Publications by authors named "Sungmin Park"

70 Publications

Simultaneous Enhanced Efficiency and Stability of Perovskite Solar Cells Using Adhesive Fluorinated Polymer Interfacial Material.

ACS Appl Mater Interfaces 2021 Jul 21. Epub 2021 Jul 21.

School of Chemical Engineering, Sungkyunkwan University, Suwon 16419, Republic of Korea.

For enhancing the performance and long-term stability of perovskite solar cell (PSC) devices, interfacial engineering between the perovskite and hole-transporting material (HTM) is important. We developed a fluorinated conjugated polymer PFPT3 and used it as an interfacial layer between the perovskite and HTM layers in normal-type PSCs. Interaction of perovskite and PFPT3 via Pb-F bonding effectively induces an interfacial dipole moment, which resulted in energy-level bending; this was favorable for charge transfer and hole extraction at the interface. The PSC device achieved an increased efficiency of 22.00% with an open-circuit voltage of 1.13 V, short-circuit current density of 24.34 mA/cm, and fill factor of 0.80 from a reverse scan and showed an averaged power conversion efficiency of 21.59%, which was averaged from forward and reverse scans. Furthermore, the device with PFPT3 showed much improved stability under an 85% RH condition because hydrophobic PFPT3 reduced water permeation into the perovskite layer, and more importantly, the enhanced contact adhesion at the PFPT3-mediated perovskite/HTM interface suppressed surface delamination and retarded water intrusion. The fluorinated conjugated polymeric interfacial material is effective for improving not only the efficiency but also the stability of the PSC devices.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/acsami.1c05822DOI Listing
July 2021

A Nationwide Study on the Incidence of Breast Cancer in Korean Women with Osteoporosis Receiving Raloxifene Treatment.

J Breast Cancer 2021 Jun 14;24(3):280-288. Epub 2021 May 14.

Department of Breast Surgery, Chungbuk National University Hospital, College of Medicine, Chungbuk National University, Cheongju, Korea.

Purpose: Raloxifene is a selective estrogen receptor modulator (SERM), and raloxifene treatment for osteoporosis is reimbursable under the Korean National Health Insurance. Evidence suggests that SERMs use reduces the risk of breast cancer in Asian population. Herein, we retrospectively investigated the protective effect of raloxifene on breast cancer rates in Korean population.

Methods: Using the Health Insurance Review and Assessment Service database, we selected women with osteoporosis aged 50 years and above. Patients treated for at least 2 years with raloxifene were assigned to the user group, whereas the remaining patients were assigned to the non-user group. The effect on breast cancer risk was assessed using the Cox proportional-hazards model with a time-dependent covariate to adjust for immortal time bias.

Results: A total of 322,870 women who were registered between 2010 and 2011 were included. The user group comprised 0.7% (n = 2,307) of the total population. The mean age was 65.7 ± 8.0 years and 67.2 ± 8.6 years in the user and non-user groups, respectively ( < 0.001). There was no difference in the previous use of estrogen replacement between the 2 groups ( = 0.087). The incidence of breast cancer per 1,000 person-years was 0.49 (n = 8) and 0.68 (n = 1,714) in the user and non-user groups, respectively (hazard ratio [HR], 0.63, 95% confidence interval [CI], 0.32-1.27). HR decreased with increase in the treatment duration, but this change was not statistically significant (HR, 1.00, 95% CI, 0.32-3.11 in 2-3 years; HR, 0.63, 95% CI, 0.20-1.94 in 3-4 years; and HR, 0.41, 95% CI, 0.10-1.65 in 4-5 years).

Conclusion: Long-term treatment with raloxifene in women with osteoporosis was not significantly associated with a reduction in breast cancer rates. However, further investigation is required for a conclusive proof.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.4048/jbc.2021.24.e28DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8250100PMC
June 2021

4D Printing of Hygroscopic Liquid Crystal Elastomer Actuators.

Small 2021 Jun 2;17(23):e2100910. Epub 2021 May 2.

Department of Polymer Science and Engineering, Pusan National University, Busan, 46241, Republic of Korea.

Liquid crystal elastomers (LCEs) are broadly recognized as programmable actuating materials that are responsive to external stimuli, typically heat or light. Yet, soft LCEs that respond to changes in environmental humidity are not reported, except a few examples based on rigid liquid crystal networks with limited processing. Herein, a new class of highly deformable hygroscopic LCE actuators that can be prepared by versatile processing methods, including surface alignment as well as 3D printing is presented. The dimethylamino-functionalized LCE is prepared by the aza-Michael addition reaction between a reactive LC monomer and N,N'-dimethylethylenediamine as a chain extender, followed by photopolymerization. The humidity-responsive properties are introduced by activating one of the LCE surfaces with an acidic solution, which generates cations on the surface and provides asymmetric hydrophilicity to the LCE. The resulting humidity-responsive LCE undergoes programmed and reversible hygroscopic actuation, and its shape transformation can be directed by the cut angle with respect to a nematic director or by localizing activation regions in the LCE. Most importantly, various hygroscopic LCE actuators, including (porous) bilayers, a flower, a concentric square array, and a soft gripper, are successfully fabricated by using LC inks in UV-assisted direct-ink-writing-based 3D printing.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/smll.202100910DOI Listing
June 2021

Breast Cancer Statistics in Korea, 2018.

J Breast Cancer 2021 Apr;24(2):123-137

Department of Surgery, Research Institute of Clinical Medicine, Jeonbuk National University Hospital, Jeonbuk National University and Biomedical Research Institute, Jeonju, Korea.

