Crack-Based Sensor with Microstructures for Strain and Pressure Sensing.

Recent extensive research on flexible electronics has led to the development of various flexible sensors. In particular, sensors inspired by the slit organs of a spider, which utilize cracks in a metal film to measure strain, have garnered considerable interest. This method exhibited significantly high sensitivity, repeatability, and durability in measuring strain. In this study, a thin-film crack sensor was developed using a microstructure. The results exhibited its ability to simultaneously measure the tensile force and pressure in a thin film, further expanding its applications. Furthermore, the strain and pressure characteristics of the sensor were measured and analyzed using an FEM simulation. The proposed method is expected to contribute to the future development of wearable sensors and artificial electronic skin research.

Ammonium transporter 1 increases rice resistance to sheath blight by promoting nitrogen assimilation and ethylene signalling.

Sheath blight (ShB) significantly threatens rice yield production. However, the underlying mechanism of ShB defence in rice remains largely unknown. Here, we identified a highly ShB-susceptible mutant Ds-m which contained a mutation at the ammonium transporter 1;1 (AMT1;1) D358 N. AMT1;1 D358 N interacts with AMT1;1, AMT1;2 and AMT1;3 to inhibit the ammonium transport activity. The AMT1 RNAi was more susceptible and similar to the AMT1;1 D358 N mutant; however, plants with higher NH4+ uptake activity were less susceptible to ShB. Glutamine synthetase 1;1 (GS1;1) mutant gs1;1 and overexpressors (GS1;1 OXs) were more and less susceptible to ShB respectively. Furthermore, AMT1;1 overexpressor (AMT1;1 OX)/gs1;1 and gs1;1 exhibited a similar response to ShB, suggesting that ammonium assimilation rather than accumulation controls the ShB defence. Genetic and physiological assays further demonstrated that plants with higher amino acid or chlorophyll content promoted rice resistance to ShB. Interestingly, the expression of ethylene-related genes was higher in AMT1;1 OX and lower in RNAi mutants than in wild-type. Also, ethylene signalling positively regulated rice resistance to ShB and NH4+ uptake, suggesting that ethylene signalling acts downstream of AMT and also NH4+ uptake is under feedback control. Taken together, our data demonstrated that the AMT1 promotes rice resistance to ShB via the regulation of diverse metabolic and signalling pathways.

Selective Liquid Sliding Surfaces with Springtail-Inspired Concave Mushroom-Like Micropillar Arrays.

Herein, a mushroom-like reentrant structure is proposed, inspired by springtails, to create a selective liquid sliding surface by implementing a simple yet sturdy silicon fabrication and lithography method. The fabricated arrays display high structural fidelity, presenting a novel geometry of a concave tip. The mushroom-like head shape of these structures is found to have superomniphobicity, which is independent of a variation of temperatures for even low surface tension liquids such as mineral oil. A design rule for the novel cap of the proposed structures, which results in a selective liquid sliding property with deionized (DI) water and mineral oil, is also investigated. It is demonstrated that oil starts to slide at a roll-off angle (ROA) 10° and then DI water rolls off at ROA 15° on the same fabricated transparent and flexible surface with repeatable durability.

Directional Clustering of Slanted Nanopillars by Elastocapillarity.

The unidirectional clustering induced by capillary force of drying liquids between pillars is investigated and a theoretical model to set a criterion of the unidirectional clustering of the slanted nanopillars is proposed.

Moth-Eye TiO2 Layer for Improving Light Harvesting Efficiency in Perovskite Solar Cells.

A moth-eye nanostructured mp-TiO2 film using conventional lithography, nano-imprinting and polydimethyl-siloxane (PDMS) stamping methods is demonstrated for the first time. Power conversion efficiency of the moth-eye patterned perovskite solar cell is improved by ≈11%, which mainly results from increasing light harvesting efficiency by structural optical property.

Outflow monitoring of a pneumatic ventricular assist device using external pressure sensors.

