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Microfluidic technology, also known as lab-on-a-chip, enables the fabrication of low-cost, user-friendly, and portable detection devices. Microfluidic chips can be utilized for detecting biological and chemical analytes in various liquid samples, including water or biofluids such as urine, blood, and sweat. The specific and quantitative detection of ions has garnered increased attention in recent years due to their potential harm to environmental and human health. Inorganic ions are special chemicals that hold positive or negative charges with relatively small molecular weights. Among the various types of microfluidic platforms, paper-based systems are favored as simple analytical tools that rely on the generation of hydrophilic–hydrophobic contrast on filter paper. In this study, a paper-based microfluidic device was developed as an analytical tool for quantifying several ions, such as iron (Fe3+). The reaction spot was created by simply melting a wax crayon to form hydrophobic barriers that define hydrophilic zones. After spotting Fe3+ samples and potassium thiocyanate (KSCN) as a detection reagent on the reaction zone, an immediate and obvious color change was observed with different ion concentrations ranging between 50 and 500 ppm. While the naked-eye detection of color change was easy at high concentrations, quantifying ion concentrations in samples required the use of a smartphone camera. The captured images were then analyzed using ImageJ software (Java 1.8.0-internal (32-bit)). The developed paper-based microfluidic device exhibited good performance in quantifying Fe3+ ions in samples. Indeed, this simple platform is easy to store and transport, and allows the transportation of aqueous solutions without the need for external pumping or a power supply. [ABSTRACT FROM AUTHOR]

This paper contains an interpretation of the results obtained from Fourier Transform Infrared micro-spectroscopy (µ-FTIR) and Pyrolysis - Gas Chromatography coupled with Mass Spectrometry (Py-GC-MS) techniques applied on the crayons used by Edvard Munch (1863-1944) and now stored at the Munch Museum (MUNCH). Around 100 of different brands from Edvard Munch's collection of reference materials available at the Munch Museum were analyzed. Micro-destructive methods as µ-FTIR and Py-GC-MS were used to characterize the constituent materials of crayon samples, with a special focus on organic binding medium, to allow the classification of different brands of crayons. Two natural waxes (beeswax and carnauba wax) were identified by µ-FTIR, but the most specific chemical information on wax mixtures was attained by Py-GC-MS. The present study adds more analytical data on Edvard Munch's legacy and was developed under the framework of the collaborative research project "THE SCREAM-Touchstone for Heritage Endangered by Salt Crystallization: a Research Enterprise on the Art of Munch" between the HERCULES Laboratory and the Munch Museum in Oslo. [ABSTRACT FROM AUTHOR]

Previous research suggests that parent-child art making can foster opportunities for closeness between children and parents. Most studies however, have focused on artmaking that involves paint and paper, or non-digital drawing technologies. There is a need for researchers to consider how a wider range of technologies, including digital technologies, might shape the interactions between children and parents during art-making. This is particularly important given current concerns that digital technologies are impacting negatively on children's social interactions and their intimacy with others. This study takes a social semiotic perspective to explore how child-parent closeness was supported by different technologies. A three year old child and her father were observed across eight episodes of art-making in the home using a range of four technologies (two digital and two non-digital). A multimodal interaction analysis of the video data suggested that the different technologies were characterised by different types of interaction and distinct forms of closeness between the child and parent. These differences did not correspond neatly to a digital/non-digital divide, but instead related to a network of material factors, embodied actions and the participants' sociocultural investment in each technology. [ABSTRACT FROM AUTHOR]

This article presents the development and application of a low-cost passive monitor for indoor formaldehyde (CH2O) monitoring. The system is based on the diffusion sampling of formaldehyde and the pararosaniline reaction on a collection filter, followed by the elution and analysis of the product by spectrophotometry. The system was validated against a standard atmosphere of formaldehyde with 99% of collection efficiency. The device was applied in the assessment of formaldehyde emissions for school supplies (glitter glue, modeling clay, crayons, glue stick, felt pen, and plastic ink), in which the highest concentrations of formaldehyde were obtained for the felt-tip pen (approximately, 170 µg/g) and the lesser to glue stick (14 µg/g). The application of the passive sampler in a primary classroom environment demonstrated that relative high levels of formaldehyde can be measured in schools are usually considered to be linked to the high density of furniture in the classrooms, but it was also verified that school supplies can significantly contribute in the concentrations of formaldehyde indoor when associated to poor ventilation. [ABSTRACT FROM AUTHOR]

In this study, a fluorescence sensing approach for lead ion (Pb2+) was developed using in situ growth of methylamine lead bromine (MAPbBr3) perovskite on an aluminum hydroxide (Al(OH)3) thin layer. The Al(OH)3 thin layer could be obtained on a glass slide by liquid phase deposition and is of a large specific surface area and insoluble in water. After sulfhydryl functionalization, the Al(OH)3 thin layer reveals effective adsorption and excellent enrichment ability to Pb2+ and is additionally used as the substrate for the in situ growth of lead halogen perovskite. The fluorescence sensing of Pb2+ could be realized by the fluorescence intensity of lead halogen perovskite on the Al(OH)3 layer. The linear relationship between the fluorescence intensity and the concentration of Pb2+ was found in the range from 80 to 1500 mg/kg. The detection limit of Pb2+ is found to be 40 mg/kg, which is lower than the maximum permission of lead residue in student products (90 mg/kg) stipulated by the National Standard of the People's Republic of China (GB21027-2020). After being grinded and pre-treated, soluble lead in watercolor paint and crayon samples can be extracted by the sulfhydryl functionalization Al(OH)3 layer, then lead halogen perovskite can be generated in situ on the layer to achieve the fluorescence sensing for the determination of soluble lead in the samples. [ABSTRACT FROM AUTHOR]

School equipment has not been a common object of interest for dialectologists and therefore this article focuses on two issues that have not been discussed to date, i.e. names of an item used for removing marks made by a pencil and a verb for sharpening a pencil, crayon, etc. The research material is the data collected by means of an online survey. The geography of the analysed lexemes, their presence in selected lexicographic sources and origin is discussed. [ABSTRACT FROM AUTHOR]

Crayons and colored pencils for children may contain toxic elements (TEs) exhibiting potential risk for children's health including cognitive development, after their ingestion, through mouthing and chewing and eventually, their accumulation. The aim of this study was to determine total content of As, Pb, Cr, Cd, Ni and Sb and estimate their bioaccessibility conducting artificial saliva extraction. Sixty samples of colored pencils and crayons from 10 manufacturers were analyzed. Microwave acid assisted digestion followed by inductively coupled plasma optical spectroscopy (ICP-OES) was performed for determination of total content of TEs. Simulation of extraction by artificial saliva was applied to get more reliable data when bioavailability is concerned. The total concentrations of TEs were higher in colored pencils than in crayons and their maximum levels were: 5.78, 9.36, 9.97, 0.615, and 6.63 mg kg-1 for As, Pb, Cr, Cd and Ni, respectively. Concentration of Sb was below the detection limit for all investigated samples. This study showed that concentration of As and Pb in several samples did not comply with European Union regulative. Bioaccessibility study showed the high degree of leaching of Cr and As from pencils, but regardless of extracted portions, concentrations of selected investigated TEs were below allowed levels. [ABSTRACT FROM AUTHOR]

The article presents suggestions on teaching the Grades K-2 students about crayon science. It is advised to give each student a crayon and a Crayon Observation Sheet and let them draw a picture of their crayon and record observations. It is suggested to allow students to share their ideas and review with them how each component is made and assembled in a box of crayons.