Breast cancer is the most common malignancy in Korean women, and its incidence continues to increase. The Korean Breast Cancer Society (KBCS) established a nationwide breast cancer database through its online enrollment program in 1996. This study aimed to analyze the clinical characteristics of breast cancer in Korea, and to assess the pattern of changes in breast cancer management in 2018. We analyzed the KBCS and Korea Central Cancer Registry (KCCR) databases in 2018. In 2018, 28,157 patients were newly diagnosed with breast cancer, of whom 4,510 had noninvasive breast cancer and 23,647 had invasive breast cancer. The age-standardized rate of breast cancer in 2018 was 79.0 per 100,000 women (65.6 invasive, 13.4 noninvasive). The median age of female patients diagnosed with breast cancer in 2018 was 52 years, and the incidence of breast cancer was the highest in the 40-49-years age group (9,432 patients, 33.6%). The proportion of patients with stage 0 and stage I breast cancer continued to increase, accounting for 63.8% of cases, and breast-conserving surgery was performed more often than mastectomy (66.2% vs. 33.0%). The most common subtypes of breast cancer were hormone receptor [HR]-positive and human epidermal growth factor receptor-2 (HER2)-negative types (65.9% of cases), while the HR-negative and HER2-positive types accounted for 9.2% of cases. According to the KCCR data, from 2014 to 2018, the 5-year relative survival rate of patients with breast cancer was 93.3%, which was 14.0% higher than that from 1993 to 1995 (79.3%). The clinical characteristics of breast cancer in Korea have been changing, and national databases can improve our understanding of the disease characteristics of Korean women. Therefore, updating the KBCS registry is important for the effective management of breast cancer in Korea.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.4048/jbc.2021.24.e22DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8090800PMC
April 2021

An Integrative Transcriptome-Wide Analysis of Amyotrophic Lateral Sclerosis for the Identification of Potential Genetic Markers and Drug Candidates.

Int J Mol Sci 2021 Mar 22;22(6). Epub 2021 Mar 22.

Department of Computer Engineering, Dongguk University, Seoul 04620, Korea.

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative neuromuscular disease. Although genome-wide association studies (GWAS) have successfully identified many variants significantly associated with ALS, it is still difficult to characterize the underlying biological mechanisms inducing ALS. In this study, we performed a transcriptome-wide association study (TWAS) to identify disease-specific genes in ALS. Using the largest ALS GWAS summary statistic (n = 80,610), we identified seven novel genes using 19 tissue reference panels. We conducted a conditional analysis to verify the genes' independence and to confirm that they are driven by genetically regulated expressions. Furthermore, we performed a TWAS-based enrichment analysis to highlight the association of important biological pathways, one in each of the four tissue reference panels. Finally, utilizing a connectivity map, a database of human cell expression profiles cultured with bioactive small molecules, we discovered functional associations between genes and drugs to identify 15 bioactive small molecules as potential drug candidates for ALS. We believe that, by integrating the largest ALS GWAS summary statistic with gene expression to identify new risk loci and causal genes, our study provides strong candidates for molecular basis experiments in ALS.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3390/ijms22063216DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8004271PMC
March 2021

Eco friendly nanofluidic platforms using biodegradable nanoporous materials.

Sci Rep 2021 Feb 15;11(1):3804. Epub 2021 Feb 15.

Department of Electrical and Computer Engineering, Seoul National University, Seoul, 08826, Republic of Korea.

Splendid advancement of micro/nanofluidic researches in the field of bio- and chemical-analysis enables various ubiquitous applications such as bio-medical diagnostics and environmental monitoring, etc. In such devices, nanostructures are the essential elements so that the nanofabrication methods have been major issues since the last couple of decades. However, most of nanofabrication methods are sophisticated and expensive due to the requirement of high-class cleanroom facilities, while low-cost and biocompatible materials have been already introduced in the microfluidic platforms. Thus, an off-the-shelf and biodegradable material for those nanostructures can complete the concept of an eco-friendly micro/nanofluidic platform. In this work, biodegradable materials originated from well-known organisms such as human nail plate and denatured hen egg (albumen and yolk) were rigorously investigated as a perm-selective nanoporous membrane. A simple micro/nanofluidic device integrated with such materials was fabricated to demonstrate nanofluidic phenomena. These distinctive evidences (the visualization of ion concentration polarization phenomenon, ohmic/limiting/over-limiting current behavior and surface charge-governed conductance) can fulfill the requirements of functional nanostructures for the nanofluidic applications. Therefore, while these materials were less robust than nano-lithographically fabricated structures, bio-oriented perm-selective materials would be utilized as a one of key elements of the biodegradable and eco friendly micro/nanofluidic applications.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/s41598-021-83306-wDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7884701PMC
February 2021

Is mastectomy with immediate reconstruction safe for patients undergoing neoadjuvant chemotherapy? A nationwide study from Korean Breast Cancer Society.

Breast Cancer 2021 Jul 14;28(4):874-883. Epub 2021 Feb 14.

Department of Surgery, Korea University Anam Hospital, Korea University College of Medicine, Seoul, Republic of Korea.

Purpose: In this study, we compared the prognoses of patients who underwent mastectomy with immediate breast reconstruction (IBR) after neoadjuvant chemotherapy with those who underwent mastectomy.

Methods: This retrospective study included 87,995 patients who were surgically treated for primary breast cancer between 2008 and 2014. We compared the three groups of patients who were divided based on the following surgeries: breast-conserving surgery (BCS), mastectomy, and mastectomy with IBR.

Results: Of the 3295 patients who were treated with neoadjuvant chemotherapy, 482 patients achieved a pathological complete response (pCR) and 2813 patients did not (non-pCR). In survival analysis of the pCR patients, the 5-year Overall Survival (5 yr OS) between those who underwent mastectomy with IBR and mastectomy (P = 0.639) In the non-pCR group, 5 yr OS of the mastectomy with IBR group was 90.0%, while those of the mastectomy group was 84.4% in patients with clinical stage II (P = 0.032). In a multivariate analysis by Cox regression method revealed that the prognoses of the patients who underwent mastectomy with IBR were not different from those of patients who underwent mastectomy group in both groups (the pCR group and the non-pCR group).

Conclusion: In the pCR group, the prognoses of patients who underwent mastectomy with IBR were not different from those of patients who underwent mastectomy. In the non-pCR group, women in the mastectomy with IBR group had shown worse prognoses than the mastectomy group in advanced clinical stage. Appropriate operation should be determined depending on the status of individualized patients.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s12282-021-01223-2DOI Listing
July 2021

Skin Commensal Fungus and Its Lipases.

