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Paper has the potential to dramatically reduce the cost of electronic components. In fact, paper is 10 000 times cheaper than crystalline silicon, motivating the research to integrate electronic materials on paper substrates. Among the different electronic materials, van der Waals materials are attracting the interest of the scientific community working on paper-based electronics because of the combination of high electrical performance and mechanical flexibility. Up to now, different methods have been developed to pattern conducting, semiconducting and insulating van der Waals materials on paper but the integration of superconductors remains elusive. Here, the deposition of NbSe2, an illustrative van der Waals superconductor, on standard copy paper is demonstrated. The deposited NbSe2 films on paper display superconducting properties (e.g. observation of Meissner effect and resistance drop to zero-resistance state when cooled down below its critical temperature) similar to those of bulk NbSe2., Paper has the potential to dramatically reduce the cost of electronic components but the integration of electronic materials is challenging. Here the integration of NbSe2, a van der Waals superconductor, on paper is demonstrated.

In this work, a novel paper-based analytical device (PAD) coupled to LED induced fluorescence (LIF) detection (fPAD) for the rapid, selective, and sensitivequantification of phenylalanine (Phe) in neonatal samples was developed. EnzymesPhenylalanine dehydrogenase (PheDH) and diaphorase were immobilized on a papermicrozone previously modified with zinc oxide nanoparticles (ZnONPs) coated withchitosan (CH-ZnONPs). Phe was extracted from the blood spots collected samples on filter paper and was mixed with nicotinamide adenine dinucleotide (NAD+) and resazurin. Then the mixture was deposited on the reaction microzone of the fPAD where PheDH converts the Phe and NAD+ to phenylpyruvate and NADH, respectively.Finally, NADH was oxidized by diaphorase with the consequent reduction fromresazurin to resorufin. This latter was detected by LIF using an excitation wavelength of 535 nm and an emission of 580 nm in a synchronized video microscope. We compare the responses of the PADs with and without nanomaterials to demonstrate the improved analytical performance of the developed devices. For this, the PADs were modified with the same concentration of horseradish peroxidase (HRP). The fluorescent signal obtained from the PADs with nanomaterials was higher than that of the unmodified PADs.Our method exhibited within- and between-assay variation coefficients below 5.23% and 6.67%, was 0.125 μM. The proposed fPAD allowed the simple, rapid, low-cost, and sensitivedetection of Phe in neonatal blood samples. Fil: Moreira, Cristian Matias. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Química de San Luis. Universidad Nacional de San Luis. Facultad de Química, Bioquímica y Farmacia. Instituto de Química de San Luis; Argentina Fil: Marin Barroso, Evelyn del Valle. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Química de San Luis. Universidad Nacional de San Luis. Facultad de Química, Bioquímica y Farmacia. Instituto de Química de San Luis; Argentina Fil: Pereira, Sirley Vanesa. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Química de San Luis. Universidad Nacional de San Luis. Facultad de Química, Bioquímica y Farmacia. Instituto de Química de San Luis; Argentina Fil: Raba, Julio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Química de San Luis. Universidad Nacional de San Luis. Facultad de Química, Bioquímica y Farmacia. Instituto de Química de San Luis; Argentina Fil: Messina, Germán Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Química de San Luis. Universidad Nacional de San Luis. Facultad de Química, Bioquímica y Farmacia. Instituto de Química de San Luis; Argentina Fil: Bertolino, Franco Adrián. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Química de San Luis. Universidad Nacional de San Luis. Facultad de Química, Bioquímica y Farmacia. Instituto de Química de San Luis; Argentina

Uniformly dispersing silver nanowires (AgNWs) in polymer matrices is of paramount importance for developing high-performance electromagnetic interference (EMI) shielding materials. Herein, new flexible and robust high-efficiency bacterial cellulose (BC)-based EMI shielding papers were developed via a modified step-by-step in situ biosynthesis method, in which, AgNWs were well distributed in the BC network. The BC nanofibers and AgNWs could form an effective entangled network with hydrogen bonding, efficiently strengthening the produced BC/AgNW papers. An electrical conductivity of 608365 S m1 was achieved for a BC/AgNW paper with a AgNW content of 36.5 wt%, which is superior to almost all AgNW-containing papers reported so far. Moreover, the BC/AgNW paper could sustain mechanical deformation and vigorous washing, without losing electrical conductivity. Additionally, this paper presents an ultrahigh specific EMI shielding effectiveness of 6400 dB mm1, which is higher than almost all previously reported AgNW-based polymer composites. The proposed approach in this study provides a facile and scalable fabrication route for producing flexible and highly conductive BC/AgNW papers, which are of great potential as electrically conductive components and EMI shielding elements in advanced applications., This work was supported by the National Natural Science Foundation of China (Grant Nos. 51973058 and 31870963), Jiangxi Provincial Natural Science Foundation (Grant No. 20202ACBL214007), Key Research and Development Program of Jiangxi Province (Grant No. 20192ACB80008) and the Key Project of Natural Science Foundation of Jiangxi Province (20202ACBL204013)., info:eu-repo/semantics/publishedVersion

For the first time, a novel analytical method based on a paper based enzymatic biosensor assisted by digital image processing and first-order multivariate calibration has been reported for rapid determination of nitrate in food samples. The platform of the biosensor includes a piece of Whatman filter paper impregnated with Griess reagent (3-nitroaniline, 1-naphthylamine and hydrochloric acid) and nitrate reductase. After dropping a distinct volume of nitrate solution onto the biosensor surface, nitrate reductase selectively reduces nitrate to nitrite and then the Griess reagent selectively reacts with nitrite to produce a red colored azo dye. Therefore, the color intensity of the produced azo dye is correlated with nitrate concentration. After image capture, the images were processed and digitized in the MATLAB environment by the use of an image processing toolbox and the vectors produced by the digital image processing step were used as inputs of the first-order multivariate calibration algorithms. Several multivariate calibration algorithms and pre-processing techniques have been used to build multivariate calibration models for verifying which technique offers the best predictions towards nitrate concentrations in synthetic samples and the best algorithm has been chosen for nitrate determination in potato, onion, carrot, cabbage and lettuce samples as real cases. Fil: Jalalvand, Ali R.. Kermanshah University Of Medical Sciences; Irán Fil: Mahmoudi, Majid. Kermanshah University Of Medical Sciences; Irán Fil: Goicoechea, Hector Casimiro. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional del Litoral; Argentina

The design of selective and efficient catalysts for electrochemical CO2 reduction is highly desirable yet still challenging, in particular, if the aim is to make them binder-free and self-standing. Here, we report a new and straightforward strategy to incorporate Ni single atoms into a commercially available carbon paper to prepare a self-standing electrode. This is accomplished by consecutive acid activation, adsorption of Ni2+ ions, and pyrolysis steps. Structural characterizations and calculations based on density functional theory consistently suggest that the Ni single atoms are coordinated with three N and one S atoms on the carbon paper. When used for CO2 electroreduction, the electrode exhibits an optimal selectivity (91%), activity (3.4 mA cm-2), and stability (at least 14 h) for CO production in water at an overpotential of 660 mV. This report may inspire the design and incorporation of single atoms of various metal types into carbon papers, or other kinds of carbon substrates, for a wide range of electrocatalytic processes. This journal is

A series of bio-based additives derived from citric acid as a renewable chemical source were synthesised. The chemical composition and purity of 1–4 were confirmed by the combination of NMR, FTIR and MS. The thermal behaviour, stability and degradation pattern of the compounds 1–4 were investigated by TGA and DSC methods. PVC based formulations with compounds 1–4 were prepared through a simple mixing method. The formulations were treated at different temperatures (130–210 °C) to investigate the potential of these materials in industrial curing settings. L*a*b* data were used to monitor and to assess a colour change in the coated paper samples; this showed a correlation with degradation data of the pure compounds 1–4. SEM analysis of the final paper samples indicated that the compounds 1–4 show gas formation within the cellular structure; however compounds 3 and 4 result in a glossy smooth surface. This study showed that the compounds 3 and 4 exhibit promising properties in PVC formulations for application in industrial settings.

