Octafluoronaphthalene as a thermal-annealing-free volatile solid additive enables high-performance organic solar cells.

A thermal annealing-free solid additive octafluoronaphthalene was developed for high-performance organic solar cells. In an additive-modified device, an impressive power conversion efficiency of 18.59% from 17.27% was achieved with simultaneously enhanced current density from 26.86 to 27.53 mA cm-2 and fill factor from 74.34% to 78.85%.

Conformational Locking Control of 2D Outer Side Chains via Fluorine Atom Positioning for Improving the Thermal Stability of Organic Solar Cells.

Alongside high power conversion efficiencies (PCEs), device stability, especially thermal issues, is another key factor for the successful commercialization of nonfullerene acceptor (NFA)-based organic solar cells (OSCs). Considering the significant effects of the side-chain engineering of NFAs on molecular packing and/or locking strongly associated with the thermal stability of OSCs, herein, we present two new isomeric NFAs with 4-fluoro- and 2-fluoro-substituted hexylphenyl two-dimensional (2D) outer side chains (4FY and 2FY, respectively). In contrast with the 2FY having a horizontal stretching conformation, 4FY exhibits a diagonal stretching conformation of the 2D outer side chains and a higher dipole moment, resulting in a huge difference in their crystalline/aggregation characteristics, i.e., 4FY possesses a higher crystallinity with a denser molecular packing than the 2FY neat film, as evidenced by thermal and morphological characterizations. Encouragingly, relative to the one based on 2FY, the OSC based on 4FY delivers a PCE as high as 16.4%, together with excellent thermal stability (88.4% PCE retention under 85 °C for 360 h), which is attributed to a more optimal and robust blend morphology induced by its better compatibility into the used donor component and stronger crystallinity. This work demonstrates that in addition to the improved photovoltaic property, the appropriate F-positioning on the 2D outer side chains can play a key role in controlling their conformations, which can promote the increase of the thermal stability of OSCs.

Ship Hull-Fouling Diatoms on Korean Research Vessels Revealed by Morphological and Molecular Methods, and Their Environmental Implications.

Ship biofouling is one of the main vectors for the introduction and global spread of non-indigenous organisms. Diatoms were the early colonizers of ship hulls; however, their community composition on ships is poorly understood. Herein, we investigated the diatom community on the hull samples collected from two Korean research vessels Isabu (IRV) and Onnuri (ORV) on September 2 and November 10, 2021, respectively. IRV showed low cell density (345 cells/cm2) compared to ORV (778 cells/cm2). We morphologically identified more than 15 species of diatoms from the two research vessels (RVs). The microalgae in both RVs were identified as Amphora, Cymbella, Caloneis, Halamphora, Navicula, Nitzschia, and Plagiogramma. Of them, the genus Halamphora was found to be predominant. However, both RVs had a varied dominant species with a significant difference in body size; Halamphora oceanica dominated at IRV, and Halamphora sp. at ORV, respectively. Molecular cloning showed similar results to morphological analysis, in which Halamphora species dominated in both RVs. The hull-attached species were distinct from species found in the water column. These results revealed diatoms communities that are associated with ship hull-fouling at an early stage of biofilm formation. Moreover, ships arriving from different regions could show some variation in species composition on their hull surfaces, with the potential for non-indigenous species introduction.

Spectroscopic Study into Lanthanide Speciation in Deep Eutectic Solvents.

