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Nitric oxide (NO) in human tears regulates numerous ocular surface processes, such as tear generation, corneal wound healing, conjunctival vascular tone, and so forth. Any deviation from its normal concentration is linked to various ocular syndromes, including microbial keratitis, conjunctivitis, pterygium, dry eye, retinitis, glaucoma, and so forth. Therefore, precise monitoring of NO in tears can be considered as a potential biomarker for ocular diseases. Here, we report a highly sensitive and selective electrochemical NO sensor using carbon ink-based electrodes. Counter, working (WE), and reference electrodes have been designed and painted on a butter paper by using carbon ink. To improve the sensing performance, the WE has been modified with a gold nanoparticle (Au NP)-deposited carbon cloth (CC). Such a paper-based sensor demonstrated high sensitivity of ∼0.34 μA μM -1 cm -2 , ultralow detection limit of ∼2.35 nM, wide linear range of 10 nM-0.4 mM, and fast response time (0.35 s). The sensor also showed excellent stability and selectivity toward the interfering agents in human body fluids. Such a low-cost, flexible paper-based sensor was employed for the detection of NO in artificial tears.

In this work, a sustainable 3D carbon aerogel (AO-WPC) is prepared from waste paper (WP), and used for efficient antibiotics removal from water. The AO-WPC aerogel shows good mechanical property and can recover after 100th of 30 % compression strain. The specific surface area of AO-WPC aerogel is up to 654.58 m 2 /g. More importantly, this aerogel reveals proper pore size distribution, including micro sized macropores between carbon fibers and intrinsic nano scale mesopores (11.86 nm), which is conducive to remove antibiotics from water. Taking tetracycline (Tc) as an example, the maximum adsorption capacity and adsorption rate of AO-WPC for Tc are as high as 384.6 mg/g and 0.510 g/(mg‧min), respectively, which exhibits significant advantages over most of the recent absorbents, and the adsorption toward Tc reveals good resistance to various environmental factors, including pH, various ions, and dissolved organic matter (DOM). Moreover, good thermal stability enables the AO-WPC aerogel to be regenerated through simple burning, and the adsorption capacity of Tc only decreases by 10.4 % after 10 cycles. Mechanism research shows that hydrogen bonding and π-π electron-donor-acceptor (EDA) interaction play the important role in the adsorption. The excellent mechanical property and adsorption performance imply good practical prospect of the AO-WPC aerogel., Competing Interests: Declaration of Competing Interest We declare no conflict of interest. This manuscript has not been published or presented elsewhere in part or in entirety, and is not under consideration by another journal. There are no conflicts of interest to declare. All authors have contributed to, read, and approved this submitted manuscript in its current form., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Plastics are ubiquitous in today's lifestyle, and their indiscriminate use has led to the accumulation of plastic waste in landfills and oceans. The waste accumulates and breaks into micro-particles that enter the food chain, causing severe threats to human health, wildlife, and the ecosystem. Environment-friendly and bio-based degradable materials offer a sustainable alternative to the vastly used synthetic materials. Here, a polylactic acid and carbon nanofiber-based membrane and a paper-based colorimetric sensor have been developed. The membrane had a surface area of 3.02 m 2 g -1 and a pore size of 18.77 nm. The pores were evenly distributed with a pore volume of 0.0137 cm 3 g -1 . The membrane was evaluated in accordance with OECD guidelines and was found to be safe for tested aquatic and terrestrial models. The activated PLA-CNF membrane was further used as a bio-based electrode for the electrochemical detection of nitrates (NO 3 - ) in water samples with a detection limit of 0.046 ppm and sensitivity of 1.69 × 10 -4 A ppm -1 , whereas the developed paper-based colorimetric sensor had a detection limit of 156 ppm for NO -2 . This study presents an environment-friendly, low-carbon footprint disposable material for sensing applications as a sustainable alternative to plastics.3 - . This study presents an environment-friendly, low-carbon footprint disposable material for sensing applications as a sustainable alternative to plastics.

The rapid discrimination of bacteria is currently an emerging trend in the fields of food safety, medical detection, and environmental observation. Traditional methods often require lengthy culturing processes, specialized analytical equipment, and bacterial recognition receptors. In response to this need, we have developed a paper-based fluorescence sensor array platform for identifying different bacteria. The sensor array is based on three unique carbon quantum dots (CQDs) as sensing units, each modified with a different antibiotic (polymyxin B, ampicillin, and gentamicin). These antibiotic-modified CQDs can aggregate on the bacterial surface, triggering aggregation-induced fluorescence quenching. The sensor array exhibits varying fluorescent responses to different bacterial species. To achieve low-cost and portable detection, CQDs were formulated into fluorescent ink and used with an inkjet printer to manufacture paper-based sensor arrays. A smartphone was used to collect the responses generated by the bacteria and platform. Diverse machine learning algorithms were utilized to discriminate bacterial types. Our findings showcase the platform's remarkable capability to differentiate among five bacterial strains, within a detection range spanning from 1.0 × 10 3  CFU/mL to 1.0 × 10 7  CFU/mL. Its practicality is further validated through the accurate identification of blind bacterial samples. With its cost-effectiveness, ease of fabrication, and high degree of integration, this platform holds significant promise for on-site detection of diverse bacteria., (© 2024. The Author(s).)

China's pulp and paper industry (CPPI) has been always the main carbon emission source in recent years. However, the analysis on influencing factors of carbon emissions from this industry is insufficient. To address the issue, the CO 2 emissions from CPPI are estimated in the period of 2005-2019, the driving factors of CO 2 emissions are investigated by the logarithmic mean Divisia index (LMDI) method, the decoupling state of economic growth and CO 2 emissions is determined by Tapio decoupling model, and finally, future CO 2 emissions are predicted under four scenarios by the STIRPAT model to explore the potential of carbon peaking. The results show that CPPI exhibits a rapid increase and a fluctuating downward trend in CO 2 emissions during the period of 2005-2013 and 2014-2019, respectively. The main promoting and inhibiting factors to the increase of CO 2 emission are per capita industrial output value and energy intensity, respectively. There are five decoupling states of CO 2 emissions and economic growth during the study period, and the CO 2 emissions exhibit a weak decoupling state with the industrial output value growth in most years of the study period. It is very difficult to realize the carbon peaking goal by 2030 under the baseline and fast development scenarios. Therefore, efficient low carbon and strong low-carbon development policies are necessary and urgent for the realization of carbon peaking goal and the sustainable development of CPPI., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Three specific catalysts, namely ZIF-67 (zeolitic imidazolate framework-67), Co@NCF (Co@Nitrogen-Doped Carbon Framework), and 3D NCF (Three-Dimensional Nitrogen-Doped Carbon Framework), were prepared and studied for pulp and paper mill effluent degradation using heterogeneous activation of peroxymonosulfate (PMS). Numerous characterizations, including scanning electron microscopy (SEM), X-ray diffraction (XRD), and N 2 adsorption, were used to characterize the properties of three different catalysts. 3D NCF is remarkably effective at heterogeneous activation of PMS to generate sulfate radicals to degrade pulp and paper mill effluent (PPME) compared to the other as-prepared catalysts. The catalytic activity reveals a sequence of 3D NCF > Co@NCF > ZIF-67.3D NCF could degrade organic pollutants in 30 min at an initial COD concentration of 1146 mg/L of PPME, 0.2 g/L catalysts, 2 g/L PMS, and 50 °C. Consequently, it was observed that the degradation of PPME using 3D NCF followed first-order kinetics, with an activation energy of 40.54 kJ mol -1 . Overall, 3D NCF/PMS system reveals promising performance for PPME removal., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Inc. All rights reserved.)