BACKGROUND: In this study, a new algorithm was developed for estimating the pump outflow of a pneumatic ventricular assist device (p-VAD). The pump outflow estimation algorithm was derived from the ideal gas equation and determined the change in blood-sac volume of a p-VAD using two external pressure sensors. OBJECTIVES: Based on in vitro experiments, the algorithm was revised to consider the effects of structural compliance caused by volume changes in an implanted unit, an air driveline, and the pressure difference between the sensors and the implanted unit. METHODS: In animal experiments, p-VADs were connected to the left ventricles and the descending aorta of three calves (70-100 kg). Their outflows were estimated using the new algorithm and compared to the results obtained using an ultrasonic blood flow meter (UBF) (TS-410, Transonic Systems Inc., Ithaca, NY, USA). RESULTS: The estimated and measured values had a Pearson's correlation coefficient of 0.864. The pressure sensors were installed at the external controller and connected to the air driveline on the same side as the external actuator, which made the sensors easy to manage.

Highly Reproducible Perovskite Solar Cells with Average Efficiency of 18.3% and Best Efficiency of 19.7% Fabricated via Lewis Base Adduct of Lead(II) Iodide.

High efficiency perovskite solar cells were fabricated reproducibly via Lewis base adduct of lead(II) iodide. PbI2 was dissolved in N,N-dimethyformamide with equimolar N,N-dimethyl sulfoxide (DMSO) and CH3NH3I. Stretching vibration of S═O appeared at 1045 cm(-1) for bare DMSO, which was shifted to 1020 and 1015 cm(-1) upon reacting DMSO with PbI2 and PbI2 + CH3NH3I, respectively, indicative of forming the adduct of PbI2·DMSO and CH3NH3I·PbI2·DMSO due to interaction between Lewis base DMSO and/or iodide (I(-)) and Lewis acid PbI2. Spin-coating of a DMF solution containing PbI2, CH3NH3I, and DMSO (1:1:1 mol %) formed a transparent adduct film, which was converted to a dark brown film upon heating at low temperature of 65 °C for 1 min due to removal of the volatile DMSO from the adduct. The adduct-induced CH3NH3PbI3 exhibited high charge extraction characteristics with hole mobility as high as 3.9 × 10(-3) cm(2)/(V s) and slow recombination rate. Average power conversion efficiency (PCE) of 18.3% was achieved from 41 cells and the best PCE of 19.7% was attained via adduct approach.

Identification and expression analysis of a novel R-type lectin from the coleopteran beetle, Tenebrio molitor.

We have identified novel ricin-type (R-type) lectin by sequencing of random clones from cDNA library of the coleopteran beetle, Tenebrio molitor. The cDNA sequence is comprised of 495 bp encoding a protein of 164 amino acid residues and shows 49% identity with galectin of Tribolium castaneum. Bioinformatics analysis shows that the amino acid residues from 35 to 162 belong to ricin-type beta-trefoil structure. The transcript was significantly upregulated after early hours of injection with peptidoglycans derived from Gram (+) and Gram (-) bacteria, beta-1, 3 glucan from fungi and an intracellular pathogen, Listeria monocytogenes suggesting putative function in innate immunity.

Molecular cloning, sequence characterization and expression analysis of a CD63 homologue from the coleopteran beetle, Tenebrio molitor.

CD63, a member of the tetraspanin membrane protein family, plays a pivotal role in cell growth, motility, signal transduction, host-pathogen interactions and cancer. In this work, the cDNA encoding CD63 homologue (TmCD63) was cloned from larvae of a coleopteran beetle, Tenebrio molitor. The cDNA is comprised of an open reading frame of 705 bp, encoding putative protein of 235 amino acid residues. In silico analysis shows that the protein has four putative transmembrane domains and one large extracellular loop. The characteristic "Cys-Cys-Gly" motif and "Cys188" residues are highly conserved in the large extracellular loop. Phylogenetic analysis of TmCD63 revealed that they belong to the insect cluster with 50%-56% identity. Analysis of spatial expression patterns demonstrated that TmCD63 mRNA is mainly expressed in gut and Malphigian tubules of larvae and the testis of the adult. Developmental expression patterns of CD63 mRNA showed that TmCD63 transcripts are detected in late larval, pupal and adult stages. Interestingly, TmCD63 transcripts are upregulated to the maximum level of 4.5 fold, in response to DAP-type peptidoglycan during the first 6 h, although other immune elicitors also caused significant increase to the transcript level at later time-points. These results suggest that CD63 might contribute to T. molitor immune response against various microbial pathogens.