Deep eutectic solvents are a new class of green solvents that are being explored as an alternative for used nuclear fuel and critical material recycling. However, there is a paucity of knowledge regarding metal behavior in them. This paper explores the underlying chemistry of rare-earth elements in choline chloride-based deep eutectic solvents by using a multi-technique spectroscopic methodology. Results show that speciation is highly dependent on the choice of the hydrogen-bond donor. Collected EXAFS data showed Ln3+ coordination with ethylene glycol and urea in their respective solvents and coordination with chloride in the lactic acid system. Generalized coordination environments were determined to be [LnL4-5], [LnL7-10], and [LnL5-6] in the ethylene glycol, urea, and lactic acid systems, respectively. Collected UV/vis spectra for Nd3+ and Er3+ showed variations with changing solvents, showing that Ln-Cl interactions do not dominate in these systems. Luminescence studies were consistent, showing varying emission spectra with varying solvent systems. The shortest luminescent lifetimes were observed in the choline chloride-ethylene glycol deep eutectic solvent, suggesting coordination through O-H groups. Combining all collected data allowed Eu3+ coordination geometries to be assigned.

Gold nanoparticle-DNA aptamer-assisted delivery of antimicrobial peptide effectively inhibits Acinetobacter baumannii infection in mice.

Acinetobacter baumannii causes multidrug resistance, leading to fatal infections in humans. In this study, we showed that Lys AB2 P3-His-a hexahistidine-tagged form of an antimicrobial peptide (AMP) loaded onto DNA aptamer-functionalized gold nanoparticles (AuNP-Apt)-can effectively inhibit A. baumannii infection in mice. When A. baumannii-infected mice were intraperitoneally injected with AuNP-Apt loaded with Lys AB2 P3-His, a marked reduction in A. baumannii colonization was observed in the mouse organs, leading to prominently increased survival time and rate of the mice compared to those of the control mice treated with AuNP-Apt or Lys AB2 P3-His only. This study shows that AMPs loaded onto AuNP-Apt could be an effective therapeutic tool against infections caused by multidrug-resistant pathogenic bacteria in humans.

Regulator of ribonuclease activity modulates the pathogenicity of Vibrio vulnificus.

RraA, a protein regulator of RNase E activity, plays a unique role in modulating the mRNA abundance in Escherichia coli. The marine pathogenic bacterium Vibrio vulnificus also possesses homologs of RNase E (VvRNase E) and RraA (VvRraA1 and VvRraA2). However, their physiological roles have not yet been investigated. In this study, we demonstrated that VvRraA1 expression levels affect the pathogenicity of V. vulnificus. Compared to the wild-type strain, the VvrraA1-deleted strain (ΔVvrraA1) showed decreased motility, invasiveness, biofilm formation ability as well as virulence in mice; these phenotypic changes of ΔVvrraA1 were restored by the exogenous expression of VvrraA1. Transcriptomic analysis indicated that VvRraA1 expression levels affect the abundance of a large number of mRNA species. Among them, the half-lives of mRNA species encoding virulence factors (e.g., smcR and htpG) that have been previously shown to affect VvrraA1 expression-dependent phenotypes were positively correlated with VvrraA1 expression levels. These findings suggest that VvRraA1 modulates the pathogenicity of V. vulnificus by regulating the abundance of a subset of mRNA species.

Rediscovery of antimicrobial peptides as therapeutic agents.

In recent years, the occurrence of antibiotic-resistant pathogens is increasing rapidly. There is growing concern as the development of antibiotics is slower than the increase in the resistance of pathogenic bacteria. Antimicrobial peptides (AMPs) are promising alternatives to antibiotics. Despite their name, which implies their antimicrobial activity, AMPs have recently been rediscovered as compounds having antifungal, antiviral, anticancer, antioxidant, and insecticidal effects. Moreover, many AMPs are relatively safe from toxic side effects and the generation of resistant microorganisms due to their target specificity and complexity of the mechanisms underlying their action. In this review, we summarize the history, classification, and mechanisms of action of AMPs, and provide descriptions of AMPs undergoing clinical trials. We also discuss the obstacles associated with the development of AMPs as therapeutic agents and recent strategies formulated to circumvent these obstacles.

Evaluation of Accuracy of a Three-Dimensional Printed Model in Open-Wedge High Tibial Osteotomy.