A paper-based assay for visualization of auramine O (AO) was for the first time established by using CFMs as a ratiometric fluorescent probe (RFP). The CFMs were melamine formaldehyde microspheres (MFMs) incorporated with carbon dots (CDs), where the CDs species as sensing units and MFMs as a signal amplification carrier. The proposed RFP can quantitatively measure AO content from 0.0 to 10.0 μM and exhibited an ultralow limit of detection (LOD, 15.7 nM). In particular, obvious luminescence color change of CFMs from blue to green was perceived with naked-eyes and therefore, a solution-based and a paper-based visualization platform were respectively proposed for on-site visual detection of AO with LODs of 1.15 μM and 0.83 μM, separately. Finally, those fluorescence methods were adopted in sensitively quantitative measurement of AO within various food and drug samples, providing new prospects for analysts and technical support in food quality monitoring., Competing Interests: Declaration of Competing Interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Qin Hu reports financial support was provided by Natural Science Foundation of Jiangsu Province, China. Jie Han reports financial support was provided by National Natural Science Foundation of China., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Water waves are viable low-carbon and renewable sources of power that can be optionally combined with triboelectric nanogeneration (TENG). Herein, we report on the synthesis of a TENG device based on green wrinkled paper tribolayers (W-TENG) assembled in grids (G-TENG) with channels that enable contact-separation modes involving metal balls that roll in phase with the waves. The paper's wrinkle wavelength and amplitude were adjusted by using a crepe blade at a given angle with respect to a drying cylinder, as well as the speed and torque. Polar hierarchical superhydrophobic cellulose micro/nanostructures, proposed as positive tribolayers with enhanced contact area and triboelectric density. The negative (biodegradable) tribolayers were prepared by electrospinning aqueous suspensions of polyvinyl alcohol and poly (ethylene oxide) reinforced with cellulose nanofibers. The charge transfer by the W-TENG reached up to 40 nC in air and retained 27 nC under 85 % relative humidity, ~5 and 7 times higher than those measured in planar TENG counterparts. A G-TENG array charging time (100-μF capacitor) of ~188 s was measured when the voltage of the capacitor raised to ~1.5 V. Overall, we introduce a new, scalable TENG system that is demonstrated for its remarkable ability to harvest blue energy., Competing Interests: Declaration of competing interest The authors declared that they have no conflicts of interest to this work. We declare that we do not have any commercial or associative interest that represents a conflict of interest in connection with the work submitted., (Copyright © 2022. Published by Elsevier B.V.)

Cellulose paper-based materials are highly flexible, hydrophilic, low-cost, and environmentally friendly and are good substrates for use as humidity sensors. Therefore, developing a paper-based humidity sensor with facile fabrication, low cost, and high sensitivity is important for expanding its practical applications. Herein, we propose a CI/FP self-powered humidity sensor based on everyday items such as writing and drawing carbon ink (CI), cellulose filter paper (FP), and polyester conductive adhesive tape, which is fabricated with the help of facile dip-coating and pasting methods. This sensor is self-powered, and the paper-based material itself can absorb water molecules in a humid environment to generate humidity-related voltage and current, which can indirectly reflect the ambient humidity level. They are characterized by a wide relative humidity (RH) sensing range (11-98%), good linearity ( R 2 = 0.97011), high response voltage (0.19 V), and excellent flexibility (over 1000 bends). This humidity sensor can be successfully applied to monitor human health (breathing, coughing), air humidity, and noncontact humidity sensing (skin, wet objects). This work not only proposes a low-cost and facile method for flexible humidity sensors but also provides a valuable strategy for the development of self-powered wearable electronics.

Microfluidic paper-based sensors as a new type of microsample detection technology are widely used in medical diagnosis, environmental monitoring, and food safety testing. Inkjet printing has the advantages of simplicity, speed, flexibility, high resolution, low cost, and efficient mass production and has become one of the most cutting-edge technologies in the manufacture of paper-based sensors. In this work, a fully inkjet printing preparation method was proposed for paper-based sensors, which can achieve high-precision, multichannel, and visual fluorescence detection. Three kinds of fluorescent carbon dots (CDs; r-CDs, b-CDs, and y-CDs) were fabricated into inkjet ink by adding a suitable ratio of solvent, PEG, and surfactant FS3100 to control its viscosity, surface tension, and other influencing factors, obtaining the best-visualized fluorescence response on paper. To optimize the full inkjet printing process of the paper-based sensor, we studied the influence of factors such as the hydrophobic material AKD formula, postprocessing conditions, and the structure of the hydrophilic and hydrophobic channels on the paper-based detection accuracy, and it was found that proper AKD concentration, curing time, and temperature can make AKD fully react with paper-based surface groups and produce more hydrophobic groups on the surface and inside of the filter paper, which can form paper-based microfluidic sensors with clear boundaries and fast transmission speed at low cost and high efficiency. The fabricated sensor is used for the fluorometric determination of vitamin C (AA), NO 2 - , and sunset yellow (SY) at the same time, and the limits of visual detection by eyes are 6 mmol/L (NO 2 - ), 60 μmol/L (SY), and 40 mmol/L (AA). The mechanism of inkjet printing is investigated in detail, which is simple, reliable, and easy to realize mass production and can realize highly sensitive, on-site, and visual detection for food additives.

Soil organic carbon can be increased through sympathetic land management and/or directly by incorporating carbon rich amendments. Herein, a field experiment amended paper crumble (PC) to soil at a normal deployment rate of 50 t ha -1 , and at higher rates up to 200 t ha -1 . The nominal 50 t ha -1 PC amendment resulted a mean increase in soil carbon of 12.5 g kg -1 . Using a modified Roth-C carbon fate model, the long-term (50 years) carbon storage potential of a 50 t ha -1 PC amendment was determined to be 0.36 t O C ha -1 . Modelling a rotational (4 yearly) 50 t ha -1 PC amendment indicated 6.65 t O C e. These results support the use of PC to deliver significant levels of soil recarbonisation. Beyond carbon, PC was observed to influence other soil properties. Benefits observed included, decreased bulk density, increased water holding capacity, and increased cation exchange capacity. While PC amendment did not significantly increase wheat (Triticum aestivum) crop yield, manifold benefits in terms of increased SOC, long-term carbon storage potential, and improved soil quality sustain PC as a beneficial soil conditioner.-1 uplift would accrue after 50 years. Contextualised for the average farm in the East of England (~120 ha, with 79 % as arable), PC derived increases in SOC would be equivalent to 2310 t CO 2 e. These results support the use of PC to deliver significant levels of soil recarbonisation. Beyond carbon, PC was observed to influence other soil properties. Benefits observed included, decreased bulk density, increased water holding capacity, and increased cation exchange capacity. While PC amendment did not significantly increase wheat (Triticum aestivum) crop yield, manifold benefits in terms of increased SOC, long-term carbon storage potential, and improved soil quality sustain PC as a beneficial soil conditioner., Competing Interests: Declaration of competing interest Brian Reid reports financial support was provided by Research England., (Copyright © 2022 The Authors. Published by Elsevier B.V. All rights reserved.)