Patterning of Metal Halide Perovskite Thin Films and Functional Layers for Optoelectronic Applications.

In recent years, metal halide perovskites have received significant attention as materials for next-generation optoelectronic devices owing to their excellent optoelectronic properties. The unprecedented rapid evolution in the device performance has been achieved by gaining an advanced understanding of the composition, crystal growth, and defect engineering of perovskites. As device performances approach their theoretical limits, effective optical management becomes essential for achieving higher efficiency. In this review, we discuss the status and perspectives of nano to micron-scale patterning methods for the optical management of perovskite optoelectronic devices. We initially discuss the importance of effective light harvesting and light outcoupling via optical management. Subsequently, the recent progress in various patterning/texturing techniques applied to perovskite optoelectronic devices is summarized by categorizing them into top-down and bottom-up methods. Finally, we discuss the perspectives of advanced patterning/texturing technologies for the development and commercialization of perovskite optoelectronic devices.

Ultrasensitive and Highly Stretchable Multiple-Crosslinked Ionic Hydrogel Sensors with Long-Term Stability.

Flexible hydrogels are receiving significant attention for their application in wearable sensors. However, most hydrogel materials exhibit weak and one-time adhesion, low sensitivity, ice crystallization, water evaporation, and poor self-recovery, thereby limiting their application as sensors. These issues are only partly addressed in previous studies. Herein, a multiple-crosslinked poly(2-(methacryloyloxy)ethyl)dimethyl-(3-sulfopropyl)ammonium hydroxide-co-acrylamide) (P(SBMA-co-AAm)) multifunctional hydrogel is prepared via a one-pot synthesis method to overcome the aforementioned limitations. Specifically, ions, glycerol, and 2-(methacryloyloxy)ethyl)dimethyl-(3-sulfopropyl)ammonium hydroxide are incorporated to reduce the freezing point and improve the moisture retention ability. The proposed hydrogel is superior to existing hydrogels because it exhibits good stretchability (a strain of 2900%), self-healing properties, and transparency through effective energy dissipation in its dynamic crosslinked network. Further, 2-(methacryloyloxy)ethyl)dimethyl-(3-sulfopropyl)ammonium hydroxide as a zwitterion monomer results in an excellent gauge factor of 43.4 at strains of 1300-1600% by improving the ion transportability and achieving a strong adhesion of 20.9 kPa owing to the dipole-dipole moment. The proposed hydrogel is promising for next-generation biomedical applications, such as soft robots, and health monitoring.

Bioinspired On-Demand Directional Droplet Manipulation Surfaces.

In this study, we exploited the properties of nature-inspired hierarchical structures to propose surfaces capable of on-demand directional droplet manipulation. A microline polydimethylsiloxane structure that simulated a bamboo leaf was fabricated, and silica particles were embedded onto its surface to create hierarchical structures. The as-fabricated multiscale line structures exhibited anisotropic wetting properties along the advancing direction. As the embedded particle size increased, the perpendicular roll-off angle (ROA) decreased and the anisotropic roll-off characteristic disappeared, adopting lotus-leaf characteristics. Consequently, the fabricated surface exhibited characteristics of both bamboo and lotus leaves. The roll off could be controlled through different ROAs by changing the particles size of silica on the same surface.

Robust and Transparent Lossless Directional Omniphobic Ultra-Thin Sticker-Type Film with Re-entrant Micro-Stripe Arrays.

Directional droplet-sliding control without wetting the surface is immensely required in advanced surface engineering, including biological and chemical analyses or green technology. However, the development of robust and transparent thin sticker-type directional omniphobic films for portable usage in smart microfluidic platforms is rare. In this study, we report a novel perfluoropolyether (PFPE) directional omniphobic film (PDOF). The PDOF is a robust and transparent ultra-thin sticker-type film that can control the anisotropic sliding of various liquid droplets on the surface. The PFPE is a chemically stable and turgid material compared to polydimethylsiloxane (PDMS), which is often used to fabricate liquid-repellent thin films. A well-designed fabrication criterion through adhesion engineering in the soft-molding process was developed using the PFPE to obtain a PDOF with a thickness of 56 µm, with re-entrant micro-stripe structures on the surface. The fabricated PDOF showed intriguing liquid sliding properties based on the direction and spacing of the microstructures. This aspect is defined as an anisotropic factor.