The purpose of this study was to evaluate the usefulness of a three-dimensional (3D) printed model for open-wedge high tibial osteotomy (HTO). This study retrospectively evaluated 20 patients with medial knee osteoarthritis and varus deformity. Between October 2015 and July 2016, the patients underwent open-wedge HTO using a 3D printed model. The mean age of patients was 55.2 years (range, 51-60 years). The mean preoperative mechanical femorotibial angle (mFTA) was varus 7.8 degrees (range, varus 4.7-11.6 degrees). After measuring the target angle using full-length lower limb weight-bearing radiography, the osteotomy was simulated using 3D images obtained from computed tomography (CT) with the 3D Slicer program. On the basis of the simulated osteotomy section and the target angle, the model was then designed and printed. Open-wedge HTO was then performed by applying the 3D printed model to the opening gap. The accuracy of osteotomy and the change in posterior tibial slope (PTS) angle were evaluated. The weight-bearing line on the tibial plateau was corrected from a preoperative mean of 19.5 ± 9.8% to a postoperative mean of 63.1 ± 6.1% (p < 0.001). The postoperative values were not statistically significantly different from the preoperative target points (p = 0.688). The mFTA was corrected to a postoperative mean of valgus 3.8 ± 1.4 degrees. The PTS angle showed no significant change (p = 0.256). A 3D printed model using CT may be useful for preoperative planning of open-wedge HTO. Satisfactory correction can be obtained without a change in the PTS.

Engineering of a tumor cell-specific, cytosol-penetrating antibody with high endosomal escape efficacy.

The main obstacles for practical uses of cytosol-penetrating peptides and proteins include their lack of cell- or tissue-specific targeting and limited cytosolic access owing to the poor endosomal escape ability. We have previously reported a cytosol-penetrating, human IgG1 antibody TMab4-WYW, generally referred to as a cytotransmab (CT), which reaches the cytosol of living cells but nonspecifically because it is endocytosed via a ubiquitously expressed receptor called heparan sulfate proteoglycan (HSPG). Here, our aim was to construct a next-generation CT with tumor cell specificity and improved endosomal escape efficiency. We first substantially reduced the HSPG-binding activity of TMab4-WYW and then fused a cyclic peptide specifically recognizing tumor-associated epithelial cell adhesion molecule (EpCAM) to the N terminus of the light chain for EpCAM-mediated endocytosis, while maintaining the endosomal escape ability in the light chain variable domain (VL), thus generating epCT05. Then, we separately engineered another CT, dubbed epCT65-AAA, with an endosomal escape ability only in the heavy chain variable domain (VH) but not in VL, by functional grafting of the endosomal escape motif of epCT05 VL to the VH. We finally combined the heavy chain of epCT65-AAA and the light chain of epCT05 to create epCT65 with endosomal escape capacity in both the VH and VL. epCT65 effectively localized to the cytosol of only EpCAM-expressing tumor cells and showed approximately twofold improved endosomal escape efficiency, as compared with CTs with endosomal escape motifs in either VH or VL. The full-IgG format CT, epCT65, with a tumor cell-specific cytosol-penetrating activity, has a great potential for practical medical applications, e.g., as a carrier for cytosolic delivery of payloads.

A highly stretchable and conductive 3D porous graphene metal nanocomposite based electrochemical-physiological hybrid biosensor.

Recently, highly stretchable and flexible electrodes essential for wearable electronic devices has been reported. However, their electrical resistances are high, the fabrication processes are complicated and involve a high cost, and deformations such as stretching can lead to the degradation on electrical performance. To address these issues, a novel fabrication process (both inexpensive and simple) for the highly stretchable and conductive electrodes using well patterned 3D porous laser-induced graphene silver nanocomposite was developed. The fabricated electrode exhibited a high, uniform electrical conductivity even under mechanical deformations. Addition of platinum and gold nanoparticles (PtAuNP) on the 3D porous LIG greatly improved the electrochemical performance for wearable glucose sensor applications. The fabricated glucose sensor exhibited low detection limit (5 µM), and acceptable detection range from 0 to 1.1 mM (covers the glucose range in sweat), and high linearity (0.99). In addition, the fabricated pH sensor also exhibited a linear response (66 mV/pH) at the range from 4 to 7. This work successfully demonstrates the potential of this novel fabrication technique and stretchable LIG metal nanocomposite for wearable electrochemical-physiological hybrid biosensors.

