Ko, Seung Hwan WILEY‐VCH Verlag 2013 Advanced Functional Materials Vol.23 No.34

<P><B>Abstract</B></P><P>As an alternative to the brittle and expensive indium tin oxide (ITO) transparent conductor, a very simple, room‐temperature nanosoldering method of Ag nanowire percolation network is developed with conducting polymer to demonstrate highly flexible and even stretchable transparent conductors. The drying conducting polymer on Ag nanowire percolation network is used as a nanosoldering material inducing strong capillary‐force‐assisted stiction of the nanowires to other nanowires or to the substrate to enhance the electrical conductivity, mechanical stability, and adhesion to the substrate of the nanowire percolation network without the conventional high‐temperature annealing step. Highly bendable Ag nanowire/conducting polymer hybrid films with low sheet resistance and high transmittance are demonstrated on a plastic substrate. The fabricated flexible transparent electrode maintains its conductivity over 20 000 cyclic bends and 5 to 10% stretching. Finally, a large area (A4‐size) transparent conductor and a flexible touch panel on a non‐flat surface are fabricated to demonstrate the possibility of cost‐effective mass production as well as the applicability to the unconventional arbitrary soft surfaces. These results suggest that this is an important step toward producing intelligent and multifunctional soft electric devices as friendly human/electronics interface, and it may ultimately contribute to the applications in wearable computers.</P>

Anomalous Stretchable Conductivity Using an Engineered Tricot Weave

Lee, Yong-Hee,Kim, Yoonseob,Lee, Tae-Ik,Lee, Inhwa,Shin, Jaeho,Lee, Hyun Soo,Kim, Taek-Soo,Choi, Jang Wook American Chemical Society 2015 ACS NANO Vol.9 No.12

<P>Robust electric conduction under stretching motions is a key element in upcoming wearable electronic devices but is fundamentally very difficult to achieve because percolation pathways in conductive media are subject to collapse upon stretching. Here, we report that this fundamental challenge can be overcome by using a parameter uniquely available in textiles, namely a weaving structure. A textile structure alternately interwoven with inelastic and elastic yarns, achieved via a tricot weave, possesses excellent elasticity (strain up to 200%) in diagonal directions. When this textile is coated with conductive nanomaterials, proper textile engineering allows the textile to obtain an unprecedented 7-fold conductivity increase, with conductivity reaching 33,000 S cm<SUP>–1</SUP>, even at 130% strain, due to enhanced interyarn contacts. The observed stretching conductivity can be described well using a modified 3D percolation theory that reflects the weaving effect and is also utilized for stretchable electronic interconnects and supercapacitors with high performance.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/ancac3/2015/ancac3.2015.9.issue-12/acsnano.5b05465/production/images/medium/nn-2015-05465x_0008.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/nn5b05465'>ACS Electronic Supporting Info</A></P>

Lesquerella <i>FAD3-1</i> gene is responsible for the biosynthesis of trienoic acid and dienoic hydroxy fatty acids in seed oil

Lee, Kyeong-Ryeol,Kim, Eun-Ha,Jeon, Inhwa,Lee, Yongjik,Chen, Grace Q.,Kim, Hyun Uk Elsevier 2019 INDUSTRIAL CROPS AND PRODUCTS Vol.134 No.-