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., (© 2022. The Author(s).)

Paper-based carbon working electrodes were modified with mercury or bismuth films for the determination of trace metals in aqueous solutions. Both modification procedures were optimized in terms of selectivity and sensitivity for the determination of different heavy metals, aiming their simultaneous determination. Cd (II), Pb (II) and In (III) could be quantified with both films. However, Cu (II) could not be determined with bismuth films. The modification with mercury films led to the most sensitive method, with linear ranges between 0.1 and 10 µg/mL and limits of detection of 0.4, 0.1, 0.04 and 0.2 µg/mL for Cd (II), Pb (II), In (III) and Cu (II), respectively. Nevertheless, the bismuth film was a more sustainable alternative to mercury. Tap-water samples were analyzed for the determination of metals by standard addition methodology with good accuracy, by using a low-cost and easily disposable paper-based electrochemical platform. This system demonstrated its usefulness for monitoring heavy metals in water., Competing Interests: The authors declare no conflict of interest.

Functional laser scribing carbon paper (LSCP) decorated with highly uniform Ni nanoparticles were constructed through a facile electroless plating. The nanocomposites were characterized by high resolution scanning electron microscope, X-ray photoelectron spectroscopy, electrochemical impedance spectroscopy, cyclic voltammetry and chronoamperometry. The results showed high electron transferring kinetics of this sensor, which can be ascribed to their excellent properties such as rich pore channels, excellent structural durability, and large surface area. These properties facilitated mass transfer and electron conductions. Notably, a systematical response surface methodology simulating-modeling-predicting-optimizing design was employed to simulate, model and optimize processing parameters to gain the optimal conductivity of 8.52 × 10 6  S m -1 . The obtained sensor owned high electrochemical activity and wide linear responses (0.80 μM-2.50 mM and 4.50 mM-15.20 mM), low detection limit of 20 nM (S/N = 3) to the glucose detection. The glucose determination in human serum and perspiration samples are also successful. Therefore, LSCP/NN provides an excellent sensing platform towards flexible biosensors in monitoring physical conditions., (Copyright © 2019 Elsevier B.V. All rights reserved.)

In recent years, stable and photoluminescence (PL) tunable fluorescent materials known as carbon dots (CDs) have seen rapid development. Here, a simple, low-cost, and environmentally friendly approach has been developed to synthesize the orange-red CDs (OR-CDs) with paper tissues as the precursor in the presence of ethanol and concentrated sulfuric acid. The average diameter of the OR-CDs was measured at around 1.25 nm. The as-prepared OR-CDs are composed of carbon cores with the graphite structure distributed in the middle and wrapped or entangled by polymers for the outside. Moreover, the PL characteristics of the OR-CDs under the dilute solution state and the concentrated solution state, respectively, were explored. The former with the blue light showed prominent excitation-dependent characteristics in the range from 365 to 420 nm; the latter rendered the excitation-independent property with distinguished orange-red fluorescence emission. With an increase in the concentration, the emission fluorescence intensities gradually increased under the excitation wavelength of 540 nm, which can be attributed to the aggregation-induced emission property of the OR-CDs. By virtue of their excellent PL properties and low toxicity, we believe that the OR-CDs have potential applications in various optoelectronic areas, especially in white LED fields.

A fluorescent paper strip immunoassay in conjunction with carbon nanodots@silica (CND@SiO 2 ) as a label was developed for the quantitative measurements of human serum amyloid A1 (hSAA1) in serum at clinically significant concentrations for lung cancer diagnosis. Monodispersed CND@SiO 2 was prepared by cohydrolysis between silane-crosslinked carbon nanodots and silica precursors via the Ströber method and further attached covalently to anti-hSAA1 (14F8) monoclonal antibody [anti-hSAA1(14F8)] specific to the hSAA1 target. The hSAA1 concentrations were then determined by quantifying the blue fluorescence intensity upon 365 nm excitation of the captured hSAA1 with anti-hSAA1(14F8)-CND@SiO 2 conjugates in the test line on a paper strip where anti-hSAA1 (10G1) monoclonal antibody was physisorbed. The developed fluorescent paper strip with CND@SiO 2 can detect hSAA1 at concentrations ranging from 0.1 to 5 nM (R 2  = 0.995), with a limit of detection of  0.258 nM in 10 mM phosphate buffer pH 7.4 containing human serum albumin. The performance of  recovery (90.98-109.17%) and repeatability (coefficients of variation < 8.46%) obtained was also acceptable for quantitative determinations. The platform was employed for direct determination of hSAA1 concentrations in undiluted serum samples from lung cancer patients (relative standard deviation (RSD) < 7.46%) and healthy humans (RSD < 3.96%). The results were compared with those obtained using a commercially available enzyme-linked immunosorbent assay alongside liquid chromatography with tandem mass spectrometry measurements., (© 2021. The Author(s), under exclusive licence to Springer-Verlag GmbH Austria, part of Springer Nature.)

In this work, zinc-doped carbon dots (Zn-CDs) were anchored on a three-dimensional wheel type paper-based microfluidic chip, and were decorated with 6-mercaptonicotinic acid (MNA) and L-cysteine (L-Cys) for highly sensitive and rapid fluorescence detection of Cu 2+ . Zn-CDs were first anchored on paper through the amide bonds between the carboxyl groups of the Zn-CDs and the amino groups of the paper. Afterwards, Zn-CDs were decorated with MNA and L-Cys, effectively preventing the Zn-CDs from aggregation. The nitrogen atom on the pyridine ring and the carboxylic acid groups in MNA and L-Cys coordinated with Cu 2+ to form a nonfluorescent ground-state complex, causing the fluorescence quenching of the Zn-CDs. The three-dimensional rotary design could simplify the operation process and achieve simultaneous analysis of multiple samples with different concentrations. Under optimal conditions, the fluorescent sensor exhibits linear response for the determination of Cu 2+ in the range from 0.1 to 60 μg L -1 with the detection limit (LOD) of 0.018 μg L -1 . The proposed strategy provides a novel way for the highly sensitive detection of Cu 2+ in a complex water environment.