Reduced graphene oxide (rGO) integrated nano-fibrillated cellulose (NFC) grafted poly(ionic liquid) (PIL) composite paper with enhanced hydrophobicity, ductility and toughness was fabricated by vacuum filtration of an aqueous dispersion of rGO/NFC-graft-PIL (NFC-g-PIL). The NFC-g-PIL was synthesized by growing PIL chains from the NFC surface using free radical polymerization of a pyridinium acrylate-based ionic liquid monomer. publishedVersion

Colorimetric detection methods that produce results readable by eye are important for diagnostic tests in resource-limited settings. In this work, we have compared three main types of colorimetric methods – enzymatic reactions, silver deposition catalyzed by gold nanoparticles, and polymerization-based amplification – in a paper-based immunoassay for detection of Plasmodium falciparum histidine-rich protein 2, a biomarker of malarial infection. We kept the binding events in the immunoassay constant in order to isolate the effect of the detection method on the outcome of the test. We have highlighted that the optimal readout time in a test can vary significantly – ranging from immediately after addition of a visualization agent to 25 minutes after addition of a visualization agent – depending on the colorimetric method being used, and accurate time keeping is essential to prevent false positives in methods where substantial color develops over time in negative tests. We have also shown that the choice of a colorimetric method impacts the calculated limit-of-detection, the ease of visual perception of the readout, and the total cost of the assay, and therefore directly impacts the feasibility and the ease-of-use of a test in field settings., Massachusetts Institute of Technology (Jonathan Whitney Fund), Massachusetts Institute of Technology (Haas Family Fellowship in Chemical Engineering), Massachusetts Institute of Technology (Charles E. Reed Faculty Initiative Fund)

The gluten-free diet is a unique, effective treatment for different conditions related to gluten consumption. Therefore, it is crucial the availability of new methodologies for the sensitive and specific determination of gluten content in food samples. Herein, a screen printed electrode modified with carbon nanofibers coupled to a paper immunoaffinity platform was reported for the determination of gliadin in foods samples. The paper microzone covalently functionalized with specific anti-gliadin antibodies was placed on the modified electrode surface for the electrochemical determination of gliadin. The surface of the electrode modified with carbon nanofibers was characterized by scanning electron microscopy (SEM) and cyclic voltammetry (CV), which showed the improved sensitivity of the modified surface. The developed device was evaluated using different flour samples obtaining a favorable response. The calculated limit of detection for the device in analyzed samples was 0.005 mg kg -1 and for the enzyme-linked immunosorbent assay was 1.5 mg kg -1 . The coefficient of variation (CV) for the determination of 20 μg kg -1 of gliadin was 4.11%. The disposable electrochemical sensor developed, represents an easy-to-use and low-cost strategy for the determination of gliadin in food samples. Fil: Marin Barroso, Evelyn del Valle. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Química de San Luis. Universidad Nacional de San Luis. Facultad de Química, Bioquímica y Farmacia. Instituto de Química de San Luis; Argentina Fil: Messina, Germán Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Química de San Luis. Universidad Nacional de San Luis. Facultad de Química, Bioquímica y Farmacia. Instituto de Química de San Luis; Argentina; Argentina Fil: Bertolino, Franco Adrián. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Química de San Luis. Universidad Nacional de San Luis. Facultad de Química, Bioquímica y Farmacia. Instituto de Química de San Luis; Argentina; Argentina Fil: Raba, Julio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Química de San Luis. Universidad Nacional de San Luis. Facultad de Química, Bioquímica y Farmacia. Instituto de Química de San Luis; Argentina; Argentina Fil: Pereira, Sirley Vanesa. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Química de San Luis. Universidad Nacional de San Luis. Facultad de Química, Bioquímica y Farmacia. Instituto de Química de San Luis; Argentina; Argentina

Reproduced from Ref. Green Chem., 2016,18, pp. 1117-1124. with permission from the Royal Society of Chemistry., Recent progress in portable and wearable electronics has promoted a growing demand for high-performance and flexible energy-storage devices that are abundant and affordable. Because reduced graphene oxide (rGO), originating from inexpensive graphite, serves as a higher-performance energy-storage electrode than conventional activated carbons and carbon nanotubes, research and development of rGO/polymer composite electrodes for flexible supercapacitors have become a center of attraction. However, the fabrication of rGO-based flexible electrodes frequently requires a long time with high-temperature treatment or toxic chemical treatment, resulting in the lack of scalability and eco-friendliness. Here we show a fast, scalable, and environment-compatible route to fabricate a high-performance rGO/cellulose paper supercapacitor electrode. Single-layer graphene oxide (GO) sheets and recycled waste pulp fibers were successfully fabricated into a paper composite by a well-established scalable papermaking process, followed by a room-temperature, additive-free, and millisecond-timescale flash reduction process. The as-prepared rGO/paper electrode had a high specific capacitance, up to 212 F g-1, for an all paper-based flexible supercapacitor, comparable to those of state-of-the-art rGO-based electrodes, while dramatically decreasing the reduction time of GO from the conventional hour timescale to milliseconds. This work will pave the way for green, flexible, and mass-producible energy-storage paper in future wearable electronics.

The transport of molecules and particles across adjacent flow streams is a key process in several operations implemented in microfluidic paper-based analytical devices (μPADs). Here, the transverse dispersion of analytes was quantitatively evaluated by theory and experiments. Different tests were carried out to independently measure the coefficients of both Brownian diffusion and mechanical dispersion under capillary-driven flow. The dispersion width was found to be independent of fluid velocity and analyte properties, and fully determined by the dispersivity coefficient, which is a characteristic of the paper microstructure. This information introduces a change of paradigm for the design of mixers, diluters, and concentration gradient generators on μPADs; therefore, efforts were made to rationalize these operations on paper. The research reveals that mixers and concentration gradient generators can be much more efficient than their counterparts made on conventional microchannels; in contrast, separators such as the H-filter need to be appropriately engineered on paper, because the working principle can be hindered by mechanical dispersion. The knowledge gained throughout this work would contribute to the design of μPADs with a new level of precision and control over the formation of localized concentration profiles. Fil: Urteaga, Raul. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Física del Litoral. Universidad Nacional del Litoral. Instituto de Física del Litoral; Argentina Fil: Elizalde, Emanuel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Física del Litoral. Universidad Nacional del Litoral. Instituto de Física del Litoral; Argentina Fil: Berli, Claudio Luis Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Desarrollo Tecnológico para la Industria Química. Universidad Nacional del Litoral. Instituto de Desarrollo Tecnológico para la Industria Química; Argentina

In this work, an application of a design of experiments approach for the optimization of an isoniazid assay on a single-area inkjet-printed paper-based analytical device (PAD) is described. For this purpose, a central composite design was used for evaluation of the effect of device geometry and amount of assay reagents on the efficiency of the proposed device. The factors of interest were printed length, width, and sampling volume as factors related to device geometry, and amounts of the assay reagents polyvinyl alcohol (PVA), NH4OH, and AgNO3. Deposition of the assay reagents was performed by a thermal inkjet printer. The colorimetric assay mechanism of this device is based on the chemical interaction of isoniazid, ammonium hydroxide, and PVA with silver ions to induce the formation of yellow silver nanoparticles (AgNPs). The in situ-formed AgNPs can be easily detected by the naked eye or with a simple flat-bed scanner. Under optimal conditions, the calibration curve was linear in the isoniazid concentration range 0.03-10 mmol L-1 with a relative standard deviation of 3.4% (n = 5 for determination of 1.0 mmol L-1). Finally, the application of the proposed device for isoniazid determination in pharmaceutical preparations produced satisfactory results.

