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A highly sensitive sensor based on carbon fiber paper modified with a shungite–copper formazanate composite is presented for the voltammetric determination of lidocaine. The synthesized organometallic complex, composite, and modified electrode are characterized by infrared spectroscopy, high-resolution mass spectrometry, elemental analysis, scanning electron microscopy, and cyclic and linear sweep voltammetry. The twofold increase in the current of the lidocaine oxidation peak on the modified electrode compared to the unmodified one is associated with the sensitizing effect of the composite modifier, which is due to an increase in the electroactive area and the number of lidocaine binding sites on the electrode surface. The sensor exhibits a wide dynamic range from 2 to 2120 µM with a low limit of detection of 0.18 µM lidocaine and high sensitivity of 0.755 µA/V µM. The interelectrode and intraelectrode repeatability of the analytical signal do not exceed 3.5%. The sensor response is stable within three weeks. The developed sensor was used for the determination of lidocaine in pharmaceuticals. The results of an analysis of real samples demonstrated good reproducibility (RSD ≤ 5.5%) and recovery (98–102%). [ABSTRACT FROM AUTHOR]

Highlights: The large-scale, high-strength, super-tough, and multifunctional nacre-like heterocyclic aramid (HA)/MXene@polypyrrole (PPy) (HMP) nanocomposite papers were fabricated using the in-situ assembly of PPy onto the HA/MXene hydrogel template. The "brick-and-mortar" layered structure and abundant hydrogen-bonding interactions among MXene, PPy, and HA respond cooperatively to external stress and effectively increase the mechanical properties of HMP nanocomposite papers. The templating effect from HA/MXene was utilized to guide the assembly of conducting polymers, leading to high electrical conductivity and outstanding electromagnetic interference shielding performance. Robust, ultra-flexible, and multifunctional MXene-based electromagnetic interference (EMI) shielding nanocomposite films exhibit enormous potential for applications in artificial intelligence, wireless telecommunication, and portable/wearable electronic equipment. In this work, a nacre-inspired multifunctional heterocyclic aramid (HA)/MXene@polypyrrole (PPy) (HMP) nanocomposite paper with large-scale, high strength, super toughness, and excellent tolerance to complex conditions is fabricated through the strategy of HA/MXene hydrogel template-assisted in-situ assembly of PPy. Benefiting from the "brick-and-mortar" layered structure and the strong hydrogen-bonding interactions among MXene, HA, and PPy, the paper exhibits remarkable mechanical performances, including high tensile strength (309.7 MPa), outstanding toughness (57.6 MJ m−3), exceptional foldability, and structural stability against ultrasonication. By using the template effect of HA/MXene to guide the assembly of conductive polymers, the synthesized paper obtains excellent electronic conductivity. More importantly, the highly continuous conductive path enables the nanocomposite paper to achieve a splendid EMI shielding effectiveness (EMI SE) of 54.1 dB at an ultra-thin thickness (25.4 μm) and a high specific EMI SE of 17,204.7 dB cm2 g−1. In addition, the papers also have excellent applications in electromagnetic protection, electro-/photothermal de-icing, thermal therapy, and fire safety. These findings broaden the ideas for developing high-performance and multifunctional MXene-based films with enormous application potential in EMI shielding and thermal management. [ABSTRACT FROM AUTHOR]

Flax (Linum usitatissimum) is a bast fiber plant known for its long fibers, making it an excellent source of pulp for paper production. In Ethiopia, flax is primarily cultivated for oil, with the residual straw utilized for papermaking. This study focuses on pulping flax straw using the Kraft process and investigates its chemical composition, proximate analysis, and morphological properties. The proximate analysis revealed an ash content of 4.13% and moisture content of 11%. Chemical composition analysis showed cellulose at 51.34%, hemicellulose at 25.20%, lignin at 14.12%, ash at 4.13%, and extractives at 5.21%. The morphological properties included a fiber length of 1.41 mm, diameter of 16.78 μm, lumen width of 9.45 μm, and cell wall thickness of 3.77 μm. Flax straw exhibited an acceptable Runkel ratio (0.8) and flexibility coefficient (56.32), placing it within the range of non-wood fibers. SEM analysis of the pulp's morphology was conducted to assess fiber structure, including the presence of cracks. Pulp quality and length are directly linked to paper strength. Various pulping conditions were studied using a full-factorial design, with optimum conditions being 10% alkaline, 131.74°C, and 120 min of cooking time, yielding a pulp with a Kappa number of 10.45 and a yield of 40.56%. The resulting paper demonstrated standard tensile, tearing, and burst strengths, indicating that flax straw is a promising raw material for paper production. [ABSTRACT FROM AUTHOR]

Activated carbon paper is a type of porous carbon material with a highly developed pore structure and a large specific surface area. It finds extensive applications in adsorption, complexation, and catalyst support. To prepare high-performance activated carbon paper, this study investigates the changes in performance and structure of Poly(p-phenylene terephthalamide) (PPTA) paper under CO2 activation, ZnCl2 activation, H3PO4 activation, and NaOH activation conditions. The research reveals that carbon paper after CO2 activation has a certain tensile strength (0.36 MPa), while chemically activated carbon paper lacks tensile strength. Incorporating 15% carbon fiber (CF) into PPTA paper increases the tensile stress (1.26 MPa) and tensile strain (4.18%) of the activated carbon paper. NaOH-activated carbon paper has the highest specific surface area (1321.6 m2/g), the most disordered carbon structure (ID/IG = 1.22), the lowest carbon yield (23.9%), and a pore rate 4.16% higher than that of CO2-activated samples. The activated carbon paper prepared by ZnCl2 activation has the highest content of C = N bonds, with the nitrogen content of pyridine increasing by 31.8% compared to CO2 activation. This indicates that ZnCl2 protects the N elements in PPTA paper during the activation process, preventing their decomposition during carbonization. The activated carbon paper prepared by H3PO4 activation has the lowest electrical conductivity (1.62 S/cm). [ABSTRACT FROM AUTHOR]

Paper bookbindings have been disregarded for centuries by scholars since they were only considered temporary covering materials for manuscripts and books. Recently, there is a willingness to reconsider these bindings and to evaluate their role. Thanks to the collaboration with the Marciana National Library in Venice, which stores an impressive collection of 849 detached bindings, the current research provides a chemical-physical elucidation about the composition and the manufacture of paper bookbindings realized between the 16th and the eighteenth century in the Venetian area. A selection of bookbindings was analysed by the means of complementary methods (thickness measurements, Attenuated Total Reflection—Fourier-Transform Infrared Spectroscopy (ATR-FTIR), Pyrolysis–Gas Chromatography–Mass Spectrometry (Py-GC–MS) and X-Ray Fluorescence (XRF)). Data evidence the presence of cellulose as the main component of paper pulp; hemicellulose and lignin were identified too, probably related to the presence of linen/hemp rags in the paper production. Gelatine was detected muck likely related to paper sizing; among inorganic additives CaCO3 was found in all samples. The presence of waxy material may be due to past undocumented conservation treatments. [ABSTRACT FROM AUTHOR]