As China's demand for paper products increases, China's paper industry faces enormous pressure to reduce greenhouse gas emissions. By using material flow analysis in combination with input-output analysis, this study measured the waste paper recovery rate in a more accurate method and analyzed the impact of waste paper recycling on the carbon emissions from China's paper industry. China's waste paper recovery rate estimated in this study was close to 70% in 2017, much higher than that of 48% obtained with the traditional method. The regression results displayed a negative relationship between waste paper recovery rate and CO 2 emissions per unit of paper consumption during 2000-2017 in China. The rolling regression results further indicated that the impact of waste paper recycling was becoming stronger on reducing CO 2 emissions per unit of paper consumption in China. Since an inverted "U" shape relationship exists between waste paper recovery rate and its reduction effect on carbon emissions from the paper industry, the regression results suggested that China's waste paper recovery rate has not reached the optimal level with regard to carbon emissions from China's paper industry. Thus, although China's waste paper recovery rate has reached a relatively high level, currently waste paper recycling is still an effective method to reduce carbon emissions from China's paper industry.

Silver nanoparticles (AgNPs) have been widely used for sterilization due to their broad-spectrum bactericidal properties. However, there exist the problems of premature releasing and accumulative toxicity when free AgNPs are applied. This study proposed a one-pot hydrothermal strategy to synthesize carbon spheres immobilized silver nanoparticles (AgNPs@CS). The synthesis involves with silver ammonia solution as Ag precursor, and corn stalk as green reducing agent and carbon precursor. Furthermore, AgNPs@CS was anchored by cellulose nanofibers (CNF) to obtain the antibacterial composite paper. The obtained CNF/AgNPs@CS paper exhibited superior antibacterial properties against E. coli and S. aureus. Notably, the accumulative release rate of AgNPs from AgNPs@CS was 10.2% in 9 days, while that from CNF/AgNPs@CS paper was only 6.7% due to the anchoring effect of both CS and CNF, which was low for avoiding the cumulative toxicity problem. In addition, the mechanical and barrier properties of CNF/AgNPs@CS paper were also improved by 29.4% (tensile index), 2.7% (tear index), 7.4% (burst index), 10% (folding endurance), 0.8% (water vapor transmission) and 9.4% (oxygen transmission rate), respectively. Therefore, the composite paper has potential application as a medical antibacterial material., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Paper Sensor detection methods are attractive in wide analytical applications. Presented herein is a paper sensor and fluorescence methods that was firstly developed to detect curcumin (Cur) based on fluorescence resonance energy transfer (FRET) between nitrogen-doped carbon quantum dots (NCQDs) and Cur. The facile fluorescent method was demonstrated to detect Cur in the range of 0-2600 μM with a detection limit of 0.13 μM. And facile paper sensor of Cur was fabricated and displayed at concentration of 0 μM, 100 μM, 200 μM, 300 μM, 400 μM, 500 μM and 600 μM, respectively. In additions, it was realized for determination of Cur in real samples including orange juice and curry solution. Compared with the reported methods, the present method is simple, rapid and sensitive for detecting Cur., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Herein, an easy and effective ratiometric fluorescent nanoprobe for the selective detection of Pb2+ and pyrophosphate (PPi) was developed based on label-free carbon dots (CDs). The CDs showed dual emission bands at 477 and 651 nm under a single-wavelength excitation (391 nm). Pb2+ and PPi were sequentially detected by the sensor with high reliability and accuracy via the exploitation of the fluorescence intensity ratio (F477/F651). The dual emission sensor exhibited high selectivity and excellent sensitivity for Pb2+ and PPi than for other analytes with detection limits as low as 0.055 μM and 0.089 μM, respectively. Moreover, the fluorescent CDs changed from pink to cyan and from cyan to pink and could be used as a fluorescent paper sensor for the visual detection of Pb2+ and PPi. To the best of our knowledge, this is the first report on the ratiometric fluorescence detection of Pb2+ and PPi by CDs; therefore, the as-synthesized CDs show great potential for application in the determination of Pb2+ and PPi in real samples.

Screen-printed carbon electrodes (SPCE) functionalized with MXene-based three-dimensional nanomaterials are reported for rapid determination of creatinine. Ti 3 C 2 T X MXene with in situ reduced AuNPs (MXene@AuNP) were used as a coreactant accelerator for efficient immobilization of enzymes. Creatinine could be oxidized by chitosan-embedded creatinine amidohydrolase, creatine amidinohydrolase, or sarcosine oxidase to generate H 2 O 2 , which could be electrochemically detected enhanced by Prussian blue (PB). The enzyme@CS/PB/MXene@AuNP/SPCE detected creatinine within the range 0.03-4.0 mM, with a limit of detection of 0.01 mM, with an average recovery of 96.8-103.7%. This indicates that the proposed biosensor is capable of detecting creatinine in a short amount of time (4 min) within a ± 5% percentage error, in contrast with the standard clinical colorimetric method. With this approach, reproducible and stable electrochemical responses could be achieved for determination of creatinine in serum, urine, or saliva. These results demonstrated its potential for deployment in resource-limited settings for early diagnosis and tracking the progression of chronic kidney disease (CKD)., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Austria, part of Springer Nature.)

An electrochemical sensor based on an electroactive nanocomposite was designed for the first time consisting of electrochemically reduced graphene oxide (ERGO), polyaniline (PANI), and poly(alizarin red S) (PARS) for ciprofloxacin (CIPF) detection. The ERGO/PANI/PARS-modified screen-printed carbon electrode (SPCE) was constructed through a three-step electrochemical protocol and characterized using FTIR, UV-visible spectroscopy, FESEM, CV, LSV, and EIS. The new electrochemical CIPF sensor demonstrated a low detection limit of 0.0021 μM, a broad linear range of 0.01 to 69.8 μM, a high sensitivity of 5.09 μA/μM/cm 2 , and reasonable selectivity and reproducibility. Moreover, the ERGO/PANI/PARS/SPCE was successfully utilized to determine CIPF in milk with good recoveries and relative standard deviation (< 5%), which were close to those with HPLC analysis., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Austria, part of Springer Nature.)