Electrically conductive flexible carbon papers were prepared, based on hydroxyl functionalized few layer graphene (G-OH). G-OH was obtained from the reaction of KOH with nanosized graphite with a very high surface area (HSAG), greater than 300 m2 g−1, and with high shape anisotropy, with the help of mechanical and thermal energy. Wide angle X-ray and Raman analyses showed that the core of G-OH had the structure of infinite and ideal graphene layers and that the interlayer distance between the few stacked graphene layers was the same as in pristine HSAG. Hydroxyl groups were thus essentially located in peripheral positions. High resolution transmission electron microscopy revealed the presence of graphene aggregates made by a number of layers as low as 6. Stable water suspensions were obtained, with concentrations up to 4 mg mL−1. Mild centrifugation of such suspensions had interesting efficiency as a method for producing few layer graphene: about 35% by mass of pristine HSAG was isolated as few layer graphene from supernatant suspensions. Flexible and electrically conductive carbon papers were prepared by coating a paper support with a G-OH water suspension. This work demonstrates that carbon papers can be prepared without adopting the traditional oxidation–reduction procedure, avoiding harsh reaction conditions, dangerous and toxic reagents, solvents and catalysts.

The process of stabilization is essential in the production of carbon fibers from lignins. During stabilization, the initially thermoplastic lignin polymer is converted to a thermoset polymer allowing for high-temperature treatment without a change in shape. In this work, hardwood (HKL) and softwood (SKL) Kraft lignins were stabilized in air at temperatures between 190 and 340 °C before carbonization at 800 °C in a nitrogen atmosphere. Due to the differences in side-chain linkages, functional groups and molar mass, the lignins exhibit different structural changes upon stabilization and hence develop different porosities upon carbonization. Both lignins undergo major crosslinking reactions in the side chains at low temperatures and degradation reactions at high temperatures during stabilization. Crosslinking gives rise to narrow pore size distributions with mainly (sub-) nanometer pores, whereas degradation reactions lead to a more open pore structure with additional mesoporosity (>2 nm). When both types of reactions take place simultaneously, highly accessible (sub-) nanoporosity can be effectively created, which boosts the performance of supercapacitors operating in 6 M KOH(aq). This effect terminates when the crosslinking reactions cease and mainly degradation reactions take place, which occurs in HKL at 340 °C. SKL shows both a lower degree of crosslinking and degradation and hence develops less specific surface area. The optimum performance in an aqueous alkaline supercapacitor is achieved with HKL stabilized at 310 °C. It shows a specific gravimetric capacitance of 164 F g−1 at 0.1 A g−1 and 119 F g−1 at 250 A g−1 with a capacitance retention of more than 90% after 10 000 cycles. M. J. M. L. and D. C. A. thank Spanish Ministry of Science, Innovation and Universities and FEDER (project RTI2018-095291-B-I00) for financial support. C. P. G. and C. O'K. thank Shell. MMT and PS thank RISE AB for co-funding Philipp Schlee's PhD position.

International audience; A rapid and effective dissolution and activation of cellulose was demonstrated by a reversible reaction of CO2 with the hydroxyl groups of the cellulose backbone in the presence of 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU). The obtained carbonate complex of cellulose was subsequently subjected to in situ derivatization with succinic anhydride without the need of any additional catalyst under very mild conditions. As a result of optimization studies, cellulose was succesfully converted to cellulose succinates with degrees of substitution (DS) ranging from 1.51 to 2.64, depending on the reaction conditions and the molar ratio of succinic anhydride. The optimized reaction conditions were successfully applied to different types of cellulose samples including microcrystalline cellulose (MCC) and organosolv wood pulp (WP), exhibiting similar conversions. Furthermore, the carboxylic acid moiety, introduced by the succinylation, was further converted via Passerini three-component reactions (Passerini-3CR) and Ugi four-component reactions (Ugi-4CR). 31 P NMR revealed the quantitative conversions of carboxylic acid moieties on the cellulose backbone under mild conditions. The obtained products were thoroughly characterized by ATR-IR, 1 H, 13 C, and 31 P NMR spectroscopies as well as by gel permeation chromatography (GPC). Thermal properties of the obtained products were investigated by differential scanning calorimetry (DSC) and by thermogravimetric analysis (TGA), revealing glass transitions (Tg) for all the Passerini and Ugi products between 76-116 °C and high thermal stability between 263-290 °C. The reported methodology represents a very mild, highly efficient and sustainable route for the dissolution of cellulose and the synthesis of cellulose succinates. The subsequent modifications of the obtained cellulose succinates via multicomponent reactions resulted in materials with improved thermal properties and offers a straightforward and versatile modification strategy for cellulose.

The valorization of vegetable waste can create opportunities to produce new valuable bioplastics.In thisstudy, a one-step process to fully convert a variety of vegetable waste materials into bioplasticfilms is reported. The process is carried out in a diluted aqueous HCl solution at room temperature,it is easily scalable, and with no environmental concerns associated with the use of organic ordangerous chemicals. The generated bioplastics arecompletely biodegradable and environmentallyfriendly. Freestanding, flexible bioplastic films were obtained from vegetable waste like carrot,parsley, radicchio and cauliflower. They have similar mechanical properties with other bioplastics, like thermoplastic starch, and showed to have little migration in a food simulant. The color andthe functional properties (i.e. antioxidant capability) of the starting vegetables are preserved inthe bioplastics, thanks to the mild conditions of the fabrication process. The new conversionprocess allows the blending of the bioplastics with other natural or synthetic polymers, in order to improve their mechanical and gas barrier properties, like the oxygen permability (OP), thusexpanding their field of applications. Poly vinyl alcohol (PVA)/carrot bioplastic film showed an OPof 31.2 cm3 μm m−2 day−1 kPa−1, which is lower than the OP for other synthetic films, like highdensity polyethylene films (HDPE), and similar to edible materials like chitosan. &nbsp

Environmental concerns have brought attention to the requirement for more efficient and renewable processes for chemicals production. Lignin is the second most abundant natural polymer, and might serve as a sustainable resource for manufacturing fuels and aromatic derivatives for the chemicals industry after being depolymerised. In this work, the mediator 2,2′-azino-bis(3-ethylbenthiazoline-6-sulfonic acid) diammonium salt (ABTS), commonly used with enzyme degradation systems, has been evaluated by means of cyclic voltammetry (CV) for enhancing the oxidation of the non-phenolic lignin model compound veratryl alcohol and three types of lignin (organosolv, Kraft and lignosulfonate) in the ionic liquid 1-ethyl-3-methylimidazolium ethyl sulfate, ([C2mim][C2SO4]). The presence of either veratryl alcohol or organosolv lignin increased the second oxidation peak of ABTS under select conditions, indicating the ABTS-mediated oxidation of these molecules at high potentials in [C2mim][C2SO4]. Furthermore, CV was applied as a quick and efficient way to explore the impact of water in the ABTS-mediated oxidation of both organosolv and lignosulfonate lignin. Higher catalytic efficiencies of ABTS were observed for lignosulfonate solutions either in sodium acetate buffer or when [C2mim][C2SO4] (15 v/v%) was present in the buffer solution, whilst there was no change found in the catalytic efficiency of ABTS in [C2mim][C2SO4]–lignosulfonate mixtures relative to ABTS alone. In contrast, organosolv showed an initial increase in oxidation, followed by a significant decrease on increasing the water content of a [C2mim][C2SO4] solution.