J Microbiol Biotechnol 2021 May;31(5):637-644

Department of Systems Biotechnology, Chung-Ang University, Anseong 17546, Republic of Korea.

is the most abundant genus in the fungal microflora found on human skin, and it is associated with various skin diseases. Among the 18 different species of that have been identified to date, and are the most predominant fungal species found on human skin. Several studies have suggested a possible link between and skin disorders. However, our knowledge on the physiology and pathogenesis of in human body is still limited. is unable to synthesize fatty acids; hence, it uptakes external fatty acids as a nutrient source for survival, a characteristic compensated by the secretion of lipases and degradation of sebum to produce and uptake external fatty acids. Although it has been reported that the activity of secreted lipases may contribute to pathogenesis of , majority of the data were indirect evidences; therefore, enzymes' role in the pathogenesis of infections is still largely unknown. This review focuses on the recent advances on in the context of an emerging interest for lipases and summarizes the existing knowledge on , diseases associated with the fungus, and the role of the reported lipases in its physiology and pathogenesis.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.4014/jmb.2012.12048DOI Listing
May 2021

Enhanced third-harmonic generation by manipulating the twist angle of bilayer graphene.

Light Sci Appl 2021 Jan 21;10(1):19. Epub 2021 Jan 21.

Department of Energy Systems Research, Ajou University, 206 Worldcup-ro, Yeongtong-gu, Suwon, 16499, Republic of Korea.

Twisted bilayer graphene (tBLG) has received substantial attention in various research fields due to its unconventional physical properties originating from Moiré superlattices. The electronic band structure in tBLG modified by interlayer interactions enables the emergence of low-energy van Hove singularities in the density of states, allowing the observation of intriguing features such as increased optical conductivity and photocurrent at visible or near-infrared wavelengths. Here, we show that the third-order optical nonlinearity can be considerably modified depending on the stacking angle in tBLG. The third-harmonic generation (THG) efficiency is found to significantly increase when the energy gap at the van Hove singularity matches the three-photon resonance of incident light. Further study on electrically tuneable optical nonlinearity reveals that the gate-controlled THG enhancement varies with the twist angle in tBLG, resulting in a THG enhanced up to 60 times compared to neutral monolayer graphene. Our results prove that the twist angle opens up a new way to control and increase the optical nonlinearity of tBLG, suggesting rotation-induced tuneable nonlinear optics in stacked two-dimensional material systems.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/s41377-020-00459-5DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7820413PMC
January 2021

An Accelerated Wound-Healing Surgical Suture Engineered with an Extracellular Matrix.

Adv Healthc Mater 2021 03 18;10(6):e2001686. Epub 2021 Jan 18.

Department of Chemistry and Institute of Biological Interfaces, Sogang University, 35-Baekbeom-ro, Mapo-gu, Seoul, 04107, Republic of Korea.

A suture is a ubiquitous medical device to hold wounded tissues together and support the healing process after surgery. Surgical sutures, having incomplete biocompatibility, often cause unwanted infections or serious secondary trauma to soft or fragile tissue. In this research, UV/ozone (UVO) irradiation or polystyrene sulfonate acid (PSS) dip-coating is used to achieve a fibronectin (FN)-coated absorbable suture system, in which the negatively charged moieties produced on the suture cause fibronectin to change from a soluble plasma form into a fibrous form, mimicking the actions of cellular fibronectin upon binding. The fibrous fibronectin coated on the suture can be exploited as an engineered interface to improve cellular migration and adhesion in the region around the wounded tissue while preventing the binding of infectious bacteria, thereby facilitating wound healing. Furthermore, the FN-coated suture is found to be associated with a lower friction between the suture and the wounded tissue, thus minimizing the occurrence of secondary wounds during surgery. It is believed that this surface modification can be universally applied to most kinds of sutures currently in use, implying that it may be a novel way to develop a highly effective and safer suture system for clinical applications.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/adhm.202001686DOI Listing
March 2021

Progress in Materials, Solution Processes, and Long-Term Stability for Large-Area Organic Photovoltaics.

Adv Mater 2020 Dec 5;32(51):e2002217. Epub 2020 Oct 5.

Advanced Photovoltaics Research Center, Korea Institute of Science and Technology, Seoul, 02792, Republic of Korea.

Organic solar cells based on bulk heterojunctions (BHJs) are attractive energy-conversion devices that can generate electricity from absorbed sunlight by dissociating excitons and collecting charge carriers. Recent breakthroughs attained by development of nonfullerene acceptors result in significant enhancement in power conversion efficiency (PCEs) exceeding 17%. However, most of researches have focused on pursuing high efficiency of small-area (<1 cm ) unit cells fabricated usually with spin coating. For practical application of organic photovoltaics (OPVs) from lab-scale unit cells to industrial products, it is essential to develop efficient technologies that can extend active area of devices with minimized loss of performance and ensured operational stability. In this progress report, an overview of recent advancements in materials and processing technologies is provided for transitioning from small-area laboratory-scale devices to large-area industrial scale modules. First, development of materials that satisfy requirements of high tolerability in active layer thickness and large-area adaptability is introduced. Second, morphology control using various coating techniques in a large active area is discussed. Third, the recent research progress is also underlined for understanding mechanisms of OPV degradation and studies for improving device long-term stability along with reliable evaluation procedures.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/adma.202002217DOI Listing
December 2020

Continuous and spontaneous nanoparticle separation by diffusiophoresis.

Lab Chip 2020 11;20(22):4118-4127

Department of Electrical and Computer Engineering, Seoul National University, Seoul 08826, Republic of Korea. and Nano Systems Institute, Seoul National University, Seoul 08826, Republic of Korea and Inter-university Semiconductor Research Center, Seoul National University, Seoul 08826, Republic of Korea.