There is a growing emphasis on fostering green growth and lowering carbon emissions in order to achieve sustainable economic development. This study uses the Tapio decoupling model and analyzes the factors influencing changes in carbon emissions from manufacturing in India utilizing the log mean Divisia index (LMDI) techniques. Furthermore, the nexus between carbon emission intensity, information and communication technology (ICT), total factor productivity (TFP), skill, and energy intensity has been analyzed using the system-GMM approach. It is based on the plant-level Annual Survey of Industries (ASI) datasets for the organized manufacturing sector of India from 2001 to 2002 to 2019 2020 for the major 21 Indian states/UT. The findings reflect the presence of weak decoupling in the manufacturing sector both at the aggregate level and in states. This indicates that both output and emissions are increasing; however, output growth surpasses emission growth, which signifies an effort to transition towards more environmentally friendly production methods and enhanced energy efficiency. The output and population effect are found to be leading factors in carbon emissions, while energy intensity is found to be reducing the effect. Further, the system-GMM estimates show that ICT and energy intensity positively affect total factor productivity, while with an increase in carbon emission intensity, productivity declines. The study confirms the existence of an inverted N-shaped Kuznets curve in the sector. This present study will contribute to formulating energy and environmental strategies to reduce emissions and promote adopting cleaner energy sources. These efforts will facilitate the attainment of carbon neutrality and enhance energy efficiency within the sector., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Photoluminescent carbon dots (CDs) have garnered significant interest owing to their distinctive optical and electronic properties. In contrast to semiconductor quantum dots, which incorporated toxic elements in their composition, CDs have emerged as a promising alternative, rendering them suitable for both environmental and biological applications. CDs exhibit astonishing features, including photoluminescence, charge transfer, quantum confinement effect, and biocompatibility. Recently, CDs derived from green sources have drawn a lot of attention due to their strong photostability, reduced toxicity, better biocompatibility, enhanced fluorescence, and simplicity. These attributes have shown great promise in the areas of LED technology, bioimaging, photocatalysis, drug delivery, biosensing, and antibacterial activity. In contrast, this review offers a comprehensive overview of various green sources utilized to produce CDs and methodologies, along with their merits and demerits, with a notable emphasis on physiochemical properties. Additionally, the paper provides insight into the bibliometric analysis and recent advancements of CDs in sensing, photocatalysis, and antibacterial activity. In this field, extensive research is underway, and a total of 7,438 articles have been identified. Among these, 4242 articles are dedicated to sensing applications, while 1518 and 1678 focus on adsorption and degradation. Carbon dots demonstrate exceptional sensing capabilities within the nanomolar range with a selectivity of up to 95% for pollutants. They exhibit excellent degradation efficiency exceeding 90% within 10-130 min and possess an adsorption capacity from 100 to 800 mg/g. These fascinating qualities render them suitable for diverse applications., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Food analysis is significantly important in monitoring food quality and safety for human health. Traditional methods for food detection mainly rely on benchtop instruments and require a certain amount of analysis time, which promotes the development of portable sensors. Portable sensing methods own many advantages over traditional techniques such as flexibility and accessibility in diverse environments, real-time monitoring, cost-effectiveness, and rapid deployment. This review focuses on the portable approaches based on carbon dots (CDs) for food analysis. CDs are zero-dimensional carbon-based material with a size of less than 10 nm. In the manner of sensing, CDs exhibit rich functional groups, low biotoxicity, good biocompatibility, and excellent optical properties. Furthermore, there are many methods for the synthesis of CDs using various precursor materials. The incorporation of CDs into food science and engineering for enhancing food safety control and risk assessment shows promising prospects., (© 2024 Institute of Food Technologists.)

This work presents a simple hydrothermal synthesis of nitrogen-doped carbon dots (N-CDs), fabrication of microfluidic paper-based analytical device (μPAD), and their joint application for colorimetric determination of total cholesterol (TC) in human blood. The N-CDs were characterized by various techniques including transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and X-ray powder diffraction (XRD), and the optical and electronic properties of computational models were studied using the time-dependent density functional theory (TD-DFT). The characterization results confirmed the successful doping of nitrogen on the surface of carbon dots. The N-CDs exhibited high affinity toward 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid)-diammonium salt (ABTS) with the Michaelis-Menten constant ( K M ) of 0.018 mM in a test for their peroxidase-like activity. Particularly, since hydrogen peroxide (H 2 O 2 ) is the oxidative product of cholesterol in the presence of cholesterol oxidase, a sensitive and selective method of cholesterol detection was developed. Overall, the obtained results from TD-DFT confirm the strong adsorption of H 2 O 2 on the graphitic N positions of the N-CDs. The laminated three-dimensional (3D)-μPAD featuring a 6 mm circular detection zone was fabricated using a simple wax screen printing technique. Classification of TC according to the clinically relevant criteria (healthy, <5.2 mM; borderline, 5.2-6.2 mM; and high risk, >6.2 mM) could be determined by the naked eye within 10 min by simple comparison using a color chart. Overall, the proposed colorimetric device serves as a low-cost, rapid, simple, sensitive, and selective alternative for TC detection in whole blood samples that is friendly to unskilled end users.

We explored the use of filter paper soaked in whole blood for measuring carbon (C) and nitrogen (N) stable isotopes, often used in feeding ecology or diet studies, to better understand drivers of exposure to contaminants. Our results showed no statistically or biologically relevant differences in C and N stable isotope measures between our gold standard (whole blood with anticoagulant) and eluates from processed, blood-soaked filter paper. Our data supported the effectiveness of using filter paper for assessing C and N stable isotopes in blood to address feeding ecology and other uses. The ease of sampling and processing should allow blood-soaked filter paper to be used in sampling of live (e.g., captured, stranded) and lethally taken (e.g., hunter-killed) wild vertebrates.

A new strategy for the fluorescent and colorimetric sensing of hydrogen peroxide (H 2 O 2 ) and glucose based on the metal oxide - carbon-dot hybrid structure was investigated. The sensing system is related to the catalytic oxidation reaction of glucose-by-glucose oxidase (GOx) to H 2 O 2 . In this study, a metal oxide hybrid with nitrogen-doped carbon dots (MFNCDs) that showed intrinsic peroxidase-like activity was synthesized and used as a catalyst instead of GOx to oxidize 3,3',5,5'-tetramethylbenzidine (TMB) to blue-emitting oxidized TMB (oxTMB) in the presence of hydrogen peroxide (H 2 O 2 ). The fluorescence of MFNCDs/TMB at 405 nm was quenched in the presence of H 2 O 2 through the inner filter effect (IFE) and electron transfer within MFNCDs, oxTMB, and glucose system. Therefore, the fluorescence and absorbance intensity can be applied to the quantitative determination of the concentration of H 2 O 2 and glucose with a wide linear range. The detection limit for H 2 O 2 and glucose based on the colorimetric method were as low as 84 nM and 0.41 μM, respectively. In contrast, the detection limit for H 2 O 2 and glucose based on the fluorescent method were as low as 97 nM and 0.85 μM, respectively. Furthermore, the colorimetric readout on the paper device based on the changing color of the solution could also be integrated with a smartphone platform to conduct the on-site analysis of glucose without the use of the spectrometer. In addition, this dual sensor can be applied to detect glucose in real serum with highly accurate results, making it a good candidate for biosensor applications., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Paper-based devices have been very much in the foreground of analytical science recently. This work innovatively proposed a fluorescent paper-based sensor (FPS) constructed on a hybrid polydimethylsiloxane (PDMS)/paper platform where cellulose papers functionalized with carbon dots (CDs) as fluorophores by Schiff base chemistry were loaded on the grooves array of a designed PDMS plate. As a proof of concept, the performance of FPS was investigated with folic acid (FA) as the target analyte. Under optimal conditions, FPS enabled a rapid fluorescence quenching response to FA via inner filter effect in a wide range of 1-300 μmol L -1 with the limit of detection of 0.28 μmol L -1 . The feasibility of FPS was further verified by the detection of FA in orange juice and urine samples with satisfactory results. The covalent modification of CDs on paper endowed the FPS with good assay reproducibility and stability. Interestingly, FPS achieved a more sensitive assay of FA than the conventional strategy, by which the same CDs were directly used to detect FA in a solution-based system. The FPS illuminated a novel strategy for construction of reliable and sensitive assays based on paper-based devices. It is of paramount importance for its practical application in biosensing and clinical diagnosis. Graphical abstract.