Electrodeposition of nanoparticles on graphene is described, providing a convenient approach for making graphene–nanoparticle composites as well as insight into the electrochemical activity of graphene. To avoid complications due to surface contamination, chemical vapour deposition grown graphene was used directly on its copper growth substrate. We identify and isolate two nanoparticle growth processes for both silver and palladium deposition: electroless deposition that appears to occur preferentially at defects and edges next to the underlying copper, and conventional electrodeposition that occurs uniformly across the graphene surface. We show that control over electrodeposited nanoparticle size and number density can be achieved through varying electrodeposition conditions. The resultant nanoparticles are homogeneously dispersed across the graphene surface, suggesting that here both edge-plane and basal-plane graphene sites are electroactive. These results demonstrate that, as with other carbon nanostructures, electrodeposition is a powerful and flexible tool for forming functional composites with graphene.

Organic semiconductor materials are widely used in the field of organic electronic devices due to their wide variety, low price, and light weight. However, their developments are still restrained by their low stability and carrier mobility. Density functional theory (DFT) was used to study the influence of doped oxygen group elements (O, S, Se, and Te) on the properties of organic semiconductor materials (seven-membered benzothiophene, o-pentacene, thiophene derivatives, and pentacene) in this paper. Based on the calculation of EHOMO, ELUMO, ΔE, and total energy, the performances of organic semiconductor materials without and with doped elements were compared, and it was found that the doping of multi-element Te makes the material have high stability and potential high mobility. For these studied organic semiconductor materials, when the atoms of the doped site change in the order of O, S, Se, and Te, the carrier mobility gradually increases, and the molecules show a tendency of stability. In this paper, promising doping elements and doping methods for these studied molecules are determined through calculations and screening out suitable materials more efficiently and economically without a large amount of repetitive experimental work, which may provide a theoretical basis and guidance for preparing high-performance organic semiconductor materials.

In this reply, we address the concerns that were raised about our paper on CsPbBr3 single crystals. M. Szafranski criticized the dielectric and DSC data in our original paper claiming that they were a ´ ffected by the experimental artefacts or poor quality of the investigated single crystals, as his DSC and dielectric data did not show any low temperature anomalies in CsPbBr3. We argue in this reply that our main conclusions were not made based on the DSC and dielectric experiments. Here, we emphasize the importance of other experiments like EPR and XRD that were performed to understand if there are any structural transformations of CsPbBr3 at low temperatures. We believe that M. Szafranski did not take ´ into account all the discussion that was presented in our original paper. We hope to clear the doubts in this reply. published

25I-NBOH is a new potent serotonin 5-HT2A receptor agonist recently identified in blotter paper seizures. This compound is a thermolabile molecule that undergoes degradation under routine gas chromatography– mass spectrometry analysis leading to misidentification. In this paper, the voltammetric behavior of 25I-NBOH and 2C-I was investigated and their electroanalytical characteristics were determined. A novel, fast and sensitive electrochemical method for the detection of 25I-NBOH using a SPCE is described and all method characteristics demonstrated the method to be analytically valuable. This method is selective and achieves full differentiation between 25I-NBOH, 2C-I and 25I-NBOMe.

In this paper, small angle X-ray scattering has been used to study a series of ionic liquids, alkylammonium alkanoates ([N0 0 0 n][CmCO2]), with varying alkyl chain lengths in the cation and the anion. We investigate the behaviour and the structure of such ionic liquids in their neat state, and in binary mixtures with water. To the best of our knowledge, this is the first structural study dealing with the behaviour of propylammonium propanoate [N0 0 0 3][C2CO2], butylammonium propanoate [N0 0 0 4][C2CO2], propylammonium butanoate [N0 0 0 3][C3CO2] and butylammonium butanoate [N0 0 0 4][C3CO2] when mixed in water. Generally, in the ionic liquids containing alkyl chains on both the cation and the anion, the correlation distance and the resulting scattering peak, which signal intermediate range order, are affected equally by both of the chains. The interesting result obtained regarding these systems is that the shift of the pre- and principal peaks with the addition of water depends on the overall molar concentration of the chains and is generally cumulative. Although, for a given sum of cation and anion chain lengths, the shift is reliant on the cation-anion combination in the neat state, it is not the case in their mixtures with water. In some recent papers, it has been reported that with addition of water, the pre-peak position remains constant, but our results show a shift in both pre- and principal Q peaks.

Understanding the interplay between topology and ordering in systems on curved manifolds, governed by anisotropic interactions, takes a central role in many fields of physics. In this paper, we investigate the effects of lattice symmetry and local positional order on orientational ordering in systems of long-range interacting point quadrupoles on a sphere in the zero temperature limit. Locally triangular spherical lattices show long-range ordered quadrupolar configurations only for specific symmetric lattices as strong geometric frustration prevents general global ordering. Conversely, the ground states on Caspar-Klug lattices are more diverse, with many different symmetries depending on the position of quadrupoles within the fundamental domain. We also show that by constraining the quadrupole tilts with respect to the surface normal, which models interactions with the substrate, and by considering general quadrupole tensors, we can manipulate the ground state configuration symmetry., 16 pages, 8 figures, Supplemental material

Total reflection X-ray fluorescence (TXRF) is a powerful technique for trace elemental analysis of various liquid samples. A small volume of the liquid sample is dropped onto a flat substrate, and the dried residue is measured using TXRF. Usually, the substrate surface is treated with a silicone solution to make it hydrophobic. Such hydrophobic substrates are useful to concentrate the analyte at a small point, leading to a dot-type residue. However, the solution sample will provide a residue with a height of several tens of μm depending on the matrix of the solution, in which self-absorption is a serious problem. In this paper, the authors applied a He atmospheric pressure plasma jet (APPJ) treatment to a glass substrate to obtain a hydrophilic surface. The chemical properties of the glass substrate surface were drastically changed by the application of the He APPJ. The contact angle of the liquid droplet was 5.2° on the APPJ-treated glass, while it was 88.8° on the glass with a silicone layer. A droplet of the liquid solution smoothly spread over the APPJ-treated glass substrate, leading to a thin film-like residue. The recovery and detection limits for TXRF analysis of a standard solution sample were improved especially for low-Z elements by using the APPJ-treated glass substrates. This new sample preparation technique was also applied for TXRF analysis of a red wine sample. We found that this hydrophilic glass substrate gave a film-like residue from a small droplet of the red wine. Reasonable TXRF quantitative results were obtained by the Ga internal standard method. The preliminary experimental results suggested that the film-type residue produced on the APPJ-treated substrate was effective in decreasing the matrix effect especially for low-Z elements.

