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In this study, the performance of a paper-based, screen-printed biofuel cell with mesoporous MgO-templated carbon (MgOC) electrodes was improved in two steps. First, a small amount of carboxymethyl cellulose (CMC) was added to the MgOC ink. Next, the cathode was modified with bilirubin prior to immobilizing the bilirubin oxidase (BOD). The CMC increased the accessibility of the mesopores of the MgOC, and subsequently, the performance of both the bioanode and biocathode. CMC also likely increased the stability of the electrodes. The pre-modification with bilirubin improved the orientation of the BOD, which facilitated direct electron transfer. With these two steps, an open circuit potential of 0.65 V, a maximal current density of 1.94 mA cm−2, and a maximal power density of 465 μW cm−2 was achieved with lactate oxidase as bioanode enzyme and lactate as fuel. This is one of the highest reported performances for a biofuel cell. [ABSTRACT FROM AUTHOR]

Asymptomatic visceral leishmaniasis cases increase continuously, particularly among patients with HIV who are at risk to develop further symptoms of leishmaniasis. A simple, sensitive and reliable diagnosis is crucially needed due to risk populations mostly residing in rural communities with limited resources of laboratory equipment. In this study, a highly sensitive and selective determination of Leishmania among asymptomatic patients with Leishmania/HIV co-infection was achieved to simultaneously interpret and semi-quantify using colorimetric precipitates (gold-nanoparticle probe; AuNP-probe) and fluorescence (SYBR safe dye and distance-based paper device; dPAD) in one-step loop-mediated isothermal amplification (LAMP) assay. The sensitivities and specificities of 3 detection methods were equivalent and had reliable performances achieving as high as 95.5%. Detection limits were 102 parasites/mL (0.0147 ng/µL) which were 10 times more sensitive than other related studies. To empower leishmaniasis surveillance as well as prevention and control, this dPAD combined with SYBR safe and gold nanoparticle probe LAMP assay is reliably fast, simple, inexpensive and practical for field diagnostics to point-of-care settings in resource-limited areas which can be set up in all levels of healthcare facilities, especially in low to middle income countries. [ABSTRACT FROM AUTHOR]

Milk adulteration is a common problem in developing countries, and it can lead to fatal diseases in humans. Despite several studies to identify different adulterants in milk samples, the effects of multiple adulterants remain unexplored. In this work, a three-dimensional (3D) paper-based microfluidic device is designed and fabricated to simultaneously detect multiple chemical adulterants in milk. This device comprises a top cover, a bottom cover, and a middle layer composed of transportation and a detection zone. By making cuts on the middle layer's support, the device's flow path is characterised by optimum and uniform velocity. For the first time, seven adulterants (urea, detergents, soap, starch, hydrogen peroxide, sodium-hydrogen-carbonate, and salt) are detected in the milk sample simultaneously with specificity evaluation and detailed color interference analysis. Only 1–2 mL of sample volume is required to detect 7 adulterants at one time. We have used only 10 μ L of the reagent's volume for the colorimetric reaction and found the results within a few seconds. Observation reveals that the limit of detection (LOD) of the adulterants lies in the range between 0.05 % (vol./vol.) to 0.2 % (vol./vol.) using the colorimetric detection technique. The unknown quantity of the added adulterants is measured using the calibration curves obtained from the experiments results. The repeatability and reproducibility of the process, sensitivity, and the linear range of detection of the calibration curves and the statistical study of the color intensity data are thoroughly analysed herein. In any resource-limited setting, this simple, portable, and user-friendly 3D microfluidic device is expected to be used for testing liquid foods before consumption. [ABSTRACT FROM AUTHOR]

As members of a social species, we spend most of our time interacting with others. In interactions, we tend to mutually align our behavior and brain responses to communicate more effectively. In a semi-computerized version of the Rock-Paper-Scissors game, we investigated whether people show enhanced interpersonal neural synchronization when making explicit predictions about others' actions. Across four experimental conditions, we measured the dynamic brain activity using the functional near-infrared spectroscopy (fNIRS) hyperscanning method. Results showed that interpersonal neural synchrony was enhanced when participants played the game together as they would do in real life in comparison to when they played the game on their own. We found no evidence of increased neural synchrony when participants made explicit predictions about others' actions. Hence, neural synchrony may depend on mutual natural interaction rather than an explicit prediction strategy. This study is important, as it examines one of the presumed functions of neural synchronization namely facilitating predictions. [ABSTRACT FROM AUTHOR]

