Public Health, Polio, and Pandemics: Fear and Anxiety about Health in Children's Literature.

In this article, we begin by discussing approximately thirty picture books dealing with the COVID-19 pandemic published digitally in the United States, the United Kingdom, Australia, and other English-speaking countries in the first six months of 2020. The worldwide impact of COVID-19 resulted in the rapid global digital publication of numerous English-language children's picture books aimed at informing child readers about public health concerns and how children could contribute to improving health outcomes. This exploration of contemporary picture books is intertwined with examinations of two other public health crises that appeared in literature for children: the discussion of British children's health in the Junior Red Cross Magazine in the 1920s and the American polio outbreak discussed in educational materials and fiction in the 1940s and 1950s. These comparisons not only enable us to situate the COVID-19 pandemic within a history of transnational responses to concerns about children's health but also to expand our understanding of how children are positioned to take individual responsibility for community public health issues. This wide range of Anglophone texts published in the United Kingdom, the United States, and around the world demonstrates the extent to which adults attempt to guide children towards specific behaviours to promote individual health. They also reflect a common understanding of childhood in which children have an obligation to contribute to societal wellbeing through their individual actions.

Random lasers from photonic crystal wings of butterfly and moth for speckle-free imaging.

Several biological membranes have been served as scattering materials of random lasers, but few of them include natural photonic crystals. Here, we propose and demonstrate a facile approach to fabricating high-performance biological photonic crystal random lasers, which is cost-effective and reproducible for mass production. As a benchmark, optical and lasing properties of dye-coated Lepidoptera wings, including Papilio ulysses butterfly and Chrysiridia rhipheus moth, are characterized and show a stable laser emission with a superior threshold of 0.016 mJ/cm2, as compared to previous studies. To deploy the proposed devices in practical implementation, we have applied the as-fabricated biological devices to bright speckle-free imaging applications, which is a more sustainable and more accessible imaging strategy.

Study of laser actions by bird's feathers with photonic crystals.

Random lasers had been made by some biomaterials as light scattering materials, but natural photonic crystals have been rarely reported as scattering materials. Here we demonstrate the ability of natural photonic crystals to drive laser actions by sandwiched the feathers of the Turquoise-Fronted Amazon parrot and dye between two plastic films. Parrot feathers comprise abundant photonic crystals, and different color feathers compose of different ratios of the photonic crystal, which directly affect the feather reflectance. In this study, the multi-reflection scattering that occurred at the interface between the photonic crystal and gain media efficiently reduce the threshold; therefore, the more photonic crystal constitutes in the feathers; the lower threshold can be obtained. The random lasers can be easily made by the integration of bird feather photonic crystals and dye with a simple and sustainable manufacturing approach.

Sonochemical synthesis and anchoring of zinc oxide on hemin-mediated multiwalled carbon nanotubes-cellulose nanocomposite for ultra-sensitive biosensing of H2O2.

In this work, the metal oxide and biopolymer nanocomposites on multiwalled carbon nanotubes (MWCNT) were prepared using a simple sonochemical method. The hexagonal nanorods of zinc oxide (ZnO NR) were synthesized by probe sonication (frequency = 20 kHz, amplitude = 50) method and were integrated on ultrasonically functionalized MWCNT-cellulose nanocrystals (MWCNT-CNC) for the first time. The stable hemin bio-composites also were prepared using the bath sonication (37 kHz of frequency, 150 W of power) method, and was used for the selective and ultrasensitive electrochemical detection of H2O2. The UV-Vis spectroscopy studies confirmed the presence of native hemin on MWCNT-CNC/ZnO NR nanocomposite. Cyclic voltammetry studies revealed that an enhanced redox electrochemical behaviour of hemin was observed on hemin immobilised MWCNT-CNC/ZnO NR nanocomposite than that of other hemin modified electrodes. Also, the MWCNT-CNC/ZnO NR/hemin modified SPCE showed 2.3 folds higher electrocatalytic activity with a lower reduction potential (-0.2 V) towards H2O2 than that of other investigated hemin modified electrodes including hemin/MWCNT and hemin/CNC-ZnO. The fabricated biosensor displayed a stable amperometric response (-0.2 V vs Ag/AgCl) in the linear concentration of H2O2 ranging up to 4183.3 µM with a lower detection limit of 4.0 nM.

Ultrasonic assisted functionalization of MWCNT and synergistic electrocatalytic effect of nano-hydroxyapatite incorporated MWCNT-chitosan scaffolds for sensing of nitrofurantoin.