Self-Assembled Artificial Nanocilia Actuators.

Self-assembly of nanoparticles (NPs) is a powerful route to constructing higher-order structures. However, the programmed self-assembly of NPs into non-close-packed, 3D, shape-morphing nanocilia arrays remains elusive, whereas dynamically actuated nanometer cilia are universal in living systems. Here, a programmable self-assembly strategy is presented that can direct magnetic NPs into a highly ordered responsive artificial nanocilia actuator with exquisite nanometer 3D structural arrangements. The self-assembled artificial NP cilia can maintain their structural integrity through the interplay of interparticle interactions. Interestingly, the nanocilia can exhibit a field-responsive actuation motion through "rolling and sliding" between assembled NPs rather than bending the entire ciliary beam. It is demonstrated that oleic acid coated over the NPs acts as a lubricating bearing and enables the rolling/sliding-based actuation of the cilia.

Silver-Reduced Poly(Ethylene Glycol) Diacrylate Composites with Microline Arrays for Directional Bending Sensors.

Herein, a soft and flexible polymer composite sensor with a surface structure is manufactured that is sensitive to a wide range of mechanical stimuli, including small actions and large motions. A polymer sensor performing with a piezoresistive mechanism is proposed by synthesizing a new conductive polymer composite to fabricate a microline structure by itself, named Ag-reduced poly(ethylene glycol) diacrylate (PEGDA) composite directional bending sensor (ACBS). A simple but effective process of forming nanoparticles (NPs) and surface structures is a notable characteristic. High sensitivity to a small stimulus was achieved by forming Ag NPs within PEGDA, particularly concentrating on the surface and applying the microline structure. With the structural characteristics of a line structure, the ACBS achieved anisotropic sensitivity to bulk motion along the arranged line direction. The excellent sensitivity of this polymer sensor was experimentally demonstrated via water droplets, blowing, and breathing. Combining the advantages of a simple synthetic and simple fabrication process along with the fabrication ability of the microsurface structure with the material itself and the conductive Ag/PEGDA integrated layer, this ACBS is outstanding as a soft and flexible polymer composite sensor and has potential application in physical devices such as wearable devices and biosensors.

Efficacy and Safety of Botulinum Toxin Type A (NABOTA) for Post-stroke Upper Extremity Spasticity: A Multicenter Phase IV Trial.

OBJECTIVE: To evaluate the efficacy and safety of Daewoong botulinum toxin type A (NABOTA) after its launch in South Korea. METHODS: This prospective, multicenter, open-label phase IV clinical trial included 222 patients with stroke. All patients visited the clinic at baseline and at weeks 4, 8, and 12 after injection of upto 360 units of NABOTA into the wrist, elbow, and finger flexor muscles at the first visit. The primary outcome was the change in Modified Ashworth Scale (MAS) score for the wrist flexor muscles between baseline and week 4. The secondary outcomes were the changes in MAS, Disability Assessment Scale (DAS), and Caregiver Burden Scale (CBS) scores between baseline and each visit, and the Global Assessment Scale (GAS) score at week 12. RESULTS: There was a statistically significant decrease in the MAS score for the wrist flexors between baseline and week 4 (-0.97±0.66, p<0.001). Compared with baseline, the MAS, DAS and CBS scores improved significantly during the study period. The GAS was rated as very good or good by 86.8% of physicians and by 60.0% of patients (or caregivers). The incidence of adverse events was 14.4%, which is smaller than that in a previous trial. CONCLUSION: NABOTA showed considerable efficacy and safety in the management of upper limb spasticity in stroke patients.

0.5% Liposome-encapsulated 5-aminolevulinic acid (ALA) photodynamic therapy for acne treatment.