Social insects are highly diverse in their social structures, aside from the consistent presence of reproductive castes. Among social insects, the Australian paper wasp Ropalidia plebeiana constructs extremely dense colony aggregations consisting of hundreds of colonies within a few square meters; however, little is known about the aggregation structures. We genetically analyzed the colony and population structure of R. plebeiana, and concomitant variations in colony sex ratios. In spring, the foundress (candidate queen) group started their colonies on a single old comb from the previous season, subsequently dividing these old combs via relatedness-based comb-cutting. Female philopatry, a prerequisite condition of Local Resource Competition (LRC), was confirmed. The colony sex ratio of reproductive individuals (male and female offspring for the next generation) became slightly male-biased in larger colonies, as predicted under LRC. However, the number of foundresses was positively associated with the number of reproductive individuals, suggesting that Local Resource Enhancement (LRE) also operates. Although the population structure appears to meet the prerequisites of LRC, the sex ratio appears to be modulated by factors other than LRC. Rather, through LRE, the availability of female helpers at the founding stage is likely to mitigate the sex ratios predicted under LRC. [ABSTRACT FROM AUTHOR]

Many studies have been conducted on measuring avian influenza viruses and their hemagglutinin (HA) antigens via electrochemical principles; most of these studies have used gold electrodes on ceramic, glass, or silicon substrates, and/or labeling for signal enhancement. Herein, we present a paper-based immunosensor for label-free measurement of multiple avian influenza virus (H5N1, H7N9, and H9N2) antigens using flexible screen-printed carbon nanotube-polydimethylsiloxane electrodes. These flexible electrodes on a paper substrate can complement the physical weakness of the paper-based sensors when wetted, without affecting flexibility. The relative standard deviation of the peak currents was 1.88% when the electrodes were repeatedly bent and unfolded twenty times with deionized water provided each cycle, showing the stability of the electrodes. For the detection of HA antigens, approximately 10-μl samples (concentration: 100 pg/ml–100 ng/ml) were needed to form the antigen–antibody complexes during 20–30 min incubation, and the immune responses were measured via differential pulse voltammetry. The limits of detections were 55.7 pg/ml (0.95 pM) for H5N1 HA, 99.6 pg/ml (1.69 pM) for H7N9 HA, and 54.0 pg/ml (0.72 pM) for H9N2 HA antigens in phosphate buffered saline, and the sensors showed good selectivity and reproducibility. Such paper-based sensors are economical, flexible, robust, and easy-to-manufacture, with the ability to detect several avian influenza viruses. [ABSTRACT FROM AUTHOR]

Unprecedented in the literature, levulinic acid (LA), one of the top value-added intermediates of chemical industry, is obtained from cigarette butts as cellulose feedstock by means of a one-pot hydrothermal process carried out at 200 °C for 2 h and catalysed by phosphoric acid. The protocol avoids the use of more aggressive and toxic H2SO4 and HCl, that are generally employed on several cellulose sources (e.g. sludge paper), thus minimizing corrosion phenomena of plants. Neither chemical pre-treatment of butts nor specific purification procedure of LA are required. Notably, by simply modifying acid catalyst (e.g. using CH3COOH), another top value-added fine chemical such as 5-hydroxymethylfuraldehyde (HMF) is obtained, thus widening the scope of the method. Being cigarette filters a waste available in quantities of megatonnes per year, they represent an unlimited at no cost source of cellulose, thus enabling the up-scale to an industrial level of LA production. [ABSTRACT FROM AUTHOR]

Pencil traces drawn on print papers are shown to function as strain gauges and chemiresistors. Regular graphite/clay pencils can leave traces composed of percolated networks of fine graphite powders, which exhibit reversible resistance changes upon compressive or tensile deflections. Flexible toy pencils can leave traces that are essentially thin films of graphite/polymer composites, which show reversible changes in resistance upon exposure to volatile organic compounds due to absorption/desorption induced swelling/ recovery of the polymer binders. Pencil-on-paper devices are low-cost, extremely simple and rapid to fabricate. They are light, flexible, portable, disposable, and do not generate potentially negative environmental impact during processing and device fabrication. One can envision many other types of pencil drawn paper electronic devices that can take on a great variety of form factors. Hand drawn devices could be useful in resource-limited or emergency situations. They could also lead to new applications integrating art and electronics. [ABSTRACT FROM AUTHOR]

