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Point-of-care testing (POCT) biosensors are rapidly developing in recent years because of the urgent needs for rapid test and home test. Among various types of POCT biosensors, paper-based biosensors have occupied large market share owing to the advantages of cost-effectiveness, portability and simplicity. To further meet the increasing requirement of POCT in various application scenes, the functionalization of paper is highly demanded. Metal-organic framework (MOF), a multifunctional porous material, is introduced in the design of paper-based biosensors, significantly improving the sensing property and application potential. This review provides a summary of the recent advances and emerging trends of MOF-functionalized paper-based biosensors (MOF@paper), including different types of substrates, fabrication methods, detection mechanisms and applications. On account of the multifunctionality and superior performance of MOF@paper biosensors, this field should possess promising prospect in scientific researches, translational medicine and clinical applications. • Multifunctional MOF endows paper-based biosensors with diverse detection properties. • The substrates and fabrication methods for MOF@paper biosensors are reviewed. • Various detection mechanisms are summarized and discussed. • MOF@paper biosensors are promising in diagnosis, food, environment and other related applications. [ABSTRACT FROM AUTHOR]

• Efforts to enhance PMFC performance are reviewed. • Both exciting advancements and current limitations are discussed. • An innovative strategy of multi-scale simultaneous optimization is proposed. Paper-based microfluidic fuel cell (PMFC) has attracted great attention in the microfluidic fuel cell field in recent years. It utilizes the spontaneous capillary flow of reactant solutions in paper-based porous substrate to achieve passive transportations of fuel and oxidant, solving the fluid driving issue encountered in traditional microfluidic fuel cells and thus having broad application prospects in medical detection, wearable devices, micro sensors, environmental monitoring, and many other fields. However, the commercialization of this technology is impeded by the low output performance caused by the limited mass and energy transfer in PMFCs. To enhance the mass and energy transfer in PMFCs, numerous research studies have been conducted via experimental optimization of the cell materials and structures. Numerical analyses focusing on the structure–activity relationship of PMFCs were also performed recently. To provide a comprehensive and thorough review about the efforts devoted to improving performance of PMFC, research papers relevant to PMFC since its invention in 2014 have been extracted in this work and significant works were filtered to highlight the exciting advancements. The experimental studies were classified and discussed based on the key components involved in the PMFC system, followed by a critical review of the limited computational models. Potential directions for future research were also provided, aimed at overcoming the current technological challenges in PMFCs. Importantly, an innovative strategy of multi-scale simultaneous optimization of the cell properties is proposed considering the typical multi-scale feature of the PMFC system, which could inspire the designing of advanced cell materials with optimal multi-scale structures for applications of PMFCs. [ABSTRACT FROM AUTHOR]

Replacing nonbiodegradable plastics with environmentally friendly cellulose materials has emerged as a key trend in environmental protection. This study highlights the development of a strong and hydrophobic micro-nano fibrillated cellulose paper (MNP) through the incorporation of micro-nano fibrillated cellulose fiber (MNF) and chitin nanocrystal (Ch), followed by the impregnation of polymethylsiloxane (PMHS). A low-acid, heat-assisted colloidal grinding strategy was employed to prepare MNF with a high aspect ratio effectively. Ch was incorporated as a reinforcing matrix into the cellulose fiber scaffold through straightforward mechanical mixing and mechanical hot-pressing treatments. Compared to pure MNP, the 5Ch-MNP exhibited a 25 % improvement in tensile strength, reaching 170 MPa, and showed enhanced barrier properties against oxygen and water vapor. The impregnation of PMHS rapidly confers environmentally resistant hydrophobic properties to 1 % PMHS-5Ch-MNP, leading to a water contact angle exceeding 112°, and a 290 % increase in tensile strength under wet conditions. Additionally, the paper demonstrated excellent antibacterial adhesion properties, with the adhesion rates for E. coli and S. aureus exceeding 98 %. This study successfully produced functional cellulose paper with remarkable mechanical properties and barrier properties, as well as hydrophobicity, using a simple, efficient, and environmentally friendly method, making it a promising substitute for petroleum-based plastics. [ABSTRACT FROM AUTHOR]

Unprinting of paper can reduce multiple life-cycle stages in the recycling of paper to yield significant environmental impact. Laser-unprinting has been demonstrated for uncoated paper but causes significant damage to coated paper. This work explores a scalable optical (non-laser) process for unprinting coated paper. Printed coated paper is exposed to pulsed broad-spectrum Intense Pulsed Light (IPL) from a xenon lamp and the toner is then removed by dabbing gently with an ethanol wipe. While black toner is easily unprinted, unprinting of colored prints (red, blue, green) is best realized by incorporating an initial overprint of black toner. An unprinting throughput on the order of mm2/s is achieved. Three distinct regimes of unprinting are identified based on the extent of toner removal and damage of the paper. The optical properties of the unprinted paper, characterized via UV–Visible spectrophotometry, are correlated to these regimes to understand the potential for in-situ optical process monitoring. Scanning Electron Micrography and Fourier-Transform Infrared Spectroscopy are performed to understand the underlying mechanisms that govern the occurrence of the different unprinting regimes. Further, the potential impact of the developed approach on recycling of paper is discussed in the context of the capabilities of current optical unprinting approaches and the potential elimination of life-cycle stages in conventional paper recycling. • Intense Pulsed Light can scalably unprint toner from coated paper with minimal chemical usage. • Our overprinting approach enables colored prints to be removed as well. • Unprinting throughput of mm2/s is achieved. • Three distinct unprinting regimes exist, depending on process parameters and toner types. • Thermal weakening of toner-coating bonds and cracking are the primary governing mechanisms. [ABSTRACT FROM AUTHOR]

• Magnesium oxyhydroxide colloid was obtained by pulsed laser ablation of Mg in water. • Magnesium oxyhydroxide lamellas effectively bind to the surface of the paper fibers. • Magnesium oxyhydroxide colloid treatment bleaches, hardens and stabilizes the paper. • The treatment proposed is highly effective and surpasses the conventional techniques. Magnesium-containing nanocolloids were synthesized by nanosecond pulsed laser ablation (PLAL) of a Mg target in water. As-prepared colloids contained 2-D lamellar nanostructures of magnesium oxyhydroxide Mg 5 O(OH) 8 (Mg-NSs) with a thickness of 5–10 nm and a length/width up to one micron. The colloids obtained were used for the first time to restore old, low-quality paper (a Russian book from the beginning of the 20th century). All results were compared to conventional treatment with basic magnesium carbonate. It was found that Mg-NSs facilitated effective deacidification and conservation treatment of the paper. Paper pH increased after treatment and remained stable upon artificial aging. Moreover, treatment led to an increase in paper whiteness of up to 10% and paper strengthening up to 25%. In general, the treated paper became more resistant to the deterioration processes during aging. Thus, colloid of Mg 5 O(OH) 8 lamellar nanostructures obtained by PLAL in water is a promising agent for paper restoration and conservation. [ABSTRACT FROM AUTHOR]

Developing high-performance and low-cost electrocatalysts for the hydrogen evolution reaction (HER) favorably promotes large-scale hydrogen production from water. Here, we design a nanocomposite of Co 9 S 8 -Ni 9 S 8 nanodiscs (CNS) in-situ grown from polypyrrole hollow nanospheres (PHS) on carbon paper (CP) via unipolar pulse electrodeposition (UPED) technique as HER catalyst in alkaline media. The lattice structure along with the interlacing nanodiscs-like morphology of the Co 9 S 8 -Ni 9 S 8 mischcrystal is controllable by UPED method. The optimal CNS/PHS/CP electrode obtained with pulse potential of − 0.80 V exhibits favorable catalytic activity with low overpotential (186 mV at 10 mA cm−2), superior stability performance (for 100 h with no current density decay), and high electrochemically active surface area up to 1925 cm2, which should be attributed to the interlacing Co 9 S 8 -Ni 9 S 8 mischcrystal with rich active sites, the ingenious combination with conductive polymer, and the integrated electron-proton conductive network. This work will provide a new sight to design low-cost bimetallic sulfide-based electrocatalysts for high-performance HER in water splitting. [Display omitted] • In-situ growth of Ni 9 S 8 -Co 9 S 8 is controllable by unipolar pulse electrodeposition. • Precise regulation of mischcrystal lattice works on the morphology optimization. • Escape from binder contributes to high conductivity and HER catalytic activity. • Integrated frame, large ECSA and rich active sites lift HER dynamics and stability. • The CNS-0.80 catalyst exhibits low overpotential and superior long-term stability. [ABSTRACT FROM AUTHOR]