More accurate correction can be obtained using a three-dimensional printed model in open-wedge high tibial osteotomy.

PURPOSE: The purpose of this study was to compare the accuracy of the preoperative planning method using a three-dimensional (3D) printed model with that of a method using picture archiving and communication system (PACS) images in high tibial osteotomy (HTO). METHODS: Patients who underwent HTO using a 3D printed model (20 patients) and a method based on PACS images (20 patients) from 2012 to 2016 were compared. After obtaining the correction angle, in the 3D printed method, the wedge-shaped 3D printed model was designed. The PACS method used preoperative radiographs. The accuracy of HTO for each method was compared using radiographs obtained at the first postoperative year. The preoperative and postoperative posterior tibial slope angles were also compared. RESULTS: The weight-bearing line was corrected 21.2 ± 11.8% from preoperatively to 61.6 ± 3.3% postoperatively in the 3D group and from 19.4 ± 12.3% to 61.3 ± 8.1% in the PACS group. The mean absolute difference with the target point was lower in the 3D group (2.3 ± 2.5) than in the PACS group (6.2 ± 5.1; p = 0.005). The number of patients in an acceptable range was higher in the 3D group than in the PACS group. The posterior tibial slope angle was not significantly different in the 3D group (8.6°-8.9°), but was significantly different in the PACS group (9.9°-10.5°, p = 0.042). CONCLUSIONS: In open-wedge HTO, a more accurate correction for successful results could be obtained using the 3D printed model. LEVEL OF EVIDENCE: IV.

Interpretation of dynamic tensile behavior by austenite stability in ferrite-austenite duplex lightweight steels.

Phenomena occurring in duplex lightweight steels under dynamic loading are hardly investigated, although its understanding is essentially needed in applications of automotive steels. In this study, quasi-static and dynamic tensile properties of duplex lightweight steels were investigated by focusing on how TRIP and TWIP mechanisms were varied under the quasi-static and dynamic loading conditions. As the annealing temperature increased, the grain size and volume fraction of austenite increased, thereby gradually decreasing austenite stability. The strain-hardening rate curves displayed a multiple-stage strain-hardening behavior, which was closely related with deformation mechanisms. Under the dynamic loading, the temperature rise due to adiabatic heating raised the austenite stability, which resulted in the reduction in the TRIP amount. Though the 950 °C-annealed specimen having the lowest austenite stability showed the very low ductility and strength under the quasi-static loading, it exhibited the tensile elongation up to 54% as well as high strain-hardening rate and tensile strength (1038 MPa) due to appropriate austenite stability under dynamic loading. Since dynamic properties of the present duplex lightweight steels show the excellent strength-ductility combination as well as continuously high strain hardening, they can be sufficiently applied to automotive steel sheets demanded for stronger vehicle bodies and safety enhancement.

Analysis of acetabular orientation and femoral anteversion using images of three-dimensional reconstructed bone models.