Water pollution due to organic dyes and radionuclides is a challenging issue to the modern world. Cheap and efficient adsorbents are needed for their removal from wastewaters. Carbon-doped magnesium oxide (C-MgO) and calcium carbonate (C-CaCO 3 ) were synthesized by the in situ hydrothermal treatment of Mg(OH) 2 and Ca(OH) 2 with carbon, and applied for the removal of eriochrome black T (EBT) at pH = 2.0 and uranium (U(VI)) at pH = 6.0. The Langmuir monolayer adsorption capacities of C-MgO (3.62 × 10 -4  mol/g for EBT and 8.10 × 10 -4  mol/g for U(VI)) were higher than those of C-CaCO 3 (2.53 × 10 -4  mol/g for EBT and 5.92 × 10 -4  mol/g for U(VI)). The high adsorption capacity of C-MgO was also evidenced with DFT calculations which showed that the sorption energies (ΔE) of C-MgO for EBT (20.62 kcal/mol) and U(VI) (63.41 kcal/mol) were higher than those of C-CaCO 3 for EBT (10.21 kcal/mol) and U(VI) (34.29 kcal/mol). In all cases, the electrostatic interactions were involved in the adsorption process. The sorption kinetic data followed pseudo-second-order kinetics. The results demonstrate that both C-MgO and C-CaCO 3 are reusable and can be effectively applied for the elimination of EBT and U(VI) from wastewater.

Utilizing renewable energy (RE) and embracing the digital economy (DIG) can significantly contribute to achieving economic, energy, and climate goals by promoting carbon reduction. In this regard, public debt (DEB) is particularly important since it provides the funds required to achieve these goals by investing in renewable energy and digital economy projects. This study examines the impact of public debt on the link between renewable energy and carbon emissions (CE), as well as the association between the digital economy and carbon emissions in emerging economies from 2003 to 2022. The study employed cross-sectional augmented autoregressive distributed lag (CS-ARDL) estimation to check the relationship between the variables. The findings of our study suggest that the integration of renewable energy sources and the growth of the digital economy have a positive impact on reducing carbon emissions. On the other hand, public debt has a positive effect on carbon emissions. In addition, the findings support the notion that interaction terms (RE × DEB) and (DIG × DEB) have a diminishing effect on carbon emissions. It can be concluded that the reduction of carbon emissions is contingent upon the utilization of public debt to promote the growth of renewable energy and the digital economy. Based on our study, it is recommended that emerging economies' needs focus on boosting renewable energy usage and digital economy initiatives. Additionally, it is necessary for these economies to maintain a sustainable level of debt., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

A ratiometric fluorescence sensor has been established based on dual-excitation carbon dots (D-CDs) for the detection of flavonoids (morin is chosen as the typical detecting model for flavonoids). D-CDs were prepared using microwave radiation with o-phenylenediamine and melamine and exhibit controllable dual-excitation behavior through the regulation of their concentration. Remarkably, the short-wavelength excitation of D-CDs can be quenched by morin owing to the inner filter effect, while the long-wavelength excitation remains insensitive, serving as the reference signal. This contributes to the successful design of an excitation-based ratiometric sensor. Based on the distinct and differentiated variation of excitation intensity, morin can be determined from 0.156 to 110 µM with a low detection limit of 0.156 µM. In addition, an intelligent and visually lateral flow sensing device is developed for the determination  of morin content in real samples with satisfying recoveries, which indicates the potential application for human health monitoring., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Austria, part of Springer Nature.)

To overcome the limitations of current methods for diagnosing paracoccidioidomycosis (PCM), it is critical to develop novel diagnostic strategies that can be implemented in low-resource settings and dramatically improve turnaround times. This study focused on the development of a portable molecular test to screen for Paracoccidioides spp. The proposed approach integrated double-tagging polymerase chain reaction (PCR) and a paper-based lateral flow assay (LFA) for readout, using carbon nanoparticles as a signal generation system. Primers tagged with biotin and digoxigenin were employed to conduct the double-tagging PCR, which can be conveniently carried out on portable thermocyclers. This method can generate billions of tagged DNA copies from a single target molecule, which can be rapidly detected by the LFA platform, providing results within minutes. Avidin-modified carbon nanoparticles served as a signal generation system, enabling detection in the immunochromatographic assay. The LFA demonstrated the capability to detect double-tagged amplicons as low as 0.21 ng or 0.10 ng, depending on whether the results were assessed visually or with a smartphone equipped with an image processor. These findings suggest that the proposed approach holds great promise as a point-of-care diagnostic tool for the early and accurate detection of PCM in low-resource settings. The diagnostic test is rapid and inexpensive, requires minimal handling and can be easily introduced into the general practitioner's armoury for ambulatory screening of infection. This innovative approach has the potential to make a substantial contribution to PCM diagnosis, ultimately reducing morbidity and mortality associated with this disease., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Austria, part of Springer Nature.)

Nature-based Solutions (NbS) are integral to efforts to keep global warming below 2°C in accordance with the United Nations' 2015 Paris Agreement on Climate Change. Yet the transboundary governance dimensions of NbS remain unclear and largely undocumented. In Southeast Asia, NbS have emphasised the conservation and/ or sustainable commodification of carbon sinks found in terrestrial and mangrove forests, seagrass meadows, peatlands and agricultural soils. Mostly project-driven and fixed-term, these "solutions" have often failed to meet their social and ecological objectives. Increasingly, they have added to cross-border problems of: (1) displaced carbon emissions; and (2) economic migration and societal dispossession. This perspective paper delineates a transboundary governance research agenda to mitigate these trade-offs and enhance the co-benefits of NbS in carbon sinks. Building on NbS literature, it identifies cross-sector, multi-scalar and interdisciplinary pathways to improve transboundary cooperation, inclusion and equity in carbon sink governance in varying Southeast Asian contexts., (© 2023. The Author(s).)

This paper describes the development of simple, sustainable, and low-cost strategies for signal enhancement on paper-based carbon platforms through gold nanoparticles electrogenerated from small volumes of tetrachloroauric (III) acid solutions. Carbon ink is deposited on a hydrophilic working area of the paper delimited with hydrophobic wax. This maskless procedure is fast and cuts down ink waste. The connection of this working electrode to the potentiostat is ensured with the use of screen-printed electrodes (SPEs). Close contact of the whole area of both carbon electrodes improves the precision of the nanostructuration. Resulting gold-modified paper-based carbon working electrodes (AuNPs-PCWEs) were characterized by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM), and electron dispersion X-ray spectrometry (SEM/EDX). This methodology was applied for the first time to the inorganic arsenic determination in commercial white wines by chronoamperometric stripping of the electrodeposited As(0). In an optimized system, As(III) was reduced and deposited as As(0) on the nanostructured surface by applying a potential of -0.3 V during 180 s. Then, anodic stripping chronoamperometry was performed at +0.4 V. The analytical signal was the current recorded at 30 s. On the other hand, As(V) was chemically reduced to As(III) with 0.2 M KI, and total determination of arsenic could be carried out. As(V) was determined as the difference between total As and As(III). Then, this fast, simple and low-cost method can be employed for speciation purposes. Limits of detection for As(III) and total arsenic (in the presence of KI) are 2.2 μg L -1 and 2.4 μg L -1 , respectively, and indicate that this method is suitable for regulated quality control.