Significant improvements in the activity of a carbon-based electrode for the electro-oxidation of aqueous sulfur dioxide were obtained by introducing surface oxygen functionalities through the anodization of carbon fiber paper (CFP) in sulfuric acid solution. Electrodes of varying surface oxygen content (2.9 atomic% to 25.6 atomic%) and relative proportion of different types of oxygen functional groups were obtained by changing the anodization potential and the concentration of sulfuric acid. The activity of the optimal electrode was quantified by exchange current density and charge transfer resistance, respectively. The exchange current density was about 2.17-times the pristine CFP electrode (17.6 × 10−4 μ A cm − 2 compared to 8.09 × 10−4 μ A cm − 2). The morphological and structural changes in the electrode on anodization were determined using field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD) and Raman analysis. The chemical analysis of the electrode surface, done using X-ray photoelectron spectroscopy (XPS), showed a strong correlation between the electrode's activity and the ratio of the percentage of hydroxyl groups to the sum of percentages of epoxy and carbonyl groups. The electrode performed well in an accelerated stability test based on cyclic voltammetry for over 1000 cycles. [Display omitted] • Anodization of CFP induces high activity for SO 2 electro-oxidation. • The activity measured by exchange current density increases by 2.17 times. • Hydroxyl group promotes but expoxy and carbonyl group inhibit activity of electrode. [ABSTRACT FROM AUTHOR]

• Aspects related to water consumption of P. peruviana were evaluated under different managements. • P. peruviana vegetative growth is favored by high temperatures. • Mulching reduced Kc values of P. peruviana in all phenological stages. • The Kc of P. peruviana can be estimated by means of NDVI. • Recycled paper mulch reduced soil evaporation and water consumption by the P. peruviana crop by 30.6%. The application of soil mulching has been widely used to increase crop production; however, few research studies have comprehensively evaluated the use of recycled paper as soil mulch and its effects in relation to water savings and crop coefficients. The objective was to evaluate the effects of mulching with recycled paper on evaporation and evapotranspiration of Physalis peruviana and to determine the crop coefficients in its development stages. The study was carried out in two cultivation cycles at the Lysimetric Station of Viçosa, MG, Brazil. The experiments were set up in a randomized block design with four replicates, where four lysimeter treatments were applied: P. peruviana cultivation without recycled paper mulch (C); P. peruviana cultivation with recycled paper mulch (CP); lysimeter with only recycled paper mulch (P); and lysimeter cultivated with Bahiagrass (G). Irrigation and drainage volumes in each lysimeter were measured daily to calculate crop evapotranspiration (ETc), reference evapotranspiration (ETo) and, therefore, the crop coefficients (Kc). In addition, crop phenology, fruit characteristics, gas exchange, yield and normalized difference vegetation index (NDVI) were also evaluated. For the first cultivation cycle, over 218 days, the values of water consumption in the lysimeters C, CP, P and G were 405, 291, 88 and 444 mm, respectively. For the second cycle, over 206 days, the values of water consumption were 416, 279, 94 and 331 mm, respectively. Recycled paper significantly reduced water consumption, especially in the initial and late-season stages, also reducing Kc values. The Kc values for P. peruviana were 0.25, 0.55, 1.05 and 0.46 in cultivation with mulch and 0.45, 0.85, 1.35 and 0.48 in cultivation without mulch for the initial, development, mid-season and late-season stages, respectively. NDVI can be used to estimate the Kc values of P. peruviana. Recycled paper mulch reduced water consumption by 30.6% and increased gas exchange and yield of P. peruviana in cycles 1 and 2, respectively. [ABSTRACT FROM AUTHOR]

Most guidelines recommend regular physical exercise to all pregnant women. However, because of the anatomical and physiological changes which occur during pregnancy, high-intensity exercise and forms of extreme sports can place the pregnant woman and her fetus at risk of harm. [ABSTRACT FROM AUTHOR]

• The counterfeit of paper money became quite widespread and it is increasingly difficult to distinguish counterfeits from originals. • A non-destructive investigation campaign allowed studying a Chinese paper money collection officially dated from the 13th to the 20th century. • The combined use of MA-XRF with Raman provided significant results for distinguishing original paper money from forgeries. • The identification of modern dyes allowed correctly dating all the banknotes. • The literature on analysis of ancient paper money, is not extensive. This suggests to develop a universally recognized and reliable protocol. Paper money was first used in China as early as the sixth century AD. Since that time, counterfeits have circulated in parallel with authentic paper money. After WWII the interest of art collectors in historical emergency paper money surged and counterfeiting became a complex phenomenon. In fact, the use of scientific investigation for determining the authenticity of historical paper money is still limited to few cases. In this work nine pieces of Chinese paper money (from the fourteenth to nineteenth century) were investigated by combining non-invasive MA-XRF imaging and Raman spectroscopy. Analytical results on the paper money demonstrated how the complementary use of both non-invasive techniques can provide an excellent tool for discriminating modern materials from historical ones, allowing us to identify seven counterfeits in the set of nine investigated paper moneys. [ABSTRACT FROM AUTHOR]

The assessment of the risk of virus transmission through papers, such as postcards, is important. However, the stability of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and influenza A virus (IAV) on different types of papers is currently unknown. Investigation of the survival time of these viruses on different types of papers will provide insights into their risk of long-distance transport by postal items. We evaluated the stability of SARS-CoV-2 and IAV, mixed with a culture medium, on the surface of postcards with various coatings, including plain paper (PP), inkjet paper (IP), and inkjet photo paper (IPP). The surface structure of each paper was microscopically assessed. The surface structures of PP, IP, and IPP varied greatly depending on the presence or absence, and type, of coat layer, regardless of the base material. IP and IPP surfaces were less conducive to virus survival than PP surfaces, because of the difference in surface shapes. The survival times of SARS-CoV-2 on each paper were approximately 59.8 (PP), 6.5 (IP), and 9.8 h (IPP), and significantly longer than those of IAV (10.3, 1.8, and 3.3 h, respectively). The risk of SARS-CoV-2 transmission via paper, such as postcards, is significantly higher than that of IAV transmission. While PP, IP, and IPP have the same base material, their surface structures differ, which affects viral stability. The IP and IPP surfaces are less suitable for virus survival. This study provides novel insights into the risks of viral transmission via paper. [ABSTRACT FROM AUTHOR]

Laser-induced graphene (LIG) technology featuring low-cost, high-efficiency and scalability has presented great advantages in micro-supercapacitors (MSCs) fabrication. However, the limited capacitance of LIG based MSCs is still hindering their further development. Herein, we introduce joule heating as a critical in-situ treatment merged with the assembly of laser-induced graphene paper based MSCs (LIGP-MSCs) toward capacitive enhancement. By increasing heating-treatment temperature from ∼20 to 500 °C, the number of nanopores in LIGP continuously increases, attributed to the gradual decomposition of amorphous carbon components. The resulting joule-heated LIGP (J-LIGP) with improved specific surface area (160.97–533.49 m2/g) and pore volume (0.179–0.553 cm3/g) as well as superhydrophilic surface is highly suitable to be employed as J-LIGP-MSCs microelectrodes. By investigating process dependent performance, the J-LIGP-MSCs heated at 500 °C for 60 min delivers a significantly improved specific areal capacitance (C A) of 13.71 mF/cm2 at 10 mV/s, which is approximately six-fold higher than that of unheated LIGP-MSCs. By further exploring and optimizing the process efficiency, J-LIGP-MSCs with a C A of 12.61 mF/cm2 has been achieved by 550 °C heating for only 5 min. Along with superior mechanical flexibility, cyclability and structural modularity, the proposed in-situ joule heating treatment is finally proved to be a universal approach for consistently enhancing the C A of LIG based MSCs processed under various chemical modifications. A facile and general approach for enhancing the capacitance performance of laser-induced graphene paper based MSCs (LIGP-MSCs) are creatively proposed and demonstrated by an in-situ joule heating processing strategy, revealing outstanding potential for fabrication of high-performance LIG based MSCs. [Display omitted] [ABSTRACT FROM AUTHOR]

[Display omitted] • Cerium – Manganese Catalytic Ceramic Paper very active for soot oxidation. • Spray method showed to be efficient for anchoring catalytic species on fibers. • Experiments at bench scale showed good soot filtration capacities. • Citric Acid addition during impregnation improved catalytic distribution on fibers. Diesel Particulate filters are considered one of the most efficient technologies to reduce particulate matter emitted by diesel engines. In this paper we study the development of catalytic ceramic papers based on Mn-Ce and their applications as soot particle filters in bench scale tests. Ceramic papers were prepared by a dual polyelectrolyte papermaking method and were impregnated with Mn and Ce precursors through a wet-spray procedure using a commercial fogger. Catalytic ceramic papers were tested as catalysts for the combustion of soot, which was obtained both from the burning of diesel fuel and directly from a bench test. In addition, the filtering capacity of catalytic ceramic papers was tested through opacity measurements by placing the ceramic papers in a suitable case at the end of the engine. Mn-Ce based catalysts were active in the soot combustion. The addition of citric acid considerably improved the catalytic performance of all the systems studied. This beneficial effect of citric acid is related to an improvement in the distribution of the catalytic material onto the ceramic fibers, being the mixed equimolar oxide Mn-Ce the most active catalyst. [ABSTRACT FROM AUTHOR]