In the engine of heavy trucks, the built-in fuel filter assumes the role of "lungs". The core of the filter, namely the fuel filter paper, acts as a filter for small impurities and separates oil and water. In order to be able to separate minute impurities from the fuel, in this study, we prepared a novel fuel oil filter paper with high efficiency and high dust holding capacity based on wet-laid forming by laminating PBT/PP two-component melt-blown nonwoven material and cellulose nanocrystals (CNC)-doped cellulose wood fiber pulp with the fiber mesh combination forming technology. The effects of the CNC mixing ratio, surface density of melt-blown nonwoven material layer, surface density of cellulose wood pulp paper layer and calendaring pressure on the pore size and filtration performance of the composite samples were investigated, and the filtration efficiency of the composite samples on the tiny impurities in the fuel were also studied. The results showed that the novel composite fuel filter paper material prepared by the combined forming technology of fibrous web had high filtration efficiency and dust holding capacity, and the filtration efficiency of the composite samples could respectively reach 99.90% and 99.52% for particles larger than 14 μm and 4 μm in diameter in the fuel. At the same time, the dust holding capacity of the composite sample can reach up to 27.63 mgcm−2. [ABSTRACT FROM AUTHOR]

The Progress in International Reading Literacy Study (PIRLS) was conducted in paper and online reading modes in 2016 using the same samples of students in a number of countries. Differences in reading literacy scores were found in several European countries. In some countries, the differences favored the electronic reading mode. Yet in others, the paper reading mode was favored. As the electronic reading mode differs substantially in the cognitive demands compared to the paper mode, it can be expected that the differences between the two modes are related to the variables related to technology: availability and access, general use, use for educational purposes in class or out-of-school, and self-efficacy with technology. This study investigates the Information and Communication Technology (ICT) factors related to the differences in paper and online reading in six European countries participating in both modes in PIRLS 2016. This study uses linear regression models as the application of multilevel modeling is not suitable because of the low between-school variances across countries. The results from this study show limited support for the relative effect that the student individual, school, and classroom ICT variables have on the differences between paper and electronic reading. Access to technology is related to mode differences only in Italy, and the use of computer devices in and out of school is related to the mode differences in Italy and Portugal. Student self-efficacy is related to the mode differences in Portugal and Slovenia. School resources show significant effects in Denmark (computers to students ratio) and Italy (instruction affected by digital resource shortages). None of the classroom variables showed any significant relationship in any of the countries. In addition, socio-economic status (which is proxied by the variable on home resources for learning) is a significant predictor in half of the countries. In addition to these findings, the general technological context within countries is discussed as part of an evaluation of the difference in reading in the two test delivery modes. The general uptake of technology in different social and economic aspects, as measured by the Digital Economy and Society Index (DESI), follows the differences between the two reading modes. [ABSTRACT FROM AUTHOR]

Background: This study aims to identify trends, research gaps, leading journals, institutions, countries, and authors by examining the top 100 cited Yttrium-90 Radioembolization (Y90) research articles. The insights gained will assist funding and collaboration efforts in Y90 research. The team analyzed 981 articles from 36 peer-reviewed journals, gathering data on authors, publication year, journal, citations, affiliations, keywords, and references. Author affiliations were scrutinized to pinpoint institutions and countries. p values < 0.05 were deemed statistically significant. The most cited paper (703 citations) was authored by Salem et al. (2010), and the journal with the most publications (16) was Journal of Vascular and Interventional Radiology. There was no significant correlation between journal impact factor and citation metrics. A decreasing trend in the number of top 100 articles was observed since the peak period (2008–2013). Most papers were published in high-impact factor (IF > 3, n = 31/35) and SCImago Q1 journals (86/100), with Northwestern University, Clínica Universidad de Navarra, and Ludwig Maximilian University of Munich being the leading institutions. The most prolific authors were Salem, R., Lewandowski, R.J., and Mulcahy, M.F., with Salem, R. as the most influential. A statistically significant positive correlation between collaborative links and published articles was also discovered. Short conclusion: The top 100 cited articles were primarily published in high-impact journals, and Northwestern University and the USA showed greater productivity and collaboration. These findings have crucial implications for researchers, policymakers, and institutions, aiding in the improvement of Y90 application and understanding in clinical practice. [ABSTRACT FROM AUTHOR]

The pulp and paper industry is critical to global industrial and economic development. Recently, India's pulp and paper industries have been facing severe competitive challenges. The challenges have impaired the environmental performance and resulted in the closure of several operations. Assessment and prediction of the performance of the Indian pulp and paper industry using various parameters is a critical task for researchers. This study proposes a framework for performance assessment and prediction based on Data Envelopment Analysis (DEA), Artificial Neural Networks, and Deep Learning (DL) to assist industry administration and decision-making. We presented a case study based on eight industries to demonstrate the methodology's applicability. This study analyses and predicts industry performance based on sample data observations over 30 years. The result suggests the DEA-DL-based efficiency prediction has an overall MSE of 0.08 compared with the actual efficiency. Furthermore, the efficiency rankings are compared between the three techniques. The results suggest that the integrated DEA-DL method is primarily accurate in most scenarios with the actual values. The findings of this study provide a comprehensive analysis of environmental performance for policymakers. [ABSTRACT FROM AUTHOR]

Background The bleach-boosting capability of xylanases is well-known. The use of xylanase pre-treatment before the application of chemical bleach has multiple advantages including (i) lesser use of polluting chemicals of the traditional bleaching process; (ii) less damage to the cellulosic fbers, therefore better recyclability; and (iii) better brightness of chemical bleach. The major impediment in the application is the availability of commercial enzymes that are active at the elevated temperature and pH that exist during the industrial pulping process. In the present paper, xylanase having suitability for application in deinking is reported. Results The xylanase used showed high deinking potential. Optimal deinking was obtained at the xylanase dosing of 20U/g of the dried pulp at 60°C for a treatment time of 1h. It could bring about a 50% reduction in the usage of chemical bleach that was applied after xylanase pre-treatment. The comparison of FTIR spectra showed changes in intensity without signifcant changes in the functional group signatures implying that there is negligible damage to the fber strength in the xylanase pre-treatment process as compared to the chemical bleach process. Conclusion The xylanase used in this study was efective in deinking paper pulp and can be used for bio-bleaching of recycled paper. [ABSTRACT FROM AUTHOR]

In this paper, by a simple hydrothermal method vertically aligned ZnO nanorod arrays were grown on the carbon fiber paper (CFP) and then through a facile chemical bath deposition method CuO nanosheets were loaded on ZnO nanorod arrays, following by thermal spraying method, carboxylated carbon nanotubes (CCNTs) were successfully integrated with CuO/ZnO@CFP to form a binder-free CuO/ZnO-CCNT@CFP sensor. The sensor shows enhanced sensing activity for baicalein and luteolin determination due to the improved structural integration and synergism of different electrode material components. Remarkably, the CuO/ZnO-CCNT@CFP sensor showed good linear relationships over wide concentration ranges of 0.03–0.70 µM and 0.70–20 µM for baicalein and 0.03–0.45 µM and 0.45–8.5 µM for luteolin detection, with the detection limits of 1.7 nM for baicalein and 0.5 nM for luteolin, respectively. More importantly, the CuO/ZnO-CCNT@CFP sensor was utilized in the simultaneous determination of baicalein and luteolin, delivering linear ranges of 0.4–14 µM (baicalein) and 0.2–6 µM (luteolin) with the limit of detection of 0.05 µM and 0.03 µM, respectively. In addition, the developed CuO/ZnO-CCNT@CFP electrode was further investigated to detect baicalein and luteolin in traditional herbal medicine samples, showing satisfied results in comparison with analytic results from high performance liquid chromatography. [ABSTRACT FROM AUTHOR]

