Optoelectrical and mechanical properties of multiwall carbon nanotube-integrated DNA thin films.

Thin films made of deoxyribonucleic acid (DNA), dissolved in an aqueous solution, and cetyltrimethyl-ammonium-modified DNA (CDNA), dissolved in an organic solvent, utilising multiwall carbon nanotubes (MWCNTs) are not yet well-understood for use in optoelectronic device and sensor applications. In this study, we fabricate MWCNT-integrated DNA and CDNA thin films using the drop-casting method. We also characterise the optical properties (i.e. absorption spectra, Fourier-transform infrared spectra, Raman spectra, photoluminescence, and time-of-flight secondary ion mass spectrometry) to study spectral absorption, interaction, functional group, chirality, and compositional moiety and its distribution of MWCNTs in DNA and CDNA thin films. The electrical property for conductance and the mechanical characterisations of hardness, modulus and elasticity for stability are also discussed. Lastly, to show the feasibility of directional alignment of MWCNTs in DNA thin films, we perform an alignment experiment with MWCNTs in DNA via brushing and shearing methods, and we evaluate the results using polarised optical microscopy. Our simple methodology to align ingredients in DNA and CDNA thin films leveraging various optical, electrical and mechanical properties, provides great potential for the development of efficient devices and sensors.

Phase, current, absorbance, and photoluminescence of double and triple metal ion-doped synthetic and salmon DNA thin films.

We fabricated synthetic double-crossover (DX) DNA lattices and natural salmon DNA (SDNA) thin films, doped with 3 combinations of double divalent metal ions (M2+)-doped groups (Co2+-Ni2+, Cu2+-Co2+, and Cu2+-Ni2+) and single combination of a triple M2+-doped group (Cu2+-Ni2+-Co2+) at various concentrations of M2+ ([M2+]). We evaluated the optimum concentration of M2+ ([M2+]O) (the phase of M2+-doped DX DNA lattices changed from crystalline (up to ([M2+]O) to amorphous (above [M2+]O)) and measured the current, absorbance, and photoluminescent characteristics of multiple M2+-doped SDNA thin films. Phase transitions (visualized in phase diagrams theoretically as well as experimentally) from crystalline to amorphous for double (Co2+-Ni2+, Cu2+-Co2+, and Cu2+-Ni2+) and triple (Cu2+-Ni2+-Co2+) dopings occurred between 0.8 mM and 1.0 mM of Ni2+ at a fixed 0.5 mM of Co2+, between 0.6 mM and 0.8 mM of Co2+ at a fixed 3.0 mM of Cu2+, between 0.6 mM and 0.8 mM of Ni2+ at a fixed 3.0 mM of Cu2+, and between 0.6 mM and 0.8 mM of Co2+ at fixed 2.0 mM of Cu2+ and 0.8 mM of Ni2+, respectively. The overall behavior of the current and photoluminescence showed increments as increasing [M2+] up to [M2+]O, then decrements with further increasing [M2+]. On the other hand, absorbance at 260 nm showed the opposite behavior. Multiple M2+-doped DNA thin films can be used in specific devices and sensors with enhanced optoelectric characteristics and tunable multi-functionalities.

Relationship between aerobic fitness and progression of coronary atherosclerosis.

Cross-sectional data suggest that the degree of coronary atherosclerosis is associated with aerobic fitness. However, there are limited longitudinal data addressing whether aerobic fitness is a predictor of coronary atherosclerosis progression. This study investigated whether peak oxygen consumption is related to a longitudinal increase in coronary calcium scores. Study subjects were voluntary participants in a health screening program who underwent a cardiopulmonary function test and repeated coronary calcium scoring. Individuals with clinical cardiovascular disease were excluded. The final sample included 4843 subjects with 14,856 records. The treadmill exercise test was performed using a modified Bruce protocol and Agatston coronary artery calcium (CAC) scores were measured using multi-detector CT. The mean age of the participants was 52 ± 6 years and 4.7 % were female. In a multi-level mixed effect regression model, increased CAC scores over time were significantly less likely in individuals with a higher VO2peak after adjusting for age, gender, hypertension, HbA1c, smoking status and LDL cholesterol levels (p < 0.001). Aerobic fitness has a protective effect on the progression of coronary atherosclerosis in an asymptomatic middle-aged population.

Evaluating the efficacy of secondary transurethral resection of the bladder for high-grade Ta tumors.

