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This work presents a unique approach to the design, fabrication, and characterization of paper-based origami robotic systems consisting of stackable pneumatic actuators. These paper-based actuators (PBAs) use materials with high elastic modulus-to-mass ratios, accordion-like structures, and direct coupling with pneumatic pressure for extension and bending. The study contributes to the scientific and engineering understanding of foldable components under applied pneumatic pressure by constructing stretchable and flexible structures with intrinsically nonstretchable materials. Experiments showed that a PBA possesses a power-to-mass ratio greater than 80 W/kg, which is more than four times that of human muscle. This work also illustrates the stackability and functionality of PBAs by two prototypes: a parallel manipulator and a legged locomotor. The manipulator consisting of an array of PBAs can bend in a specific direction with the corresponding actuator inflated. In addition, the stacked actuators in the manipulator can rotate in opposite directions to compensate for relative rotation at the ends of each actuator to work in parallel and manipulate the platform. The locomotor rotates the PBAs to apply and release contact between the feet and the ground. Furthermore, a numerical model developed in this work predicts the mechanical performance of these inflatable actuators as a function of dimensional specifications and folding patterns. Overall, we use stacked origami actuators to implement functionalities of manipulation, gripping, and locomotion as conventional robotic systems. Future origami robots made of paper-like materials may be suitable for single use in contaminated or unstructured environments or low-cost educational materials.

In recent decades, there has been a growing interest in the recycling of organic materials such as paper mill biosolids (PB) and biochar for use as soil amendments. However, the benefits of co-application of PB and biochar and its effects on soil phosphorus (P) availability remain unknown. An incubation study was conducted on two acidic soils to assess the effect of two PB types (2.5% w/w) co-applied with three rates (0%, 2.5%, and 5% w/w) of pine (Pinus strobus L.) biochar on soil P fractions. An unfertilized control and a mineral NP fertilizer were used as a reference. Soil P fractions were determined by Hedley procedure after 2 and 16 wk of incubation. Material fractionation indicated that the PB containing the highest total P and the lowest Al content had the highest proportion of labile P, whereas most P in the biochar was in a stable form. The incubation study revealed that the P-rich PB increased P availability in both soils to a level comparable to mineral fertilizer at the end of the incubation. The addition of biochar to PB, however, did not affect soil P availability, but the highest rate induced a conversion of P fixed to Al and Fe oxides towards recalcitrant forms, particularly in the sandy loam soil. We conclude that co-applying biochar and PB could be more beneficial than application biochar alone and soils amended with such a mixture would be expected to release part of their P slowly over a longer period of time.

The prevalence of diabetes has increased over the past years. Therefore, developing minimally invasive, user-friendly and cost-effective glucose biosensors is necessary especially in low-income and developing countries. Cellulose paper-based analytical devices have attracted the attention of many researchers due to affordability, not requiring trained personnel, and complex equipment. This paper describes a microfluidic paper-based analytical device for the detection of glucose in tear with the naked eye. The paper-based biosensor fabricated by laser CO2, and GOx/HRP enzymatic solution coupled with TMB was utilized as reagents. A sample volume of 10 µl was needed for the biosensor operation and the results were observable within 5 minutes. To evaluate the device performance, color intensity-based and distance-based results were analyzed by ImageJ and Tracker. Distance-based results showed a linear behavior in the range of 0.1–0.6 mM with an R2 = 0.967 and LOD of 0.2 mM. The results could be perceived by the naked eye without any need to further equipment or trained personnel in a relatively short time (3–5 minutes). Moreover, glucose concentration could be obtained non-invasively by tears collected by this µPAD.

Amending croplands with forest residues may help in restoring soil properties in fields subject to intensive land management. Despite their known benefits when applied separately, co-application of wood biochar with paper mill biosolids (PB) has seen little investigation under field conditions. A study was initiated in Québec, QC, Canada, to determine the effect of a single application of wood biochar with and without PB on the nitrogen (N) and phosphorus (P) availability of two pH-neutral to alkaline loamy soils. Biochar at 0, 10, and 20 Mg dry weight·ha−1 and PB at 30 Mg wet weight·ha−1 were applied before planting of corn (Zea mays L.) and soybean [Glycine max (L.) Merr.] in 2018. Residual effect of this co-application was determined under soybean and corn in the subsequent year. In both years, corn received supplemental N and P from mineral fertilizers according to local agronomic recommendations. Co-applying biochar and PB reduced soil NO3-N availability in the year of application and decreased corn yield by 1.0 Mg·ha−1 compared with biochar or PB applied alone, but these amendments did not affect soybean yields. In the following year, the previous biochar addition increased soybean yield by 0.6 Mg·ha−1 but had little effect on corn. For both years, biochar addition induced a large increase in soil Mehlich-3 P. This study revealed that wood biochar positively impacted P status of these soils but was not a source of N to crops even when co-applied with PB.