Materials that provide dynamically tunable infrared (IR) response are important for many applications, including active camouflage and thermal management. However, current IR-tunable systems often exhibit limitations in mechanical properties or practicality of their tuning modalities, or require complex and costly fabrication methods. An additional challenge relates to providing compatibility between different spectral channels, such as allowing an object to be reversibly concealed in the IR without making it appear in the visible range. Here, we demonstrate that conducting polymer-cellulose papers, fabricated through a simple and cheap approach, can overcome such challenges. The papers exhibit IR properties that can be electrochemically tuned with large modulation (absolute emissivity modulation of 0.4) while maintaining largely constant response in the visible range. Owing to high ionic and electrical conductivity, the tuning of the top surface can be performed electrochemically from the other side of the paper even at tens of micrometer thicknesses, removing the need for overlaying electrode and electrolyte in the optical beam path. These features enabled a series of electrically tunable IR devices, where we focus on demonstrating dynamic radiative coolers, thermal camouflage, anti-counterfeiting tags, and grayscale IR displays. The conducting polymer-cellulose papers are sustainable, cheap, flexible and mechanically robust, providing a versatile materials platform for active and adaptive IR optoelectronic devices. [ABSTRACT FROM AUTHOR]

Background: Oil spills are widespread and can cause devastating environmental consequences. Rapid oil identification is critical to find the origin of the spill, monitor the environment, and lead to informed mitigation measures. The current standard methods in oil spill identification are precise and reliable, but require extensive sample preparation, long instrument runs, and time-consuming data processing. Direct analysis in real time time-of-flight mass spectrometry (DART-ToF MS) has been employed to screen for spilled petroleum oils, with results obtained in mere hours. The present study introduced an innovative, simple, and fast oil sampling method using hydrophobic filter paper and demonstrated its compatibility with DART-ToF MS analysis. Motor oils, jet fuels, marine diesels, crude oils, intermediate fuel oils, heavy fuel oils, and diluted bitumen were collected using the filter paper sampling method. Classification models were constructed from the spectral data by heat map inspection followed by principal component analysis (PCA) and discriminant analysis of principal components (DAPC). Oil slicks and weathered oil slicks were prepared from five oil types, and samples from each slick were collected using filter paper. Results: The filter paper technique allowed for effective oil sampling and data acquisition by DART-ToF MS for diluted source oils, oil slicks and weathered oil slicks. Classification via the constructed DAPC models indicated that the DART-ToF MS instrument in tandem with filter paper sampling and multivariate statistics can accurately identify common oil types, with significant improvement of sample collection and turnaround time. Conclusions: The promising classification results, simple sample collection, and rapid data analysis illustrate the potential use of hydrophobic filter paper and DART-ToF MS as tools in managing large scale oil spill emergency situations. [ABSTRACT FROM AUTHOR]

We previously used a grinder to prepare cellulose nanofibers (CNFs) that were then added to pulp to improve the wet strength of paper, with subsequent alkali treatment further improving its wet tensile strength. However, mass production of CNF using ultra-fine grinders is not feasible; moreover, fabricating paper sheets by first preparing CNFs and adding them to pulp is a complex process. Therefore, in this study, we directly fibrillated pulp using a refiner instead separately preparing CNFs, with the refined pulp used to make paper sheets, thereby simplifying the process. The resulting dried sheets were subsequently treated with 8 and 16 wt% NaOH, after which the co-reinforcing effect of the refiner and NaOH treatments on the wet tensile strength of paper was examined. Unexpectedly, wet tensile strength of 39 and 45 MPa was achieved. These values are higher than values obtained using the CNFs and NaOH treatment, and comparable to the dry strength of untreated and unrefined pulp sheet. Moreover, the dewatering time of the refiner-treated pulp was significantly shorter than that of the CNF-mixed pulp, which reduces the time required to prepare paper. This study demonstrated that refiner-treated pulp is more suitable than CNF-mixed pulp for improving paper wet strength. [ABSTRACT FROM AUTHOR]

In 1980, Prof. Bimla Buti derived, for the first time, an exact solution for localized nonlinear ion-acoustic waves in a plasma with two electron components. Her theory predicted that in the presence of a second electron component, ion-acoustic holes (i.e., solitons with density dips) can exist in addition to regular ion-acoustic solitons having density humps. In 1982, Temerin, et al. [1] reported the observations of ion holes in the Earth's auroral acceleration region between 6000 and 8000 km altitude by S3-3 spacecraft, thus confirming the theoretical predictions of Buti's model. Later on, ion holes were observed on auroral field lines by the Viking spacecraft [2,3] and the Polar spacecraft [4]. It is indeed a nice example where theory leads space experiments and observations. [ABSTRACT FROM AUTHOR]

Purpose: The aim of our study was to use the chondro-osseous border (COB) as an indispensable assessment criterion to evaluate the quality of baby hip ultrasonography (US) images in the literature pertaining to the application of Graf's technique. Materials and methods: Our literature review search yielded 144 articles. Of these, 41 contained images that were stated to be based on the application of Graf's technique. Two reviewers, a radiologist and an orthopaedic surgeon, both course instructors for the use of baby hip US for developmental dysplasia of the hip (DDH), independently evaluated the articles to assess the diagnostic validity of the published images on the basis of a single criterion: the identification of the COB. Results: Of the 41 articles which were analyzed, 15 contained images without a COB, which corresponds to 36% (roughly, one out of three). Articles from countries where universal screening is performed (Germany, Italy, Switzerland, Mongolia) were all correct. All the articles from Turkey, a country which has made significant contribution with published material about Graf's technique over many years, and most of the articles from China (80%), where Graf's technique has become popular in recent years, contained correct images. Conclusion: Published literature lacks strict criteria for the publication of correct images corresponding to Graf's technique in baby hip US. This fact raises concerns about the quality of published material (and, as a corollary, the quality of clinical application of the technique) and should have ramifications on scientific journal policies regarding the publication of such manuscripts. [ABSTRACT FROM AUTHOR]

In this study, two methods were examined to optimize the immobilization of antibodies on paper when conducting a paper-based enzyme-linked immunosorbent assay (P-ELISA). Human IgG, as a test-capture protein, was immobilized on paper via the formation of Schiff bases. Aldehyde groups were introduced onto the surface of the paper via two methods: NaIO4 and 3-aminopropyltriethoxysilane (APTS) with glutaraldehyde (APTS-glutaraldehyde). In the assay, horseradish peroxidase-conjugated anti-human IgG (HRP-anti-IgG) binds to the immobilized human IgG, and the colorimetric reaction of 3,3′,5,5′-tetramethylbenzyzine (TMB) produces a blue color in the presence of H2O2 and HRP-anti-IgG as a model analyte. The immobilization of human IgG, the enzymatic reaction conditions, and the reduction of the chemical bond between the paper surface and immobilized human IgG all were optimized in order to improve both the analytical performance and the stability. In addition, the thickness of the paper was examined to stabilize the analytical signal. Consequently, the APTS-glutaraldehyde method was superior to the NaIO4 method in terms of sensitivity and reproducibility. Conversely, the reduction of imine to amine with NaBH4 proved to exert only minimal influence on sensitivity and stability, although it tended to degrade reproducibility. We also found that thick paper was preferential when using P-ELISA because a rigid paper substrate prevents distortion of the paper surface that is often caused by repeated washing processes. [ABSTRACT FROM AUTHOR]