<P><B>Abstract</B></P> <P>Lesquerella (<I>Physaria fendleri</I>) contains a major unusual hydroxy fatty acid, lesquerolic acid (14-hydroxy-eicos-cis-11-enoic acid, C20:1-OH), at 55–60% of seed oil which has industrial value. The remaining seed oil comprises mainly common fatty acids including α-linolenic acid (octadec-<I>cis</I>-9,12,15-enoic acid, C18:3) at 10.7–15.8%. C18:3 is produced from linoleic acid (octadec-cis-9,12-enoic acid, C18:2) by FATTY ACID DESATURASE3. Previous seed transcriptome analysis uncovers two fatty acid desaturase 3 <I>(FAD3</I>) transcripts, <I>PfFAD3-1</I> and <I>PfFAD3-2</I>. To determine the activity of PfFAD3-1 and PfFAD3-2, <I>PfFAD3-1</I> and <I>PfFAD3-2</I> were introduced into an Arabidopsis FAD3-deficient mutant (<I>fad3-2</I>) which has reduced C18:3 from 20.0% in wild-type to 1.6% in <I>fad3-2</I>. Among 20 T<SUB>2</SUB> transgenic lines expression <I>PfFAD3-1</I>, C18:3 increased variably from 2.5 to 29.9% demonstrating that <I>PfFAD3-1</I> acted as a functional FAD3. Among 32 T<SUB>2</SUB> transgenic lines expressing <I>PfFAD3-2</I>, C18:3 content ranged from 1.0 to 3.6%, showing that PfFAD3-2 failed to recover the loss of C18:3 in <I>fad3-2</I>. Sequence comparison among known FAD3s revealed putative variation in PfFAD3-2 which might cause the absence of PfFAD3-2. In addition, lesquerella accumulates a minor hydroxy fatty acid, densipolic acid (12-hydroxy-octadec-cis-9,15-enoic acid, C18:2OH) at about 1%. C18:2OH has been shown to be produced by a FAD3 in Arabidopsis (AtFAD3) using ricinoleic acid (12-hydroxy-9-cis-octadecenoic acid, 18:1-OH) as substrate. To test if either of PfFAD3s is able to convert C18:1-OH to C18:2-OH, <I>PfFAD3-1</I> or <I>PfFAD3-2</I> was transferred into a CL37 Arabidopsis which already expresses a castor (<I>Ricinus communis</I>) fatty acid hrdroxylase <I>FAH12</I> gene (<I>RcFAH12</I>) and consequently accumulates C18:1-OH and C18:2-OH at 13.7% and 3.4%, respectively. Among 43 transgenic CL37 lines expressing <I>PfFAD3-1</I>, C18:2-OH level varied from 0.2 to 7.2%, and four of these lines exceeded to the background level of 3.4% in CL37. Whereas among 23 transgenic CL37 lines expressing <I>PfFAD3-2</I>, C18:2-OH level ranged from 0.4 to 3.4%, none exceeding 3.4%. The results consist with our notion that <I>PfFAD3-1</I>, not <I>PfFAD3-2</I>, exerts FAD3 function which includes converting C18:1-OH to C18:2-OH. Factors limiting PfFAD3s function in CL37 are discussed.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Lesquerella PfFAD3-1 gene encodes a functional fatty acid desaturase 3 enzyme. </LI> <LI> PfFAD3-1 desaturates linoleic acid and ricinoleic acid in Arabidopsis. </LI> <LI> Lesquerella PfFAD3-2 protein is intact but does not possess fatty acid desaturase 3 activity. </LI> <LI> PfFAD3-1 may be utilized for future basic and applied research to develop new oilseeds. </LI> </UL> </P>

Survival analysis for colon subsite and rectal cancers

Inhwa Lee(이인화),Seung-Hyun Baek(백승현),Hyunsung Kim(김현성),Hong-Jae Jo(조홍재),Nahm-Gun Oh(오남건),Sanghwa Ko(고상화) 대한종양외과학회 2015 Korean Journal of Clinical Oncology Vol.11 No.2

Purpose: The survival rates of patients with colorectal cancers have been well documented in many studies. Some studies have shown that proximal colon cancers have inferior survival rates when compared with distal colon cancers. However, the prognostic significance of tumor location with respect to survival remains controversial. By using data from a single physician, we analysed patient survival rates based on colon cancer subsite location, including rectal cancers. Methods: We retrospectively analysed 881 patients with colorectal cancers between 1987 and 2008. Colon subsite locations were defined as cecum, ascending colon, transverse colon, descending colon, sigmoid colon, and rectum. Subsite-specific survival analyses were performed using Kaplan-Meier analysis and Cox proportional hazards ratios. The median follow-up time was 93 months. Results: A total of 689 colorectal cancer cases were included in our analysis, of which 14 were cecum (2.0%), 95 were ascending colon (13.8%), 21 were transverse colon (3.0%), 25 were descending colon (3.6%), 129 were sigmoid colon (18.7%), and 405 were rectum (58.8%) cancers. The 5-year overall survival rates were 77.8% for all colorectal cancers, which consisted of 92.9% for cecal cancer, 69.5% for ascending colon cancer, 76.2% for transverse colon cancer, 84.0% for descending colon cancer, 82.2% for sigmoid colon cancer, and 77.5% for rectal cancer. Conclusion: Ascending colon cancer was associated with the poorest survival outcome, whereas descending colon cancer was associated with the best survival outcome except cecal cancer. Moreover, the survival rate associated with left colon cancer was better than the survival for right colon and rectal cancer.