This paper describes a novel approach to fabricate paper-based electric circuits consisting of a paper matrix embedded with three-dimensional (3D) microchannels and liquid metal. Leveraging the high electric conductivity and good flowability of liquid metal, and metallophobic property of paper, it is possible to keep electric and mechanical functionality of the electric circuit even after a thousand cycles of deformation. Embedding liquid metal into paper matrix is a promising method to rapidly fabricate low-cost, disposable, and soft electric circuits for electronics. As a demonstration, we designed a programmable displacement transducer and applied it as variable resistors and pressure sensors. The unique metallophobic property, combined with softness, low cost and light weight, makes paper an attractive alternative to other materials in which liquid metal are currently embedded.

Foldable organic memory on cellulose nanofibril paper with bendable and rollable characteristics is demonstrated by employing initiated chemical vapor deposition (iCVD) for polymerization of the resistive switching layer and inkjet printing of the electrode, where iCVD based on all-dry and room temperature process is very suitable for paper electronics. This memory exhibits a low operation voltage of 1.5 V enabling battery operation compared to previous reports and wide memory window. The memory performance is maintained after folding tests, showing high endurance. Furthermore, the quick and complete disposable nature demonstrated here is attractive for security applications. This work provides an effective platform for green, foldable and disposable electronics based on low cost and versatile materials.

Xylanase is commonly applied in pulp and paper industries to ease cost-related and environmental pressures. The effect of xylanase treatment on pulp bleaching is well-established, however, few studies were conducted on the effects of xylanase treatment in pulp yellowing, especially the mechanism of pulp yellowing inhibition by xylanase treatment. In this study, pure xylanase (EC 3.2.1.8) was applied to treat wheat straw chemical pulp (CP) and poplar chemi-thermo-mechanical pulp (CTMP) to determine their effects on pulp brightness and on light- and heat-induced yellowing. The xylanase treatment decreased the post-color number of the pulps during light- and heat-induced yellowing. However, differences were observed in the yellowing inhibition between the wheat straw CP and poplar CTMP. The changes in chemical components of pulps after the xylanase treatment, for example, lignin, hemicellulose, and HexA contents, and analysis of UV-vis absorption spectra and Fourier transform infrared-attenuated total reflectance spectrum were used to explore the pulp yellowing inhibition causes by the xylanase treatment.

We report the transient memory device by means of a water soluble SSG (solid sodium with glycerine) paper. This material has a hydroscopic property hence it can be soluble in water. In terms of physical security of memory devices, prompt abrogation of a memory device which stored a large number of data is crucial when it is stolen because all of things have identified information in the memory device. By utilizing the SSG paper as a substrate, we fabricated a disposable resistive random access memory (RRAM) which has good data retention of longer than 10 6  seconds and cycling endurance of 300 cycles. This memory device is dissolved within 10 seconds thus it can never be recovered or replicated. By employing direct printing but not lithography technology to aim low cost and disposable applications, the memory capacity tends to be limited less than kilo-bits. However, unlike high memory capacity demand for consumer electronics, the proposed device is targeting for security applications. With this regards, the sub-kilobit memory capacity should find the applications such as one-time usable personal identification, authentication code storage, cryptography key, and smart delivery tag. This aspect is attractive for security and protection system against unauthorized accessibility.

Here, we discuss the development of a paper-based diagnostic device that is inexpensive, portable, easy-to-use, robust, and capable of running simultaneous tests to monitor a relevant inflammatory protein for clinical diagnoses i.e. C-reactive protein (CRP). In this study, we first attempted to make a paper-based diagnostic device via the wax printing method, a process that was used in previous studies. This device has two distinct advantages: 1) reduced manufacturing and assay costs and operation duration via using wax printing method to define hydrophobic boundaries (for fluidic devices or general POC devices); and, 2) the hydrophilicity of filter paper, which is used to purify and chromatographically correct interference caused by whole blood components with a tiny amount of blood sample (only 5 μL). Diagnosis was based on serum stain length retained inside the paper channels of our device. This is a balanced function between surface tension and chromatographic force following immune reactions (CRP assays) with a paper-embedded biomarker.