Traditionally, cellulose nanofiber (CNF) production has primarily relied on virgin cellulose sources. Yet, the shift to using paper mill sludge (PMS) as a source for CNF underscores the significance of reusing and recycling industrial byproducts. PMS contains significant amounts of cellulose that can be extracted as a raw material. The purpose of present study is to provide a sustainable approach to PMS utilization as a paper coating additive in the cellulose nanofibrils (CNFPMS) form via simply scalable wire-wound rod coating method. The effect of CNFPMS additive amounts at two coating layers on microstructure and surface properties of coatings such as porosity, air permeability surface roughness and optical properties such as brightness, gloss and CIE L*a*b* is studied, which they can also provide insight for the eventual print performance. Results indicated that the obtained CNFPMS in paper coating shows 52% decrease in porosity, presenting significant improvement in the coating microstructure. The marginal increase in permeability coefficient and surface roughness, 54% and 10%, respectively, suggests improving color reproduction and preventing color density losses. Optical analysis showed slight decrease in brightness and gloss, as was expected. Notably, the lightness was improved, which also indicates increasing color gamut volume in printing applications. As a result, the current work offers a sustainable approach to manage PMS for use in paper coatings as a high-value-added material. [ABSTRACT FROM AUTHOR]

This study aims to characterise the so-called Sialkoti paper used to produce Pahari drawings preserved today in the Wereldmuseum in Leiden (Netherlands) (WML). These works originate from the Punjab Hills in India (today Himachal Pradesh) and are commonly known as 'Pahari miniature paintings'. The paper upon which these drawings are executed is said to have been produced in Sialkot during the eighteenth and nineteenth centuries when papermaking was an integral part of an overall regional economy correlated with other sectors such as agriculture and the textile industry. Although the term Sialkoti refers to identified papermills in Sialkot (now Pakistan), the paper from this region is yet to be subjected to a systematic study. This article therefore explores the paper(s) in question through macro- and microscopic observations of structure, pulp and fibres. The study of historical sources, complemented by the analysis of paper samples and fibre identification, has revealed that the pulp would have been prepared from a variety of manufactured products using different technologies, such as rags, cloth, mats, rope and other plant-based materials made from local bast fibres which, once tattered, were recycled to prepare the pulp. Microscopic study reveals that a variety of fibre combinations under different conditions and processing steps were used, in particular sunn hemp fibre (Crotalaria juncea L.), a plant species that has until now rarely been identified in historical paper. In addition, the presence of kenaf and jute fibres, as well as a significant quantity of cotton fibres, have also been demonstrated. To overcome the lack of comparative materials, our work was supported by a comparative study of several materials made from sunn hemp now held in the Ethnobotany Collection at Kew Gardens. Samples were taken from these materials and provided useful reference micrographs for the identification of the WML samples. The quality of the paper used by Pahari artists, as well as the raw materials available and their processing, are discussed in detail. Putting all the data, including technical and historical information into perspective, we conclude that the Pahari artists used a paper of inferior quality compared to other types of paper used for other purposes such as the creation of illuminated manuscripts in the Punjab plains. This study therefore provides useful analytical and material evidence that complements previous historical, technical and anthropological studies. [ABSTRACT FROM AUTHOR]

Paper- and paperboard-based materials are alternatives to petroleum-based plastics in food packaging but unsuitable for their poor moisture and oil resistance. In this sense, fluorinated compounds improve water and grease repellency, though their use is controversial. This Perspective discusses main techniques to combine fluorinated compounds with paper and paperboard, including water and oil contact angles and grease resistance values, and summarizes main legal aspects in Europe and the United States. [ABSTRACT FROM AUTHOR]

Frequency-domain dielectric spectroscopy (FDS) technology is commonly utilized for assessing the condition of power equipment with oil–paper insulation. Nonetheless, its application in practical field conditions is limited because of the constantly changing temperature in the measurement environment and the equipment under inspection. To address this issue, this paper presents a method for separating the conductance and polarization components in dielectric response, and conducts experiments to measure the dielectric curves of oil–paper samples at five different temperatures. Subsequently, the dielectric curves in the entire frequency range are decomposed into three distinct microscopic dielectric processes: low-frequency conductivity, low-frequency polarization, and high-frequency polarization. The impact of temperature variation on these microscopic dielectric processes is investigated to establish a connection between them and the physical meaning of the complex dielectric constant. This leads to proposing a new method for temperature translation normalization of dielectric curves. Experimental results reveal that each microscopic dielectric curve undergoes translation due to temperature changes, with varying amplitudes of translation. Based on the temperature translation characteristics of these microscopic processes, the suggested temperature translation normalization method for dielectric responses demonstrates excellent efficacy, aiding in the precise assessment of power equipment insulation status. [ABSTRACT FROM AUTHOR]

The pulp and paper industry generates vast quantities of paper sludge, posing significant environmental challenges due to its disposal in landfills or incineration. This study explores the potential of valorizing paper sludge by incorporating it into particleboard production. It aims to optimize sludge content and particle size to enhance board properties—a novel approach to waste management in the wood composites industry. Through systematic variation of sludge content (0–25%) and particle size (< 0.5 to > 2 mm), we assessed the mechanical and physical properties such as internal bond strength (IB), modulus of rupture (MOR), modulus of elasticity (MOE), water absorption (WA), and thickness swelling (TS). The findings indicate that incorporating paper sludge at moderate levels (5–15%) with optimized particle sizes (< 1 mm) significantly improves the mechanical properties of the particleboard, including increased IB, MOR, and MOE while reducing WA and TS. Principal Component Analysis (PCA) further supported these results, revealing that higher-density boards with enhanced mechanical properties absorb less water, highlighting the interrelationship between structural integrity and moisture resistance. The PCA also identified thickness swelling as an independent factor, suggesting that while mechanical properties can be optimized, additional strategies are needed to control swelling. In conclusion, this study demonstrates that up to 15% paper sludge can be effectively used in particleboard production without compromising quality, provided particle size is carefully controlled. This approach not only offers a sustainable solution for managing paper sludge but also contributes to the development of eco-friendly composite materials, aligning with circular economy principles. [ABSTRACT FROM AUTHOR]

Scitility’s tool Argos identifies work whose authors have a record of misconduct. [ABSTRACT FROM AUTHOR]

Researchers have created a modern infrared (IR) sensor that is both super-sensitive and highly flexible. This remarkable device possesses impressive properties of exceptional sensitivity (24,000%), high responsiveness (1.25 A/W), and fast response time (3 ms). This innovation stands out for its unique construction: an ultrathin layer of lead sulfide (PbS) deposited on a standard Whatman filter paper. This design achieves a photo-current 32 times greater than previous record-holding PbS thin films. The key advantage is its unmatched flexibility. This sensor can bend and flex without breaking, maintaining its IR detection capabilities even after enduring extreme bending cycles. This breakthrough paves the way for a new era of wearable IR photo sensors, flexible electronics, and medical applications. [ABSTRACT FROM AUTHOR]