The separation of nanoparticles has drawn critical attention in various microfluidic applications including chemical analysis, diagnostics and environmental monitoring. Thus, a number of nanoparticle separation methods have been extensively proposed. However, most of the conventional methods require complicated structured devices, expensive manufacturing processes, and external power sources. While a spontaneous diffusiophoretic separation device based on an ion exchange mechanism could overcome such drawbacks, the recovery of separated particles and the inevitable development of an acidic environment due to the release of H+ from the cation exchange membrane limit its practical applicability. Therefore, in this work, we present a simple but robust nanoparticle separation method based on spontaneously induced diffusiophoresis, which is operated in a continuous manner to overcome the limitations of conventional methods. First, we confirmed that the particle exclusion distance followed the previously developed scaling law of diffusiophoresis. Consequently, we demonstrated the separation of nanoparticles of 40 nm, 200 nm and 2 μm diameter by utilizing the fact that the exclusion distances of various particles were proportional to their diffusiophoretic mobility. Furthermore, the use of Tris buffer increased the diffusiophoretic migration of nanoparticles due to the enhanced concentration gradient, and enabled the produced solution to be compatible with pH-sensitive bio-samples. Therefore, we expect this continuous and spontaneous diffusiophoretic separation platform to be useful in practical applications for analyzing various nano-meter scale bio-particles.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1039/d0lc00593bDOI Listing
November 2020

Characteristics and prognosis of 17 special histologic subtypes of invasive breast cancers according to World Health Organization classification: comparative analysis to invasive carcinoma of no special type.

Breast Cancer Res Treat 2020 Nov 13;184(2):527-542. Epub 2020 Aug 13.

Division of Breast and Endocrine Surgery, Department of Surgery, Korea University Anam Hospital, Korea University College of Medicine, 73 Inchon-ro, Seongbuk-gu, 02841, Seoul, Republic of Korea.

Background: Breast cancer is a heterogeneous disease with various histopathologic subtypes. Except for invasive carcinoma of no special type (NST), other subtypes are rare with limited data. The purpose of this study was to analyze the characteristics and prognosis of special histopathologic subtypes of breast cancer compared to NST.

Methods: A total of 136,140 patients were analyzed using the Korean Breast Cancer Society Registry database between January 1996 and March 2019. The clinicopathologic features and survival outcomes of special type breast carcinoma were compared with those of NST.

Results: The prevalence of special subtypes other than NST was 13.7% (n = 18,633). Compared to NST, patients with lobular, medullary, metaplastic, and micropapillary carcinoma had larger tumors (p < 0.001). Patients with mucinous, tubular, medullary, metaplastic, and cribriform carcinoma presented with less node metastasis (p < 0.001), contrary to patients with micropapillary carcinoma. Patients with lobular, mucinous, tubular, papillary, and cribriform carcinoma presented as luminal A subtype much more often (p < 0.001). Micropapillary carcinoma included more luminal B subtype (p < 0.001). Typically, medullary and metaplastic carcinoma included more triple-negative subtypes (p < 0.001). In survival analysis, only medullary (Hazard Ratio (HzR) 0.542, 95% CI 0.345 to 0.852, p = 0.008) and metaplastic carcinoma (HzR 1.655, 95% CI 1.317 to 2.080, p < 0.001) showed significantly different overall survival from NST by multivariate analysis.

Conclusion: Breast cancer had distinct clinicopathologic features according to histopathologic subtype. However, special types of breast cancer had similar survival outcomes compared to NST when adjusting for other prognostic factors, except for metaplastic carcinoma and medullary carcinoma.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s10549-020-05861-6DOI Listing
November 2020

Breast Cancer Statistics in Korea in 2017: Data from a Breast Cancer Registry.

J Breast Cancer 2020 Apr 7;23(2):115-128. Epub 2020 Apr 7.

Department of Surgery, Research Institute of Clinical Medicine, Jeonbuk National University Hospital, Jeonbuk National University and Biomedical Research Institute, Jeonju, Korea.

This article describes the breast cancer statistics in Korea, including the incidence, type of surgical procedure, stage, and molecular subtype, using the Korean Breast Cancer Society (KBCS) and Korea Central Cancer Registry data. There were a total of 26,534 new breast cancer diagnoses in 2017 in Korea, of which 4,139 were carcinoma cases and 22,395 were invasive cancer cases. The age standardized rate of breast cancer was 75.3 per 100,000 women in 2017 (63.0 of invasive carcinoma and 12.3 of carcinoma ), and it has been steadily increasing across all age groups. Breast cancer occurred most commonly in the 40-49 age group. Compared to 2016, breast conserving surgery (BCS) has increased, and 67.4% of patients were treated with BCS in 2017. The proportions of stage 0 and stage I have continued to increase, accounting for 60.7%. The most common subtype of breast cancer was hormone receptor (HR) positive and human epidermal growth factor receptor-2 (HER2) negative type comprising 65.9% of the cases, whereas HR negative and HER2 positive type was the rarest comprising 10.2% of the cases. The 5-year relative survival rate of breast cancer patients had increased by 14.0% from 79.2% in 1993-1995 to 93.2% in 2013-2017. It is essential to actively enter breast cancer data into the KBCS registry to improve our understanding.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.4048/jbc.2020.23.e24DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7192743PMC
April 2020

Understanding the Performance of Organic Photovoltaics under Indoor and Outdoor Conditions: Effects of Chlorination of Donor Polymers.

ACS Appl Mater Interfaces 2020 May 6;12(20):23181-23189. Epub 2020 May 6.

Department of Materials Engineering and Convergence Technology and ERI, Gyeongsang National University, Jinju 660-701, Republic of Korea.

Understanding the effects of the chemical structures of donor polymers on the photovoltaic properties of their corresponding organic photovoltaic (OPV) devices under various light-intensity conditions is important for improving the performance of these devices. We synthesized a series of copolymers based on poly[(2,6-(4,8-bis(5-(2-thioethylhexyl)thiophen-2-yl)benzo[1,2-:4,5-']dithiophene))--(5,5-(1',3'-di-2-thienyl-5',7'-bis(2-ethylhexyl)benzo[1',2'-:4',5'-']dithiophene-4,8-dione))] (PBDB-TS) and studied the effects of chlorine substitution of its thiophene-substituted benzodithiophene (BDT-Th) unit on its photovoltaic properties. Chlorination of the polymer resulted in a bulk heterojunction (BHJ) morphology optimized for efficient charge transport with suppressed leakage current and an increased open-circuit voltage of the OPV device; this optimization led to a remarkable enhancement of the OPV device's power conversion efficiency (PCE) not only under the condition of 1 sun illumination but also under a low light intensity mimicking indoor light; the PCE increased from 8.7% for PBDB-TS to ∼13% for the chlorinated polymers, PBDB-TS-3Cl, and PBDB-TS-4Cl under the 1 sun illumination condition and from 5.3% for PBDB-TS to 21.7% for PBDB-TS-4Cl under 500 lx fluorescence illuminance. Interestingly, although the OPV PCEs under 1 sun illumination were independent of the position of chlorine substitution onto the polymer, PBDB-TS-4Cl exhibited better performance under simulated indoor light than its derivative PBDB-TS-3Cl. Our results demonstrate that efficient light absorption and charge-carrier generation play key roles in achieving high OPV efficiency under low-light-intensity conditions.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/acsami.0c02712DOI Listing
May 2020

Pyrolytic remediation of crude oil-contaminated soil.