The achievable performance of conventional repetitive control (CRC) is constrained by the error amplification at the non-harmonic frequencies, the intrinsic sensitivity to the signal period shift and the limited tracking frequency range under fixed sampling rate. To remedy these undesirable behaviors, a notch-filter-based repetitive control (NF-RC) is proposed based on the spectrum-selection filtering scheme in this paper with application to fast tool servos (FTSs). The loop-shaping property of this NF-RC can be flexibly designed by the cascade of a series of parameterized IIR notch filters without the aforementioned limitations of the CRC, so as to provide a unified formula for various RCs and even resonant control schemes. A general realization along with several simplified versions of the IIR notch filter is derived for the digital implementation of the NF-RC. Comparative trajectory tracking experiments on a self-developed FTS have validated the superiorities of the proposed NF-RC in terms of the performance improvement for periodic reference tracking, the robustness against the signal period variations and the trackable frequency range under fixed sampling rate. Taking advantage of an excellent comprehensive performances of the NF-RC scheme, the radial sinusoidal surface and the water-drop surface were successfully produced with high form precision and excellent surface quality after the FTS-based diamond turning. • A novel notch-filter-based repetitive control (RC) scheme is proposed. • This RC scheme can suppress the nonperiodic errors amplification. • This RC scheme can maintain the robustness against the signal frequency fluctuation. • This RC scheme can track any harmonic references under a fixed sampling rate. • This RC scheme provides a unified design framework for various existing RCs. • Two high-accuracy micro-structured surfaces are fabricated with this RC scheme. [ABSTRACT FROM AUTHOR]

• Vaginal foreign bodies represent a clinical and diagnostical challenge. • Most common symptoms are vaginal discharge and vaginal blood loss. Only 10% of patients presented with the complaint of a possible foreign object. Although a minority of patients develop complications, those with a battery as a foreign object are at a higher risk of mucosal injuries. • Ultrasonography is the most utilized diagnostic method, with a sensitivity of 79.9%. Radiography showed more false-negative than true-positive results, with a sensitivity of 33.3%. • Vaginoscopy is the gold standard for definitive diagnosis and therapy, as outpatient or under anesthesia. • A possible context of sexual violence should be considered, regardless the nature of the object. Vaginal foreign bodies represent a clinical and diagnostical challenge in pediatric gynecology. Several case reports, case series and retrospective studies have been published, highlighting rare or complex cases. A comprehensive systematic review is lacking. Published English-language articles on vaginal foreign objects in patients aged 16 years and younger, with full-text availability were included. Articles on adult patients and patients with an object migrating from the abdominal cavity into the vagina were excluded. Out of the 215 screened articles 75 were included, comprising a total of 522 patients. The age ranged from 6 months to 16 years, with an average of 6 years and 3 months. The presenting symptoms were documented in 340 patients, with the two most common being vaginal bleeding (n = 172) and vaginal discharge (n = 134). Toilet paper or tissue was the most common object, in 155 out of 447 patients. Ultrasonography was the most utilized diagnostic method, with a sensitivity of 79.9 %. Radiography showed more false-negative than true-positive results, with a sensitivity of 33.3 %. Complications were reported in 35 patients. Evidence of sexual abuse was found in a small group of 16 patients. Vaginoscopy under sedation was the most frequently used therapeutic approach. A swift and accurate diagnosis is crucial, with clinical examination and ultrasonography playing pivotal roles. Vaginoscopy is the gold standard for definitive diagnosis and therapy. Attention should be given to a potential context of sexual abuse. [ABSTRACT FROM AUTHOR]

In the current work, cellulose nanofibers (CNF) were isolated from unbleached kraft pulps of date palm fruit stalks (DPFS) and date palm rachis (DPR) residues by ultrafine grinding. The isolated CNF were characterized by high-resolution transmission electron microscopy (HR-TEM), X-ray diffraction (XRD), zeta potential measurement, tensile strength properties, contact angle, as well as oil-proof testing. The CNF were applied as a coating material for cardboard paper sheets made from unbleached kraft DPFS and DPR pulps. The results showed that CNF from DPFS and DPR had close dimensions (4–14 nm in width and several microns in length) but their zeta potential was different (−44.65 eV and −51.46 eV for CNF from DPFS and DPR pulps, respectively), as well as their crystallinity (79.4% and 75.5% for CNF from DPFS and DPR pulps, respectively). CNF films from DPFS had tensile stress and Young's modulus of 113.3 MPa and 3.81 GPa, respectively, while those from DPR had tensile stress and Young's modulus of 71.0 MPa and 2.93 GPa, respectively. Films from DPFS CNF showed lower hydrophilicity than that from DPR, nevertheless excellent oil-proof property was obtained in both kinds of films. Coating of cardboard sheets prepared from unbleached kraft DPFS and DPR pulps with CNF layer of about 7-µm thickness resulted in significant changes in some physical properties of paper sheets, such as decreasing their air permeability, water vapor transmission rate, and water absorption; both kinds of CNF imparted paper sheets good oil-proof properties. CNF coating also imparted paper sheets remarkable wet tensile strength properties. The results showed the feasibility of utilizing date palm wastes in producing CNF films with distinct properties from low-cost unbleached kraft pulp, as well as using these CNF as a multi-functional coating material in papermaking industry. • Cellulose nanofibers (CNF) were isolated from unbleached date palm pulps. • The properties of CNF were dependent on the date palm residue used. • CNF films had excellent oil-proof and good mechanical properties. • CNF were successfully used for coating cardboard sheets. • CNF coating improved wet strength, air, oil, and moisture barrier properties. [ABSTRACT FROM AUTHOR]

Exploring functional paper-based materials in advanced electronics meets the requirements of high-value utilization of biological resources and sustainable development. Herein, a facile strategy of impregnating cellulose-based polyurethane into cellulose paper was developed to fabricate highly transparent paper with desirable requirements. The novelty of this work lies in the development of a sustainable technology to prepare highly transparent and hazy paper, which uses a facile impregnation treatment of cellulose-based polyurethane to obtain functional paper with high transparency, high optical haze, low surface roughness, hydrophobicity, excellent tensile strength, water barrier property, and shape memory behavior. The desirable characteristics were attributed to the tight combination of cellulose paper and cellulose-based polyurethane based on covalent and hydrogen bonds. The desirable properties of highly transparent paper included high optical transmittance (84.1% at 800 nm), high optical haze (92.6% at 800 nm), low root-mean-square roughness (0.28 nm), excellent tensile strength (37.62 MPa), hydrophobicity (water contact angle of 115.5°), water barrier property, and shape memory behavior. Especially, the transparent paper with carbon nanotubes lines has high conductivity even after bending, folding and immersing. The ideal characteristics of highly transparent and hazy paper provide vast opportunities for the development of flexible electronic devices. [Display omitted] • A facile strategy by impregnating paper with functional polymers was developed. • Transparent paper was endowed with high transmittance, high haze and hydrophobicity. • Ideal characteristics were attributed to the functional cellulose-based polyurethane. • Transparent paper possess a minimum surface roughness compared with previous studies. • Transparent paper with CNTs has high conductivity even after folding and immersing. [ABSTRACT FROM AUTHOR]

The reduced graphene oxide paper (rGOP) has been irradiated with different energy and dose, namely 200 keV and 1000 keV electron with dose ranging from 2 × 1014 e/cm−2 × 1016 e/cm−2, using a ground-based irradiation simulator. The electrical properties, surface morphology, structural defects, interlayer spacing, thermal stability of rGOP before and after irradiation were systematically investigated. Results indicate that the electrical resistance and the I D /I G ratio increases pose irradiation, indicative of defect presence. The ratio of total carbon to total oxygen atoms (C/O) is 4.7 in pristine materials, with no obvious alteration in materials irradiated with 200 keV electron, while increased to 6.8 subjected to 1000 keV electrons. The 1000 keV electron irradiated material exhibits improved morphology from the SEM image. The above results were further verified by the change in the spacing of graphene layers in the material. FLUKA simulation results demonstrated that the 1000 keV electron can pass through penetrate the rGOP, while the 200 keV electron is in the near surface for irradiated materials. Changes in resistance of rGOP are attributed to defects, structural disorder, oxygen-containing functional groups, and variations in the total C/O atom ratio. The results show that the structure and properties of rGOP can be influenced by irradiation energy and dose of electron. • The different energy and dose electron irradiation effect on reduced graphene oxide paper was studied. • The defects, disorder structure and total C/O ratio of materials were changed. • The surface electrical property, surface morphology and thermal stability and of materials was influenced. [ABSTRACT FROM AUTHOR]

This article described the low-cost hibiscus flower based colorimetric paper sensor to monitor the quality and freshness of raw fish. The extract of hibiscus flower was used to develop pH sensing paper strips for qualitative analysis. The sensitivity of paper sensor was checked by colorimetric detection of ammonia gas and then it was implemented to monitor the freshness of fish visually. The extract of hibiscus flower containing anthocyanin molecules are the key molecule for visual detection of spoiled food. The above molecule was spectroscopically analyzed with change in pH of the solution before and after the interaction of food products. We also studied the variation of both color and shade of paper sensor with change in pH at natural and artificial light conditions. The color information extracted from images and their relationship with pH was explored in red, green, blue (RGB) and hue, saturation, and value (HSV) color spaces by the image-J software for qualitative monitoring of food. Anthocyanin based paper sensor is used as a convenient and real time smart food sensor in packaging application. [Display omitted] • Hibiscus flower containing Anthocyanin molecule can be used to develop smart pH sensors. The sensor showed colour variation from red to green at different pH. • The physicochemical and structural properties of anthocyanin are correlated with fabricated sensors at different pH for the colour variation. • The anthocyanin-based sensor shows high sensitivity towards visual detection of ammonia gas and further it was used to monitor the quality and the freshness of the fish. • The change in color of the sensor was previously recorded by web cam and analyzed by image J software and spectroscopic techniques. [ABSTRACT FROM AUTHOR]

