56016 research outputs found
Sort by
Controlling Morphologies of Redox-Responsive Polymeric Nanocarriers for a Smart Drug Delivery System
No full textRedox-responsive nanocarriers using disulfides or thiols have received considerable attention owing to the higher levels of glutathione (GSH) in cancer cells than those in extracellular fluids. Nevertheless, the normal-to-cancer-cell selectivity of these nanocarriers has not yet been clarified. Nanocarriers exhibit different cytotoxicities depending on the morphologies they adopt under the redox-active conditions typically existing in cancerous cells. Therefore, not only GSH levels but also reactive oxygen species (ROS) levels and other complex cancerous cell conditions must be considered for the development of smart drug delivery systems. In this article, we review the structural design of redox-responsive polymers that exhibit different morphological changes in environments akin to cancerous cells (e. g., GSH- and ROS-abundant conditions). In addition, we propose a molecular design for the spatiotemporal control of nanocarrier morphology depending on the levels of both GSH and ROS upon photoirradiation to increase the cytotoxicity difference between normal and cancer cells
Bianisotropic Metasurface for Spatial Separation of Multiple Harmonic Waves
No full textAn approach to tuning harmonic responses of surface impedance is introduced to spatially separate fundamental, third-harmonic, and fifth-harmonic waves by focusing on the physical implementation perspective. The concept of the bianisotropic metasurface is adopted to refract the wave toward different angles by assigning identical phase gradients at fundamental and third-harmonic frequencies. On the other hand, high-sheet impedance is realized by maintaining the in-phase condition at the fifth harmonic to bypass the incident wave without refraction. The target properties of each unit cell are implemented using I-shaped patterns based on a three-stacked-layer topology. Different sizes and intervals are applied for the I-shaped patterns, and only their horizontal lengths are tuned to achieve the desired sheet impedances. The feasibility of the proposed approach is validated for the fundamental frequency of 10 GHz and two of odd harmonics through far-and near-field measurements. The results confirm that the fabricated metasurface separates the superimposed harmonic waves toward 44 ??? , 10 ??? , and 0 ??? with the measured refraction efficiencies of 65.6%, 67.2%, and 74% at 10, 30, and 50 GHz, respectively
Germline DNA-Repair Genes and HOXB13 Mutations in Korean Men with Metastatic Prostate Cancer: Data from a Large Korean Cohort
No full textPurpose: Germline mutations in DNA damage repair (DDR) genes such as BRCA2 have been associated with prostate cancer (PC) risk but has not been thoroughly evaluated for metastatic prostate cancer (mPC) in Asian men. This study attempts to evaluate frequency of DDR mutations in the largest cohort of Koreans. Materials and Methods: We recruited 340 patients with mPC unselected for family history of cancer and compared to 495 controls. Whole genome sequencing was applied to assess germline pathogenic/likely pathogenic variants (PV/LPVs) in 26 DDR genes and HOXB13, including 7 genes (ATM, BRCA1/2, CHEK2, BRIP1, PALB2, and NBN) associated with hereditary PC. Comparisons to published Caucasian and Japanese cohorts were performed. Results: Total of 28 PV/LPVs were identified in 30 (8.8%) patients; mutations were found in 13 genes, including BRCA2 (15 men [4.41%]), ATM (2 men [0.59%]), NBN (2 men [0.59%], and BRIP1 (2 men [0.59%]). Only one patient had HOXB13 mutation (0.29%). A lower rate of overall germline variant frequency was observed in Korean mPC compared to Caucasians (8.8% vs. 11.8%), but individual variants notably differed from Caucasian and geographically similar Japanese cohorts. PV/ LPVs in DDR genes tended to increase gradually with higher Gleason scores (GS 7, 7.1%; GS 8, 7.5%; GS 9-10, 9.9%).Conclusions: BRCA2 was the most frequently mutated gene common to different cohorts supporting its importance, but dif-ferences in variant distribution in Korean mPC underscore the need for ethnic-specific genetic models. Future ethnic-specific analyses are warranted to verify our findings
Nanofiber-laden hydrogels for biomedical applications
No full textHydrogels are widely used in biomedical engineering, most notably as drug delivery systems, cell culture scaffolds and biosensors. Mechanical properties of hydrogels are generally controlled by the crosslinking density of the polymeric network. But this inevitably leads to significant changes in their permeability. To resolve this issue, the strategy of incorporating short nanofibers into the hydrogels is employed. This allowed the control of mechanics only with a small amount of nanofibers without changing the polymer concentration. Furthermore, new functionalities could be introduced to the hydrogels by incorporating nanofibers prepared using various types of functional polymers
????????? ????????? ???????????? ?????? ??????????????? ??????????????? ??? ??? ?????? ????????? ????????? - ???????????? ???????????? ????????????
No full text