Developing an innovative "Test Paper" based on virgin nanoporous silicon (NPSi) which shows intense visible emission and excellent fluorescence stability. The visual fluorescence quenching "Test Paper" was highly selective and sensitive recognizing Cu 2+ at μmol/L level. Within the concentration range of 5 × 10 -7 ~50 × 10 -7 mol/L, the linear regression equation of I PL  = 1226.3-13.6[C Cu 2+ ] (R = 0.99) was established for Cu 2+ quantitative detection. And finally, Cu 2+ fluorescence quenching mechanism of NPSi prober was proposed by studying the surface chemistry change of NPSi and metal ions immersed-NPSi using XPS characterization. The results indicate that SiH x species obviously contribute to the PL emission of NPSi, and the introduce of oxidization state and the nonradiative recombination center are responsible for the PL quenching. These results demonstrate how virgin NPSi wafer can serve as Cu 2+ sensor. This work is of great significant to promote the development of simple instruments that could realize rapid, visible and real-time detection of various toxic metal ions.

Metaldehyde is extensively used worldwide as a contact and systemic molluscicide for controlling slugs and snails in a wide range of agricultural and horticultural crops. Contamination of surface waters due to run-off, coupled with its moderate solubility in water, has led to increased concentration of the pesticide in the environment. In this study, for the first time, rapid analysis (<~1 minute) of metaldehyde residues in water is demonstrated using paper spray mass spectrometry (PS-MS). The observed precursor molecular ions of metaldehyde were confirmed from tandem mass spectrometry (MS/MS) experiments by studying the fragmentation patterns produced via collision-induced dissociation. The signal intensity ratios of the most abundant MS/MS transitions for metaldehyde (177 → 149 for protonated ion) and atrazine (221 → 179) were found to be linear in the range 0.01 to 5 ng/mL. Metaldehyde residues were detectable in environmental water samples at low concentration (LOD < 0.1 ng/mL using reactive PS-MS), with a relative standard deviation <10% and an R 2 value >0.99, without any pre-concentration/separation steps. This result is of particular importance for environmental monitoring and water quality analysis providing a potential means of rapid screening to ensure safe drinking water.

Multiple and complex functionalities are a demand nowadays for almost all materials, including common day-to-day materials such as paper, textiles, wood, etc. In the present report, the surface temperature control of different types of materials, including paper and textiles, was demonstrated by Joule heating of metallic-web transparent electrodes both by direct current and by RF induced eddy currents. Polymeric submicronic fiber webs were prepared by electrospinning, and metal sputtering was subsequently performed to transform them into flexible transparent electrodes. These electrodes were thermally attached to different substrates, including paper, textiles and glass. Using thermochromic inks, we demonstrated a high degree of control of the substrates' surface temperature by means of the Joule effect. Metallic fiber webs appear to be excellently suited for use as transparent electrodes for controlling the surface temperature of common materials, their highly flexible nature being a major advantage when dealing with rough, bendable substrates. This kind of result could not be achieved on bendable substrates with rough surfaces such as paper or textiles while employing classical transparent electrodes i.e. metal oxides. Moreover, contactless heating with induced currents is a premiere for transparent electrodes and opens up a score of new application fields.

Competitive environments in which individuals compete for mutually-exclusive outcomes require rational decision making in order to maximize gains but often result in poor quality heuristics. Reasons for the greater reliance on lose-shift relative to win-stay behaviour shown in previous studies were explored using the game of Rock, Paper, Scissors and by manipulating the value of winning and losing. Decision-making following a loss was characterized as relatively fast and relatively inflexible both in terms of the failure to modulate the magnitude of lose-shift strategy and the lack of significant neural modulation. In contrast, decision-making following a win was characterized as relatively slow and relatively flexible both in terms of a behavioural increase in the magnitude of win-stay strategy and a neural modulation of feedback-related negativity (FRN) and stimulus-preceding negativity (SPN) following outcome value modulation. The win-stay/lose-shift heuristic appears not to be a unified mechanism, with the former relying on System 2 processes and the latter relying on System 1 processes. Our ability to play rationally appears more likely when the outcome is positive and when the value of wins are low, highlighting how vulnerable we can be when trying to succeed during competition.