PURPOSE: The need for secondary transurethral resection of the bladder (re-TURB) in patients with high-grade Ta tumors has not been assessed. This study aimed to compare the outcomes of patients with high-grade Ta tumors who did and did not undergo re-TURB. MATERIALS AND METHODS: This study used data from the Seoul National University Prospectively Enrolled Registry for Urothelial Cancer-Transurethral Bladder Tumor Resection (SUPER-UC-TURB). Patients with high-grade Ta tumors who underwent TURB between March 2016 and December 2019 were included. Following the initial TURB, if the pathology results showed a tumor grade higher than high-grade Ta, re-TURB was performed according to the surgeon's recommendation. The recurrence-free survival rate was assessed by Kaplan-Meier analysis and Cox regression analysis between patients who did and did not undergo re-TURB. RESULTS: In total, 187 patients with high-grade Ta who underwent initial TURB were included, of whom 115 underwent re-TURB and 72 did not. Patients in the re-TURB group had a significantly higher 2-year recurrence-free survival rate than did those in the no re-TURB group (81.3% vs. 60.1%; p=0.005). Whether patients underwent re-TURB was a significant predictor of the risk of bladder cancer recurrence in both the univariate (HR, 0.52; 95% CI, 0.27-0.98; p=0.044) and multivariate (HR, 0.41; 95% CI, 0.19-0.97; p=0.041) analysis. CONCLUSIONS: The risk for bladder cancer recurrence was increased, and the 2-year recurrence-free survival was significantly decreased, in patients with high-grade Ta tumors who did not undergo re-TURB. Thus, re-TURB is beneficial in patients with high-grade Ta bladder cancer.

Nanomaterial-Embedded DNA Films on 2D Frames.

Recently, 3D printing has provided opportunities for designing complex structures with ease. These printed structures can serve as molds for complex materials such as DNA and cetyltrimethylammonium chloride (CTMA)-modified DNA that have easily tunable functionalities via the embedding of various nanomaterials such as ions, nanoparticles, fluorophores, and proteins. Herein, we develop a simple and efficient method for constructing DNA flat and curved films containing water-soluble/thermochromatic dyes and di/trivalent ions and CTMA-modified DNA films embedded with organic light-emitting molecules (OLEM) with the aid of 2D/3D frames made by a 3D printer. We study the Raman spectra, current, and resistance of Cu2+-doped and Tb3+-doped DNA films and the photoluminescence of OLEM-embedded CTMA-modified DNA films to better understand the optoelectric characteristics of the samples. Compared to pristine DNA, ion-doped DNA films show noticeable variation of Raman peak intensities, which might be due to the interaction between the ion and phosphate backbone of DNA and the intercalation of ions in DNA base pairs. As expected, ion-doped DNA films show an increase of current with an increase in bias voltage. Because of the presence of metallic ions, DNA films with embedded ions showed relatively larger current than pristine DNA. The photoluminescent emission peaks of CTMA-modified DNA films with OLEMRed, OLEMGreen, and OLEMBlue were obtained at the wavelengths of 610, 515, and 469 nm, respectively. Finally, CIE color coordinates produced from CTMA-modified DNA films with different OLEM color types were plotted in color space. It may be feasible to produce multilayered DNA films as well. If so, multilayered DNA films embedded with different color dyes, ions, fluorescent materials, nanoparticles, proteins, and drug molecules could be used to realize multifunctional physical devices such as energy harvesting and chemo-bio sensors in the near future.

Geriatric assessment using the G8 to predict postoperative complications in patients undergoing major uro-oncologic surgery: Comparison with the Charlson Comorbidity Index.

OBJECTIVE: To evaluate the ability of the G8 assessment to predict postoperative complications in older adults undergoing major uro-oncologic surgery in comparison with the Charlson Comorbidity Index (CCI). MATERIALS AND METHODS: The study included patients ≥65 years old who underwent major uro-oncologic surgery between December 2017 and December 2019 and were enrolled in the Seoul National University Prospectively Enrolled Registry for Genitourinary Cancer (SUPER-GUC). Odds ratio (OR) smoothing was used to visualize risk according to G8 scores. Chi-square tests were used to compare postoperative complication rates according to G8 score or CCI category. RESULTS: A total of 657 patients undergoing radical prostatectomies (n = 372, 56.6%), partial/radical nephrectomies (n = 149, 22.7%), radical cystectomies (n = 76, 11.6%), and nephroureterectomies (n = 60, 9.1%) were included. Complication rates did not significantly differ between patients with CCI scores ≥1 and those with CCI scores of 0 (15.0% vs. 12.4%, p = 0.34). However, the complication rate was significantly higher in patients with G8 scores ≤14 than in those with G8 scores >14 (18.1% vs. 10.5%, p = 0.005). When the OR smoothing curve was used to divide patients into three groups based on G8 scores of <10, 10-14, and > 14, we observed significant differences in complication rates among the groups (37.5% vs. 16.9%. vs. 10.5%; p = 0.001). CONCLUSION: The G8 can aid in predicting postoperative complications in patients ≥65 years old. Comprehensive geriatric assessment is warranted in patients with G8 scores ≤14 prior to major uro-oncologic surgery. Older patients with G8 scores <10 should be counseled regarding the very high risk of surgery.