Root exudates control critical processes in the rhizosphere, retaining water, selecting for beneficial microorganisms or solubilising nutrients prior to uptake by the plant. Analysing root exudation patterns however is challenging because existing methods are often destructive and unable to resolve spatial and temporal variations in the production of root exudates. Here, we present a paper-based microfluidic device with integrated colorimetric sensors for the continuous extraction and analysis of root exudates along plant roots. The microfluidic device used standard filter paper wax printer to create channels for water to carry the exudates towards the sensors. TiO 2 nanotubes/alginate hydrogel-based sensors were used to analyse the glucose content of the root exudates of living plants. The study shows that the paper microfluidic substrate successfully extracts the released glucose from the root, and transfers it to the hydrogel-based sensor to be colorimetrically detected from independent sections of the root at different times, up to 7 days. This method was tested on two different wheat varieties Triticum aestivum (rgt Tocayo and Filon varieties), where significant differences in exudation patterns were recorded. This research demonstrates the feasibility of low-cost technological solution for high precision screening and diagnostic of the biochemical composition of root exudates. • Simple paper device allows continuous extraction of exudates along roots. • Wax printing creates microfluidic channels that transport exudates to a sensor. • Image analysis predict glucose concentration from colorimetric sensor. • Wheat varieties have different concentration of glucose in their root exudates. [ABSTRACT FROM AUTHOR]

Paper-based packaging is experiencing a resurgence due to its inherent biodegradability and recyclability. To meet the barrier properties required for certain applications, a coating is necessary. This coating must enhance functionality without compromising the environmental sustainability of the substrate. With this goal in mind, we prepared waterborne dispersions of biodegradable poly(lactic acid) (PLA) using a PEG-PLA-PEG triblock copolymer as the main surfactant. We achieved formulations with good stability over a 6-month period and high solids content (∼40 wt%). The waterborne dispersions underwent analysis by dynamic light scattering (DLS), size exclusion chromatography (SEC), gravimetric tests, and rotational rheology with and without xanthan gum (0.2–0.8 wt%) as a thickener. Subsequently, the thickened dispersions were coated at 60 °C onto a paper substrate. SEM analyses revealed the formation of a polymer layer on the paper surface with thickness and morphology dependent on the processing conditions. Partial interpenetration between the coating and the paper fibers was observed, resulting in excellent adhesion between the layers. The coated paper exhibited good barriers to liquid and water vapor, with Cobb60 < 5 g/m2 and water vapor transmission rate (WVTR) < 100 g/(m2∙day) for coating weights ≤15 g/m2, comparable to the performance of solvent-based PLA paper coatings. The surface energy of the coating was approximately 50 dyne/cm, higher than that of neat PLA, making it suitable for printing with common inks. Furthermore, the coated paper can be fully pulped in water, indicating that it can still be recycled in the paper stream, albeit with potentially increased processing time due to the coating weight. [Display omitted] • A PEG-PLA-PEG block copolymer was proven to stabilize waterborne PLA dispersions. • Dispersions with 40 % solid content were obtained. • The dispersions thickened with xanthan gum were successfully coated on paper at 60 °C. • PLA-coated paper had similar water barrier properties to its oil-based counterpart. • Repulping of PLA-coated paper is possible but slower than for uncoated paper. [ABSTRACT FROM AUTHOR]

Sensor arrays, which draw inspiration from the mammalian olfactory system, are fundamental concepts in high-throughput analysis based on pattern recognition. Although numerous optical sensor arrays for various targets in aqueous media have demonstrated their diverse applications in a wide range of research fields, practical device platforms for on-site analysis have not been satisfactorily established. The significant limitations of these sensor arrays lie in their solution-based platforms, which require stationary spectrophotometers to record the optical responses in chemical sensing. To address this, this review focuses on paper substrates as device components for solid-state sensor arrays. Paper-based sensor arrays (PSADs) embedded with multiple detection sites having cross-reactivity allow rapid and simultaneous chemical sensing using portable recording apparatuses and powerful data-processing techniques. The applicability of office printing technologies has promoted the realization of PSADs in real-world scenarios, including environmental monitoring, healthcare diagnostics, food safety, and other relevant fields. In this review, we discuss the methodologies of device fabrication and imaging analysis technologies for pattern recognition-driven chemical sensing in aqueous media. [Display omitted] • Cross-reactive sensors are applied to paper-based arrays for simultaneous detection. • Portable digital recorders can be used for detecting various responses. • Imaging analysis techniques can accelerate accurate data processing. [ABSTRACT FROM AUTHOR]

Microfluidic paper-based point-of-care assays are a highly valuable technology with many promising applications in public health and environmental monitoring. High-sensitivity detection of certain trace substances is one of the critical important considerations for practical usage of microfluidic point-of-care techniques. Over the past decade, luminescence nanoprobes have been increasingly emerged as powerful toolboxes to achieve exceptional sensitivity and low detection limits for many chemical sensors. In this Review, we provide an overview of the fundamental principles underlying paper-based microfluidic point-of-care detection. We highlight various luminescence nanoprobes, including nano-diamonds, upconversion luminescent nanoparticles, inorganic quantum dots, and carbon dots, along with their corresponding sensing mechanisms. In subsequent sections, we emphasize the requisite utilization of specialized readout equipment for the effective implementation of fluorescence detection. Moreover, we summarize key microfluidic design strategies capable of achieving enhanced precision in the detection processes. We also discuss future research directions and the main challenges to be addressed for fluorescence nanoprobes-inspired paper-based microfluidic point-of-care technology. • Microfluidic point-of-care paper-based Luminescence assays. • Luminescence nanoprobes and corresponding mechanism. • Portable devices for signal readout and diagnosis. [ABSTRACT FROM AUTHOR]

This paper presents the development and optimization of a cost-effective paper electrochemical sensor for the detection of TNT using Fe 3 O 4 –Au core-shell nanoparticles modified with cysteamine (Fe 3 O 4 @Au/CA). The sensor was constructed by modifying a graphite paste with the aforementioned nanoparticles, which facilitated the formation of a Meisenheimer complex between cysteamine and TNT as an electron donor and an electron acceptor, respectively. The central composite design was employed to optimize four key parameters pH, modifier percentage, contact time, and buffer type to enhance the performance of the sensor. The detection limit was found to be 0.5 nM of TNT, while the linear range of the electrode response spanned from 0.002 μM to 10 μM. The simplicity and low cost of the sensor make it highly attractive for practical applications, particularly in scenarios where rapid and on-site TNT detection is required. [Display omitted] • Fabrication of a paper-based TNT sensor based on the Meisenheimer complexation. • Synergistic effect of Fe 3 O 4 @Au NPs improves the sensor's electrochemical properties. • The RSM-CCD optimization approach was used for the statistical optimization. • The detection limit of the sensor was 0.5 nM in the linear range of 0.002–10 μM. • The developed sensor can detect TNT in aqueous and soil samples, without extraction. [ABSTRACT FROM AUTHOR]

Dopamine, the main catecholamine neurotransmitter plays an important role in renal, cardiovascular, central nervous systems, and pathophysiological processes. The abnormal dopamine levels can result in neurological disorders such as Parkinson's, Alzheimer's, schizophrenia, acute anxiety, neuroblastoma and also contribute to cognitive dysfunctions. Given the widespread importance of dopamine concentration levels, it is imperative to develop sensors that are able to monitor dopamine. Herein, we have developed pre-anodized disposable paper electrode modified with 1-pyrenebutyric acid, for the selective and sensitive determination of dopamine. The sensor was characterized with Fourier transform infrared spectroscopy, Energy dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy, and electrochemical techniques for addressing the robust formation and electrochemical activity. The modified electrode exhibited excellent electrocatalytic activity towards dopamine without the common interference from ascorbic acid. The calibration plot for the dopamine sensor resulted linear range from 0.003 μM to 0.5 μM with a detection limit of 0.11 nM. The sensor's potential utility was tested by monitoring dopamine concentration changes in rat brain homogenates when subjected to neurotoxicity. The developed sensor was validated with gold-standard UV–Vis spectroscopy studies and computational studies were performed to understand the interaction between 1-pyrenebutyric acid and dopamine. [Display omitted] • Pre-anodized paper electrode with π-π stacked pyrene butyric acid for selective detection of dopamine. • The sensor exhibited a detection limit of 0.11 nM with excellent selectivity. • Dopamine concentration changes in rat brain homogenates when subjected to CKD induced neurotoxicity was studied. [ABSTRACT FROM AUTHOR]