Contamination of the environment by mercury(II) ions (Hg(2+)) poses a serious threat to human health and ecosystems. Up to now, many reported Hg(2+) sensors require complex procedures, long measurement times and sophisticated instrumentation. We have developed a simple, rapid, low cost and naked-eye quantitative method for Hg(2+) environmental analysis using a paper-based colorimetric device (PCD). The sample solution to which platinum nanoparticles (PtNPs) have been added is dispensed to the detection zone on the PCD, where the 3,3,5,5-tetramethylbenzidine (TMB) substrate has been pre-loaded. The PtNPs effect a rapid oxidization of TMB, inducing blue colorization on the PCD. However, Hg(2+) in the solution rapidly interact with the PtNPs, suppressing the oxidation capacity and hence causing a decrease in blue intensity, which can be observed directly by the naked eye. Moreover, Hg(2+) at concentrations as low as 0.01 uM, can be successfully monitored using a fiber optic device, which gives a digital readout proportional to the intensity of the blue color change. This paper-based colorimetric device (PCD) shows great potential for field measurement of Hg(2+).

Herein we present a novel approach for the quantification of active pharmaceutical ingredients (APIs) using mass spectrometry imaging. This strategy uses a filter paper previously "eluted" with a MALDI matrix solution as a support for analyte application. Samples are submitted to mass spectrometry imaging (MSI) and quantification through characteristic fingerprints is ultimately performed. Results for the content of rosuvastatin from a known formulation are comparable to those obtained with a validated HPLC method.

Stochasticity plays an important role in the evolutionary dynamic of cyclic dominance within a finite population. To investigate the stochastic evolution process of the behaviour of bounded rational individuals, we model the Rock-Scissors-Paper (RSP) game as a finite, state dependent Quasi Birth and Death (QBD) process. We assume that bounded rational players can adjust their strategies by imitating the successful strategy according to the payoffs of the last round of the game, and then analyse the limiting distribution of the QBD process for the game stochastic evolutionary dynamic. The numerical experiments results are exhibited as pseudo colour ternary heat maps. Comparisons of these diagrams shows that the convergence property of long run equilibrium of the RSP game in populations depends on population size and the parameter of the payoff matrix and noise factor. The long run equilibrium is asymptotically stable, neutrally stable and unstable respectively according to the normalised parameters in the payoff matrix. Moreover, the results show that the distribution probability becomes more concentrated with a larger population size. This indicates that increasing the population size also increases the convergence speed of the stochastic evolution process while simultaneously reducing the influence of the noise factor.

Unlabelled: Breathalyzers estimate Blood Alcohol Content (BAC) from the concentration of ethanol in the breath. Breathalyzers are easy to use but are limited either by their high price and by environmental concerns, or by a short lifetime and the need for continuous recalibration. Here, we demonstrate a proof-of-concept disposable breathalyzer using an organic electrochemical transistor (OECT) modified with alcohol dehydrogenase (ADH) as the sensor. The OECT is made with the conducting polymer poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (, Pedot: PSS), and is printed on paper. ADH and its cofactor nicotinamide adenine dinucleotide (NAD(+)) are immobilized onto the OECT with an electrolyte gel. When the OECT-breathalyzer is exposed to ethanol vapor, the enzymatic reaction of ADH and ethanol transforms NAD(+) into NADH, which causes a decrease in the OECT source drain current. In this fashion, the OECT-breathalyzer easily detects ethanol in the breath equivalent to BAC from 0.01% to 0.2%. The use of a printed OECT may contribute to the development of breathalyzers that are disposable, ecofriendly, and integrated with wearable devices for real-time BAC monitoring.

This work reports a novel way of producing an inexpensive substrate support to assemble a sensing film, designed for the electrical transduction of an intended biomolecule. The support uses cellulose paper as substrate, made hydrophobic with solid wax and covered by a home-made conductive ink having graphite as core material. The hydrophobicity of the paper was confirmed by contact angle measurements and the conductive ink composition was optimized with regard to its adhesion, conductivity, and thermal stability. This support was further modified targeting its application in quantitative analysis. Carnitine (CRT) was selected as target compound, a cancer biomarker. The recognition material consisted of an antibody-like receptor film for CRT, tailored on the support and prepared by electrically-sustained polymerization of 3,4-ethylenedioxythiophene (EDOT) or dodecylbenzenesulfonic acid (DBS). Fourier transform infrared spectroscopy (FTIR) and Raman spectroscopy analysis confirmed the presence of the polymeric film on the support, and the performance of the devices was extensively evaluated with regard to linear response ranges, selectivity, applicability, and reusability. Overall, the paper-based sensors offer simplicity of fabrication, low cost and excellent reusability features. The design could also be extended to other applications in electrical-based approaches to be used in point-of-care (POC).

