24 research outputs found

    Transparent and Superamphiphobic Surfaces from Mushroom-Like Micropillar Arrays

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    Transparent, superamphiphobic surfaces that repel both water and oils are prepared from mushroom-like micropillar arrays consisting of nanoparticles only at the top of the pillars by controlled compartment filling of silica nanoparticles into the bottom of the poly­(dimethylsiloxane) (PDMS) mold, followed by infiltration of epoxy and UV curing. Because silica nanoparticle decorated pillar heads are more resistant to O<sub>2</sub> plasma than the polymer pillars, we can precisely control the head size of micropillars and nanoroughness on top of the pillar heads by varying the O<sub>2</sub> plasma time. The combination of nanoroughness and mushroom-like micropillars leads to superhydrophobicity and oil repellency to different organic solvents. High transparency is achieved by increasing the spacing ratio of micropillars. Last, we demonstrate anisotropic wetting on the hierarchical surface can be achieved by combining photolithography, replica molding, and self-assembly techniques

    An introduction to retinoblastoma genetics.

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    <p>Retinoblastoma is initiated by loss-of-function of the tumor suppressor gene <i>RB1</i> (<i>RB1</i><sup><i>-/-</i></sup>) in one eye (unilateral) or both eyes (bilateral). There are different implications for care for different scenarios. Notably, a rare cause of non-heritable retinoblastoma is unrelated to <i>RB1</i>, amplification of the gene <i>MYCN</i>.</p

    Mean test scores pre-, post- and one-year post-workshop.

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    <p>Scores are patterned according to the question category. The leftmost column displays what a perfect test would look like, where “risks to individual” questions encompass 50% of the test, and “family planning” and “retinoblastoma causative genetics” are the subject of 25% of the questions each. The weighted score for each category is listed on the right of the column for pre-, post- and one-year post-workshop scores. Error bars indicate standard deviation per category.</p

    Tannic-Acid-Enriched Poly(vinyl alcohol) Nanofibrous Membrane as a UV-Shie lding and Antibacterial Face Mask Filter Material

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    Face masks are increasingly important in the battle against infectious diseases and air pollution. Nanofibrous membranes (NFMs) are promising filter layers for removing particulate matter (PM) without restricting air permeability. In this study, tannic-acid-enriched poly(vinyl alcohol) (PVA–TA) NFMs were fabricated by electrospinning PVA solutions containing large amounts of tannic acid (TA), a multifunctional polyphenol compound. We were able to prepare uniform electrospinning solution without coacervate formation by inhibiting the robust hydrogen bonding between PVA and TA. Notably, the NFM maintained its fibrous structure even under moist conditions after heat treatment without the use of a cross-linking agent. Further, the mechanical strength and thermal stability of the PVA NFM were improved by the introduction of TA. The functional PVA NFM with a high TA content showed excellent UV-shielding (UV-A: 95.7%, UV-B: 100%) and antibacterial activity against Escherichia coli (inhibition zone: 8.7 ± 1.2 mm) and Staphylococcus aureus (inhibition zone: 13.7 ± 0.6 mm). Moreover, the particle filtration efficiency of the PVA–TA NFM for PM0.6 particles was 97.7% at 32 L min–1 and 99.5% at 85 L min–1, indicating excellent filtration performance and a low pressure drop. Therefore, the TA-enriched PVA NFM is a promising mask filter layer material with excellent UV-blocking and antibacterial properties and has the potential for various practical applications

    Shape Control of Ag Nanostructures for Practical SERS Substrates

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    Large-area, highly ordered, Ag-nanostructured arrays with various geometrical features were prepared for use as surface-enhanced Raman scattering (SERS)-active substrates by the self-assembly of inorganic particles on an SU-8 surface, followed by particle embedding and Ag vapor deposition. By adjusting the embedding time of the inorganic particles, the size of the Ag nanogap between the geometrically separated hole arrays and bowl-shaped arrays could be controlled in the range of 60 nm to 190 nm. More importantly, the SU-8 surface was covered with hexagonally ordered nanopillars, which were formed as a result of isotropic dry etching of the interstices, leading to triangular-shaped Ag plates on nanopillar arrays after Ag vapor deposition. The size and sharpness of the triangular Ag nanoplates and nanoscale roughness of the bottom surface were adjusted by controlling the etching time. The potential of the various Ag nanostructures for use as practical SERS substrates was verified by the detection of a low concentration of benzenethiol. Finite-difference time-domain (FDTD) methodology was used to demonstrate the SERS-activities of these highly controllable substrates by calculating the electric field intensity distribution on the metallic nanostructures. These substrates, with high sensitivity and simple shape-controllability, provide a practical SERS-based sensing platform