Sci Total Environ 2020 Apr 7;713:136498. Epub 2020 Jan 7.

Department of Earth Resources and Environmental Engineering, Hanyang University, 222, Wangsimni-ro, Seongdong-gu, Seoul 04763, Republic of Korea. Electronic address:

Deterioration of our terrestrial environment due to decreasing soil quality brought on by crude oil spills and leakages is a major issue. In this study, soil samples were prepared by mixing clay (bentonite) and sand contaminated with 5 and 10 wt% crude oil (in order to study the effect of oil concentration), and weathered in a laboratory to simulate actual contaminated soil. Volatilization of light oil was inhibited in clay rich-soil, resulting in higher contamination after weathering. The efficiency of the pyrolytic treatment was evaluated by comparing the weight change and n-hexane extractable material (HEM) content of the soil samples. The working temperature influenced pyrolysis efficiency more than the reaction time. A residual amount of 0.29-0.61 wt% (below the soil pollution standard) was observed in the samples with high clay content and pollution level (by pyrolysis for 30 min at 400 °C). Infrared analysis of treated soil samples showed a reduction in alkyl functionality (CH), confirming a decrease in hydrophobicity and an improvement in water holding capacity (WHC). Seed germination and plant growth were relatively better in the pyrolyzed soil. The field applicability of the pyrolytic treatment process was confirmed at laboratory and pilot scale, as well as by treating soil samples collected from actual polluted sites.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.scitotenv.2020.136498DOI Listing
April 2020

Reversibly pH-responsive gold nanoparticles and their applications for photothermal cancer therapy.

Sci Rep 2019 12 27;9(1):20180. Epub 2019 Dec 27.

Department of Chemistry, Myongji University, 116 Myongji Ro, Yongin, Gyeonggi-do, 17058, South Korea.

Microenvironment responsive nanomaterials are attractive for therapeutic applications with regional specificity. Here we report pH responsive gold nanoparticles which are designed to aggregate in acidic condition similar to cancer environment and returned to its original disassembled states in a physiological pH. The pH responsive behavior of the particles is derived by change of electrostatic interaction among the particles where attraction and repulsion play a major role in low and high pH of the environment, respectively. Since different electrostatic interaction behavior of the particles in varied pH is induced not by irreversible chemical change but by simple protonation differences, the pH responsive process of assembly and disassembly is totally reversible. The low pH specific aggregation of gold nanoparticles resulted in red shift of plasmonic absorption peak and showed higher photothermal efficacy in acidic pH than in normal physiological pH. The low pH specific photothermal effect with long wave laser irradiation was directly applied to cancer specific photothermal therapy and resulted higher therapeutic effect for melanoma cancer cells than non-pH responsive gold nanoparticles.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/s41598-019-56754-8DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6934723PMC
December 2019

Nanoelectrokinetic bufferchannel-less radial preconcentrator and online extractor by tunable ion depletion layer.

Biomicrofluidics 2019 May 30;13(3):034113. Epub 2019 May 30.

Department of Chemical and Biological Engineering, Jeju National University, Jeju 63243, South Korea.

Among various preconcentration strategies using nanofluidic platforms, a nanoscale electrokinetic phenomenon called ion concentration polarization (ICP) has been extensively utilized due to several advantages such as high preconcentration factor and no need of complex buffer exchange process. However, conventional ICP preconcentrator had difficulties in the recovery of preconcentrated sample and complicated buffer channels. To overcome these, bufferchannel-less radial micro/nanofluidic preconcentrator was developed in this work. Radially arranged microchannel can maximize the micro/nano membrane interface so that the samples were preconcentrated from each microchannel. All of preconcentrated plugs moved toward the center pipette tip and can be easily collected by just pulling out the tip installed at the center reservoir. For a simple and cost-effective fabrication, a commercial printer was used to print the nanoporous membrane as "Nafion-junction device." Various analytes such as polystyrene particle, fluorescent dye, and dsDNA were preconcentrated and extracted with the recovery ratio of 85.5%, 79.0%, and 51.3%, respectively. Furthermore, we used a super inkjet printer to print the silver electrode instead of nanoporous membrane to preconcentrate either type of charged analytes as "printed-electrode device." A Faradaic reaction was used as the main mechanism, and we successfully demonstrated the preconcentration of either negatively or positively charged analytes. The presented bufferchannel-less radial preconcentrator would be utilized as a practical and handy platform for analyzing low-abundant molecules.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1063/1.5092789DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6542650PMC
May 2019

Childbirth in young Korean women with previously treated breast cancer: The SMARTSHIP study.

Breast Cancer Res Treat 2019 Jul 24;176(2):419-427. Epub 2019 Apr 24.

Department of Surgery, Catholic Kwandong University International St. Mary's Hospital, Catholic Kwandong University College of Medicine, 25 Simgok-ro 100 beon-gil, Seo-gu, Incheon, 22711, Republic of Korea.

Purpose: Alongside the modern trend of delaying childbirth, the high incidence of breast cancer among young women is causing significant pregnancy-related problems in Korea. We estimated the incidence of childbirth for young Korean breast cancer survivors compared with women who did not have breast cancer using a nationally representative dataset.

Methods: Using a database from the National Health Insurance Service in South Korea, we analyzed 109,680 women who were between 20 and 40 years old between 2007 and 2013. They were prospectively followed, and childbirth events were recorded until December 31, 2015. We compared childbirth rates and characteristics between the breast cancer survivors and the noncancer controls.

