Search

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.)

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.

Non-wood paper production, such as bamboo paper, is an alternative to meet the massive demand for paper consumption in the recent era. Bamboo paper, made from Bambusa vulgaris fibers and manufactured with the addition of activated nano-carbon, shows an improvement in paper quality. However, there is a potential worry with the incorporation of activated carbon since it may hinder the degradation process of paper. Concerning the substance's life cycle, degradation assisted by the fungal decomposer of this new product is crucial. This study investigated the effects of the white-rot fungi, viz. Phlebiopsis sp and Pycnoporus sp., on the degradation of bamboo paper with- or without- activated nano-carbon (BPAC and BPNAC). In vitro experiments that combined two variables (Fungal agents and Paper types) were carried out for 12 weeks. The results revealed that Pycnoporus sp. was more effective in decomposing both BPAC and BPNAC rather than Phlebiopsis sp. After being degraded by Phlebiopsis sp. and Pycnoporus sp. for 12 weeks, the remaining mass of BPAC was 64.14% and 48.96%, respectively, while the BPNAC was 69.89% and 38.25%, respectively. The ability of these fungal agents on composite-paper degradation was compared to other similar studies. Further investigation and possible applications were discussed.

Copyright of Indonesian Journal of Forestry Research is the property of Indonesian Journal of Forestry Research and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The effect of bipolar and driving electrodes materials and also the electrolyte conductivity on the required potential for the beginning of the water electrolysis in the paper-based closed cell bipolar electrochemistry is investigated. The importance of the electrode material is studied by placement of various carbon paste mixtures as an electrode on the paper. Carbon paste mixtures are prepared with different carbon allotropes and various binders such as paraffin and ionic liquids. The effect of hydrophobicity, conductivity, and presence of common additives such as gold nanoparticle is discussed in detail. The role of electrolyte conductivity on the needed ∆E for water electrolysis initialization is investigated. It has been proved that even in the absence of ionic current in the closed bipolar setups, electrolyte conductivity can be effective. [ABSTRACT FROM AUTHOR]

The surface of paper was treated to control wettability using argon-carbon plasma generated by a direct current-pulsed (frequency: 60 kHz) sputtering device with parallel-arrangement magnets. After plasma treatment, the C–C bond percentage in the C 1s region was inversely proportional to the C–OH bond percentage, while the ratio of C=O and O–C=O bonds only changed slightly. The change ratios for the increase in C–C and the decrease in the C–OH bonds were approximately the same, and the change ratio increased from approximately 5%–11% with an increase in the plasma current. The reduction ratio of the contact angle decreased from 0.945 to 0.182 (°/s) with increasing plasma current. These results indicate that the water resistance of the paper surface was enhanced after the simple plasma treatment, and wettability could be easily controlled by changing the substitution ratio between C–OH and C–C elements, achieved by altering the plasma current. • Papers were plasma-treated using DC-pulsed sputtering with parallel-aligned magnets. • C–C and C–OH bond percentages were inversely proportional after plasma treatment. • Substitution ratio between C–OH and C–C was changed by varying the plasma current. • Contact angle reduction ratio on paper decreased with increase in plasma current. [ABSTRACT FROM AUTHOR]