This work demonstrates the application of urea-powered paper-based fuel cells (PFCs) with Hydrogen Peroxide (H2O2) as the oxidant to drive a flexible electronic circuit (ring oscillator (RO)), for the first time. Herein, the electrochemical performance of four different PFCs has been studied by employing non-precious electrodes as the anode and cathode. These are the membraneless PFC with (i) Toray carbon paper (CP) (ii) Nickel (Ni)-mesh (iii) Nickel Cobalt nanoparticles supported on reduced Graphene Oxide loaded on the CP (Ni Co@rGo@CP) and (iv) membrane-based PFC with Ni Co@rGo@CP as the electrodes. In each PFC the same electrode is employed on both the sides. A single membraneless-PFC with Ni-Co@rGo@CP as electrodes delivered a peak power density (Pmax) of 55 µW cm−2, maximum current density (Jmax) of 371 µA cm−2 and an open-circuit voltage (OCV) of 0.7 V at 3 M urea. While, a single membrane-based PFC assembled on an anion exchange membrane with Ni-Co@rGo@CP electrodes, delivered a Pmax of ≈70 µW cm−2 and Jmax of ≈500 µA cm−2 at an OCV of 0.7 V with 3 M urea. Subsequently, a stack of two membrane-based PFCs delivered an OCV of ≈1.4 V for 400 s. Finally, this stack is employed as a power source to drive a RO. The measured frequency and peak-to-peak voltage are 37.52 kHz and 1.04 V, respectively. This demonstration opens a window to implement self-contained flexible electronic system using PFCs as the power source with minimal e-waste. [ABSTRACT FROM AUTHOR]

In this study, we developed a simple, low-temperature method to synthesize carbonized polymer nanosheets (CPNSs) using sodium alginate, a biopolymer derived from algae, and diammonium hydrogen phosphate. These nanosheets are produced through a solid-state pyrolysis at 180 °C, involving dehydration, cross-linking through phosphate ester bonds, and subsequent carbonization, forming 2D structured CPNSs. These synthesized CPNSs exhibit excellent bacterial adsorption capabilities, particularly against V. parahaemolyticus and S. aureus. When applied to ordinary filter paper, the CPNS-modified paper efficiently filters bacteria from aquaculture water, removing over 98% of V. parahaemolyticus within two hours and maintaining effectiveness after 24 h. In contrast, control filter paper showed significantly reduced efficiency over the same period. Our filtration tests demonstrated enhanced survival rates for shrimp in aquaculture systems, highlighting the potential of CPNSs-modified filter paper as a suitable treatment to reduce the microbiological contamination levels in recirculating aquaculture systems in the event of a disease outbreak. [ABSTRACT FROM AUTHOR]

Plant-fibre ancient-books with cultural significance should be protected from moisture and pollution. In this work, a strategy of surface in-situ protection (building composite coating) was adopted to achieve good hydrophobicity, moisture-proofness and ink-contamination resistance at the surface of archaistic paper. By pre-ring opening of epoxy-based poly(vinyl silsesquioxane) (POSS) and spray of POSS/polyvinylidene fluoride (PVDF) mixed solution, in-situ construction of POSS/PVDF composite coating at the surface of ancient paper was achieved. Compared to water-absorbing ancient paper, POSS/PVDF co-modified ancient paper shows strong humidity resistance. The surface of co-modified ancient paper (epoxy-group pre-ring opening for 45 min) displays high hydrophobicity (water contact angle of ~142.6°), ascribed to greatly improved surface roughness of paper fibres as well as complete coverage of high-content Si/F elements on fibre surface. POSS-modified and neat ancient-paper materials show surface water contact angles of ~113.9° and 0°, respectively. Robust ink-resistance of POSS/PVDF co-modified ancient-paper surface is realized. The innovation in this work lies in perfect synergy of cage-shaped POSS and threadlike PVDF in coating. This work might open a way for surface nondestructive-protection to ancient-books for damp-proof, hydrophobic and anti-fouling characteristics. [ABSTRACT FROM AUTHOR]

This work proposed an approach to multi-component non-metallic materials, namely regular polygonal paper honeycomb sandwich tubes filled with polyethylene (PE) foam, and focused on the influence of drop impact parameters and structural parameters on the deformation characteristics and energy absorption of the filled tubes. Axial drop impact tests were employed to exert drop impact loading on cross-sections of the specimens with a square drop weight. The results showed that the X-direction filled tube (X-DFT) had a higher crushing strength and yield strength than that of the Y-direction filled tube (Y-DFT). As the tubular cross-section edge number of the filled tube increased, the specific energy absorption (SEA) and specific total efficiency (STE) decreased. Under the same axial drop impact loading conditions, the SEA and STE of the X-DFT were superior to those of the Y-DFT. As the edge number of the tubular cross-section or the tubular length ratio increased, the SEA and STE of the filled honeycomb tube decreased significantly. While the impact energy increased, the SEA and STE of the filled tubes increased approximately linearly. This work investigated the influence of drop-impact and structural parameters on deformation characteristics and energy absorption. It is expected to provide supplementary documentation for the advancement of cushion protection technology and the optimization of product structure. [ABSTRACT FROM AUTHOR]

This paper replies to “Can AI Believe?”—an insightful commentary on “Can AI Know?” Addressing the substantive concern, this paper argues that AI systems can possess knowledge-conducive dispositional beliefs, rather than mere dispositions to believe, akin to certain human perceptual and manipulated beliefs. In response to the dialectical concern, it defends the appropriateness of the original dilemmatic reasoning. The commentators’ claim that proponents of innate knowledge deny knowledge’s need for experience is critically examined. [ABSTRACT FROM AUTHOR]

Mechanochromic photonic crystals are attractive due to their force-dependent structural colors; however, showing unrecordable color and unsatisfied performances, which significantly limits their development and expansion toward advanced applications. Here, a thermal-responsive mechanochromic photonic crystal with a multicolor recordability-erasability was fabricated by combining non-close-packing mechanochromic photonic crystals and phase-change materials. Multicolor recordability is realized by pressing thermal-responsive mechanochromic photonic crystals to obtain target colors over the phase-change temperature followed by fixing the target colors and deformed configuration at room temperature. The stable recorded color can be erased and reconfigured by simply heating and similar color-recording procedures respectively due to the thermoswitchable on-off mechanochromism of thermal-responsive mechanochromic photonic crystals along with solid-gel phase transition. These thermal-responsive mechanochromic photonic crystals are ideal rewritable papers for ink-freely achieving multicolor patterns with high resolution, difficult for conventional photonic papers. This work offers a perspective for designing color-recordable/erasable and other stimulus-switchable materials with advanced applications. Mechanochromic photonic crystals are extremely attractive due to their force-dependent structural colors yet are limited by unrecordable color and unsatisfactory performances. Here, the authors report a thermal-responsive mechanochromic photonic crystal with multicolor recordability-erasability. [ABSTRACT FROM AUTHOR]