In the present work, we report the fabrication of stable composite of chitosan hydrogels (CHI) on multiwalled carbon nanotubes (MWCNT) using a simple ultrasonic-assisted method. Also, rod-like hydroxyapatite nanoparticles (HA NPs) were synthesised using a hydrothermal route and were incorporated into the highly conductive MWCNT-CHI scaffolds using an ultrasonication method. The functionalization of MWCNT and preparation of HA NPs on MWCNT-CHI nanocomposite were done using the sonication over the frequency of 37 kHz with the ultrasonic power capable of 150 W (Elmasonic Easy 60H bath sonicator). The resulting hybrid HA NPs/MWCNT-CHI nanocomposites have an excellent surface area and high surface to volume ratio, which leads to the sensitive detection of nitrofurantoin than pristine MWCNT and HA NPs. The complete elemental and morphological analyses of the HA NPs/MWCNT-CHI nanocomposites were characterised by XRD, FTIR, RAMAN, FESEM, TEM, EDX, and elemental mapping techniques. Electrochemical analysis of the HA NPs/MWCNT-CHI nanocomposites was carried out by cyclic voltammetry, electrochemical impedance spectroscopy and amperometry methods. The modified glassy carbon electrode (GCE) of HA NPs/MWCNT-CHI nanocomposites exhibit the nitrofurantoin detection activity at the linear range of 0.005-982.1 µM with the detection limit of 1.3 nM. The synergistic electrocatalytic activity of HA NPs/MWCNT-CHI nanocomposites modified GCE is correlated to the sensitivity of 0.16 µAµM-1 cm-2 with excellent precision and accuracy towards the sensing of nitrofurantoin.

Resonant energy transfer and light scattering enhancement of plasmonic random lasers embedded with silver nanoplates.

The resonant energy transfer enhancement from a plasmonic random laser (PRL) has been investigated by means of a dye-covered PVA film with embedded silver nanoplates (DC-PVA/AgNPs). Different sizes and morphologies of AgNPs were adopted to shift the localized surface plasmon resonance (LSPR) and intensify recurrent light scattering between the AgNPs. For better overlap between surface plasmon resonance and the photoluminescence of fluorescent molecules with appropriately-sized silver nanoprisms, the slope efficiency of the PRL was greatly enhanced and the lasing threshold was obviously reduced. In addition, the photon lifetime for the DC-PVA/AgNPs film reveals an apparent decline around 1.39 ns owing to better coupling with LSPR. The stronger light scattering of samples with bigger-sized silver nanoprisms has been demonstrated by coherent back scattering measurements, which reveals a smaller transport mean free path around 3.3 µm. With α-stable analysis, it has been successfully demonstrated that the tail exponent α can be regarded as an identifier of the threshold of random lasing.

Facile synthesis of cellulose microfibers supported palladium nanospindles on graphene oxide for selective detection of dopamine in pharmaceutical and biological samples.

The cost-effective synthesis of novel functional nanomaterials has received significant attention in the physical and chemical sciences due to their improved surface area, high catalytic activity along with unique morphological features. This paper reports a facile and eco-friendly synthesis of spindle-like palladium nanostructures (PdSPs) on graphene oxide-cellulose microfiber (GO-CMF) composite for the first time. The GO-CMF/PdSPs composite was synthesized by an electrochemical method without the use of additional surfactants and capping agents. The synthesized materials were characterized and confirmed by using transmission electron microscopy, high-resolution scanning electron microscopy, X-ray diffraction spectroscopy, Raman spectroscopy and Fourier-transform infrared spectroscopy. As-synthesized GO-CMF/PdSPs composite modified electrode was used as a selective electrocatalyst for the oxidation of dopamine (DA). The electrochemical redox behaviors of DA were investigated using cyclic voltammetry (CV). The CV results revealed that the GO-CMF/PdSPs composite modified electrode has 10 folds enhanced oxidation current response to DA than GO, PdSPs and GO-CMF modified GCEs. Under optimized conditions, the GO-CMF/PdSPs composite sensor exhibits a linear response to DA in the concentration range from 0.3 to 196.3 µM with the lower detection limit of 23 nM. The nanocomposite electrode also shows promising features towards the reliable and selective detection of DA, which includes high stability, reproducibility and high selectivity towards the commonly interfering species such as ascorbic acid, uric acid, and dihydroxybenzene isomers. The sensor was successfully tested for the real-time detection of DA in the commercial DA injections and human serum samples.

Enhanced reversible redox activity of hemin on cellulose microfiber integrated reduced graphene oxide for H2O2 biosensor applications.