Paper-based writing electronics has received a lot of interest recently due to its potential applications in flexible electronics. To obtain ultra-low resistivity paper-based writing electronics, we developed a kind of ink with high concentration of Ag Nano-particles (up to 80 wt%), as well as a related dispensing writing system consisting an air compressor machine and a dispenser. Additionally, we also demonstrated the writability and practical application of our proposed ink and writing system. Based on the study on the effect of sintering time and pressure, we found the optimal sintering time and pressure to obtain high quality Ag NPs wires. The electrical conductivity of nano-silver paper-based electronics has been tested using the calculated resistivity. After hot-pressure sintering at 120 °C, 25 MPa pressure for 20 minutes, the resistivity of silver NPs conductive tracks was 3.92 × 10(-8) (Ωm), only 2.45 times of bulk silver. The mechanical flexibility of nano-silver paper-based electronics also has been tested. After 1000 bending cycles, the resistivity slightly increased from the initial 4.01 × 10(-8) to 5.08 × 10(-8) (Ωm). With this proposed ink preparation and writing system, a kind of paper-based writing electronics with ultra-low resistivity and good mechanical flexibility was achieved.

X-ray phase and dark-field imaging techniques provide complementary and inaccessible information compared to conventional X-ray absorption or visible light imaging. However, such methods typically require sophisticated experimental apparatus or X-ray beams with specific properties. Recently, an X-ray speckle-based technique has shown great potential for X-ray phase and dark-field imaging using a simple experimental arrangement. However, it still suffers from either poor resolution or the time consuming process of collecting a large number of images. To overcome these limitations, in this report we demonstrate that absorption, dark-field, phase contrast, and two orthogonal differential phase contrast images can simultaneously be generated by scanning a piece of abrasive paper in only one direction. We propose a novel theoretical approach to quantitatively extract the above five images by utilising the remarkable properties of speckles. Importantly, the technique has been extended from a synchrotron light source to utilise a lab-based microfocus X-ray source and flat panel detector. Removing the need to raster the optics in two directions significantly reduces the acquisition time and absorbed dose, which can be of vital importance for many biological samples. This new imaging method could potentially provide a breakthrough for numerous practical imaging applications in biomedical research and materials science.

Rock, Paper, Scissors (RPS) represents a unique gaming space in which the predictions of human rational decision-making can be compared with actual performance. Playing a computerized opponent adopting a mixed-strategy equilibrium, participants revealed a non-significant tendency to over-select Rock. Further violations of rational decision-making were observed using an inter-trial analysis where participants were more likely to switch their item selection at trial n + 1 following a loss or draw at trial n, revealing the strategic vulnerability of individuals following the experience of negative rather than positive outcome. Unique switch strategies related to each of these trial n outcomes were also identified: after losing participants were more likely to 'downgrade' their item (e.g., Rock followed by Scissors) but after drawing participants were more likely to 'upgrade' their item (e.g., Rock followed by Paper). Further repetition analysis revealed that participants were more likely to continue their specific cyclic item change strategy into trial n + 2. The data reveal the strategic vulnerability of individuals following the experience of negative rather than positive outcome, the tensions between behavioural and cognitive influences on decision making, and underline the dangers of increased behavioural predictability in other recursive, non-cooperative environments such as economics and politics.