Results: Compared to 10,164 childbirths among 91,400 women without breast cancer (incidence rate: 22.3/1000), 855 childbirths occurred among 18,280 breast cancer survivors (incidence rate: 9.4/1000); the adjusted hazard ratio (HR) for childbirth was 0.41 (95% CI 0.38-0.44). Chemotherapy, endocrine therapy, and target therapy were associated with the decreasing childbirths among survivors, with corresponding adjusted HRs of 0.61 (0.53-0.70), 0.44 (0.38-0.51), and 0.62 (0.45-0.86), respectively. Breast cancer survivors had a lower probability of full-term delivery and a higher frequency of preterm labor than controls, with corresponding adjusted ORs of 0.78 (0.68-0.90) and 1.33 (1.06-1.65), respectively.

Conclusions: We showed that a history of breast cancer has a negative effect on childbirth among young premenopausal women in Korea. Breast cancer survivors should be aware that they have a higher risk for preterm labor and are less likely to have a full-term delivery than women without a history of breast cancer.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s10549-019-05244-6DOI Listing
July 2019

Use of Sentinel Lymph Node Biopsy after Neoadjuvant Chemotherapy in Patients with Axillary Node-Positive Breast Cancer in Diagnosis.

J Breast Cancer 2018 Dec 23;21(4):433-441. Epub 2018 Nov 23.

Division of Breast Surgery, Department of Surgery, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.

Purpose: This study aimed to evaluate the effects of sentinel lymph node biopsy (SLNB) on recurrence and survival after neoadjuvant chemotherapy (NAC) in breast cancer patients with cytology-proven axillary node metastasis.

Methods: We selected patients who were diagnosed with invasive breast cancer and axillary lymph node metastasis and were treated with NAC followed by curative surgery between January 2007 and December 2014. We classified patients into three groups: group A, negative sentinel lymph node (SLN) status and no further dissection; group B, negative SLN status with backup axillary lymph node dissection (ALND); and group C, no residual axillary metastasis on pathology with standard ALND.

Results: The median follow-up time was 51 months (range, 3-122 months) and the median number of retrieved SLNs was 5 (range, 2-9). The SLN identification rate was 98.3% (234/238 patients), and the false negative rate of SLNB after NAC was 7.5%. There was no significant difference in axillary recurrence-free survival (=0.118), disease-free survival (DFS; =0.578) or overall survival (OS; =0.149) among groups A, B, and C. In the subgroup analysis of breast pathologic complete response (pCR) status, there was no significant difference in DFS (=0.271, =0.892) or OS (=0.207, =0.300) in the breast pCR and non-pCR patients.

Conclusion: These results suggest that SLNB can be feasible and oncologically safe after NAC for cytology-determined axillary node metastasis patients and could help reduce arm morbidity and lymphedema by avoiding ALND in SLN-negative patients.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.4048/jbc.2018.21.e54DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6310714PMC
December 2018

Easy cuts, easy rebound: Drug expenditures with massive price cuts in Korea.

Health Policy 2019 04 20;123(4):388-392. Epub 2018 Nov 20.

College of Nursing, Seoul National University, Seoul, Republic of Korea. Electronic address:

Backgrounds: Since 2012, the Korean government has introduced 46.5% price cut for off-patent medicines in order to reign everescalating drug expenditure. This study sought to appraise the impact of the price cut measure (in the context of Korean National Health Insurance system).

Methods: We employed Korean National Health Insurance database from January 2007 until December 2016 for 120 month period. An interrupted time series analysis with segmented regression analysis was conducted to estimate the impact of price cut on overall drug spending.

Results: Drug spending significantly dropped with the price cut by 186.22 billlion Korean Won (KRW) (p < 0.0001) and the trend after the price cut has also significantly decreased by 1.33 billion KRW (p = 0.002). However, it was predicted that total expenditures showed an increasing trend and bounced back to the original level. Quantity prescribed had no significance with the price cut. Unit price had a substantial drop (β = -41.68, p < 0.0001) with the price-cut, but the trend after the intervention has increased (β = 0.16, p = 0.656) with no significance.

Conclusions: Although the price cut has successfully countered the everescalating pharmaceutical expenditures in Korea, the impact was temporary. A lack of demand-side measures resulted in an ineffectiveness and unsustainability of policy effect. Thus, more aggressive demand-side measures should be introduced in the Korean context,and both the demand and supply-sides should be balanced.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.healthpol.2018.11.002DOI Listing
April 2019

Clinical subtypes and prognosis in breast cancer according to parity: a nationwide study in Korean Breast Cancer Society.

Breast Cancer Res Treat 2019 Feb 2;173(3):679-691. Epub 2018 Nov 2.

Division of Breast and Endocrine Surgery, Department of Surgery, Korea University Anam Hospital, Korea University College of Medicine, 73 Inchon-ro, Seongbuk-gu, 02841, Seoul, Republic of Korea.

Purpose: We explored the association between parity and the risk of developing a specific subtype of breast cancer. We also assessed the association between parity and prognosis according to subtypes.

Methods: A total of 158,189 patients were enrolled in the Korean Breast Cancer Society Registry database between 1996 and 2015 in Korea. The database provided information on sex, age, number of parity, surgical method, stage, histological findings, presence of biologic markers, adjuvant therapy, and date and cause of death.

Results: The patients with higher parity showed a higher ratio of triple-negative breast cancer (TNBC) and human epidermal growth factor receptor 2 (HER2) subtypes. In univariate analysis, women with TNBC who had more than three children had a worse prognosis compared to other groups (HR 1.83; 95% CI 1.34-2.49; P < 0.001). This association was also observed in women younger than 50 years (HR 1.63; 95% CI 1.07-2.48; P = 0.021). In multivariate analysis stratified by subtypes, women who had more than three children were associated with a worse prognosis in TNBC in the total population (HR 1.53; 95% CI 1.11-2.12; P = 0.011). This association was also observed in patients younger than 50 years of age (HR 1.53; 95% CI 1.09-2.61; P = 0.017).

Conclusion: Women who had more than three children were more likely to develop hormone receptor-negative (HR-) subtypes. Women who had more than three children were associated with worse prognosis in patients younger than 50 years of age and in patients with TNBC.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s10549-018-5032-3DOI Listing
February 2019

Nanopatterned Scaffolds for Neural Tissue Engineering and Regenerative Medicine.