Pulp and paper industry produces massive amounts of sludge from wastewater treatment, which constitute an enormous environmental challenge. A possible management option is the conversion of sludge into carbon-based adsorbents to be applied in water remediation. For such utilization it is important to investigate if sludge is a consistent raw material originating reproducible final materials (either over time or from different manufacturing processes), which is the main goal of this work. For that purpose, different primary (PS) and biological sludge (BS) batches from two factories with different operation modes were sampled and subjected to pyrolysis (P materials) and to pyrolysis followed by acid washing (PW materials). All the materials were characterized by proximate analysis, total organic carbon (TOC) and inorganic carbon (IC), attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) and N 2 adsorption isotherms (specific surface area (S BET )and porosity determination). Sludge from the two factories proved to have distinct physicochemical properties, mainly in what concerns IC. After pyrolysis, the washing step was essential to reduce IC and to considerably increase S BET , yet with high impact in the final production yield. Among the materials here produced, PW materials from PS were those having the highest S BET values (387-488 m 2  g -1 ). Overall, it was found that precursors from different factories might originate final materials with distinct characteristics, being essential to take into account this source of variability when considering paper mill sludge as a raw material. Nevertheless, for PS, low variability was found between batches, which points out to the reliability of such residues to be used as precursors of carbon adsorbents., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

Though microfluidic paper analytical devices (μPADs) have attracted paramounting attentions in recent years as promising devices for low cost point-of-care tests, their real applications for blood analysis are still challenged by integrating sample preparation with different detection modes on a same μPAD. Herein, we developed a novel μPAD, which well coupled automatic serum extraction with reliable dual mode iron health tests: fluorescent analysis for Fe 3+ and colorimetric ELISA for ferritin. All these functions are made available by in situ carbon dots (CDs) and AuNPs sequential patterning techniques. For CDs immobilization, hydrothermal reaction was taken on paper, to which a patterned through-hole polydimethylsiloxane (PDMS) mask was applied. None fluorescence CDs (nF-CDs) were generated on exposed regions, while the fluorescent CDs (F-CDs) were generated simultaneously on covered regions. Sensitive serum iron quantification was realized on the F-CDs modified regions, where Fe 3+ ion can selectively quench the fluorescence of F-CDs. For AuNPs immobilization, electroless plating was taken on nF-CDs modified regions. The resulting AuNPs on nF-CDs layer on one hand triggered the coagulation of blood cells and thus led to the longest ever wicking distance for serum separation, on the other hand facilitated colorimetric enzyme linked immunosorbent assay (ELISA) for detection of serum ferritin. Combining the two readings, the μPAD can provide reliable measurement for serum iron and serum ferritin in whole blood. Furthermore, as CDs and AuNPs modified μPAD has the features of easy handling, low-cost, lightweight, and disposability, it is accounting for a promising prototype for whole blood point-of-care analysis.

Glutathione is an important antioxidant found in body fluids and tissues, which inhibit damage to essential cellular constituents caused by reactive oxygen species. The analysis of glutathione levels in biological systems is important in early clinical diagnosis. A novel, cost-effective synthetic strategy has been developed for the fluorescent probe ethylenediamine passivated carbon dots. Tissue paper was chosen as the carbon source for this "green one pot" synthesis. Glutathione could induce quenching of the fluorescence intensity of ethylenediamine passivated carbon dots through surface interactions, resulting from their aggregation. Based on this, a novel fluorescence sensor was fabricated for the determination of Glutathione in body fluids. A linear calibration graph was obtained in the range of 6.0 × 10 -7 to 5.0 × 10 -8 M with a detection limit of 1.74 × 10 -9 M. The developed sensor was successfully used for the determination of glutathione in artificial saliva samples.

This article describes a method for the modification of paper with single-wall carbon nanohorns (SWCNHs) to form stable suprastructures. The SWCNHs form stable dahlia-like aggregates in solution that are then self-assembled into superior structures if the solvent is evaporated. Dipping paper sections into a dispersion of SWCNHs leads to the formation of a thin film that can be used for microextraction purposes. The coated paper can be easily handled with a simple pipette tip, paving the way for disposable extraction units. As a proof of concept, the extraction of antidepressants from urine and their determination by direct infusion mass spectrometry is studied. Limits of detection (LODs) were 10 ng/L for desipramine, amitriptyline, and mianserin, while the precision, expressed as a relative standard deviation, was 7.2%, 7.3%, and 9.8%, respectively.

In this work, carbon papers and aerogels based on graphene layers and chitosan were prepared. They were obtained by mixing chitosan (CS) and a high surface area nanosized graphite (HSAG) in water in the presence of acetic acid. HSAG/CS water dispersions were stable for months. High resolution transmission electron microscopy revealed the presence of few graphene layers in water suspensions. Casting or lyophilization of such suspensions led to the preparation of carbon paper and aerogel, respectively. In X-ray spectra of both aerogels and carbon paper, peaks due to regular stacks of graphene layers were not detected: graphene with unaltered sp 2 structure was obtained directly from graphite without the use of any chemical reaction. The composites were demonstrated to be electrically conductive thanks to the graphene. Chitosan thus makes it possible to obtain monolithic carbon aerogels and flexible and free-standing graphene papers directly from a nanosized graphite by avoiding oxidation to graphite oxide and successive reduction. Strong interaction between polycationic chitosan and the aromatic substrate appears to be at the origin of the stability of HSAG/CS adducts. Cation-π interaction is hypothesized, also on the basis of X-ray photoelectron spectroscopy findings. This work paves the way for the easy large-scale preparation of carbon papers through a method that has a low environmental impact and is based on a biosourced polymer, graphene, and water.

Mixed sludge from a pulp and paper mill was hydrothermally carbonized at 180-260°C for 0.5-5h with the use of HCl or NaOH for determining the effect of acid and base additions during sludge carbonization. Based on the results carbonization was mainly governed by dehydration, depolymerization and decarboxylation of sludge components. Additive type had a statistically significant effect on hydrochar carbon content and carbon and energy yield, of which especially energy yield increased through the use of HCl. The theoretical energy efficiencies of carbonization increased with decreasing reaction temperature, retention time and the use of HCl and suggested that the energy requirement could be covered by the energy content of attained hydrochar. The BOD5/COD-ratios of analyzed liquid samples indicated that the dissolved organic components could be treated by conventional biological methods., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

Recycling hazardous wastes to produce value-added products is becoming essential for the sustainable progress of our society. Herein, highly porous carbon (1625 m(2)  g(-1)) is synthesized using waste tires as the precursor and used as a supercapacitor electrode material. The narrow pore-size distribution and high surface area led to good charge storage capacity, especially when used as a three-dimensional nanoscaffold to polymerize polyaniline (PANI). The composite paper was highly flexible, conductive, and exhibited a capacitance of 480 F g(-1) at 1 mV s(-1) with excellent capacitance retention of up to 98% after 10,000 charge/discharge cycles. The high capacitance and long cycle life were ascribed to the short diffusional paths, uniform PANI coating, and tight confinement of the PANI in the inner pores of the tire-derived carbon through π-π interactions, which minimized the degradation of the PANI upon cycling. We anticipate that the same strategy can be applied to deposit other pseudocapacitive materials to achieve even higher electrochemical performance and longer cycle life-a key challenge for redox active polymers., (© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