Food analysis plays a critical role in assessing human health risks and monitoring food quality and safety. Currently, there is a pressing need for a reliable, portable, and quick recognition element for point-of-care testing (POCT) to better serve the demands of on-site food analysis. Aptamer-modified paper-based analytical devices (Apt-PADs) have excellent characteristics of high portability, high sensitivity, high specificity, and on-site detection, which have been widely used and concerned in the field of food safety. The article reviews the basic components and working principles of Apt-PADs, and introduces their representative applications detecting food hazards. Finally, the advantages, challenges, and future directions of Apt-PADs-based sensing performance are discussed, to provide new directions and insights for researchers to select appropriate Apt-PADs according to specific applications. • The special composition and structure of Apt-PADs are systematically described. • In-depth description of the sensing applications of Apt-PADs and the research progress in recent years. • Intervention strategies of aptamers and paper bases to obtain high sensitivity of Apt-PADs. • Specific outlook on the future direction of Apt-PADs improvements. [ABSTRACT FROM AUTHOR]

A Eu-TDCA-Phen probe was employed for the detection of Nitrofurantoin (NFT) through a fluorescence quenching mechanism. Simultaneously, a smartphone-assisted fluorescence paper strip detection platform was designed for the visual and intelligent detection of NFT in real honey samples. [Display omitted] • A Eu-TDCA-Phen probe was synthesized and characterized. • Red fluorescence of Eu-TDCA-Phen was quenched by Nitrofurantoin (NFT). • Smartphone-assisted paper-based probe was developed for NFT detection. • A logic gate device was developed to simplify the detection process. The development of a rapid and convenient detection method for nitrofurantoin (NFT) residual is of great significance for food safety. Herein, a new fluorescent probe (Eu-TDCA-Phen) was developed for the visual and sensitive assay of NFT through the fluorescence quenching effect of inner filter effect (IFE) and photo-induced electron transfer (PET). The probe suspension demonstrates a wide linear range (0–0.16 mM), low detection limit (90 nM), high sensitivity, and rapid response time (2 min) in the "turn-off" process. To quantify the visual detection process, a smartphone-assisted test paper sensing platform was established and was applied for NFT determination in real honey samples, achieving satisfactory recovery rate ranges from 98.04 % to 105.04 %. Furthermore, a logic gate device was integrated with the sensing platform to streamline the visual detection process. The sensing platform offers several merits, including simpleness, quantification, portability and cost-effectiveness, making it highly suitable for real-time and on-site detection of antibiotics in food samples. [ABSTRACT FROM AUTHOR]

[Display omitted] • Fabrication of functionalized polymer nanoparticles via emulsion copolymerization. • Generation of oxazolidine-based polymer nanoparticles (OX-PNPs) through doping. • Optical detection of cyanide by OX-PNPs in deionized water and human blood plasma. • Optical pH sensing based on the absorption or emission spectra of OX-PNPs. • Drawing intelligent fluorescent artworks using acidochromic properties of OX-PNPs. Stimuli-responsive materials play a crucial role in developing sensor technology for rapid colorimetric and fluorometric detection applications. Their ability to undergo changes in response to external stimuli makes them suitable for creating naked-eye sensors, enabling rapid detection of hazardous ions. In this study, our main objective was to synthesize oxazolidine-based polymer nanoparticles (OX-PNPs) that exhibit dual colorimetric and fluorometric responses. These OX-PNPs were developed as sensors specifically for the detection of the cyanide ion (CN–) in solution and human blood plasma. We prepared stable emulsions of polymer nanoparticles by copolymerizing methyl methacrylate and different amounts of acrylamide through emulsion polymerization. The addition of synthesized oxazolidine to the latex samples resulted in the formation of OX-PNPs. After addition of OX-PNPs 1–7 to a solution of CN– in deionized (DI) water, instant chromogenic changes from orange to pink, accompanied by spectral shifts in the UV–Vis and increase in emission intensity spectra was observed. Notably, the detected concentration limit of OX-PNPs for CN– was found to be within the range of 3.67 × 10-9 to 1.66 × 10-8 M, surpassing the recommended guideline value for CN– in drinking water established by the World Health Organization (WHO). Furthermore, we successfully developed paper-based test strips using OX-PNPs for the colorimetric and fluorometric detection of CN– in solution. These paper test strips exhibited rapid and distinct color changes from the original orange to pink upon exposure to CN–. By employing Job's plot method, we confirmed a 1:1 stoichiometry complex formation between OX-PNPs and CN– anions. Additionally, OX-PNPs demonstrated pH-responsive behavior, displaying observable color changes in different pH solutions and on the prepared paper-based sensors across a pH range of 1–14. The pH-sensing ability of OX-PNP 7 paper strips was investigated by FESEM. These unique colorimetric and fluorometric properties make OX-PNPs ideal for applications in ionochromic and acidochromic paper-based sensors, offering immediate and reliable responses. Through this work, for the first time we present a novel application of intelligent pigments, namely oxazolidine-based polymer nanoparticles, for both intelligent artwork creation using a single pigment and as a cyanide detector in human blood plasma. These OX-PNPs hold potential for forensic medicine analysis, providing an effective means of examining cyanide-induced deaths. [ABSTRACT FROM AUTHOR]

The regenerative hydrogen/vanadium fuel cell (RHVFC) is investigated with Freudenberg carbon paper electrodes (CPs). Along with thermal treatment, the Freudenberg CPs are also treated with reduced graphene oxide (rGO) using electrophoretic deposition at 300 V. The rGO modified CP results in 25% higher power density than its untreated counterpart under the same operating conditions. In comparison to the first preliminary study, the power density reported herein is more than four times higher. Additionally, the Freudenberg CPs modified with heat treatment followed by rGO deposition facing the membrane (rGOHTFM) provide the best electrolyte discharge utilization (UE) of 99%, followed by untreated (98%) and heat treated samples (97%) at 50 mA cm−2. The rGOHTFM also record high charge and discharge energy efficiencies (η E) of 93% at the same current density, which is slightly higher than untreated CPs (η E = 91%). Cycling the system 10 times also results in higher η E and UE for rGOHTFM CP (η E = 92% and UE = 99% on average) in comparison to untreated electrodes (η E = 86% and UE = 97% on average). In comparison the widely investigated SGL 10AA CP has lower efficiencies and utilization as expected (η E = 74% and UE = 83% on average). Image 1 • Freudenberg carbon paper electrodes are studied in hydrogen/vanadium fuel cell. • Freudenberg electrodes give much better charge/discharge response to SGL 10AA. • Untreated samples have similar performance to rGO modified ones at 50 mA cm−2. • Reduced graphene oxide modification of heat treated samples gave best results. • High cycling efficiencies (92%) and electrolyte utilization (99%) are reported. [ABSTRACT FROM AUTHOR]

Functional laser scribing carbon paper (LSCP) decorated with highly uniform Ni nanoparticles were constructed through a facile electroless plating. The nanocomposites were characterized by high resolution scanning electron microscope, X-ray photoelectron spectroscopy, electrochemical impedance spectroscopy, cyclic voltammetry and chronoamperometry. The results showed high electron transferring kinetics of this sensor, which can be ascribed to their excellent properties such as rich pore channels, excellent structural durability, and large surface area. These properties facilitated mass transfer and electron conductions. Notably, a systematical response surface methodology simulating-modeling-predicting-optimizing design was employed to simulate, model and optimize processing parameters to gain the optimal conductivity of 8.52 × 106 S m−1. The obtained sensor owned high electrochemical activity and wide linear responses (0.80 μM–2.50 mM and 4.50 mM–15.20 mM), low detection limit of 20 nM (S/N = 3) to the glucose detection. The glucose determination in human serum and perspiration samples are also successful. Therefore, LSCP/NN provides an excellent sensing platform towards flexible biosensors in monitoring physical conditions. Disposable, Non-enzymatic and Ultrasensitive Carbon Fiber Paper-based Glucose Sensor has been Constructed by A Theoretical Box-Behnken Modeling-Predicting-Optimizing Design. Image 1 • A disposable, ultrasensitive and highly flexible LSCP/NN glucose biosensor is firstly constructed. • Novel nanoporous Ni networks are integrated with pulsed laser-scribed carbon paper via a rational Box-Behnken modeling-predicting-optimizing design. • The enzyme-free and binder-free LSCP/NN biosensor exhibits a wide linear glucose determination range (0.80 μM–2.50 mM; 4.5 mM–15.2 mM). • Excellent sensitivity (3415 μA mM−1 cm−2), a fast response (<1 s) and ultra-low limit of detection (20 nM). • Favorable flexibility, good accuracy and satisfactory specificity for glucose quantification in human serum and perspiration are indicated by the LSCP/NN biosensor. [ABSTRACT FROM AUTHOR]