Demonstration of Arithmetic Calculations by DNA Tile-Based Algorithmic Self-Assembly.

Owing to its high information density, energy efficiency, and massive parallelism, DNA computing has undergone several advances and made significant contributions to nanotechnology. Notably, arithmetic calculations implemented by multiple logic gates such as adders and subtractors have received much attention because of their well-established logic algorithms and feasibility of experimental implementation. Although small molecules have been used to implement these computations, a DNA tile-based calculator has been rarely addressed owing to complexity of rule design and experimental challenges for direct verification. Here, we construct a DNA-based calculator with three types of building blocks (propagator, connector, and solution tiles) to perform addition and subtraction operations through algorithmic self-assembly. An atomic force microscope is used to verify the solutions. Our method provides a potential platform for the construction of various types of DNA algorithmic crystals (such as flip-flops, encoders, and multiplexers) by embedding multiple logic gate operations in the DNA base sequences.

Metal and Lanthanide Ion-Co-doped Synthetic and Salmon DNA Thin Films.

Researchers have begun to use DNA molecules as an efficient template for arrangement of multiple functionalized nanomaterials for specific target applications. In this research, we demonstrated a simple process to co-dope synthetic DNA nanostructures (by a substrate-assisted growth method) and natural salmon DNA thin films (by a drop-casting method) with divalent metal ions (M2+, e.g., Co2+ and Cu2+) and trivalent lanthanide ions (Ln3+, e.g., Tb3+ and Eu3+). To identify the relationship among the DNA and dopant ions, DNA nanostructures were constructed while varying the Ln3+ concentration ([Ln3+]) at a fixed [M2+] with ion combinations of Co2+-Tb3+, Co2+-Eu3+, Cu2+-Tb3+, and Cu2+-Eu3+. Accordingly, we were able to estimate the critical [Ln3+] (named the optimum [Ln3+], [Ln3+]O) at a given [M2+] in the DNA nanostructures that corresponds to the phase change of the DNA nanostructures from crystalline to amorphous. The phase of the DNA nanostructures stayed crystalline up to [Tb3+]O ≡ 0.4 mM and [Eu3+]O ≡ 0.4 mM for Co2+ ([Tb3+]O ≡ 0.6 mM and [Eu3+]O ≡ 0.6 mM for Cu2+) and then changed to amorphous above 0.4 mM (0.6 mM). Consequently, phase diagrams of the four combinations of dopant ion pairs were created by analyzing the DNA lattice phases at given [M2+] and [Ln3+]. Interestingly, we observed extrema values of the measured physical quantities of DNA thin films near [Ln3+]O, where the maximum current, photoluminescence peak intensity, and minimum absorbance were obtained. M2+- and Ln3+-multidoped DNA nanostructures and DNA thin films may be utilized in the development of useful optoelectronic devices or sensors because of enhancement and contribution of multiple functionalities provided by M2+ and Ln3+.

Large-Scale Fabrication of Copper-Ion-Coated Deoxyribonucleic Acid Hybrid Fibers by Ion Exchange and Self-Metallization.

It has been a challenge to achieve deoxyribonucleic acid (DNA) metallization and mass production with a high quality. The main aim of this study was to develop a large-scale production method of metal-ion-coated DNA hybrid fibers, which can be useful for the development of physical devices and sensors. Cetyltrimethylammonium-chloride-modified DNA molecules (CDNA) coated with metal ions through self-metallization exhibit enhanced optical and magnetic properties and thermal stability. In this paper, we present a simple synthesis route for Cu2+-coated CDNA hybrid fibers through ion exchange followed by self-metallization and analyze their structural and chemical composition (by X-ray diffraction (XRD), high-resolution field emission transmission electron microscopy (FETEM), and energy-dispersive X-ray spectroscopy (EDS)) and optical (by ultraviolet (UV)-visible absorption, Fourier transform infrared (FTIR), and X-ray photoelectron spectroscopies (XPS)), magnetic (by vibrating-sample magnetometry), and thermal (by a thermogravimetric analysis) characteristics. The XRD patterns, high-resolution FETEM images, and selected-area electron diffraction patterns confirmed the triclinic structure of Cu2+ in CDNA. The EDS results revealed the formation of Cu2+-coated CDNA fibers with a homogeneous distribution of Cu2+. The UV-vis, FTIR, and XPS spectra showed the electronic transition, interaction, and energy transfer between CDNA and Cu2+, respectively. The Cu2+-coated CDNA fibers exhibited a ferromagnetic nature owing to the presence of Cu2+. The magnetization of the Cu2+-coated CDNA fibers increased with the concentration of Cu2+ and decreased with the increase in temperature. Endothermic (absorbed heat) and exothermic (released heat) peaks in the differential thermal analysis curve were observed owing to the interaction of Cu2+ with the phosphate backbone.