Adv Exp Med Biol 2018;1078:421-443

Department of Rural and Biosystems Engineering, Chonnam National University, Gwangju, South Korea.

Biologically inspired approaches employing nanoengineering techniques have been influential in the progress of neural tissue repair and regeneration. Neural tissues are exposed to complex nanoscale environments such as nanofibrils. In this chapter, we summarize representative nanotechniques, such as electrospinning, lithography, and 3D bioprinting, and their use in the design and fabrication of nanopatterned scaffolds for neural tissue engineering and regenerative medicine. Nanotopographical cues in combination with other cues (e.g., chemical cues) are crucial to neural tissue repair and regeneration using cells, including various types of stem cells. Production of biologically inspired nanopatterned scaffolds may encourage the next revolution for studies aiming to advance neural tissue engineering and regenerative medicine.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/978-981-13-0950-2_22DOI Listing
July 2019

Non-negligible Water-permeance through Nanoporous Ion Exchange Medium.

Sci Rep 2018 Aug 27;8(1):12842. Epub 2018 Aug 27.

Department of Electrical and Computer Engineering, Seoul National University, Seoul, 08826, Republic of Korea.

While the water impermeable constraint has been conventionally adopted for analyzing the transport phenomena at the interface of electrolyte/nanoporous medium, non-negligible water-permeance through the medium results in significant effect on ion and particle transportation. In this work, a rigorous theoretical and experimental analysis of the water-permeance effect were conducted based on a fully-coupled analytical/numerical method and micro/nanofluidic experiments. The regime diagram with three distinctive types of concentration boundary layers (ion depletion, ion accumulation, and intermediate) near the ion exchange nanoporous medium was proposed depending on the medium's permselectivity and the water-permeance represented by an absorbing parameter. Moreover, the critical absorbing parameters which divide the regimes were analytically obtained so that the bidirectional motion of particles were demonstrated only by altering the water-permeance without external stimuli. Conclusively, the presenting analysis of non-negligible water-permeance would be a substantial fundamental of transport phenomena at the interface of the ion exchange medium and electrolyte, especially useful for the tunable particle/ion manipulations in intermediate Peclet number environment.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/s41598-018-29695-xDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6110714PMC
August 2018

11% Organic Photovoltaic Devices Based on PTB7-Th: PCBM Photoactive Layers and Irradiation-Assisted ZnO Electron Transport Layers.

Adv Sci (Weinh) 2018 Jul 21;5(7):1700858. Epub 2018 May 21.

Department of Chemistry Kookmin University Seoul 02707 Republic of Korea.

The enhancement of interfacial charge collection efficiency using buffer layers is a cost-effective way to improve the performance of organic photovoltaic devices (OPVs) because they are often universally applicable regardless of the active materials. However, the availability of high-performance buffer materials, which are solution-processable at low temperature, are limited and they often require burdensome additional surface modifications. Herein, high-performance ZnO based electron transporting layers (ETLs) for OPVs are developed with a novel -ray-assisted solution process. Through careful formulation of the ZnO precursor and -ray irradiation, the pre-formation of ZnO nanoparticles occurs in the precursor solutions, which enables the preparation of high quality ZnO films. The -ray assisted ZnO (ZnO-G) films possess a remarkably low defect density compared to the conventionally prepared ZnO films. The low-defect ZnO-G films can improve charge extraction efficiency of ETL without any additional treatment. The power conversion efficiency (PCE) of the device using the ZnO-G ETLs is 11.09% with an open-circuit voltage (), short-circuit current density ( ), and fill factor (FF) of 0.80 V, 19.54 mA cm, and 0.71, respectively, which is one of the best values among widely studied poly[4,8-bis(5-(2-ethylhexyl)thiophen-2-yl)benzo[1,2-b;4,5-b']dithiophene-2,6-diyl-alt-(4-(2-ethylhexyl)-3-fluorothieno[3,4-b]thiophene-)-2-carboxylate-2-6-diyl)]: [6,6]-phenyl-C-butyric acid methyl ester (PTB7-Th:PCBM)-based devices.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/advs.201700858DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6051392PMC
July 2018

Catalytic degradation of phenols by recyclable CVD graphene films.

Nanoscale 2018 Mar;10(13):5840-5844

Department of Chemistry, Seoul National University, Gwanak_599, Gwanak-ro, Gwanak-gu, Seoul 151-747, Korea.

Ferrous ion-based catalysts have been widely employed to oxidatively destruct the major industrial pollutants such as phenolic compounds through advanced oxidation processes (AOPs). These agents, however, inevitably show several drawbacks including the need for pH adjustment and further purification steps to remove residual salts. Here we report the use of a chemical vapour deposition (CVD) graphene film as a novel metal-free catalyst for the AOP-based degradation of phenols in aqueous solution, which does not require additional steps for salt removal nor external energy to activate the process. We have also verified that the catalytic activity is strongly dependent on the surface area of the graphene film and the degradation efficiency can be markedly improved by exploiting an array of multiple graphene films. Finally, the recyclability of the graphene film has been validated by performing repetitive degradation tests to ensure its practical use.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1039/c8nr00045jDOI Listing
March 2018

Surface functionalized nanostructures via position registered supramolecular polymer assembly.

Nanoscale 2018 Apr;10(14):6333-6342

Department of Materials Science and Engineering, Yonsei University, Yonsei-ro 50, Seodaemun-gu, Seoul, 03722, Republic of Korea.

Versatile control of cylindrical nanostructures formed by supramolecular assembly of end-functionalized polymer blends is demonstrated not only in their orientation over large areas but also in their surface chemical functionalities. Two binary blends consisting of supramolecular analogues of diblock copolymers with complementary end-sulfonated and aminated groups are investigated, viz., mono-end-functionalized polymers of (i) one-end-sulfonated polystyrene (SPS) and one-end-aminated poly(butadiene) (APBD) and (ii) one end-aminated polystyrene (APS) and one end-sulfonated poly(butadiene) (SPBD). The orientation of the cylinders with respect to the substrate surface depends on the solvent annealing time; either hexagonally ordered vertical cylinders or in-plane ones are readily obtained by controlling the solvent annealing time. Selective chemical etching of one of the polymers provides four different chemically modified nanostructures, viz., hexagonally ordered cylindrical holes and cylindrical posts with either sulfonate or amine surface functional groups. Additional supramolecular assembly is successfully achieved by solution coating either polymers or organic dyes that complementarily interact with the functional groups on the nanostructures. Furthermore, the supramolecularly assembled nanostructures are controlled by confining them to topographically pre-patterned Si substrates with pattern geometries of various shapes and sizes to produce globally ordered vertical or in-plane cylinders with chemical functionalities on their surfaces.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1039/c7nr07852hDOI Listing
April 2018

Comparison of outcomes of surgeon-performed intraoperative ultrasonography-guided wire localization and preoperative wire localization in nonpalpable breast cancer patients undergoing breast-conserving surgery: A retrospective cohort study.