Acidification and metal mobility may present challenges in soil receiving paper mill biosolids (PB). Co-applying biochar and PB could help prevent these issues, but its effect must be assessed. The objective of this 224 d incubation study was to evaluate the effect of amending two acidic soils, a clay and sandy loam, with two PB types varying in pH (PB1, pH = 7.80; and PB2, pH = 4.51) co-applied with three rates (0%, 2.5%, and 5% w/w) of pine (Pinus strobus L.) biochar on soil pH and macro- (P, K, Ca, and Mg) and micronutrients (Cu, Zn, Fe, and Mn). In both soils, co-applying biochar and PB significantly increased soil pH and extractable K concentration compared with PB-only application, whereas amending with PB significantly increased soil extractable P concentration compared with the unamended soil. In comparison with PB only, co-applying 5% biochar and PB decreased extractable Cu concentration in both soils and extractable Fe concentration in the sandy loam soil. This study showed that co-applying biochar and PB can be more beneficial to agricultural soils than application of PB alone by supplying nutrients and helping prevent metal toxicity by raising pH, especially in acidic sandy soils.

Purpose This study aimed to determine whether continual electronic patient-reported outcome (ePRO) measurements at home can capture the fluctuations in health-related quality of life (HRQOL) scores between visits. Methods We performed a randomized controlled trial to compare the scores obtained by standard practice (paper-based measurements in the hospital) to scores by continuous measurement of ePRO at home. Metastatic cancer patients were randomly assigned to either the paper-based ( n = 50) or the ePRO group ( n = 52). EQ-5D-5L and EORTC QLQ C-30 scores were obtained on 3 different chemotherapy days in the paper-based group. Meanwhile, scores were obtained on the chemotherapy day and on days 3, 7, 10, and 14 in the ePRO group during 2 cycles. The first hypothesis of our study was that both scores at the same time points would be equivalent despite different measurement frequency, place, or mode of measurement. The second hypothesis was that PRO score–adjusted time would be different between the groups. For equivalence, the endpoint was the mean EQ-5D-5L index value on the chemotherapy day before the outpatient treatment. Only if equivalence was shown, quality-adjusted life-days (QALDs) were considered using all the data. Results The adjusted mean difference in the EQ-5D-5L index was determined to be −0.013 (95% confidence interval [CI]: −0.049 to 0.022); the 95% CI did not exceed the equivalence margin. Similarly, the mean difference in global health status (2.28 [95% CI: −2.55 to 7.11]) also showed equivalence. However, the QALD by EQ-5D-5L was significantly lower in the ePRO group by 1.36 per 30 d (95% CI: −2.22 to −0.51; P = 0.0021). Conclusions Continual measurements of the HRQOL at home by ePRO may yield more detailed profiles of the HRQOL.

Paper mill effluent has been characterized as recalcitrant because of containing lignin and its derivatives. Since biofilm system exhibits a notable potential for the removal of recalcitrant contaminants, a sequencing batch biofilm reactor (SBBR) was employed to treat coagulated recycled paper mill effluent in this study. The results indicated that the SBBR removed 91.3 % of chemical oxygen demand (COD), whilst total suspended solid (TSS) and color removal reached 83.1 % and 71.0 %, respectively. The microbial analysis suggested that three typical heterotrophic phyla, Proteobacteria, Bacteroidetes and Acidobacteria are dominant bacteria and reflected the removal of recalcitrant contaminants. The COD removal rate of SBBR is evidently superior to conventional activated sludge process due to high sludge concentration as well as long sludge retention time (SRT). Whilst the problem of sludge bulking can be successfully avoided, the blockage of reactor caused by TSS accumulation and microbial growth deserve further investigation.

Background The screening of biological hazards, chemical contaminants and allergens in food products is a major concern of food industry since they can cause serious illnesses and even lead to death. Therefore, there is a significant interest in developing low-cost, robust, and rapid detection methods for food safety and quality analysis. Conventional methods provide accurate analytical characteristics, but require well-equipped laboratories, trained personnel, costly reagents, and complicated sample preparation procedures prior to the detection in order to obtain reliable results. Hence, they are not always ideal for on-site food surveillance. Scope and approach This paper discusses the fundamentals of microfluidic paper-based analytical devices (μPADs) and reviews the recent progress in their usage for screening biological hazards, harmful chemical residues, and allergens in food products to systematically evaluate the strengths and weaknesses of this technology. It then covers future trends and useful strategies that could be employed in μPADs design and fabrication procedures to address the critical challenges in equipment-free food analysis. Key findings and conclusions μPADs offer promising avenues to revolutionize food safety and quality analysis with merits of equipment-free sample preparation and detection at low-cost. Despite the advancement in the microfluidic technology, the manufacturing of user-friendly sample-to-answer μPADs still requires intensive research studies to be employed for robust and sensitive food safety and quality analysis.

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

We present how harmful different wood extractives carried over to paper mill with unbleached softwood Kraft pulp are for the strength of packaging papers and boards. The investigations were done by simulating industrial papermaking conditions in laboratory-scale trials for handsheet production. It was found that fatty acids are the most relevant compounds in the carryover pitch extractives (CPEs), as they readily interfere in fiber–fiber bonding strength, control the properties of CPE micelles, and are furthermore the most abundant compounds. Addition of cationic starch improved strength and evened out the strength differences of handsheets with different CPE compounds. Oleic acid (unsaturated fatty acid) was an exception, as it was above average harmful for paper strength without cationic starch and also heavily impaired the functioning of cationic starch. As a whole, these findings demonstrate that fatty acids, especially unsaturated ones, are the most relevant CPE compounds contributing to the reduced efficiency of cationic starch and decreased strength of unbleached softwood Kraft paper. This makes the cleaning of process waters by precipitating CPEs on the pulp fibers harmful for paper strength.