It is crucial to develop high porosity and permeability carbon fiber paper for improving the performance of proton exchange membrane fuel cell. Herein, Porous carbon paper with gradient structure (GCP) was prepared by the process of impregnation with a solution of phenolic resin /carbon black composites, overlayer molding, carbonization and graphitization. Specially, conductive carbon black was modified by silane coupling agent (KH-550) and in-situ polymerization with phenolic resin to improve its dispersion uniformity. The microstructure, porosity, gas permeability, electric resistance and mechanic properties of the as-prepared GCP are characterized. The resultant GCP has a gradual transition of porosity from bottom layer to top layer, which constitutes diffusion channels conducive to the transport of gas and liquid. In addition, GCP exhibits superior gas permeability, conductivity, corrosion resistance and tensile strength over commercial carbon paper (CCP). It has potential application prospects for further improving the performance of fuel cells. [ABSTRACT FROM AUTHOR]

The objective of this study was to identify the manufacturer of Hanji, Korean handmade paper widely used in conservation science. To achieve this, machine learning models utilizing attenuated total reflectance–infrared spectroscopy (ATR–IR) were developed to assess the robustness and effectiveness of the computed models. Principal component analysis (PCA), partial least squares–discriminant analysis (PLS–DA), decision tree (DT), and k-NN models were constructed using IR spectral data, with the spectral region between 1800 and 1500 cm⁻1 identified as the critical input variable through Variable Importance in Projection (VIP) scores. The transformation of the obtained spectra into second derivative spectra proved beneficial in this key spectral region, leading to significant improvements in model performance. Additionally, the application of DBSCAN for outlier detection was effective in refining the dataset, further enhancing the performance of the models. Specifically, the k-NN model, when applied to the selected variables and preprocessed with the second derivative transformation, achieved an F1 score of 0.92. These findings underscore the importance of focusing on the 1800–1500 cm⁻1 spectral range and applying outlier detection techniques, such as DBSCAN, to enhance the robustness and accuracy of the Hanji classification models by eliminating the influence of atypical data points. [ABSTRACT FROM AUTHOR]

Trimethylsilyl cellulose (TMSC) was employed as the coating matrix for the application of zinc oxide nanoparticles (ZnO) onto paper surfaces and the protections of ZnO/TMSC coating against UV-induced damages and fungal spoilage were evaluated. Filter papers were immersed in 2% w/v TMSC solution loaded with ZnO and air-dried. Three ZnO/TMSC suspensions were prepared with 0.1, 0.5, and 1% w/v ZnO NPs. The presences of ZnO/TMSC protective layers were confirmed with ATR-IR spectroscopy. The coated papers exhibited high surface hydrophobicities. After the coated papers were subject to 365-nm UV irradiation at 400 W for 3 h, the contact angles dramatically dropped. The trimethylsilyl (TMS) groups exposed on the surface formed a moisture barrier and were partially removed on UV exposure. ATR-IR revealed that more TMS groups were removed in the protective layer with no ZnO. UV-irradiated papers turned yellow and papers protected with 1% ZnO/TMSC exhibited significantly lower color changes than that of the uncoated one. Compared to the TMSC-coated paper, the addition of ZnO resulted in a significant reduction in tensile strength at maximum. However, after UV irradiation, significant increases in both the strain at break and strength at maximum were only observed in 1% ZnO/TMSC-protected papers. Regarding their anti-fungal properties, the 1% ZnO/TMSC films were effective in growth inhibitions of Aspergillus sp. and Penicillium sp. on the nonirradiated papers. Despite being hydrophilic after UV-irradiation, growths of the molds were severely suppressed on the UV-irradiated paper. [ABSTRACT FROM AUTHOR]

In this study, a novel, cost-effective, and environmental-friendly acetylcholinesterase (AChE)-based electrochemical biosensor was developed and utilized for paraoxon-ethyl (PE) detection. In this biosensor, cerium oxide (CeO2) and poly(3,4 ethylenedioxythiophene):poly(styrenesulfonate) (PESOT:PSS) modified paper electrode was fabricated by a simple dip-coating method. The synergistic effect of CeO2 and PEDOT:PSS enhance the performance of AChE-based biosensor in terms of sensitivity and selectivity. The electrical conductivity and stability of the fabricated electrode are further improved with the treatment of ethylene glycol (EG). EG decreases the coulombic interactions between PEDOT and PSS molecules, causes polymer chain reorientation, and improves the non-covalent interaction between cellulose molecules and PEDOT, which further leads to higher conductivity. All electrochemical results validate that the biosensor shows good selectivity (Kselectivity < 1), high sensitivity of 52.10 µA/nM, and a low detection limit of 0.12 nM. The accuracy and applicability of the proposed biosensor were also checked with two real samples. All results validate that the fabricated paper electrode can be a promising alternative to other conventional electrodes. [ABSTRACT FROM AUTHOR]

Nucleic acid amplification testing has great potential for point-of-need diagnostic testing with high detection sensitivity and specificity. Current sample preparation is limited by a tedious workflow requiring multiple steps, reagents and instrumentation, hampering nucleic acid testing at point of need. In this study, we present the use of mixed cellulose ester (MCE) paper for DNA binding by ionic interaction under molecular crowding conditions and fluid transport by wicking. The poly(ethylene) glycol-based (PEG) reagent simultaneously provides the high pH for alkaline lysis and crowding effects for ionic binding of the DNA under high salt conditions. In this study, we introduce Paper-based Abridged Solid-Phase Extraction with Alkaline Poly(ethylene) Glycol Lysis (PASAP). The anionic mixed cellulose ester (MCE) paper is used as solid phase and allows for fluid transport by wicking, eliminating the need for pipetting skills and the use of a magnet to retain beads. Following the release of DNA from the cells due to the lytic activity of the PASAP solution, the DNA binds to the anionic surface of the MCE paper, concentrating at the bottom while the sample matrix is transported towards the top by wicking. The paper was washed by dipping it in 40% isopropanol for 10 s. After air-drying for 30 s, the bottom section of the paper (3 mm × 4 mm) was snapped off using the cap of a PCR tube and immersed in the colourimetric loop-mediated isothermal amplification (cLAMP) solution for direct amplification and colourimetric detection. The total sample processing was completed in 15 min and ready for amplification. cLAMP enabled the detection of 102 CFU/mL of Escherichia coli (E. coli) from culture media and the detection of E. coli in milk < 103 CFU/mL (10 CFU) after incubation at 68 °C for 60 min, demonstrating applicability of the method to complex biological samples. [ABSTRACT FROM AUTHOR]

In the process of conservation mounting, starch paste made from wheat flour is the glue of choice to paste reinforcing strips and backing papers, often Xuan paper, for mending and decorating aged and damaged paper-based Chinese artworks. To keep objects intact and select appropriate conservation materials, this research explored the applicability of near-infrared (NIR) spectroscopy coupled with multivariate analysis for the characterization of contemporary unsized Xuan paper with and without starch. In particular, partial least squares (PLS) regression was used to predict the degree of polymerization (DP) of the paper, i.e., one of the most important properties of paper materials, and principal component analysis (PCA) was used to detect starch and to distinguish between papers with different amounts of starch. Using 12 contemporary unsized Xuan papers, the NIR-PLS method for DP prediction was validated, and the best-performed model was generated using the logarithmic transformation of DP−1 as a response variable, with root mean square error of prediction (RMSEP) of DP 128. The NIR-PCA method was also found to be applicable to separate starch-free papers and papers treated with starch, and the results indicate that the higher the content of starch, the better PCA classification performs. This research provides supporting data for the non-destructive characterization of Xuan paper-based objects and differentiates between Xuan paper before and after treatment with starch. [ABSTRACT FROM AUTHOR]