Polymer self-assembly is used to form nanomaterials with a wide range of structures. While self-assembly of polymers in bulk has been thoroughly explored, the same process in solution remains widely used but partially unresolved, due to the formation of structures which are often kinetically trapped. In this paper we report kinetic state diagrams of polystyrene-b-poly(ethylene oxide) block copolymer in water by changing the solvent-switch assembly conditions. We study 36 different conditions for a single block copolymer, exploring three parameters: polymer concentration, temperature and rate addition of selective solvent. The data shows that polymer concentration plays an important role in determining which morphologies are accessible within a given set of experimental parameters and provides evidence that vesicles can evolve into particles with complex internal structures, supportive of recent mechanistic studies. Most importantly, the data shows a complex relationship between all parameters and the resulting kinetically trapped morphologies indicating that combinedin situandex situstudies are required to gain a fundamental understanding of kinetically controlled block copolymer assembly processes.

This paper presents the design and fabrication of a magnetic double network (DN) composite, which consists of permanent magnet chains embedded in an elastomer matrix, and was capable of large yet fully recoverable deformation. The initially connected magnets served as reusable sacrificial components in the composite. The strong magnetic attraction between neighboring magnetics endowed the composite with the high strength while the compliance of the elastomer matrix provided the high extensibility. Having a similar mechanism as DN gels, the composite was found to be significantly tougher than either of the constituents. The nonlinear behavior in the composite separated it into two coexisting phases - a softer phase with separated magnet links and a stiffer phase with connected magnet links - which led to the stress plateau on the tensile curve. Further stretching was manifested by the growth of the disconnected softer phase at the expense of the linked stiffer phase, until all magnets were separated. The unloading curves appeared drastically different from the loading curves, as the force needed to separate two magnets was much higher than the force at which two separated magnets snapped back. Such asymmetry between loading and unloading was the main cause of the hysteresis in the stress-strain curve and the energy dissipation. To further understand the physical mechanism and the damage process of the magnetic DN composite, a simple model was developed to examine the deformation and damage dissipation process of composite. With very few parameters, the model predictions agree qualitatively with the measured properties of the material, and the difference can be further reduced by accounting for the interfacial friction/adhesion, a second means of energy dissipation. With a combination of desired properties including high stretchability, self-healing, and high toughness, the magnetic DN composite is a viable candidate for various applications.

Soft elastomers with their ability to integrate strain-adaptive stiffening and coloration have recently received significant research attention for application in artificial muscle and active camouflage. However, there is a lack of theoretical understanding of their complex molecular dynamics and mechanochromic coupling/decoupling. In this study, a topological dynamics model is proposed to understand the anchoring-mediated topology signature of self-assembled elastomers. Based on the constrained molecular junction model, a free-energy function is firstly formulated to describe the working principles of strain-adaptive stiffening and coloration in the self-assembled elastomer. A coupled ternary "rock-paper-scissors" model is proposed to describe the topological dynamics of self-assembly, mechanochromic coupling and mechanoresponsive stiffening of the self-assembled elastomers, in which there are three fractal geometry components in the topology network. Finally, the proposed models are verified using the experimental results reported in the literature. This study provides a fundamental approach to understand the working mechanism and topological dynamics in the self-assembled elastomers, with molecularly encoded stiffening and coloration.

This paper describes a straightforward electrochemical method for rapid and robust urinary microRNA (miRNA) quantification using disposable biosensors that can discriminate between urine from diabetic kidney disease (DKD) patients and control subjects. Aberrant miRNA expression has been observed in several major human disorders, and we have identified a urinary miRNA signature for DKD. MiRNAs therefore have considerable promise as disease biomarkers, and techniques to quantify these transcripts from clinical samples have significant clinical and commercial potential. Current RT-qPCR-based methods require technical expertise, and more straightforward methods such as electrochemical detection offer attractive alternatives. We describe a method to detect urinary miRNAs using diazo sulfonamide-modified screen printed carbon electrode-based biosensors that is amenable to parallel analysis. These sensors showed a linear response to buffered miR-21, with a 17 fM limit of detection, and successfully discriminated between urine samples (n = 6) from DKD patients and unaffected control subjects (n = 6) by differential miR-192 detection. Our technique for quantitative miRNA detection in liquid biopsies has potential for development as a platform for non-invasive high-throughput screening and/or to complement existing diagnostic procedures in disorders such as DKD., In this study we have developed an electrochemical microRNA biosensor sensitive to 17 fM and capable of detecting an established downregulation of urinary miR-192 in diabetic kidney disease patients.

There is evidence that iron (Fe) and selenium (Se) are dysregulated in neurodegenerative diseases (ND). Disease-specific impacts on concentration distributions are anticipated for Fe (the most abundant transition metal), and Se (present at trace levels), necessitating imaging strategies that enable their simultaneous quantification in ND pre-clinical models or post-mortem samples. This paper describes methodology for the production of matrix-matched tissue homogenates containing both Fe and Se at pathophysiological levels and investigates their feasibility as calibration standards for quantitative imaging of these elements. For the first time the effect of elemental species-specific calibration on the quality of LA-ICP-MS data is evaluated by investigating whether tissue matched standards spiked with inorganic Fe and Se are suitable alternatives to those spiked with specific species (e.g. ferritin or selenoproteins). To achieve this, the correlation of the calibration graph slopes (inorganic versus metalloprotein-spiked) as well as the homogeneity of the calibration standards were monitored over a laser energy range of 1 to 6 J cm−2. For Fe, such slopes were found to agree well within the associated measurement error. In contrast, the choice of calibrant for Se was observed to have a greater impact; at 1 J cm−2 the regression slope for the selenoprotein calibration was approximately 36% less than that of inorganic Se calibration. Finally, the limit of detection of Se was improved 2-fold by mixing 25% (v/v) methanol with the laser-induced aerosol in a chamber prior to introduction into the ICP, making the simultaneous detection of both elements possible at physiologically relevant concentrations.

Exosomes have been recognized as promising sources of biomarkers for early cancer diagnosis due to their important role in the occurrence and metastasis of cancer, and so the development of a sensitive low-cost detection method for exosomes is highly desirable. In this paper, we report a fluorescence method for the competitive detection of exosomes based on an aptamer specific to CD63 (an exosome transmembrane protein). Aptamer-modified magnetic beads were hybridized with a Cy3-labeled short sequence complementary to a region of the aptamer. In the presence of exosomes, the CD63 on the exosomes bound to the aptamer, resulting in the shedding of the short sequence into the supernatant. The quantity of the exosomes could be estimated by detecting the fluorescence intensity in the supernatant. This method could detect exosomes at a concentration as low as 1.0 × 105 particles per μL under optimal conditions, and the feasibility of the method for exosome detection in complex clinical samples was also proved using simulated serum samples. The detection cost and difficulty are significantly reduced compared to conventional methods, while ensuring sensitivity, and so this method provides a basis for subsequent exosome detection in specific cancer cells.