In recent years, the carbohydrate polymers incorporated composite materials have shown significant interest in the bioanalytical chemistry due to their enhanced catalytic performances of various enzymes or mimics. This paper reports the fabrication of novel H2O2 biosensor using a hemin immobilized reduced graphene oxide-cellulose microfiber composite (hemin/RGO-CMF). The RGO-CMF composite was prepared by the reduction of GO-CMF composite using vitamin C as a reducing agent. Various physio-chemical methods have applied for the characterization of RGO-CMF composite. Cyclic voltammetry results revealed that the hemin/RGO-CMF composite shows a better redox electrochemical behavior than hemin/RGO and hemin/GO-CMF. Under optimized conditions, the hemin/RGO-CMF composite exhibit a linear response to H2O2 in the concentration range from 0.06 to 540.6 µM with the lower detection limit of 16 nM. The sensor also can able to detect the H2O2 in commercial contact lens solution and milk samples with functional recovery, which authenticates the potential ability in practical sensors.

Novel electrochemical synthesis of copper oxide nanoparticles decorated graphene-ß-cyclodextrin composite for trace-level detection of antibiotic drug metronidazole.

Over the past decades, the synthesis of inorganic and organic nanocomposites has received much attention in the range of fields including electroanalysis of organic chemicals. In this regard, we have prepared copper oxide nanoparticle (CuO NPs) decorated graphene/ß-cyclodextrin (GR-ß-CD) composites using a simple electrochemical methodology, where the CuO NPs are electrodeposited on GR-ß-CD composite modified electrodes. A stable GR-ß-CD composite was prepared by sonication of GR in ß-CD aqueous solution. As-prepared GR-ß-CD/CuO NPs composites were characterized by the high-resolution scanning electron microscopy, X-ray diffraction, and Raman spectroscopy. Cyclic voltammetry results reveal that the GR-ß-CD/CuO NPs composite modified electrode exhibits an excellent catalytic activity and lower reduction potential towards the electrochemical detection of metronidazole (MTZ) over other modified electrodes including GR, GR-ß-CD, and CuO NPs. Under optimized conditions, amperometry was used for the determination of MTZ using GR-ß-CD/CuO NPs composite modified electrodes. The response of MTZ using the composite electrodes was linear over the range from 0.002 to 210.0 µM. This sensor showed the lowest limit of detection of 0.6 nM and was much lower than the previously reported MTZ sensors. In addition, the sensor is highly sensitive, selective and durable in the presence of a range of potentially interfering electroactive compounds.

The production of an efficient visible light photocatalyst for CO oxidation through the surface plasmonic effect of Ag nanoparticles on SiO2@α-Fe2O3 nanocomposites.

A process for the photo deposition of noble Ag nanoparticles on a core-shell structure of SiO2@α-Fe2O3 nanocomposite spheres was performed to produce a CO photo oxidation catalyst. The structural analyses were carried out for samples produced using different Ag metal nanoparticle weight percentages on SiO2@α-Fe2O3 nanocomposite spheres by X-ray diffraction (XRD), field emission-scanning electron microscopy (FE-SEM), UV-vis spectroscopy, Raman spectroscopy and Fourier transform infrared spectroscopy (FTIR). A computational study was also performed to confirm the existence of the synergic effect of surface plasmon resonance (SPR) for different weight percentages of Ag on the SiO2@α-Fe2O3 nanocomposites. The mechanism for CO oxidation on the catalyst was explored using diffuse reflectance infrared Fourier transform spectroscopy (DRFIT). The CO oxidation results for the Ag (2 wt%)-SiO2@α-Fe2O3 nanocomposite spheres showed 48% higher photocatalytic activity than α-Fe2O3 and SiO2@α-Fe2O3 at stable temperature.

Vortex energy flows generated by core-shell nanospheres.

Investigated in this paper is the interaction of light and the nanospheres composed by a dielectric core with a gold-shell cladding that causes the optical vortices inside the core and the whirlpools around the shell. Different radius ratios, dimensions and the dielectric functions of nanospheres were studied using the finite-difference time-domain method. It was found that optical vortices were most likely to occur in the regions of increased absorption cross section and reduced scattering cross section. Two optical vortices of the opposite polarity, each centered in one of the particles of a dimer are created by a nanoshell dimer. The surrounding media of a nanoshell with different dielectric functions can be used to affect the energy flows generated by core-shell nanospheres.

HMGCS2 enhances invasion and metastasis via direct interaction with PPARα to activate Src signaling in colorectal cancer and oral cancer.