PURPOSE: Radiographic measurements using two-dimensional (2D) plain radiographs or planes from computed tomography (CT) scans have several drawbacks, while measurements using images of three-dimensional (3D) reconstructed bone models can provide more consistent anthropometric information. We compared the consistency of results using measurements based on images of 3D reconstructed bone models (3D measurements) with those using planes from CT scans (measurements using 2D slice images). METHODS: Ninety-six of 561 patients who had undergone deep vein thrombosis-CT between January 2013 and November 2014 were randomly selected. We evaluated measurements using 2D slice images and 3D measurements. The images used for 3D reconstruction of bone models were obtained and measured using [Formula: see text] and [Formula: see text] (Materialize, Leuven, Belgium). RESULTS: The mean acetabular inclination, acetabular anteversion and femoral anteversion values on 2D slice images were 42.01[Formula: see text], 18.64[Formula: see text] and 14.44[Formula: see text], respectively, while those using images of 3D reconstructed bone models were 52.80[Formula: see text], 14.98[Formula: see text] and 17.26[Formula: see text]. Intra-rater reliabilities for acetabular inclination, acetabular anteversion, and femoral anteversion on 2D slice images were 0.55, 0.81, and 0.85, respectively, while those for 3D measurements were 0.98, 0.99, and 0.98. Inter-rater reliabilities for acetabular inclination, acetabular anteversion and femoral anteversion on 2D slice images were 0.48, 0.86, and 0.84, respectively, while those for 3D measurements were 0.97, 0.99, and 0.97. CONCLUSION: The differences between the two measurements are explained by the use of different tools. However, more consistent measurements were possible using the images of 3D reconstructed bone models. Therefore, 3D measurement can be a good alternative to measurement using 2D slice images.

Tensile property improvement of TWIP-cored three-layer steel sheets fabricated by hot-roll-bonding with low-carbon steel or interstitial-free steel.

TWIP-cored three-layer steel sheets were newly fabricated by hot rolling of TWIP steel sheet surrounded by low-carbon (LC) or interstitial-free (IF) steel sheets. TWIP/LC or TWIP/IF interfaces were well bonded without pores or voids, while a few pearlites were thinly formed along the interfaces. The strengths and elongation of the TWIP-cored sheets increased as the volume fraction of TWIP-cored region increased, and were also well matched with the ones calculated by a rule of mixtures based on volume fraction or force fraction. According to digital image correlation and electron back-scatter diffraction analyses, very high strain hardening effect in the initial deformation stage and active twin formation in the interfacial region beneficially affected the overall homogeneous deformation in the TWIP-cored sheets without any yield point phenomenon occurring in the LC sheet and serrations occurring in the TWIP sheet, respectively. These TWIP-cored sheets can cover a wide range of yield strength, tensile strength, and ductility levels, e.g., 320~498 MPa, 545~878 MPa, and 48~54%, respectively, by controlling the volume fraction of TWIP-cored region, and thus present new applications to multi-functional automotive steel sheets requiring excellent properties.

A hybrid method to improve target registration accuracy in surgical navigation.

BACKGROUND: The accuracy of surgical navigation depends greatly on that of registration between the patient and the medical image. Point-based registration has been the most common and reliable method, which typically uses skin markers. Unfortunately, high registration accuracy around the markers is not sustained at targets deeply seated within the body. To address such increase in target registration error (TRE), we proposed a hybrid point-based registration method that incorporates anatomical landmarks near the target. MATERIAL AND METHODS: Ultrasound calibration is performed with an optical tracker for coordinate frame conversion of image coordinates into the real world. With the calibrated ultrasound probe, we could non-invasively obtain landmark positions near the target, being used together with skin markers for registration. RESULTS: In the experiment, we examined registration accuracies achieved with and without use of an anatomical landmark. We confirmed that using an additional anatomical landmark in registration resulted in an increase in fiducial regsitration error (FRE), but a significant decrease in TRE (p < 0.001). CONCLUSION: We proposed and demonstrated the effectiveness of a hybrid method that uses both artificial and anatomical landmarks for patient-to-image registration. The experimental results confirmed that an improvement in TRE was evident by the proposed method, suggesting its feasibility in various spinal surgeries.

Highly selective and sensitive electrochemical detection of dopamine using a nafion coated hybrid macroporous gold modified electrode with platinum nanoparticles.