Three-dimensional visualization of cellular and subcellular-structures in histological-tissues is essential for understanding the complexities of biological-phenomena, especially with regards structural and spatial relationships and pathologlical-diagnosis. Recent advancements in tissue-clearing technology, such as Magnified Analysis of Proteome (MAP), have significantly improved our ability to study biological-structures in three-dimensional space; however, their wide applicability to a variety of tissues is limited by long incubation-times and a need for advanced imaging-systems that are not readily available in most-laboratories. Here, we present optimized MAP-based method for paper-thin samples, Paper-MAP, which allow for rapid clearing and subsequent imaging of three-dimensional sections derived from various tissues using conventional confocal-microscopy. Paper-MAP successfully clear tissues within 1-day, compared to the original-MAP, without significant differences in achieved optical-transparency. As a proof-of-concept, we investigated the vasculature and neuronal-networks of a variety of human and rodent tissues processed via Paper-MAP, in both healthy and diseased contexts, including Alzheimer's disease and glioma. [ABSTRACT FROM AUTHOR]

One of the main objectives of microfluidic paper-based analytical devices is to present solutions particularly, for applications in low-resource settings. Therefore, screen-printing appears to be an attractive fabrication technique in the field, due to its overall simplicity, affordability, and high-scalability potential. Conversely, the minimum feature size attained using screen-printing is still rather low, especially compared to other fabrication methods, mainly attributed to the over-penetration of hydrophobic agents, underneath defined patterns on masks, into the fiber matrix of paper substrates. In this work, we propose the use of the over-penetration to our advantage, whereby an appropriate combination of hydrophobic agent temperature and substrate thickness, allows for the proper control of channel patterning, rendering considerably higher resolutions than prior arts. The implementation of Xuan paper and nail oil as novel substrate and hydrophobic agent, respectively, is proposed in this work. Under optimum conditions of temperature and substrate thickness, the resolution of the screen-printing method was pushed up to 97.83 ± 16.34 μm of channel width with acceptable repeatability. It was also found that a trade-off exists between achieving considerably high channel resolutions and maintaining high levels of repeatability of the process. Lastly, miniaturized microfluidic channels were successfully patterned on pH strips for colorimetric pH measurement, demonstrating its advantage on negligible sample-volume consumption in nano-liter range during chemical measurement and minimal interference on manipulation of precious samples, which for the first time, is realized on screen-printed microfluidic paper-based analytical devices. [ABSTRACT FROM AUTHOR]

Fabrication of unconventional energy storage devices with high stretchability and performance is challenging, but critical to practical operations of fully power-independent stretchable electronics. While supercapacitors represent a promising candidate for unconventional energy-storage devices, existing stretchable supercapacitors are limited by their low stretchability, complicated fabrication process, and high cost. Here, we report a simple and low-cost method to fabricate extremely stretchable and high-performance electrodes for supercapacitors based on new crumpled-graphene papers. Electrolyte-mediated-graphene paper bonded on a compliant substrate can be crumpled into self-organized patterns by harnessing mechanical instabilities in the graphene paper. As the substrate is stretched, the crumpled patterns unfold, maintaining high reliability of the graphene paper under multiple cycles of large deformation. Supercapacitor electrodes based on the crumpled graphene papers exhibit a unique combination of high stretchability (e.g., linear strain ~300%, areal strain ~800%), high electrochemical performance (e.g., specific capacitance ~196 F g-1), and high reliability (e.g., over 1000 stretch/relax cycles). An all-solid-state supercapacitor capable of large deformation is further fabricated to demonstrate practical applications of the crumpled-graphene-paper electrodes. Our method and design open a wide range of opportunities for manufacturing future energy-storage devices with desired deformability together with high performance. [ABSTRACT FROM AUTHOR]

Direct printing nanoparticle-based conductive inks onto paper substrates has encountered difficulties e.g. the nanoparticles are prone to penetrate into the pores of the paper and become partially segmented, and the necessary low-temperature-sintering process is harmful to the dimension-stability of paper. Here we prototyped the paper-based circuit substrate in combination with printed thermoplastic electrically conductive adhesives (ECA), which takes the advantage of the capillarity of paper and thus both the conductivity and mechanical robustness of the printed circuits were drastically improved without sintering process. For instance, the electrical resistivity of the ECA specimen on a pulp paper (6 × 10-5Ω·cm, with 50 wt% loading of Ag) was only 14% of that on PET film than that on PET film. This improvement has been found directly related to the sizing degree of paper, in agreement with the effective medium approximation simulation results in this work. The thermoplastic nature also enables excellent mechanical strength of the printed ECA to resist repeated folding. Considering the generality of the process and the wide acceptance of ECA technique in the modern electronic packages, this method may find vast applications in e.g. circuit boards, capacitive touch pads, and radio frequency identification antennas, which have been prototyped in the manuscript. [ABSTRACT FROM AUTHOR]