Wearable Textile Battery Rechargeable by Solar Energy

Lee, Yong-Hee,Kim, Joo-Seong,Noh, Jonghyeon,Lee, Inhwa,Kim, Hyeong Jun,Choi, Sunghun,Seo, Jeongmin,Jeon, Seokwoo,Kim, Taek-Soo,Lee, Jung-Yong,Choi, Jang Wook American Chemical Society 2013 Nano letters Vol.13 No.11

<P>Wearable electronics represent a significant paradigm shift in consumer electronics since they eliminate the necessity for separate carriage of devices. In particular, integration of flexible electronic devices with clothes, glasses, watches, and skin will bring new opportunities beyond what can be imagined by current inflexible counterparts. Although considerable progresses have been seen for wearable electronics, lithium rechargeable batteries, the power sources of the devices, do not keep pace with such progresses due to tenuous mechanical stabilities, causing them to remain as the limiting elements in the entire technology. Herein, we revisit the key components of the battery (current collector, binder, and separator) and replace them with the materials that support robust mechanical endurance of the battery. The final full-cells in the forms of clothes and watchstraps exhibited comparable electrochemical performance to those of conventional metal foil-based cells even under severe folding–unfolding motions simulating actual wearing conditions. Furthermore, the wearable textile battery was integrated with flexible and lightweight solar cells on the battery pouch to enable convenient solar-charging capabilities.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/nalefd/2013/nalefd.2013.13.issue-11/nl403860k/production/images/medium/nl-2013-03860k_0008.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/nl403860k'>ACS Electronic Supporting Info</A></P>

Accelerated Degradation Due to Weakened Adhesion from Li-TFSI Additives in Perovskite Solar Cells

Lee, Inhwa,Yun, Jae Hoon,Son, Hae Jung,Kim, Taek-Soo American Chemical Society 2017 ACS APPLIED MATERIALS & INTERFACES Vol.9 No.8

<P>Reliable integration of organometallic halide perovskite in photovoltaic devices is critically limited by its low stability in humid environments. Furthermore, additives to increase the mobility in the hole transport material (HTM) have deliquescence and hygroscopic properties, which attract water molecules and result in accelerated degradation of the perovskite devices. In this study, a double cantilever beam (DCB) test is used to investigate the effects of additives in the HTM layer on the perovskite layer through neatly delaminating the interface between the perovskite and HTM layers. Using the DCB test, the bottom surface of the HTM layers is directly observed, and it is found that the additives are accumulated at the bottom along the thickness (i.e., through-plane direction) of the films. It is also found that the additives significantly decrease the adhesion at the interface between the perovskite and HTM layers by more than 60% through hardening the HTM films. Finally, the adhesion-based degradation mechanism of perovskite devices according to the existence of additives is proposed for humid environments.</P>

Simultaneously Enhancing the Cohesion and Electrical Conductivity of PEDOT:PSS Conductive Polymer Films using DMSO Additives

Lee, Inhwa,Kim, Gun Woo,Yang, Minyang,Kim, Taek-Soo American Chemical Society 2016 ACS APPLIED MATERIALS & INTERFACES Vol.8 No.1

<P>Conductive polymer poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) has attracted significant attention as a hole transport and electrode layer that substitutes metal electrodes in flexible organic devices. However, its weak cohesion critically limits the reliable integration of PEDOT:PSS in flexible electronics, which highlights the importance of further investigation of the cohesion of PEDOT:PSS. Furthermore, the electrical conductivity of PEDOT:PSS is insufficient for high current-carrying devices such as organic photovoltaics (OPVs) and organic light emitting diodes (OLEDs). In this study, we improve the cohesion and electrical conductivity through adding dimethyl sulfoxide (DMSO), and we demonstrate the significant changes in the properties that are dependent on the wt % of DMSO. In particular, with the addition of 3 wt % DMSO, the maximum enhancements for cohesion and electrical conductivity are observed where the values increase by 470% and 6050%, respectively, due to the inter-PEDOT bridging mechanism. Furthermore, when OLED devices using the PEDOT:PSS films are fabricated using the 3 wt % DMSO, the display exhibits 18% increased current efficiency.</P>

Interfacial toughening of solution processed Ag nanoparticle thin films by organic residuals

Lee, Inhwa,Kim, Sanghyeok,Yun, Jeonghoon,Park, Inkyu,Kim, Taek-Soo IOP Pub 2012 Nanotechnology Vol.23 No.48

<P>Reliable integration of solution processed nanoparticle thin films for next generation low-cost flexible electronics is limited by mechanical damage in the form of delamination and cracking of the films, which has not been investigated quantitatively or systematically. Here, we directly measured the interfacial fracture energy of silver nanoparticle thin films by using double cantilever beam fracture mechanics testing. It was demonstrated that the thermal annealing temperature and period affect the interfacial fracture energy. Also it was found that the interfacial fracture resistance can be maximized with optimized annealing conditions by the formation of organic residual bridges during the annealing process. </P>

Does stress affect thyroid function in the patients who underwent thyroidectomy?

Inhwa Lee,Hyeung Kyoo Kim,Jeonghun Lee,Euy Young Soh 대한갑상선-내분비외과학회 2017 대한갑상선-내분비외과학회 학술대회 논문집 Vol.- No.-