This paper reports the continuous reductive amination of different molecules, including biomass-related compounds, over carbon-supported FeNi nanoparticles obtained on the basis of inexpensive and abundant metal precursors and cellulose. A biorefinery case study for the preparation of pyrrolidones via acid-catalyzed hydrolysis of glucose followed by reductive amination of the obtained levulinic acid is described., (© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Herein, an environment friendly paper-based biobattery is demonstrated that yields a power of 12.5W/m 3 . Whatman filter papers were used not only as support for electrode fabrication but also as separator of the biobattery. To provide electrical conductivity to the paper-based cathode and anode, commercially available eyeliner containing carbon nanoparticles and Fe 3 O 4 was directly employed as conductive ink without any binder. With an instant start-up, the as-fabricated biocompatible electrodes could hold bacteria in an active form at the anode allowing chemical oxidation of organic fuel producing current. The facile process delineated here can be employed for the tailored electrode fabrication of various flexible energy harnessing devices., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Traditional fingerprints are usually obtained by pressing an inked finger on a paper. The inks would contaminate fingers and more importantly, these fingerprints are visible and able to be photocopied. In order to develop a smart membrane for fingerprint recording and document security, microrod assemblies of carbon quantum dots (CQDs)-Eu (III) are embedded in a electrospun nanofibrous (NFs) membrane which has strong red emission under UV irradiation owing to aggregation induced Dexter energy transfer from CQDs to Eu (III) ions. A clear blue emission fingerprint could be recorded on the membrane after a finger touch because the phosphate (Pi) secreted through sweat glands blocks the solid-state Dexter energy transfer, recovering the UV-irradiated blue emissions of CQDs. The Pi-based fingerprint on the membrane, which is invisible under daylight and could not be photocopied, greatly improves the security of the fingerprint and, furthermore, has the capability to identify the people who touched the secret document through the fingerprint analysis, showing that the intelligent NFs membrane can be applied for both fingerprint security and document counterspy.

Among options for atmospheric CO 2 removal, sequestering soil organic carbon (SOC) via improved grazing management is a rare opportunity because it is scalable across millions of globally grazed acres, low cost, and has high technical potential. Decades of scientific research on grazing and SOC has failed to form a cohesive understanding of how grazing management affects SOC stocks and their distribution between particulate (POM) and mineral-associated organic matter (MAOM)-characterized by different formation and stabilization pathways-across different climatic contexts. As we increasingly look to grazing management for SOC sequestration on grazinglands to bolster our climate change mitigation efforts, we need a clear and collective understanding of grazing management's impact on pathways of SOC change to inform on-the-ground management decisions. We set out to review the effects of grazing management on SOC through a unified plant ecophysiology and soil biogeochemistry conceptual framework, where elements such as productivity, input quality, soil mineral capacity, and climate variables such as aridity co-govern SOC accumulation and distribution into POM and MAOM. To maximize applicability to grazingland managers, we discuss how common management levers that drive overall grazing pattern, including timing, intensity, duration, and frequency can be used to optimize mechanistic pathways of SOC sequestration. We discuss important research needs and measurement challenges, and highlight how our conceptual framework can inform more robust research with greater applicability for maximizing the use of grazing management to sequester SOC., (© 2024 The Authors. Global Change Biology published by John Wiley & Sons Ltd.)

The low-carbon transition is a systemic economic and social change that will inevitably have an impact on many areas of the urban system. Has China's ongoing low-carbon transition impacted urban resilience (UR) systems while achieving urban energy saving and carbon emission reduction goals? This paper uses the implementation of the carbon emissions trading pilot policy (CETPP) as a "quasi-natural experiment." It evaluates the impact of the policy on UR using a difference-in-differences model based on the data of prefecture-level cities from 2008 to 2020. The study shows that pilot carbon trading policies favor UR, and the market mechanism of carbon emissions has a heterogeneous cause influence on UR. The impact of pilot carbon trading policies on UR varies according to the respective moderating effects of institutional factors, green technology innovation, industrial structure rationalization, and output effects., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

In this work, we developed a cascade signal amplification strategy for detection of IgG antigen by combining the rolling circle amplification (RCA) technique with oligonucleotide functionalized carbon dots (CDs), based on a paper-based electrochemiluminescence (ECL) origami device (PECLOD) for the first time. In this PECLOD, three-dimensional (3D) macroporous Au-paper electrode was fabricated and employed as the working electrode for specific and efficient antibodies capture. The RCA product containing tandem-repeat sequences could serve as an excellent template for periodic assembly of CDs, which presented per protein recognition event to numerous CDs tags for ECL readout. Under the optimal conditions, the proposed strategy showed remarkable amplification efficiency, very little nonspecific adsorption with good stability, reproducibility, and accuracy. Using human IgG (H-IgG) as a model protein, the designed strategy was successfully demonstrated for the ultrasensitive detection of protein target. The results revealed that the strategy exhibited a dynamic response to H-IgG range from 1.0 fM to 25 pM with a limit of detection as low as 0.15 fM. Importantly, the methodology can be further extended to the detection of other proteins or biomarkers., (Copyright © 2015 Elsevier B.V. All rights reserved.)

To estimate a watershed's response to climate change, it is crucial to understand how human activities and climatic extremes have interacted over time. Over the last century, the Zarivar Lake watershed, Iran, has been subjected to various anthropogenic activates, including deforestation and inappropriate land-management practices alongside the implementation of conservation measures like check dams. To understand the effects of these changes on the magnitude of sediment, organic carbon (OC), and phosphorus supplies in a small sub-watershed connected to the lake over the last century, a lake sediment core was dated using 210 Pb ex and 137 Cs as geochronometers. The average mass accumulation rate (MAR), organic carbon accumulation rates (OCAR), and particulate phosphorus accumulation rates (PPAR) of the sediment core were determined to be 6498 ± 2475, 205 ± 85, and 8.9 ± 3.3 g m -2  year -1 , respectively. Between the late 1970s and early 1980s, accumulation rates were significantly higher than their averages at 7940 ± 3120, 220 ± 60, and 12.0 ± 2.8 g m -2  year -1 respectively. During this period, the watershed underwent extensive deforestation (12%) on steep slopes, coinciding with higher mean annual precipitations (more than double). Conversely, after 2009, when check dams were installed in the sub-watershed, the sediment load to the lake became negligible. The results of this research indicate that anthropogenic activities had a pronounced effect on MAR, OCAR, and PPAR, causing them to fluctuate from negligible amounts to values twice the averages over the last century, amplified by climatic factors. These results imply that implementing climate-smart watershed management strategies, such as constructing additional check dams and terraces, reinforcing restrictions on deforestation, and minimum tillage practices, can facilitate protection of lacustrine ecosystems under accelerating climate change conditions., (© 2024. This is a U.S. Government work and not under copyright protection in the US; foreign copyright protection may apply.)