Paper and packaging materials a lignocellulose-based natural biodegradable polymer that spontaneously releases acetic acid, aldehydes, alcohol, and ester-based volatile organic compounds (VOCs) upon ageing and these VOCs start degrading the paper products and decline their mechanical strength properties. The reactivity of the paper of unbleached wheat straw pulp towards acetic acid and hexanal, which has been proven to have more degrading effects on paper than other VOCs, was considered in this work. The papers were exposed to these volatile compounds for 90 days in an air-tight vessel under ambient environmental conditions. The results showed that hexanal was more destructive than acetic acid with regards to cellulose degradation and depletion in the mechanical strength properties. The paper properties like, tensile, tear and burst index, viscosity, pH and carbonyl group content was measured. The growth of the carbonyl group, evidence of the ageing effects in the paper, detected more in the paper exposed to acetic acid. However, the strength of paper properties declined more with hexanal. FE-SEM analysis of the sample showed the development of pores and damage of cellulose fibre upon ageing. Similarly, the damaging effects of VOCs on cellulose, hemicelluloses and lignin were confirmed by significantly reduced peak detection through FT-IR \analysis. The high crystallinity index of the paper products due to exposure to VOCs was detected by XRD analysis, which confirmed the degradation of the low molecular weight cellulose molecule. Thus, the results are strongly recommended that VOCs that generates due to natural or artificial ageing could be the leading cause of paper degradation. [ABSTRACT FROM AUTHOR]

Creatinine is one of the most important biomarkers to detect renal failures. The electrochemical detection of creatinine has been performed using complex enzymatic and non-enzymatic electrode arrays hindering their commercialization. In this work, a new and practical non-enzymatic electrochemical sensor was fabricated depositing copper on carbon paper electrodes by physical vapor deposition (namely Cu/CP). Surface and cross-sectional SEM images demonstrated the deposition of copper over the 3D structure of carbon paper. A thin film was found on the surface, while Cu nanowires with diameters of 180 ± 30 nm were found inside the 3D structure of CP. The thickness of the Cu film on the tubular structures of CP was of 390 ± 40 nm. High-resolution TEM images indicated that the Cu film was integrated by hierarchical structures containing terminal Cu hemispheres of 17.6 ± 2.2 nm. Additionally, interplanar distances from the selected-area electron diffraction pattern demonstrated the presence of Cu0, while Cu2O was also found. Creatinine concentrations in saliva between 16 and 400 µM indicate kidney failure. The Cu/CP electrochemical sensor detected creatinine with linear concentration ranges from 0 to 1000 µM with a r2 = 0.9936. Outstandingly, this sensor presented good reproducibility (RSD = 7.3%), and selectivity to detect creatinine in artificial saliva using interferents like urea, glucose, glycine, ascorbic and uric acids. [ABSTRACT FROM AUTHOR]

Persistence and misuse of antibiotics eventually give rise to the progression of resistance development in bacteria. Consequently, accurate, fast and cost-effective sensing devices are required to govern the presence of drugs. Herein, we design a microfluidic paper-based device (μPAD) for the detection of Rifampicin. We selected this analyte because of its persistent overuse for the treatment of tuberculosis, among the major causes of death around the world. In this work, we have integrated Fe-reinforced ZnS nanoparticles supported with rifampicin (RIF) imprinted material on the exterior of Whatman filter paper for the fabrication of paper-based microfluidic device (μPAD). In this fabricated μPAD colorimetric detection was performed, and the synergistic effect of Fe and ZnS was recorded as compared to individual nanomaterials. A distinct color indicator was used to quantify the concentration of the targeted substance by the naked eye. The fabricated paper-based sensor possessed high sensitivity for rifampicin detection, recorded linear calibration curve representing 0.1 µM LOD and excellent selectivity, in comparison to other inferring agents present in real samples. The practical application of this designed μPAD was validated by applying a real sample. [ABSTRACT FROM AUTHOR]

Highlights: A blade-coated composite paste, composed of a compressible 3D carbon skeleton, PEDOT:PSS, and CNTs, can naturally dry to form a porous electrode on paper with a micro- and nano-structured surface. The all-paper pressure sensor demonstrated an ultrahigh sensitivity of 1014 kPa−1, a wide responsive range up to 300 kPa, and an ultralow operating voltage of 0.01 V. The sensor showcased superior detection capability, ranging from subtle wrist pulses and robust finger taps to large-area spatial force. Flexible and wearable pressure sensors hold immense promise for health monitoring, covering disease detection and postoperative rehabilitation. Developing pressure sensors with high sensitivity, wide detection range, and cost-effectiveness is paramount. By leveraging paper for its sustainability, biocompatibility, and inherent porous structure, herein, a solution-processed all-paper resistive pressure sensor is designed with outstanding performance. A ternary composite paste, comprising a compressible 3D carbon skeleton, conductive polymer poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate), and cohesive carbon nanotubes, is blade-coated on paper and naturally dried to form the porous composite electrode with hierachical micro- and nano-structured surface. Combined with screen-printed Cu electrodes in submillimeter finger widths on rough paper, this creates a multiscale hierarchical contact interface between electrodes, significantly enhancing sensitivity (1014 kPa−1) and expanding the detection range (up to 300 kPa) of as-resulted all-paper pressure sensor with low detection limit and power consumption. Its versatility ranges from subtle wrist pulses, robust finger taps, to large-area spatial force detection, highlighting its intricate submillimeter-micrometer-nanometer hierarchical interface and nanometer porosity in the composite electrode. Ultimately, this all-paper resistive pressure sensor, with its superior sensing capabilities, large-scale fabrication potential, and cost-effectiveness, paves the way for next-generation wearable electronics, ushering in an era of advanced, sustainable technological solutions. [ABSTRACT FROM AUTHOR]

In the era of liquid biopsy, microRNAs emerge as promising candidates for the early diagnosis and prognosis of cancer, offering valuable insights into the disease's development. Among all the existing analytical approaches, even if traditional approaches such as the nucleic acid amplification ones have the advantages to be highly sensitive, they cannot be used at the point-of-care, while sensors might be poorly sensitive despite their portability. In order to improve the analytical performance of existing electroanalytical systems, we demonstrate how a simple chromatographic paper-based disk might be useful to rationally improve the sensitivity, depending on the number of preconcentration cycles. A paper-based electrochemical platform for miRNA detection has been developed by modifying a paper-based electrode with a methylene blue (MB)-modified single-stranded sequence (ssDNA) complementary to the chosen miRNA, namely miR-224 that is associated with lung cancer. A detection limit of ca. 0.6 nM has been obtained in spiked human serum samples. To further enhance the sensitivity, an external chromatographic wax-patterned paper-based disk has been adopted to preconcentrate the sample, and this has been demonstrated both in standard and in serum solutions. For each solution, three miR-224 levels have been preconcentrated, obtaining a satisfactory lowering detection limit of ca. 50 pM using a simple and sustainable procedure. This approach opens wide possibilities in the field of analytical and bioanalytical chemistry, being useful not only for electrochemistry but also for other architectures of detection and transduction. [ABSTRACT FROM AUTHOR]