Medicine (Baltimore) 2017 Dec;96(50):e9340

Department of Anesthesiology Department of Surgery, Chungbuk National University Hospital, Chungbuk National University College of Medicine, Cheongju, Republic of Korea.

This study aimed to determine the efficacy of intraoperative ultrasonography-guided wire localization guided breast-conserving surgery (BCS) for nonpalpable breast cancer and compare it to conventional preoperative wire localization (PWL) guided surgery.We retrospectively analyzed the medical charts of 214 consecutive nonpalpable breast cancer patients who underwent BCS using intraoperative ultrasonography-guided wire localization by a surgeon (IUWLS) and PWL, between April 2013 and March 2017. Positive surgical margins, reexcision rates, and resection volumes were investigated.Of the total cohort, 124 patients underwent BCS with IUWLS and 90 patients with PWL. The following did not differ between the IUWLS and PWL groups: positive margin status, re-excision rate, conversion rate, permanent positive margin status, reoperation rate, median optimal resection volume (ORV), median total resection volume (TRV), and median closest tumor-free margin. Rather, median (range) widest tumor-free margin was significantly smaller in the IUWLS group (9 mm [5-12]) than in the PWL group (14 mm [9-20]; P = .003]). Median (range) calculated resection ratio (CRR) was significantly lower in the IUWLS group (1.67 [0.87-9.38]) than in the PWL group (4.83 [1.63-21.04]; P = .02).In nonpalpable breast cancer patients undergoing BCS, IUWLS showed positive resection margins and reexcision rates equivalent to those of the conventional PWL method. Additionally, excision volume and widest tumor-free margin were smaller with IUWLS, confirming that healthy breast tissue is less likely to be resected with this method. Our results suggest that IUWLS offers an excellent alternative to PWL, while avoiding PWL-induced patient discomfort.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1097/MD.0000000000009340DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5815817PMC
December 2017

Bioinspired microneedle insertion for deep and precise skin penetration with low force: Why the application of mechanophysical stimuli should be considered.

J Mech Behav Biomed Mater 2018 02 7;78:480-490. Epub 2017 Dec 7.

Department of Mechanical Engineering, Inha University, Incheon 22212, Republic of Korea. Electronic address:

A mosquito is known to precisely and easily insert its proboscis to the human skin by pressing down a labium and vibrating a fascicle bundle. Its advanced skin-piercing mechanisms indicate that skin resistance to the insertion of needle-like objects can be changed by the application of mechanophysical stimuli. Here, we characterize the effect of the application of mechanophysical stimuli on skin resistance to microneedle insertion to find clues for inserting a microneedle in a deep and precise fashion with low force. Microneedles with a diameter of 60-140µm are inserted at a velocity of 0.1-2.0mm/s to full-thickness porcine skins while either uniaxial/equibiaxial stretch of 0-20% or mechanical vibration at a frequency of 1 to 1000Hz and an amplitude of 1-10µm is applied to the skins as static or dynamic mechanophysical stimulus, respectively. The values of force and depth at two events of skin puncture and maximum penetration are measured to explore changes in skin resistance induced by the application of external stimuli. The static mechanophysical stimulus applied to the skin mainly affects the precision of microneedle insertion; the application of dynamic mechanophysical stimulus controls the value and deviation of skin resistance to microneedle insertion. The application of mechanophysical stimuli, inspired from a mosquito, therefore allows a microneedle to be deeply and easily inserted to the skin in a controlled way. The findings will have broad impacts on microneedle-mediated applications and lead to an in-depth understanding of skin biomechanics.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.jmbbm.2017.12.006DOI Listing
February 2018

Genetic Diagnosis before Surgery has an Impact on Surgical Decision in BRCA Mutation Carriers with Breast Cancer.

World J Surg 2018 05;42(5):1384-1390

Breast Division, Department of Surgery, Samsung Medical Center, Sungkyunkwan University School of Medicine, 81, Irwon-ro, Gangnam-gu, Seoul, 06351, Korea.

Background: The first aim of our study was to evaluate surgical decision-making by BRCA mutation carriers with breast cancer based on the timing of knowledge of their BRCA mutation status. The second aim was to evaluate breast cancer outcome following surgical treatment.

Methods: This was a retrospective study of 164 patients diagnosed with invasive breast cancer, tested for BRCA mutation, and treated with primary surgery between 2004 and 2015 at Samsung Medical Center in Seoul, Korea. We reviewed types of surgery and timing of the BRCA test result. We compared surgical decision- making of BRCA carriers with breast cancer based on the timing of knowledge of their BRCA mutation status.

Results: Only 15 (9.1%) patients knew their BRCA test results before their surgery, and 149 (90.9%) knew the results after surgery. In patients with unilateral cancer, there was a significant difference between groups whose BRCA mutation status known before surgery and groups whose BRCA status unknown before surgery regarding the choice of surgery (p = 0.017). No significant difference was observed across surgery types of risk of ipsilateral breast tumor recurrence (p = 0.765) and contralateral breast cancer (p = 0.69).

Conclusion: Genetic diagnosis before surgery has an impact on surgical decision choosing unilateral mastectomy or bilateral mastectomy in BRCA mutation carriers with breast cancer. Knowledge about BRCA mutation status after initial surgery led to additional surgeries for patients with BCS. Thus, providing genetic counseling and genetic testing before surgical choice and developing treatment strategies for patients with a high risk of breast cancer are important.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s00268-017-4342-7DOI Listing
May 2018
-->