Synthesis of affordable electrocatalysts with high efficiency at low cost is crucial for large-scale water splitting. Molybdenum carbide (Mo 2 C) has been suggested to be a promising alternative to noble metal based electrocatalysts for water splitting. In this paper, we fabricated a nanotextured coating of wrinkled Ni-doped Mo 2 C on carbon fiber paper (CFP) from Ni, Mo and carbon black (CB) via a molten salt method. Such a novel electrocatalyst, denoted as Ni-Mo 2 C CB /CFP, shows an overpotential of 121.4, 209.3 and 426.4 mV to achieve a current density of 10, 20 and 50 mA cm−2 respectively in acidic medium. The hydrogen evolution reaction (HER) performance of other as-prepared CFP based electrodes (bare CFP, Mo 2 C/CFP, Mo 2 C CB /CFP, Ni-Mo 2 C/CFP and NiC x /CFP) also tested. We found that the addition of carbon black and the doping of Ni could significantly improve the electrocatalytic performance of Mo 2 C/CFP in terms of overpotential, Tafel slope and exchange current density. This work demonstrates a facile and scalable route using molten salt method for the synthesis of high-performance electrocatalysts from non-precious compounds on carbon materials. Image 1 • Carbon fiber paper (CFP) was employed as a carbon source and substrate of Mo 2 C. • The addition of carbon black (CB) contributes to the refinement of Mo 2 C particles. • Ni-Mo 2 C/CFP composite was prepared from Ni, Mo, CFP and CB by a molten salt method. • The Ni-Mo 2 C/CFP electrocatalyst exhibits excellent catalytic performance for HER. [ABSTRACT FROM AUTHOR]

Abstract A stable and reproducible layer of Prussian blue (PB) modified with copper was electrodeposited on carbon paper electrodes for the multiple detection of ester flavorants with a bienzymatic biosensor. Carbon fiber composite paper was investigated as high-surface, low-cost substrate for biosensor development. The pre-activation of the electrode surface by cyclic voltammetry was necessary to improve the electrochemical properties before the electrochemical deposition of Prussian blue-copper film (PB-Cu). The stability and the reproducibility of the obtained PB-Cu carbon paper electrode was demonstrated at pH 7.4, optimum for biosensor development. The developed biosensor is based on the immobilization of two enzymes (carboxyl esterase and alcohol oxidase) by cross-linking with glutaraldehyde onto PB-Cu carbon paper electrode. A mixture of key aroma ester compounds (methyl butyrate, ethyl butyrate, methyl cinnamate and ethyl cinnamate) was detected in several food samples with low interferences. Graphical abstract fx1 Highlights • Prussian blue (PB) modified with copper with improved stability at neutral pH. • Carbon fiber composite paper is a high-surface, low-cost substrates excellent for biosensor manufacturing. • Total content of ester flavorants mixtures in foods detection. • Bienzymatic biosensor based on carboxyl esterase and alcohol oxidase. [ABSTRACT FROM AUTHOR]

[Display omitted] • Surface-enhanced Raman scattering (SERS) method was used to detect the antiviral drug Acyclovir. • SERS-active plasmonic substrates were prepared using filter paper substrates decorated with silver nanoparticles. • Developed SERS-active substrates indicated favorable reproducibility and chemical stability, with a limit of detection (LOD) of 10-12 M. • FDTD simulations were carried out, and the electric field distributions as well as the enhancement factor of the developed SERS-active substrates were obtained. Acyclovir (ACV) drug, a common antiviral agent, is frequently used as the primary clinical treatment method for treating hepatitis B, herpes simplex, and varicella zoster viruses due to its potent therapeutic effect. In patients with compromised immune systems, this medication can stop cytomegalovirus infections, and high doses of this drug are required; however, such prescription leads to kidney toxicity. Therefore, timely and accurate detection of ACV is crucial in many areas. Surface-Enhanced Raman Scattering (SERS) is a reliable, rapid, and precise approach for the identification of trace biomaterials and chemicals. Filter paper substrates decorated with silver nanoparticles (AgNPs) were applied as SERS biosensors to detect ACV and control its adverse effects. Initially, a chemical reduction procedure was utilized to produce AgNPs. Afterward, UV–Vis, FE-SEM, XRD, TEM, DLS, and AFM were employed to examine the properties of prepared AgNPs. In order to prepare SERS-active filter paper substrates (SERS-FPS) to detect Molecular vibrations of ACV, AgNPs prepared by immersion method were coated on filter paper substrates. Moreover, the UV–Vis DRS analysis was carried out to assess the stability of filter paper substrates and SERS-FPS. The AgNPs reacted with ACV after being coated on SERS-active plasmonic substrates and could sensitively detect ACV in small concentrations. It was discovered that the limit of detection of SERS plasmonic substrates was 10-12 M. Moreover, the mean RSD for ten repeated tests was calculated as 4.19%. The enhancement factor for detecting ACV using the developed biosensors was calculated to be 3.024 × 105 and 3.058 × 105 experimentally and via simulation, respectively. According to the Raman results, SERS-FPS for the detection of ACV, fabricated by the present methods, showed promising results for SERS-based investigations. Furthermore, these substrates showed significant disposablity, reproducibility, and chemical stability. Therefore, the fabricated substrates are capable to be employed as potential SERS biosensors to detect trace substances. [ABSTRACT FROM AUTHOR]

• Foldscope is an efficient, low-cost, lightweight, and portable microscope. • Foldscope is an alternative for a conventional compound microscope for monitoring of the pollination process. • Foldscope can be used for field-level real-time in vivo monitoring of the pollination process. An efficient, low-cost, lightweight, and portable paper microscope can be used to monitor real-time in vivo pollination, which is not feasible with a conventional compound microscope. The advantages of paper microscopes (foldscopes) remain unexplored for in vivo field-oriented assessment of pollination. In this study, experiments were carried out to calibrate and validate the capability of foldscopes to investigate in vitro pollen traits and to understand the feasibility of using in real-time in vivo field-level investigations. Comparison of optical images of pollen morphological traits (color, size, and shape) of diverse plant species (including crops) captured using a foldscope and a compound microscope revealed little to no differences. In addition, foldscopes were calibrated to monitor and estimate in vitro pollen viability in wheat, sorghum, sunflower, chickpea, soybean, and periwinkle and to determine in vitro pollen germination in chickpea, maize, and periwinkle. Pollen tube growth was observed by time-lapse imaging of pollen from periwinkle. The foldscope efficiently captured genotypic variation in in vitro pollen germination of twelve chickpea genotypes under drought revealing the possibility of foldscopes as a tool for field level, real-time in vivo monitoring of pollination under drought. [ABSTRACT FROM AUTHOR]

Cellulose-based paper is an alternative substitution for petroleum-based polymers for packaging applications, but its mechanical performance is poor when in contact with water. Herein, chitosan was applied on cellulose-based paper via a coating approach. The effects of chitosan coatings between none and five layers on the color properties, wettability, thermal properties, mechanical performance, and overall migration in food simulants of the paper were evaluated. After the application of chitosan, chitosan first filled cavities between cellulose fibers within a network, and the chitosan film was formed on the paper surface later. This resulted in a pronounced increase in wettability and mechanical properties associated with a loss of whiteness and an increase in yellowness of the coated paper. The chitosan-coated paper became hydrophobic with a water contact angle of 94.7 ± 2.8°, and a robust improvement of 156.4% for tensile strength and 114.8% for strain at break was observed for the paper coated with three layers of chitosan in wet conditions in comparison to the uncoated paper. A reduction in the migration of the low molecular residuals from the paper could be hindered by the chitosan coating. These enhanced features revealed that chitosan-coated paper could be used as a food-contact material. • Chitosan was applied on cellulose-based paper by a coating method. • Greater mechanical properties of chitosan coated paper were observed in wet conditions. • The hydrophilicity of the paper was transformed into the hydrophobic feature with incorporation of chitosan. • A reduction in the migration of the low molecular residuals from the paper could be hindered by the chitosan coating. • The chitosan-coated paper prepared could possibly be used for direct-contact packaging. [ABSTRACT FROM AUTHOR]

The increasing pressure on natural resources and the climate has been noted by businesses and governments worldwide, who now face the difficult task of integrating paths of environmental sustainability and economic growth. One promising approach to sustainable development, reducing the pressure on natural resources and solving waste problems is circular economy. From different ways of implementing circular economy, this study focuses on the productization of industrial side streams, which carry a great deal of underutilized potential. In this article, the productization of pulp and paper industry side stream, fiber sludge, for commercial use as a dust-binding agent is studied via a descriptive, in-depth case study. Apart from inconsistent quality, fluctuating supply, cost of storage and logistics, what makes industrial side stream utilization challenging is the lack of knowledge that stakeholders have about side streams and their utilization and the lack of new value chain development for their commercial use. Therefore, it is essential for all parties involved to have a clearer vision of what is being sold for what purposes, through productization. This study found that the productization of side streams follows the same steps as the productization of any other traditional product, and the productized side streams can be added to the company's product portfolio as by-products. [ABSTRACT FROM AUTHOR]