Biopharmaceuticals are used to treat a range of diseases from arthritis to cancer, however, since the advent of these highly specific, effective drugs, there have been challenges involved in their production. The most common biopharmaceuticals, monoclonal antibodies (mAbs), are vulnerable to aggregation and precipitation during processing. Freeze thaw cycles (FTCs), which can be required for storage and transportation, can lead to a substantial loss of product, and contributes to the high cost of antibody production. It is therefore necessary to monitor aggregation levels at susceptible points in the production pathway, such as during purification and transportation, thus contributing to a fuller understanding of mAb aggregation and providing a basis for rational optimisation of the production process. This paper uses attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy and spectroscopic imaging to investigate the effect of these potentially detrimental FTCs on protein secondary structure in both static wells and under flowing conditions, using lysozyme as a model protein. The results revealed that the amount of protein close to the surface of the ATR crystal, and hence level of aggregates, increased with increasing FTCs. This was observed both within wells and under flow conditions, using conventional ATR-FTIR spectroscopy and ATR-FTIR spectroscopic imaging. Interestingly, we also observed changes in the Amide I band shape indicating an increase in β-sheet contribution, and therefore an increase in aggregates, with increasing number of FTCs. These results show for the first time how ATR-FTIR spectroscopy can be successfully applied to study the effect of FTC cycles on protein samples. This could have numerous broader applications, such as in biopharmaceutical production and rapid diagnostic testing., ATR-FTIR spectroscopy and spectroscopic imaging was used in combination with PDMS flow cells, and effectively applied to monitor the effect of repeat freeze thaw cycles (FTCs) on protein secondary structure, revealing higher aggregate levels with increasing FTCs.

Hydrogen is a major industrial chemical whose manufacture is responsible for ∼3% of global carbon dioxide emissions. >95% of hydrogen is made via reforming fossil fuels which typically co-produces hydrogen and waste carbon dioxide. Nearly all other hydrogen is co-produced with other commodity chemicals. Unfortunately, many alternative, clean hydrogen production processes are small-scale because they require major reductions in capital cost or energy prices to be economical enough for industry. Because the climate problem is urgent, and the economics of future energy is uncertain, this paper seeks to expand the options for producing industrial-scale, clean hydrogen under common, present-day economic conditions. First, we build a model to understand the economic and carbon dioxide emissions constraints of sulfur electrolysis which is an emerging process that cogenerates hydrogen and co-salable sulfuric acid and has the potential to produce up to 36% of the world's current hydrogen demand under present-day, average US economic conditions. We also use our model to evaluate water electrolysis, which cogenerates hydrogen and waste oxygen, but is not economical under present-day average US economic conditions. We then propose criteria for identifying clean hydrogen production chemistries. Using these criteria, we find enough reactions to have the combined potential to make over 150% of the world's industrial hydrogen needs under present-day, average US economic conditions while reducing cost and reducing or eliminating CO2 emissions. Given the urgency of the climate problem, we believe that an economic analysis, such as this is crucial to near-term CO2 emissions reductions.

Acoustic manipulation of microparticles and cells, called acoustophoresis, inside microfluidic systems has significant potential in biomedical applications. In particular, using acoustic radiation force to push microscopic objects toward the wall surfaces has an important role in enhancing immunoassays, particle sensors, and recently microrobotics. In this paper, we report a flexural-wave based acoustofluidic system for trapping micron-sized particles and cells at the soft wall boundaries. By exciting a standard microscope glass slide (1 mm thick) at its resonance frequencies, Lab on a Chip, 21 (3), ISSN:1473-0197, ISSN:1473-0189

The ability to easily and reliably predict quantum interference (QI) behaviour would facilitate the design of functional molecular wires with potential applications in switches, transistors and thermoelectric devices. A variety of predictive methods exist, but with the exception of computationally-expensive DFT-based charge transport simulations, these often fail to account for the experimentally observed behaviour of molecules that differ significantly in structure from alternant polycyclic aromatic hydrocarbons. By considering a range of prior studies we have developed an extension to predictive “curly arrow rules”. We show that, in most cases, these extended curly arrow rules (ECARs) can rationalise the type of QI exhibited by conjugated molecular wires containing heteroatoms, cross-conjugation and/or non-alternant structures. ECARs provide a straightforward “pen-and-paper” method to predict whether a molecular wire will display constructive, destructive or “shifted destructive” QI,i.e.whether or not its transmission function would be expected to show an antiresonance, and if this antiresonance would occur close to the Fermi energy or be shifted elsewhere.

The accurate and precisive monitoring of aflatoxin B1 (AFB1), which is one of the most hazardous mycotoxins, especially in agricultural products, is significant for human and environmental health. AFB1 generally contaminates agricultural products such as corn and feedstuff. In this paper, a novel electrochemical AFB1 immunosensor was constructed based on Ag nanocubes (AgNCs) incorporated trigonal metallic MoS2nanosheets with 1T phase (AgNCs/1T-MoS2) as signal amplification and gold nanoparticles/porous graphene nanoribbon (AuNPs/PGNR) as an electrochemical sensor platform. First, the chronoamperometry method was implemented to provide electrodeposition of AuNPs on PGNR following chemical reduction of PGNR. Immobilization of the primer AFB1 antibody was performedviaamino-gold affinity between primer antibody and AuNPs/PGNR composite. Subsequently, the conjugation of seconder antibody to AgNCs/1T-MoS2was performed by strong ?-? and electrostatic interactions. To describe the surface morphology and elemental composition of the prepared electrochemical AFB1 immunosensor, physicochemical characterization techniques such as scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and X-ray diffraction (XRD) were used. Furthermore, cyclic voltammetry (CV), differential pulse voltammetry (DPV), and electrochemical impedance spectroscopy (EIS) techniques were used to evaluate the immunosensor's electrochemical performance. The developed electrochemical AFB1 immunosensor offered a good sensitivity with a detection limit (LOD) of 2.00 fg mL?1. Finally, an electrochemical AFB1 immunosensor with satisfactory selectivity, stability and reusability was applied in wheat samples with high recovery. © The Royal Society of Chemistry and the Centre National de la Recherche Scientifique 2021.

This paper demonstrates a carbene stabilized precursor [Cu(tBuNHC)(hmds)] with suitable volatility, reactivity and thermal stability, that enables the spatial plasma-enhanced atomic layer deposition (APP-ALD) of copper thin films at atmospheric pressure. The resulting conductive and pure copper layers were thoroughly analysed and a comparison of precursor and process with the previously reported silver analogue [Ag(tBuNHC)(hmds)] revealed interesting similarities and notable differences in precursor chemistry and growth characteristics. This first report of APP-ALD grown copper layers is an important starting point for high throughput, low-cost manufacturing of copper films for nano- and optoelectronic devices.

This paper investigates the control of effective magnetic anisotropy in Permalloy linear chain arrays, achieved by tuning the symmetry arrangement of the ellipsoidal nanomagnets and the film thickness. When the ellipsoidal nanomagnets are coupled along their easy axis, stronger effective magnetic anisotropy is achieved compared to when the nanomagnets are coupled along their hard axis. A clear transition from a single domain state to a combination of complex flux closure states such as a vortex or double vortices is observed at different applied field angles when the film thickness is varied in the range from 20 nm to 100 nm. Tunable microwave absorption spectra, obtained by ferromagnetic resonance spectroscopy, established the complex interplay between the shape anisotropy and magnetostatic interactions, which becomes more intriguing at different film thicknesses and applied field angles. The micromagnetic simulations are in good agreement with the experimental results. Our results demonstrate possible ways of manipulating the effective magnetic anisotropy in arrays of nanomagnets for magnonic and microwave applications.