Wax printing is the most widely used method for fabricating microfluidic paper-based analytical devices (μPADs), but it still suffers from disadvantages like discontinuation of wax printers and need for additional equipment for heating treatment. To address these issues, this work initially describes a new class of wax printing approach for high-precision, batch fabrication of μPADs using a household 3D printer. It only involves a one patterning step of printing polyethylene wax into rice paper body. Under optimized parameters, a fabrication resolution, namely the minimum hydrophilic channel width, down to ~189 ± 30 μm could be achieved. In addition, the analytical applicability of such polyethylene wax-patterned μPADs was demonstrated well with enhanced colorimetric detection of dopamine as a model analyte by combining metal-organic framework (MOF) based nanoenzymes (ZIF-67) with a smartphone (for portable quantitative readout). The developed nanosensor could linearly detect dopamine over a concentration range from 10 to 1000 μM, with a detection limit of ca. 2.75 μM (3σ). The recovery results for analyzing several real samples (i.e., pig feed, chicken feed, pork and human serum) were between 91.82 and 102.79%, further validating its good detection accuracy for potential practical applications in food safety and medical diagnosis. [ABSTRACT FROM AUTHOR]

Some ancient Chinese paper artifacts dyed with amur cork tree bark extracts are currently preserved to different extents in museums and libraries worldwide. As traditional natural plant dyes, the long-term performance of the amur cork tree bark extract-dyed handmade paper has been questioned under a preserved environment. The photodegradation process of the extract-dyed papers was examined under accelerating artificial UVA irradiation conditions according to China national standard-paper and board- accelerated aging (exposure to light). Changes during aging were analyzed by optical observation and scanning electron microscopy (SEM), X-ray diffraction (XRD), thermogravimetric analysis (TGA), Fourier transform infrared spectrometry (FTIR), pH, and tensile strength and folding endurance tests. The results showed that the main components from extracted dyes played an important role in affecting the photodegradation properties of dyed paper. The changes in surface color, pH, morphology and mechanical properties after the artificial UVA accelerated degradation tests revealed that a suitable concentration of the extract dyes for maintaining the long-term irradiation stability of the paper is important. [ABSTRACT FROM AUTHOR]

Highlights: m-BN/PNF nanocomposite paper with nacre-mimetic layered structures prepared via sol–gel film transformation approach presents excellent thermal conductivity, incredible electrical insulation, outstanding mechanical property and thermal stability. When the mass fraction of m-BN is 50 wt%, m-BN/PNF nanocomposite paper exhibits excellent thermal conductivity and electrical insulation. The λ∥ and λ⊥ are 9.68 and 0.84 W m−1 K−1, and the volume resistivity and breakdown strength are as high as 2.3 × 1015 Ω cm and 324.2 kV mm−1, respectively. The m-BN/PNF nanocomposite paper with 50 wt% m-BN also presents outstanding mechanical properties (tensile strength of 193.6 MPa) and thermal stability (thermal decomposition temperature of 640 °C). With the rapid development of 5G information technology, thermal conductivity/dissipation problems of highly integrated electronic devices and electrical equipment are becoming prominent. In this work, "high-temperature solid-phase & diazonium salt decomposition" method is carried out to prepare benzidine-functionalized boron nitride (m-BN). Subsequently, m-BN/poly(p-phenylene benzobisoxazole) nanofiber (PNF) nanocomposite paper with nacre-mimetic layered structures is prepared via sol–gel film transformation approach. The obtained m-BN/PNF nanocomposite paper with 50 wt% m-BN presents excellent thermal conductivity, incredible electrical insulation, outstanding mechanical properties and thermal stability, due to the construction of extensive hydrogen bonds and π–π interactions between m-BN and PNF, and stable nacre-mimetic layered structures. Its λ∥ and λ⊥ are 9.68 and 0.84 W m−1 K−1, and the volume resistivity and breakdown strength are as high as 2.3 × 1015 Ω cm and 324.2 kV mm−1, respectively. Besides, it also presents extremely high tensile strength of 193.6 MPa and thermal decomposition temperature of 640 °C, showing a broad application prospect in high-end thermal management fields such as electronic devices and electrical equipment. [ABSTRACT FROM AUTHOR]

Traditional papermaking was a significant innovation that intrigued the information-sharing society in a wide range of the globe. The importance of finding the historical background hidden behind the historical traditional paper is critical to understanding societies in history. Advanced molecular biological research is applied to many forensic studies to identify the origin and criminal events. Yet, biological research refrained from the heritage science of traditional papers due to its damage to the samples. The current study explores the Pearson correlation between DNA in traditional paper and non-destructive measurement of characteristics of traditional paper. DNA concentration and purity were found to have a proportional relationship based on the CIEL*a*b* color system. The color of the traditional paper was assessed assessment shows green and yellow rather than red and blue. The DNA concentration demonstrated a positive linear correlation with the peaks of 992 cm−1, 1599 cm−1, and 1628 to 1638 cm−1 region, which were lignin-specific functional groups. The presence of lignin in traditional paper defines the colors green and yellow, which is related to the presence of a cell wall. The quantity of cell walls present is linked to DNA survival during the traditional papermaking process. Furthermore, the partial least square (PLS) regression model is established. The prediction model based on DNA, paper properties, and smoothing + the second derivative preprocessed attenuated total reflection-Fourier-transform infrared (ATR-FTIR) spectral data demonstrated valid purity predictions. The evaluation parameter of the cross-validated prediction model contains a low Root Mean Square Error of Cross-Validation (RMSECV) of 0.091 for DNA purity. The determination coefficient was close to 1. However, the further establishment of a validated DNA extraction methodology is required for the consistency of the prediction model for DNA concentration. The hierarchical clustering analysis demonstrated the agglomerative dendrogram on traditional paper samples. For the dendrogram, the Nasu paper mulberry (originating in northern Japan) was distinguished from another paper mulberry (originating in southwestern Japan) by clustering. By multivariate statistical analysis, the DNA presence and quality were predictable from the Japanese traditional papers. In addition, the clustering analysis provided the possible origin of paper mulberry materials for traditional papers. Based on the preliminary information, the need for DNA analysis on historical traditional paper can be determined. [ABSTRACT FROM AUTHOR]

Dual-emissive fluorescent carbon dots (CDs) were prepared through the solvothermal method with citric acid and urea as raw materials and dimethylformamide as the solvent. Two emission peaks were observed at 465 nm and 630 nm. Hg2+ could selectively quench the fluorescence at 630 nm, but the fluorescence intensity at 465 nm was less affected. Accordingly, a ratiometric fluorescence sensor for Hg2+ detection was developed, with a linear detection range of 0.5–40 μM and a limit of detection (LOD) of 37 nM. The dual-emissive CDs were loaded on the surface of the filter paper to fabricate Hg2+ detection test paper. The color of the test paper could be changed from pink purple to blue by the addition of Hg2+, and thus the qualitative and quantitative detection of Hg2+ could be realized. The concentration distinguishable by the naked eye reached 50 μM, and the quantitative detection range was 5–10,000 μM. This method shows excellent selectivity for Hg2+ and can be used to detect Hg2+ in real water samples, providing a highly potential sensing platform for rapid on-site detection of mercury ions. [ABSTRACT FROM AUTHOR]