Members of the IQ Consortium ″Working Group on Characterization on Amorphous Solid Dispersions″ shares here a perspective on the analytical challenges, and limitations of detecting low levels of crystalline drug substance in amorphous solid dispersions (ASDs) and associated drug products. These companies aim to employ highly sensitive commercially available analytical technologies to guide development, support control strategies, and enable registration of quality products. We hope to promote consistency in development and registration approaches and guide the industry in development of "characterization best practices" in the interest of providing high quality products for patients. The first half of this perspective highlights the unique challenges of analytical methodologies to monitor crystalline drug substance in ASDs and their associated drug products. Challenges around use of limit tests, analyte spiking experiments, and method robustness are also underscored. The latter half describes the merits and limitations of the diverse analytical "toolbox" (such as XRPD, NIR and DSC), which can be readily applied during development and, in some cases, considered for potential application and validation in the commercial QC setting when necessary. [ABSTRACT FROM AUTHOR]

Deacidification and surface self-cleaning are of great significance for the long-term preservation of historic literature. Herein, a superhydrophobic self-cleaning coating, derived from nanocellulose coated with CaCO 3 particles is constructed via chemical vapor deposition (CVD) for the first time for the preservation of historic paper. The static contact angle of superhydrophobic paper reached more than 150° and the minimum sliding angle was 6.4°. Deacidification effect was achieved with a desired pH value in the range from 7.50 to 7.77 and the maximum alkali storage was up to 1.235 mol/kg. It is found that the low-cost CaCO 3 nanoparticles can not only remove the acid substances, but also gave the paper function of self-cleaning, which is very great significant for the protection of paper-based relics. [Display omitted] [ABSTRACT FROM AUTHOR]

Improving the strength decrease caused by fungal metabolites is still an arduous task in the field of paper materials protection. A set of damaged Kangxi Dictionary from Qing Dynasty was chosen as samples in this work. The main goal of this work is to develop high-efficiency and eco-friendly media with the characteristics of antifungal and reinforcement, to preserve paper materials and continue the historical and scientific research value of cultural heritage. PHMG as an efficient antifungal was used in this work. For better behavior, the epoxy group of KH560 can be induced by the amino group in PHMG by ring opening reaction to form PHMG-KH560 colloidal complex. Spraying PHMG-KH560 on paper could establish Si-O-C bonding and increased the hydrogen bond between polymeric material and paper fibers, which simultaneously inhibited fungi and improved mechanical strength of the original paper, even after the artificial aging. PHMG-KH560 had certain antifungal activity against five fungi, such as Aspergillus versicolor, and Aspergillus Niger , and had better inhibitory effect on Cladosporium herbarum, Trichoderma viride , and Penicillium expansum. The ancient writing ink on the paper sprayed with PHMG-KH560 did not affect its visual beauty, which also indicated that the complex reagent was expected to be applied to the antifungal and reinforcement of paper materials. [ABSTRACT FROM AUTHOR]

[Display omitted] • A total of 20 different paper sludges were investigated. • A wide range of biomethane potentials was determined. • Inhibiting substances for some paper sludge were identified. • Co-digestion resulted in methane yield increase of 5–10%. • The possibility of anaerobic co-digestion could be demonstrated. In this work, the feasibility of the anaerobic digestion of paper sludge as a co-substrate in anaerobic digestion mechanical–biological treatment (MBT) plants is investigated. In the first phase, the biochemical properties, biomethane potential (BMP), and pollutant contents of 20 different industrial paper sludges are determined. Following the general evaluation in the BMP tests, the second phase of the project involves the semi-continuous co-digestion of six paper sludges in continuous stirred reactors (CSTR). Paper sludges are categorized according to their origin within the pulp and paper mills: Deinking Sludge (DS), Primary Sludge (PS) and Biological Sludge (BS). The analysis of potentially inhibiting elements shows that the concentrations of chlororganic compounds, mineral oil and some heavy metals are highest in DS, while the mean heavy metal loads in all paper sludges are relatively low compared to other industrial sludges. Large differences in total solids (TS) and volatile solids (VS) contents are observed among the different paper sludges investigated, with DS having the highest TS due to the high inorganic contents. The BMP of the investigated sludges ranges from 90 to 355 NL CH 4 kg−1 VS. In subsequent semi-continuous co-digestion experiments simulating MBT conditions, three DS and two fiber sludges (a mixture of PS and BS) show good methane generation rates, while one fiber sludge causes inhibition and indicates an increase in viscosity. In general, co-digestion of paper sludge in anaerobic digestion MBT plants can be a viable option for energy production and also facilitates a safe disposal of the paper sludge digestates. [ABSTRACT FROM AUTHOR]

Surface decorated wood-based panels with melamine formaldehyde resin (MF) impregnated paper is highly favored by consumers due to its outstanding appearance and durable performance. However, the laminated composites would encounter hygroscopic expansion and damage that affect its service and aesthetics in long-term humid environments. This study aims to construct highly durable superhydrophobic surface to address this issue. Firstly, a controlled micro rough structure on stainless steel plates which were built with sandblasting was successfully duplicated onto the surface of MF impregnated paper laminated medium density fiberboard (MDF) using the embossing method. Following that, a spray treatment with hydrophobic nanoparticles was employed to the laminated composite surface, ultimately resulting in a superhydrophobic coating with a contact angle up to 163°. To confirm the durability of the fabricated superhydrophobic layer, linear abrasion test, water droplet impact test, sand impact test, and tape peeling test were carried out. The results demonstrated that even after severe processed conditions, the contact angle of the decorated surface remained above 150°. And the decorated laminate successfully passed both self-cleaning and dirt resistance challenge, clearly indicating the outstanding durability of superhydrophobic structure. Furthermore, water absorption thickness expansion measurement was done to verify the dimensional stability of the laminate in humid conditions. This research presented a straightforward and cost-effective approach to fabricate highly durable superhydrophobic MF impregnated paper decorated laminates, offering a dependable strategy for research and applications in related domains. [ABSTRACT FROM AUTHOR]

The predictive relationship between handwriting automaticity and children's writing performance is well documented. However, less is known about the relationship between keyboarding automaticity and children's keyboard-based writing performance. In this exploratory study, we examined the unique contributions of automaticity in both writing modalities in predicting Grade 2 students (N = 49) paper-based and keyboard-based writing performance (i.e., compositional quality and fluency) after controlling for students' literacy skills (i.e., spelling, word reading, and reading comprehension), attitudes toward writing, gender, and nesting due to classroom. Multilevel modelling results showed that automaticity predicted students' paper-based compositional quality and keyboard-based compositional quality and fluency. Findings further suggested that the relationship between automaticity and writing performance was stronger in keyboard-based text composing than in paper-based text composing. These results reinforce the role of automaticity of transcription skills in predicating the writing performance of beginning writers across modalities and stress the significance of explicit pedagogy and frequent instances of practice to promote the mastery of transcription skills across modalities in the early years of schooling. [ABSTRACT FROM AUTHOR]

This article describes the synthesis of sorptive phases for bioanalysis based on the modification of cellulose paper with natural beeswax as sorbent, resulting in a substrate completely renewable and sustainable. The preparation of the sorptive phases consisted of the dissolution of beeswax in hexane, followed by its drop-casting on cellulose paper and subsequent evaporation of the solvent. The beeswax modification of paper renders it hydrophobic, enabling the extraction of the target analytes, i.e., imipramine, desipramine, amitriptyline and trimipramine, via hydrophobic interactions. The main variables affecting the extraction performance were investigated (e.g., pH, ionic strength, extraction time, eluent composition, agitation speed). The analytical workflow combines a straightforward sampling, simultaneous extraction of 30 samples in 1 h, and the rapid (<2 min) determination of the analytes via direct infusion mass spectrometry. The method provided limits of detection in the range 2.0 and 3.2 μg L−1, and the precision, expressed as relative standard deviation, was better than 5.4 % and 8.5 % for intra and inter-day analyses, respectively. The accuracy, in terms of relative recovery, ranged from 90 % to 121 % using saliva as model biofluid. [Display omitted] • Cellulose paper has been modified with natural beeswax as sorbent. • Beeswax renders paper hydrophobic enabling extraction via hydrophobic interactions. • Four tricyclic antidepressants have been extracted and determined in saliva. • Variables affecting both modification of paper and extraction have been evaluated. • Direct infusion mass spectrometry was used for determination of the analytes. [ABSTRACT FROM AUTHOR]

This article introduces a novel approach by coupling paper points with hollow fiber membrane for electroextraction (PP–HF-EE). The method was innovatively applied to extract methylene blue (MB) from large water volumes (up to 580 mL). A comprehensive study of six key parameters – organic filter, acceptor and donor phase composition, extraction time, applied voltage, and sample volume – was conducted using conventional flatbed scanning and digital image analysis. Our results revealed that extraction performance was primarily influenced by time, with low voltages (50 V) and low-conductivity organic filters (1-decanol) yielding comparable results to higher settings (300 V or 1-pentanol). Under optimized conditions (50 V, 60 min, 1-decanol as the organic filter), analytical performance parameters were assessed, demonstrating acceptable precision (RSD <18% for intra- and inter-day measurements) within a linear range of 5–100 μg L−1 (r = 0.98). PP–HF–EE demonstrated reliability through stable and reproducible electric current measurements during all extraction studies. Utilizing an extremely cost-effective detection system, PP–HF–EE achieved detection limits in the low ppb range, highlighting its potential as a promising variation of electromembrane extraction for environmental sample analysis. [Display omitted] • A new electroextraction approach for environmental samples was presented. • Paper point after extraction was subsequently examined by digital image analysis. • Quantification of methylene blue in tap water was achieved in the low ppb range. • The new electroextraction approach might be promising for environmental analysis. [ABSTRACT FROM AUTHOR]