The interface between solid electrolytes and lithium metal electrodes determines the performance of an all-solid-state battery in terms of the ability to demand high power densities and prevent the formation of lithium dendrites. This interface depends strongly on the nature of the solid electrolyte surface in contact with the metallic anode. In the garnet electrolyte/Li system, most papers have focused on the role of current inhomogeneities induced by void formation in the Li metal electrode and the presence of insulating reaction layers following air exposure. However, extended defects in the solid electrolyte induced by chemical and/or structural inhomogeneities can also lead to uneven current distribution, impacting the performance of these systems. In this work, we use complementary surface analysis techniques with varying analysis depths to probe chemical distribution within grains and grain boundaries at the surface and in the bulk of garnet-type electrolytes to explain their electrochemical performance. We show that morphology, post-treatments and storage conditions can greatly affect the surface chemical distribution of grains and grain boundaries. These properties are important to understand since they will dictate the ionic and electronic transport near the interfacial zone between metal and electrolyte which is key to determining chemo-mechanical stability.

As abundant and renewable materials with excellent mechanical and functional properties, cellulose nanomaterials are utilized in advanced structural, optical and electronic applications. However, in order to further improve and develop new cellulose nanomaterials, a better understanding of the interplay between the self-assembled materials and their building blocks is crucial. This paper describes the structure–property relationships between cellulose nanofibrils (CNFs) and their resulting self-assembled structures in the form of hydrogels and aerogels. Rheological experiments revealed that the transition from viscous to elastic state with the corresponding evolution of the properties of the CNF dispersion depends on the aspect ratio and can be described in terms of the dynamic overlap concentration. The elastic shear modulus was dependent on the aspect ratio at very low CNF concentrations, reaching a plateau, where only the concentration of CNFs was relevant. This transition point in shear modulus was exploited to determine the mesh size of the fibril network, which was found to be in excellent agreement with predictions from scaling arguments. These findings highlight the possibility to tune the self-assembled materials response directly from the bottom-up by the CNF particle structure and thus, suggest new assembly routes starting directly from the CNF design., Structure-property studies of cellulose nanofibril (CNF) gels revealed the influence of CNF morphology on the gel properties and a transition point in the shear modulus of the gels was exploited to determine the mesh size of the fibril network.

This paper describes the development of an on-chip nucleic acid (NA) extraction assay from whole blood using a centrifugal microfluidic platform that allows for pneumatic actuation of liquids during rotation. The combination of pneumatic and centrifugal forces makes it possible to perform fluidic operations without the need for integrating active control elements on the microfluidic cartridge. The cartridge is fabricated from thermoplastic polymers (e.g., Zeonor 1060R) and features a simple design that is compatible with injection molding. In addition, the cartridge is interfaced with two external vials for off-chip storage of the blood sample and retrieval of the eluted NA solution, respectively. On-chip capture of NAs is performed using an embedded solid-phase extraction matrix composed of commercial glass microfiber filters (Whatman GF/D and GF/F). The yield of the automated, on-chip extraction protocol, determined by measuring absorbance at 260 nm, is comparable to some of the best manually operated kits (e.g., Qiagen QIAamp DNA Mini Kit) while providing low assay-to-assay variability due to the high level of control provided by the platform for each processing step. The A260/A280 and A260/A230 ratios of the absorbance spectra also reveal that protein contamination of the sample is negligible. The capability of the pneumatic platform to circulate air flux through the microfluidic conduit was used to dry leftover ethanol residues retained in the capture matrix during washing. This method, applied in combination with localized heating, proved effective for reducing ethanol contamination in eluted samples from ∼12% to 1% (v/v).

Morphological control of gold nanocrystals is important as their catalytic and optical properties are highly shape dependent. In this paper we report the shapes of gold nanocrystals which deviate from the equilibrium Wulff shape due to the influence of the SrTiO3 single crystal substrates. The gold crystals are characterized by scanning tunneling microscopy (STM) and scanning electron microscopy (SEM). The nanocrystals have an equilibrium shape of a truncated octahedron with {111} and {001} facets. On all three substrate surfaces, i.e., SrTiO3(001)-(2 × 1), SrTiO3(001)-c(4 × 2), and SrTiO3(111)-(4 × 4) + (6 × 6), the height-to-width ratio of the gold crystals is not a constant as would be expected for equilibrium crystals, but instead it increases with crystal height. We propose that as the crystals increase in size, their aspect ratio heightens to relax the interfacial strain. The ratio between the {111} and {001} surface areas of our gold crystals is found to differ on the three substrates, which we speculate is due to the selective adsorption of surfactants on the {111} and {001} gold facets resulting from the different substrate surfaces. Reentrant facets of gold crystals that should be present according to their Wulff shape are not observed because these concave sites typically grow out due to kinetic considerations. This study demonstrates the significant effect of the crystal facet termination and surface reconstruction of an oxide substrate on the shape of supported gold nanocrystals.

This paper presents a methodology for cell detection and counting using a device that combines PDMS (polydimethylsiloxane) microfluidic multilayer channels with a single solid state micropore. Optimal conditions of solid-state micropore fabrication from crystalline silicon wafers are presented. Micropores of varying size can be obtained by directly etching using an etchant agent concentration of 50 wt% KOH, at varying temperatures (40, 60, 80 °C) and voltages (100, 500, 1000 mV). Scanning Electron Microscopy (SEM), and profilometry techniques have been used for the micropore characterization. In order to find optimal conditions for cell detection a COMSOL Multiphysics simulation was performed. Pressure drop, shear stress, fluid viscosities and flow rates parameters were evaluated. The potential viability of the device for cell detection and counting, avoiding cellular damage, is demonstrated. Fil: Olmos Carreno, Carol Maritza. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Tecnológica Nacional. Facultad Regional Haedo; Argentina Fil: Rosero Yánez, Gustavo Ivan. Universidad Tecnológica Nacional. Facultad Regional Haedo; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Fernández Cabada, Tamara. Universidad Tecnológica Nacional. Facultad Regional Haedo; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Booth, Ross. MilliporeSigma Corporation; Estados Unidos Fil: Der, Manuel. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Física; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Cabaleiro, Juan Martin. Universidad de Buenos Aires. Facultad de Ingeniería. Departamento de Ingeniería Mecánica. Laboratorio de Fluidodinámica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Debut, Alexis. Universidad de Las Fuerzas Armadas; Ecuador Fil: Cumbal Flores, Luis. Universidad de Las Fuerzas Armadas; Ecuador Fil: Perez, Maximiliano Sebastian. Universidad Tecnológica Nacional. Facultad Regional Haedo; Argentina. Universidad de Buenos Aires. Facultad de Ingeniería. Instituto de Ingeniería Biomédica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Lerner, Betiana. Universidad Tecnológica Nacional. Facultad Regional Haedo; Argentina. Florida International University; Estados Unidos. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina

In conventional magnets, neodymium with added heavy rare-earths is used in order to induce high output and size reduction. But as deposits of heavy rare-earths such as dysprosium (Dy) and terbium (Tb) are disproportionately distributed, it is important to reduce the amount used due to supply issues and material costs. Additionally, the use of rare-earths in applications that only need modest magnetic properties is disadvantageous and complicates their low-cost production in on-demand shapes. In this paper and as a new concept, reconfigurable rare-earths-free Wax/CoFe2O4 composite magnets were fabricated through 3D-printing. The evolution of magnetic properties was studied as a function of the magnetic field and CoFe2O4 ferrite content, allowing one to tune the magnetic response of permanent magnets. It was shown that saturation and remnant magnetization increase monotonously with ferrite content, reaching maximum values of 38.6 emu g?1 and 22.1 emu g?1, respectively, for the sample with 90% in weight of CoFe2O4 (wt%). On the other hand, the coercive field (?2500 Oe) remained constant for all samples. Additionally, the addition of ferrite nanoparticles into Wax increased the Young's modulus (from 0.06 GPa to 0.47 GPa) and improved the thermal stability of the matrix as shown by the increase of the maximum degradation rate temperature and the temperature at which 25 wt% of the sample is degraded (from 412 °C to 429 °C and from 393 °C to 424 °C, respectively). In addition, the (coercive field) × (remanence field) maximum energy product (HC × BC)MAX, which is the figure of merit of permanent magnets, was evaluated, with the value obtained being the highest reported in the literature for CoFe2O4-based magnets (i.e., 4.44 MG Oe for the sample with 90 wt% of ferrite content). Thus, the present study allowed one to establish a new way to prepare reconfigurable printable magnets based on Wax/CoFe2O4 nanoparticles for advanced technologies., The authors thank the FCT - Fundação para a Ciência e Tecnologia for financial support in the framework of the Strategic Funding UID/FIS/04650/2019 and under projects PTDC/EEI-SII/5582/2014, PTDC/BTM-MAT/28237/2017 and PTDC/EMD-EMD/28159/2017. R. B.-P. acknowledges also support from FCT (SFRH/BD/140698/2018). Finally, the authors acknowledge funding by the Spanish Ministry of Economy and Competitiveness (MINECO) through the project MAT2016-76039-C4-3-R (AEI/FEDER, UE) and funding from the Basque Government Industry and Education Department under the ELKARTEK, HAZITEK and PIBA (PIBA2018-06) programs. Funding from European Union’s Horizon 2020 Programme for Research, ICT-02-2018 – Flexible and Wearable Electronics. Grant agreement no. 824339 – WEARPLEX is acknowledged. Technical and human support provided by SGIker (UPV/EHU, MICINN, GV/EJ, EGEF and ESF) is gratefully acknowledged. P. Martins thanks FCT-Fundação para a Ciência e Tecnologia for the contract under the Stimulus of Scientific Employment, Individual Support – 2017 Call (CEECIND/03975/2017)., info:eu-repo/semantics/publishedVersion

金沢大学ナノマテリアル研究所 / 金沢大学理工研究域生命理工学系, A novel approach to control electrical conductivity using CO2 was proposed by a reversible shift of molecular structures between free ions and zwitterions. It was achieved by a new design of ionic liquids, possessing dynamic covalent bonds between anions and cations. The conductivity was finely tuned by changing the partial pressure of CO2., Embargo Period 12 months, This paper has supplementary information.

金沢大学ナノマテリアル研究所 / 金沢大学理工研究域生命理工学系, The cellulose dissolution ability of a liquid zwitterion, the most biocompatible cellulose solvent, was improved by adding a co-solvent, dimethylsulfoxide. Moreover, the biocompatibility of the liquid zwitterion was also improved by adding dimethylsulfoxide although it is toxic relative to the liquid zwitterion. This mixture is an efficient and extremely biocompatible cellulose solvent., Embargo Period 12 months, This paper has supplementary information.

Currently, atmospheric plasmas are applied to the desorption and ionization of surface adhesive materials for rapid and highly sensitive analysis. One widely used chemical ionization method applies protons generated from atmospheric water molecules to a desorbed sample; however, a detailed study of the ionization mechanism has not been addressed thus far. Therefore, this paper proposes an ionization method that adds a small, optimized amount of hydrogen to the helium plasma for generating protons in the sample ionization source. Using this technique, mass spectrometry was performed on the sample surface deposits of 2-isopropylpyridine and 4-isopropylaniline. The hydrogen flow rate was optimized to the addition ratio of 2%, and the lowest limit of detection achieved is 0.1 and 42 pmol for 2-isopropylpyridine and 4-isopropylaniline, respectively. By optimizing the hydrogen addition flow rate, the optimum number of protons for sample ionization was attained, and it became possible to realize control of proton content in the sample, irrespective of humidity and surrounding environmental factors during mass spectrometry.

The possibility of fabricating DNA-based electronics has attracted considerable attention, but constructing robust, functional DNA nanowires on hard substrates has proven to be difficult. This paper describes the production of robust one-dimensional nanofibers by self-assembly of 1,18-nucleotide-bearing bolaamphiphiles templated by salmon sperm DNA. Electrostatic force microscopy measurements of the nanofibers on a highly oriented pyrolytic graphite substrate revealed that they showed electric polarizability that varied periodically with a pitch of 20-30 nm. Atomic force microscopy, gel electrophoresis, and circular dichroism spectroscopy suggested that the periodic polarizability was derived from right-handed helicity induced by the template DNA. Salmon sperm DNA itself did not show electric polarizability.

Solid-state lithium batteries cannot achieve reasonable power densities because of dendrites, whose formation mechanisms remain uncertain. This paper applies principles of chemomechanics to investigate the critical current above which dendrites form in lithium-conductive ceramics. Applied voltage induces stress in solid electrolytes; dendrites appear to nucleate in the exemplary garnet-oxide material Li7La3Zr2O12 (LLZO) when the interfacial pressure exceeds a particular value. The critical pressure of polycrystalline LLZO correlates well with the surface-energy changes incurred by lithium plating in its grain boundaries. A derived formula, validated by experiments, predicts quantitatively how critical current varies with properties including interfacial impedance, bulk permittivity, and grain size. As well as suggesting novel strategies to create more resilient ion-conductive ceramics, the proposed mechanism rationalizes experimental observations of bulk lithium plating and explains how LLZO exhibits an electrically activated transition from stable low-current cyclability to high-current dendrite nucleation.

In order to solve the practical problem of heat transfer during the hot pressing process of a novel wood-plastic composite plywood, this paper investigates the perforation treatment of polyvinyl chloride (PVC) plastic films and their plywood composites. The PVC films were pretreated by the physical punching method, and the effects of PVC perforation diameter, hot pressing time and hot pressing temperature on the mechanical properties of the plywood composites were investigated by orthogonal experimental design. The results showed that the optimum hot pressing time was 7 min, the hot pressing temperature was 170 °C, and the PVC perforation diameter was 15 mm for the optimum mechanical properties. The punching pretreatment of PVC films gave rise to a reduction of the hot pressing time by 51 s due to improved heat transfer and heat loss by 5.06%, and allowed an increase in the initial moisture content of the veneer by 2–3%, thereby cutting down the drying cost in the veneer production process, which is conducive to energy conservation and environmental protection. Science & Technology Program in Fujian Province of China; Science & Technology Innovation Program in Fujian Agriculture and Forestry University of China

This paper shows that molecular layers grown using diazonium chemistry on carbon surfaces have properties indicative of the presence of a variety of structural motifs. Molecular layers grown with aromatic monomers with thickness between 1 and ∼15 nm display optical absorption spectra with significant broadening but no change in band gap or onsets of absorption as a function of layer thickness. This suggests that there is no extended conjugation in these layers, contrary to the conclusions of previous work. Density-functional theory modelling of the non-conjugated versions of the constituent aromatic monomers reveals that the experimental trends in optical spectra can be recovered, thereby establishing limits to the degree of conjugation and the nature of the order of as-grown molecular layers. We conclude that the absence of both shifts in band gap and changes in absorption onset is a consequence of resonant conjugation within the layers being less than 1.5 monomer units, and that film disorder is the main origin of the optical spectra. These findings have important implications for understanding charge transport mechanisms in molecular junction devices, as the layers cannot be expected to behave as ideal, resonantly conjugated films, but should be viewed as a collection of mixed nonresonantly- and resonantly-conjugated monomers.