A coral-like macroporous Au electrode with electroplated Pt nanoparticles (hybrid macroporous Au-/nPts) coated with Nafion has been fabricated for the first time and used for highly selective and sensitive determination of dopamine (DA). The physically characterized results indicated that the electroplated Pt nanoparticles were dispersed uniformly on the macroporous Au electrode. The porosity and window pore size of the fabricated macroporous Au electrode were 50% and 100-300 nm, respectively. Also the electroplated Pt nanoparticles size was approximately 10-20 nm. The cyclic voltammograms results showed that the hybrid macroporous Au-/nPts exhibited a much larger surface activation area, a roughness factor (RF) of 2024.7, much higher than that of the macroporous Au electrode, which is 46.07. The electrochemical experimental results showed that the hybrid macroporous Au-/nPts coated with Nafion exhibited a dramatic electrocatalytic effect on the oxidation of DA. At 0.1 V, it responded linearly to DA concentrations ranging from 20 µ M to 160 µ M with a detection sensitivity of 90.9 µA mM (-1) cm (-2). Furthermore, it showed wide detection ranging from 20 nM to 900 µ M. At the same time, the interference of ascorbic acid (AA) was effectively avoided because of the Nafion film coated on the surface of the hybrid electrode.

Nonenzymatic free-cholesterol detection via a modified highly sensitive macroporous gold electrode with platinum nanoparticles.

A sensitive macroporous Au electrode with a highly rough surface obtained through the use of with Pt nanoparticles (macroporous Au-/nPts) is reported. It has been designed for nonenzymatic free-cholesterol biosensor applications. A macroporous Au-/nPts electrode was fabricated by electroplating Pt nanoparticles onto a coral-like shaped macroporous Au electrode structure. The macroporous Au-/nPts electrode was physically characterized by field emission scanning electron microscopy (FESEM). It was confirmed that the Pt nanoparticles were well deposited on the surface of the macroporous Au electrode. The porosity and window pore size of the macroporous Au electrode were 50% and 100-300 nm, respectively. The electroplated Pt nanoparticle size was approximately 10-20 nm. Electrochemical experiments showed that the macroporous Au-/nPts exhibited a much larger surface activation area (roughness factor (RF)=2024.7) than the macroporous Au electrode (RF=46.07). The macroporous Au-/nPts also presented a much stronger electrocatalytic activity towards cholesterol oxidation than does the macroporous Au electrode. At 0.2 V, the electrode responded linearly up to a 5 mM cholesterol concentration in a neutral media, with a detection limit of 0.015 mM and detection sensitivity of 226.2 µA mM(-1) cm(-2). Meanwhile, interfering species such as ascorbic acid (AA), acetaminophen (AP), and uric acid (UA), were effectively avoided. This novel nonenzymatic detection electrode has strong applications as an electrochemically based cholesterol biosensor.

Fabrication and Optimization of a Nanoporous Platinum Electrode and a Non-enzymatic Glucose Micro-sensor on Silicon.

In this paper, optimal conditions for fabrication of nanoporous platinum (Pt) were investigated in order to use it as a sensitive sensing electrode for silicon CMOS integrable non-enzymatic glucose micro-sensor applications. Applied charges, voltages, and temperatures were varied during the electroplating of Pt into the formed nonionic surfactant C16EO8 nano-scaled molds in order to fabricate nanoporous Pt electrodes with large surface roughness factor (RF), uniformity, and reproducibility. The fabricated nanoporous Pt electrodes were characterized using atomic force microscopy (AFM) and electrochemical cyclic voltammograms. Optimal electroplating conditions were determined to be an applied charge of 35 mC/mm2, a voltage of -0.12 V, and a temperature of 25 °C, respectively. The optimized nanoporous Pt electrode had an electrochemical RF of 375 and excellent reproducibility. The optimized nanoporous Pt electrode was applied to fabricate non-enzymatic glucose micro-sensor with three electrode systems. The fabricated sensor had a size of 3 mm x 3 mm, air gap of 10 µm, working electrode (WE) area of 4.4 mm2, and sensitivity of 37.5 µA•L/mmol•cm2. In addition, it showed large detection range from 0.05 to 30 mmolL-1 and stable recovery responsive to the step changes in glucose concentration.