BACKGROUND: Photodynamic therapy using topical 5-aminolevulinic acid (ALA) has been successful in treating acne vulgaris, but sun avoidance for at least 48 hours after treatment is necessary due to the risk of post-treatment photosensitivity. Recently, a lower concentration of liposome-encapsulated 5-ALA was introduced to minimize this risk. OBJECTIVES: To evaluate the efficacy and safety of liposome-encapsulated 0.5% 5-ALA in the photodynamic therapy of inflammatory acne and its effects on sebum secretion in Asian skin. METHODS: Thirteen Korean subjects with inflammatory acne were administered 0.5% ALA spray before photoradiation treatment. Photoradiation was performed at 3.5-6.0 J/cm(2) three times during each of two visits, performed 2 weeks apart. Improvement of acne was evaluated subjectively and objectively based on the Korean Acne Grading System. Sebum secretion was measured quantitatively at each visit. RESULTS: The mean reduction in acne grade at the end of the treatment was 43.2%. Of the patients, 69.2% reported improvements in subjective skin oiliness, but fewer showed objective reductions in sebum secretion as determined by the Sebumeter® SM10. No serious adverse events were observed. CONCLUSION: Photodynamic therapy using liposome-encapsulated 0.5% 5-ALA improved inflammatory acne with minimal side effects in Asians.

Physical activity after ischemic stroke and its association with adverse outcomes: A nationwide population-based cohort study.

BACKGROUND: Sufficient physical activity (PA) is highly recommended to improve the prognosis after stroke. However, there have been only a few studies evaluating the changes in PA level after stroke. AIMS: We aimed to identify the changes in PA level between before and after stroke, and to determine the association between PA and adverse outcomes. METHODS: This observational, retrospective cohort study was performed using  the Nationwide Health Insurance Service (NHIS) database in South Korea. Subjects between the ages of 20 to 80 years, who had a first-ever ischemic stroke from 2010 to 2013, were included. Subjects were divided into either the "sufficient" or "insufficient" subgroups, depending on the result of the self-reported PA questionnaire. Adverse outcomes, including all-cause mortality, stroke recurrence, and myocardial infarction (MI), were collected from a post-stroke health checkup to 2017. RESULTS: Of the 34,243 subjects with ischemic stroke, only 21.24% had sufficient PA level after stroke. Among those with insufficient PA level, only 17.34% improved their PA level after stroke. Subjects with sufficient PA level after stroke, regardless of their PA level prior to stroke, showed a lower risk of composite adverse outcomes (adjusted Hazard Ratio [HR], 95% CI: 0.85, 0.80-0.90). Subjects who went from insufficient to sufficient PA level (HR 0.87, 95% CI: 0.81-0.93) showed a significantly lower risk of composite adverse outcomes. CONCLUSIONS: Achieving a sufficient PA level after ischemic stroke appears to significantly reduce major adverse events. Further effort is needed to promote the PA level after ischemic stroke.

Capillary-Induced Clustering of Thermoresponsive Micropillars.

In this study, we demonstrate the controllable clustering of thermoresponsive high-aspect-ratio hydrogel pillars by modulating the elastic modulus of the materials. Generally, high-aspect-ratio polymeric pillars readily cluster owing to the effect of capillary force and adhesion. However, this unstable behavior hinders the implementation of various functionalities such as wetting, adhesion, and energy harvesting on surfaces with such pillars. Conversely, clustering behavior may be required in the case of digital microfluidic platforms that grip tiny particles or perform biological and chemical analyses. Therefore, it is necessary to develop a reliable method for controlling the clustering behavior. To this end, we fabricate high-aspect-ratio pillars that exhibit capillary-induced clustering behavior based on the cross-linker density of the thermoresponsive hydrogel and the temperature of the surrounding environment. Through experimental and theoretical analyses, a criterion for controlling the clustering and recovery behavior of the fabricated pillars is determined. The established criterion is employed to fabricate a smart mobile camera lens cover that can produce blurred and deblurred images based on optical variations resulting from the clustering and recovery of the pillars. The results of this study can be used to fabricate high-aspect-ratio polymeric pillars for use in diverse applications.

Reliable and Robust Fabrication Rules for Springtail-Inspired Superomniphobic Surfaces.

We report a reliable and robust method for the fabrication of bioinspired superomniphobic surfaces with precise concave-cap-shaped micropillar arrays. This method includes silicon-based conventional microelectromechanical systems (MEMS) and polymer replication processes. We have elucidated two critical cases of fabrication rules for precise micromachining of a negative-shaped bioinspired silicon master. The fabricated polymeric structure replicated from the semipermanent silicon master based on the design rules exhibited high structural fidelity and robustness. Finally, we validated the superomniphobic properties, structural durability, and long-term stability of the fabricated bioinspired surfaces.