    Durable Plasmonic Cap Arrays on Flexible Substrate with Real-Time Optical Tunability for High-Fidelity SERS Devices

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    Active tunable plasmonic cap arrays were fabricated on a flexible stretchable substrate using a combination of colloidal lithography, lift-up soft lithography, and subsequent electrostatic assembly of gold nanoparticles. The arrangement of the plasmonic caps could be tuned under external strain to deform the substrate in reversible. Real-time variation in the arrangement could be used to tune the optical properties and the electromagnetic field enhancement, thereby a proving a promising mechanism for optimizing the SERS sensitivity

    Sequence of events of training workshop and testing.

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    <p>The workshop consisted of a knowledge test before and after a lecture on retinoblastoma genetics, small group discussions of case studies, and role-play presentations of case study scenarios. Informed consent was obtained from workshop participants who agreed to have their tests included in this analysis, and tested 1-year after the workshop.</p

    Controlled Insertion of Planar Defect in Inverse Opals for Anticounterfeiting Applications

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    Inverse opals have been used for structural coloration and photonic applications owing to their photonic bandgap properties. When the photonic structures contain planar defects, they provide defect modes, which are useful for lasing, sensing, and waveguiding. However, it remains a challenge to insert a planar defect into inverse opals in a reproducible manner. Here, we report a new method for producing planar-defect-inserted inverse opals using sequential capillary wetting of colloidal crystals and creating micropatterns through photolithography. Three cycles of deposition and thermal embedding of colloidal crystals into the underlying film of negative photoresist were performed. In the three cycles, opal, particle monolayer, and opal were sequentially employed, which yielded the monolayer-templated planar defect sandwiched by two inverse opals after particle removal. The planar defect provided a passband whose wavelength can be controlled by adjusting the diameter of particles for the defect layer. Moreover, the defect-inserted inverse opals can be micropatterned by photolithography as the negative photoresist is used as a matrix. The resulting micropatterns deliver a unique spectral code featured by a combination of stop band and defect mode and a graphical code dictated by photolithography, being useful for anticounterfeiting applications

    Tannic-Acid-Enriched Poly(vinyl alcohol) Nanofibrous Membrane as a UV-Shie lding and Antibacterial Face Mask Filter Material

    No full text
    Face masks are increasingly important in the battle against infectious diseases and air pollution. Nanofibrous membranes (NFMs) are promising filter layers for removing particulate matter (PM) without restricting air permeability. In this study, tannic-acid-enriched poly(vinyl alcohol) (PVA–TA) NFMs were fabricated by electrospinning PVA solutions containing large amounts of tannic acid (TA), a multifunctional polyphenol compound. We were able to prepare uniform electrospinning solution without coacervate formation by inhibiting the robust hydrogen bonding between PVA and TA. Notably, the NFM maintained its fibrous structure even under moist conditions after heat treatment without the use of a cross-linking agent. Further, the mechanical strength and thermal stability of the PVA NFM were improved by the introduction of TA. The functional PVA NFM with a high TA content showed excellent UV-shielding (UV-A: 95.7%, UV-B: 100%) and antibacterial activity against Escherichia coli (inhibition zone: 8.7 ± 1.2 mm) and Staphylococcus aureus (inhibition zone: 13.7 ± 0.6 mm). Moreover, the particle filtration efficiency of the PVA–TA NFM for PM0.6 particles was 97.7% at 32 L min–1 and 99.5% at 85 L min–1, indicating excellent filtration performance and a low pressure drop. Therefore, the TA-enriched PVA NFM is a promising mask filter layer material with excellent UV-blocking and antibacterial properties and has the potential for various practical applications
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