Mitochondrial 3-hydroxy-3-methylglutaryl-CoA synthase (HMGCS2) is the rate-limiting enzyme of ketogenesis. Growing evidence indicates that HMGCS2 may be involved in cancer progression, but its exact role is largely unknown. In this study, we demonstrate that HMGCS2 mRNA expression is associated with poor clinical prognosis and outcomes in patients with colorectal cancer (CRC) and oral squamous cell carcinoma (OSCC). In vitro, ectopic expression of HMGCS2 enhanced cancer cell motility in a ketogenesis-independent manner. Moreover, HMGCS2 promoted Src activity by directly binding to peroxisome proliferator-activated receptor alpha (PPARα), a transcriptional activator of Src. Taken together, these results suggest that HMGCS2 may serve as a useful prognostic marker and vital target for future therapeutic strategies against advanced cancer.

Electric field enhancement and far-field radiation pattern of the nanoantenna with concentric rings.

The optical antennas have the potential in various applications because of their field enhancement and directivity control. The directivity of a dipole antenna can be improved by directivity-enhanced Raman scattering structure, which is a combination of a dipole antenna and a ring reflector layer on a ground plane. The concentric rings can collect the light into the center hole. Depending upon the geometry of the antenna inside the hole, different electric field enhancements can be achieved. In this paper, we propose to combine the concentric rings with the directivity-enhanced Raman scattering structure in order to study its electric field enhancement and the far-field radiation pattern by finite-difference time-domain simulations. Compared with the structure without the concentric rings over the ground plane, it is found that our proposed structure can obtain stronger electric field enhancements and narrower radiation beams because the gold rings can help to couple the light into the nanoantenna and they also scatter light into the far field and modify the far-field radiation pattern. The designed structures were fabricated and the chemical molecules of thiophenol were attached on the structures for surface-enhanced Raman scattering (SERS) measurements. The measured results show that the structure with concentric rings can have stronger SERS signals. The effects of the dielectric layer thickness in our proposed structure on the near-field enhancements and far-field radiation are also investigated. The proposed structure can be useful for several nanoantenna applications, such as sensing or detecting.

Effects of the tip shape on the localized field enhancement and far field radiation pattern of the plasmonic inverted pyramidal nanostructures with the tips for surface-enhanced Raman scattering.

The plasmonic 2D W-shape and 3D inverted pyramidal nanostructures with and without the tips are studied. The effects of the tip height and tip tilt angle on the near field enhancement and far field radiation pattern are discussed in this paper. The localized hot spots are found around the pits and the radiation pattern can be affected by the tip structures. The inverted pyramidal nanostructures with and without the tips were fabricated and their reflection spectra and surface-enhanced Raman scattering (SERS) signals for the chemical molecules thiophenol were measured. The simulation according to the geometry parameters of the fabricated structures is demonstrated. We found that the SERS of our proposed structures with the tips can have stronger light field enhancements than the inverted pyramidal nanostructures without the tips, and the far field radiation pattern can be varied by changing the tip height and tip tilt angle. The study of surface plasmon modes and charge distributions can help the understanding of how to arrange the plasmonic structures to achieve high field enhancement and preferred far field radiation pattern. Our study can be useful for the design of the strong field enhancement SERS substrate with specific far field radiation properties. It can be also applied to the portable Raman detectors for in situ and remote measurements in specific applications.

Pot experiment to study the uptake of Cd and Pb by three Indian mustards (Brassica juncea) grown in artificially contaminated soils.

Most of the metals-contaminated and fallow lands in Taiwan are a result of irrigation with illegal effluent of factories. Phytoextraction methods can be applied to reach the target of fallow-lands reuse and earn more incomes for farmers. In many studies, Indian mustards (Brassica juncea) were planted in the metal-contaminated soils to study their suitability in phytoextraction. However, the total removal of metals by plants was quite different between accessions. In this pot study, three accessions of B. juncea (cv. 182921, cv. 211000, and cv. 426308) were planted in artificially Cd- or Pb-contaminated soils to investigate the differences between them. EDTA was applied to study its effect in increasing the bioavailability of Cd and Pb and their uptake by these Indian mustards. Experimental result showed that three accessions of Indian mustard can accumulate a high concentration of Cd and Pb when growing in the artificially Cd- and Pb-contaminated soils. Their shoot Cd or Pb concentrations were significantly enhanced, resulting from the application of EDTA. Among the three accessions, B. juncea cv. 211000 accumulated the highest concentrations of Cd and Pb in their shoots compared with B. juncea cv. 182921 and cv. 426308, but its total removal was the lowest due to its lower biomass.