Sustainable degrowth offers effective alternative strategies for tackling social and environmental problems such as climate crisis, resource depletion, biodiversity loss, and species hecatomb. However, it plays a marginal role in policy. Moreover, researchers need to operationalise many degrowth proposals in a more sufficient way for the policy. This mainly conceptual-methodological article conceptualises the problem of sustainable degrowth in policy as the problem of knowledge utilisation. How well research papers on the topic adapt to the needs of policy-makers is an important factor influencing this utilisation. This adaptation is under the control of researchers and may be seen as a necessary first step in the introduction of degrowth proposals into policy-making and further implementation. I argue that translating research papers into legislative drafts by researchers can be understood as adaptation of these papers to the policy-makers' needs. This is because the law can be understood as universal basis of public policies and fundamental language to express these policies. The legal system has a systematic, hierarchical, and logical structure while its language tends to be precise, clear, and unambiguous. Legal language may also be salient for many policy-makers. I labelled this way of adaptation as the Translational Legal Approach to Knowledge Utilisation (TLA). It can be applied beyond texts on sustainable degrowth as well. Based on the literature review, I theoretically and conceptually discuss the aforementioned hypotheses by looking at the corresponding criteria of research adaptation with characteristics of law and legal language. I provide the strongest support for the theses that translation of research papers into provisions of legislative drafts can increase readability, comprehensibility, precision, and operationalisation of degrowth research proposals, as well as helps to give them more systemic nature and incorporate policy-makers' context. Future research is needed to create a methodological framework for TLA as well as to empirically verify hypotheses made in this article. • Degrowth plays a marginal role in policies and needs better operationalisation. • The role of degrowth in policy can be seen as a problem of knowledge utilisation. • Law could be a common language between researchers and policy-makers. • Translating research papers into legislative drafts adapts them for policy-makers. • Translating degrowth proposals into legislative drafts supports their utilisation. [ABSTRACT FROM AUTHOR]

[Display omitted] • Au/Ag nanocages were prepared and used as an effective colorimetric platform. • Hydrazine in the presence of Ag+ causes the morphological change of nanocages. • A paper-based colorimetric sensor based on this change was developed for hydrazine. In this work, Au/Ag nanocages have been used as an effective platform for sensitive colorimetric detection of hydrazine. By adding hydrazine together with silver ions to the hollow Au/Ag nanocages, they undergo a morphological transformation to closed nanoboxes. This leads to a noticeable blue shift in the localized surface plasmon resonance (LSPR) peak position and a distinct color change from blue to purple in the solution. The extent of shift in the LSPR peak of the Au/Ag nanocages exhibited a direct correlation with the concentration of hydrazine within the range of 0.1 to 10.0 µM. The limit of detection (LOD) achieved was 0.03 µM, with a relative standard deviation (RSD) of 1.7% at a concentration of 0.5 µM. Furthermore, we developed a paper-based sensor with smartphone readout for hydrazine detection within the range of 0.5 to 10.0 µM, with an LOD of 0.3 µM and an RSD of 3.3% at a concentration of 2.0 µM. The effectiveness of the sensor was successfully demonstrated in the analysis of hydrazine in environmental samples. This is the first time that Au/Ag nanocages are used for simple paper-based assay. With its high sensitivity, low cost, and rapid analysis time, this method offers a promising solution for the quantitative measurement of hydrazine in environmental samples by portable paper-based test strips. [ABSTRACT FROM AUTHOR]

Present report demonstrates the application of Sb 0.3 Sn 0.7 Se 2 single crystal as a paper based flexible photodetector. Direct vapour transport grown bulk crystals of Sb 0.3 Sn 0.7 Se 2 has been converted to nanosheets by chemical assisted exfoliation process. The paper-based photodetector is fabricated and the switching action is studied. Tuning of photodetector has been carried out by 670 nm laser illumination for different bias voltages. Temporal photo-response is also studied under polychromatic light with different intensities in vacuum and open environment. The low temperature stability of photodetector has been studied for temperature range 300 K–180 K. Experimental results are obtained in terms of time resolved photocurrent under different illumination and atmospheric conditions. The flexibility and stability are also examined in detail for fabricated detector. Overall, the results suggest the application of Sb 0.3 Sn 0.7 Se 2 as a versatile flexible photodetector. Additionally, the machine learning (ML) model is trained and tested using an experimental photocurrent dataset that has a complex material design with variations in time, bias voltage, intensity, and temperature. The k-nearest neighbor algorithm exhibited outstanding performance, achieving the highest R2 value of 0.9986 when applied to a temperature dataset, with a test size of 0.4. Performance metrics such as mean absolute error and root mean squared error of various test sizes ranging from 0.4 to 0.6 are used to assess the model's accuracy and robustness in changing conditions. This comprehensive analysis not only establishes a platform for future experimental optimization of photodetector materials but also underscores the efficacy of ML regression techniques in developing high-performance photodetectors. [Display omitted] • Chemical assisted exfoliation process were used for the synthesis of SbSnSe2 nanosheets. • Synthesized nanosheets were decorated on paper for the fabrication of flexible photo-detector. • The photodetection application was demonstrated for different atmospheric conditions and different illuminations. • Low temperature stability of the detector was also studied. • KNN Machine learning model were applied to the experimental data for the prediction of photodetection behavior. [ABSTRACT FROM AUTHOR]

Sustainable strategies to improve the water resistance of cellulose paper are actively sought. In this work, polymeric microspheres (PMs), prepared through emulsion polymerization of cellulose nanofibers stabilized rubber seed oil-derived monomer, were investigated as coatings on corrugated medium paper (CMP). After infiltrating porous paper with PMs, the water-resistant corrugated papers (WRCP n) with enhanced mechanical properties were obtained. When 30 wt% PMs were introduced, WRCP 30 turned out to be highly compacted with an increased water contact angle of 106.3° and a low water vapor transmission rate of 81 g/(m2 d) at 23 °C. Meanwhile, the tensile strength of WRCP 30 increased to 22.2 MPa, a 4-fold increase from CMP. When tested in a well-hydrated state, 71% of its mechanical strength in the dry state was maintained. Even with a low content of 10 wt% PMs, WRCP 10 also exhibited stable tensile strength and water wettability during the cyclic soaking-drying process. Thus, the plant oil based sustainable emulsion polymers provide a convenient route for enhancing the overall performance of cellulose paper. • Polymeric composite microspheres (PMs) were prepared via emulsion polymerization from CNFs stabilized ERSMA emulsion. • The PMs were utilized as coatings on corrugated medium paper to fabricate high-performance packing materials. • The prepared PMs coated CMPs exhibit enhanced mechanical properties and long-term water resistance. [ABSTRACT FROM AUTHOR]

• "Ba 3 Bi 2 MoO 9 " compound does not exist. • Mainly a mixture of BaBiO 3 and BaMoO 4 was investigated before. The title paper (Materials Science & Engineering B 296 (2023) 116616) claimed the preparation and detailed characterization by different methods of a novel triple perovskite compound, Ba 3 Bi 2 MoO 9. In this comment, it is shown that the phase Ba 3 Bi 2 MoO 9 does not exist. We show that the absence of the phase analysis resulted in erroneous claims. We demonstrate that the sample in the title paper is mainly a mixture of BaBiO 3 and BaMoO 4. [ABSTRACT FROM AUTHOR]

The announcement of a progressive decrease in digitalization and the reintroduction of paper-based reading and traditional pedagogical methods in Swedish schools has initiated a worldwide debate on the uses of technology for reading in schools. This debate led us to examine the role and effects of technology on reading skills. We initiated the present research by analyzing the integration of technology practices mediated by technology in the context of reading and then expanded into a broader discussion encompassing the pedagogical implications. By reviewing the current literature, three venues of technology usage were identified: assessment, teaching reading using technology, and general uses of technology. Through the assessment lens, there is limited support for reverting to paper-based reading assessments. Four meta-analyses indicated that reading comprehension scores tend to be slightly higher in paper-based formats than on digital devices when the same text is used, but for all students, the same difference is observed. The effectiveness of using technology to teach reading comprehension is relative to the pedagogical approach employed and the specific design of the technology. The evidence indicates that well-designed digital books outperform paper-based reading. Additionally, student-centered practices using technology are associated with higher reading performance rather than reinforcing reading practices. Policy initiatives should proactively support schools and teachers in establishing student-centered technology integration practices. Finally, the extensive data available from the PISA test were widely employed to explore the impact of ICT usage on students' overall performance, yielding contradictory results explained by differences in culture, context, and teacher training. • The role and effects of technology on reading skills. • Limited support for reverting to paper-based reading assessments. • Well-designed digital books outperform paper-based reading. • Policy initiatives should support student-centered technology integration practices. [ABSTRACT FROM AUTHOR]