Morphological and Optoelectronic Characteristics of Double and Triple Lanthanide Ion-Doped DNA Thin Films.

Double and triple lanthanide ion (Ln(3+))-doped synthetic double crossover (DX) DNA lattices and natural salmon DNA (SDNA) thin films are fabricated by the substrate assisted growth and drop-casting methods on given substrates. We employed three combinations of double Ln(3+)-dopant pairs (Tb(3+)-Tm(3+), Tb(3+)-Eu(3+), and Tm(3+)-Eu(3+)) and a triple Ln(3+)-dopant pair (Tb(3+)-Tm(3+)-Eu(3+)) with different types of Ln(3+), (i.e., Tb(3+) chosen for green emission, Tm(3+) for blue, and Eu(3+) for red), as well as various concentrations of Ln(3+) for enhancement of specific functionalities. We estimate the optimum concentration of Ln(3+) ([Ln(3+)]O) wherein the phase transition of Ln(3+)-doped DX DNA lattices occurs from crystalline to amorphous. The phase change of DX DNA lattices at [Ln(3+)]O and a phase diagram controlled by combinations of [Ln(3+)] were verified by atomic force microscope measurement. We also developed a theoretical method to obtain a phase diagram by identifying a simple relationship between [Ln(3+)] and [Ln(3+)]O that in practice was found to be in agreement with experimental results. Finally, we address significance of physical characteristics-current for evaluating [Ln(3+)]O, absorption for understanding the modes of Ln(3+) binding, and photoluminescence for studying energy transfer mechanisms-of double and triple Ln(3+)-doped SDNA thin films. Current and photoluminescence in the visible region increased as the varying [Ln(3+)] increased up to a certain [Ln(3+)]O, then decreased with further increases in [Ln(3+)]. In contrast, the absorbance peak intensity at 260 nm showed the opposite trend, as compared with current and photoluminescence behaviors as a function of varying [Ln(3+)]. A DNA thin film with varying combinations of [Ln(3+)] might provide immense potential for the development of efficient devices or sensors with increasingly complex functionality.

Assembly of a tile-based multilayered DNA nanostructure.

The Watson-Crick complementarity of DNA is exploited to construct periodically patterned nanostructures, and we herein demonstrate tile-based three dimensional (3D) multilayered DNA nanostructures that incorporate two design strategies: vertical growth and horizontal layer stacking with substrate-assisted growth. To this end, we have designed a periodically holed double-double crossover (DDX) template that can be used to examine the growth of the multilayer structures in both the vertical and horizontal directions. For vertical growth, the traditional 2D double crossover (DX) DNA lattice is seeded and grown vertically from periodic holes in the DDX template. For horizontal stacking, the DDX layers are stacked by binding the connector tiles between each layer. Although both types of multilayers exhibited successful formation, the observations with an atomic force microscope indicated that the DDX layer growth achieved with the horizontal stacking approach could be considered to be slightly better relative to the vertical growth of the DX layers in terms of uniformity, layer size, and discreteness. In particular, the newly designed DDX template layer provided a parallel arrangement between each domain with substrate-assisted growth. This kind of layer arrangement suggests a possibility of using our design scheme in the construction of other periodic structures.

Prediction of 4-year risk for coronary artery calcification using ensemble-based classification.

The progression of coronary artery calcification (CAC) has been regarded as an important risk factor of coronary artery disease (CAD), which is the biggest cause of death. Because CAC occurrence increases the risk of CAD by a factor of ten, the one whose coronary artery is calcified should pay more attention to the health management. However, performing the computerized tomography (CT) scan to check if coronary artery is calcified as a regular examination might be inefficient due to its high cost. Therefore, it is required to identify high risk persons who need regular follow-up checks of CAC or low risk ones who can avoid unnecessary CT scans. Due to this reason, we develop a 4-year prediction model for a new occurrence of CAC based on data collected by the regular health examination. We build the prediction model using ensemble-based methods to handle imbalanced dataset. Experimental results show that the developed prediction models provided a reasonable accuracy (AUC 75%), which is about 5% higher than the model built by the other imbalanced classification method.

Identifying relatively high-risk group of coronary artery calcification based on progression rate: statistical and machine learning methods.

Coronary artery calcification (CAC) score is an important predictor of coronary artery disease (CAD), which is the primary cause of death in advanced countries. Early prediction of high-risk of CAC based on progression rate enables people to prevent CAD from developing into severe symptoms and diseases. In this study, we developed various classifiers to identify patients in high risk of CAC using statistical and machine learning methods, and compared them with performance accuracy. For statistical approaches, linear regression based classifier and logistic regression model were developed. For machine learning approaches, we suggested three kinds of ensemble-based classifiers (best, top-k, and voting method) to deal with imbalanced distribution of our data set. Ensemble voting method outperformed all other methods including regression methods as AUC was 0.781.