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Herbicides used on a regular basis could endanger non-target species like earthworms. The aim of this work was to test the toxic effect of atrazine and metribuzin on Aporrectodea caliginosa by filter paper contact and soil mixing techniques. Atrazine had the highest intrinsic toxicity to earthworms, with LC50 of 0.026 µg mL-1 after 72 hr of treatment. While the LC50 of metribuzin was 0.063 µg mL-1 after 72 hr by filter paper contact test. LC50 was reduced from 11.121 to 3.118 and 164.824 to 19.113 μg g soil-1 in clay soil, from 32.221 to 17.33 and 324.141 to 41.028 μg g soil-1 in soil (1:1) and from 41.234 to 30.804 and 462.255 to 70.902 μg g soil-1 in sandy clay loam soil of atrazine and metribuzin after 5 and 10 day. Generally, atrazine is more toxic than metribuzin in both tests.

Thermal comfort has always been an essential factor that affects students’ productivity and success. Students spend considerable time at their schools or universities more than any other building type except their homes. Thus, indicating the importance of providing thermal comfort in educational buildings. Many studies worldwide are conducted to assess and optimize thermal comfort inside classrooms. However, the results have not been accurate even for similar study conditions due to the differences in the studies’ conditions. This paper focuses on thermal comfort studies in educational buildings (classrooms). The studies are divided into two sections, the first covering field studies methodologies, objective, and subjective questionnaires, and the second reviewing thermal comfort results based on the climatic zone, educational level, and analysis approach. It is recommended that thermal comfort studies be carried out using rational and adaptive models as they provide more accurate, reliable results. Also, it is found that thermal comfort standards are generally inadequate to assess thermal comfort in classrooms. Thus, other international standards should be created and considered for classroom assessment. Over the past few years, the combination between nanotechnology and architecture engineering has been widely used in several disciplines because of its crucial significance in finding new nanodevices to contribute in reducing of energy consumption, particularly on construction materials. Filling functionalized tools with nanoparticles plays a critical role in improving the thermal and optical properties, particularly with respect to nanofluids applications, i.e., buildings applications of thermal comfort. The experimental results of long-term studies show that the calculation values of optimization have a consistent agreement with the experimental transmission of nanofluids models.

Spatially resolved fluid-flow modulation and its corresponding integration becomes a crucial aspect to consider when designing high-performing paper-based analytical devices. As such, high demand exists for cost-effective techniques able to selectively control flow in patternable regions of the device. In this regard, a solution composed of potassium alum and animal glue; sizing materials used in the fabrication of calligraphy Xuan paper, is successfully adapted for the first time in a revolutionary approach to efficiently modulate the capillary flow in paper microfluidic channels. Flow delays are achieved by coating the substrate systematically through the variation of parameters such as the ratio of alum to glue, the concentration of alum-glue in the solution, and the number of subsequent coating layers of alum-glue. Moreover, digitized patterning with alum-glue is developed to achieve programmable wicking profiles of accelerating, decelerating, and quasi-linear flow displacement by alternating coated and uncoated zones in the channel. Additionally, the influence of alum-glue when performing biometric assays is investigated by performing a horseradish peroxidase activity colorimetric assay and found to have negligible effects on reading, where a negligible difference of 5.2% was observed in an assay performed in a coated paper substrate, compared to an uncoated one.

Wastewater-based surveillance of the COVID-19 pandemic holds great promise; however, a point-of-use detection method for SARS-CoV-2 in wastewater is lacking. Here, a portable paper device based on CRISPR/Cas12a and reverse-transcription loop-mediated isothermal amplification (RT-LAMP) with excellent sensitivity and specificity was developed for SARS-CoV-2 detection in wastewater. Three primer sets of RT-LAMP and guide RNAs (gRNAs) that could lead Cas12a to recognize target genes via base pairing were used to perform the high-fidelity RT-LAMP to detect the N, E, and S genes of SARS-CoV-2. Due to the trans-cleavage activity of CRISPR/Cas12a after high-fidelity amplicon recognition, carboxyfluorescein-ssDNA-Black Hole Quencher-1 and carboxyfluorescein-ssDNA-biotin probes were adopted to realize different visualization pathways via a fluorescence or lateral flow analysis, respectively. The reactions were integrated into a paper device for simultaneously detecting the N, E, and S genes with limits of detection (LODs) of 25, 310, and 10 copies/mL, respectively. The device achieved a semiquantitative analysis from 0 to 310 copies/mL due to the different LODs of the three genes. Blind experiments demonstrated that the device was suitable for wastewater analysis with 97.7% sensitivity and 82% semiquantitative accuracy. This is the first semiquantitative endpoint detection of SARS-CoV-2 in wastewater via different LODs, demonstrating a promising point-of-use method for wastewater-based surveillance.

Two easy-to-use, rapid, and inexpensive colorimetric-based assays for the detection of active constituent in nasal decongestant phenylephrine hydrochloride (PHP), in solution and their respective pharmaceutical preparations were reported. The assay principle depends on the diazotized sulfadimidine (DSDM) coupling with PHP active pharmaceutical compound under alkaline conditions to produce a colored azo-dye product. A UV/VIS spectrophotometry method was utilized to monitor the color absorbance change at 460 nm, with a linear calibration graph in the concentration range of 1-20 mg L-1 and a limit of detection of 0.22 mg L-1 and limit of quantification of 0.72 mg L-1. A comparison was done using a paper-based microfluidic analytical device (µPADs) and color intensity change was measured using a Samsung note 9 camera to capture digital images and Image J software to analyze the color intensity development. A linear trend was observed above approximately 10 mg L-1. Thus, paper-based microfluidic analytical devices (µPADs) can be used as an alternative platform to conventional methods to perform a semi-quantitative PHP drug analysis. The proposed method was applied for the determination of PHP in commercial pharmaceutical preparations. KEY WORDS: Phenylephrine hydrochloride, Spectrophotometry, Paper-based microfluidic analytical devices (µPADs), Pharmaceutical preparations, Colorimetric detection Bull. Chem. Soc. Ethiop. 2022, 36(4), 727-736. DOI: https://dx.doi.org/10.4314/bcse.v36i4.1 &nbsp

Paper microfluidics has been extensively exploited as a powerful tool for environmental and medical detection applications. Both flow delay and compatibility with either polar or non-polar reagents are indispensable for the automation of detections requiring multiple reaction steps. This article reports the systematic studies of a 3D-printing protocol, characterization, and application of both the partially and fully penetrated polydimethylsiloxane (PDMS) barriers for flexible flow control in paper microfluidics. The physical parameters of PDMS barriers printed using a simple liquid dispenser were found related to the printing pressure, speed, diffusion time after printing, baking temperature, and PDMS viscosity. The capability of PDMS barriers to confine the flow of non-polar solvents was demonstrated using oil flow in both wax-and PDMS-surrounded channels. It was identified that the minimum width of channels to prevent leakage was 470 ± 54 μm, which was as narrow as that fabricated using stamps from lithography. Both the partially penetrated barriers (PPBs) and constriction channels were of the capability to delay flow in paper microfluidics. Additionally, an in silico investigation led to the further understanding that the reduction of channel cross-section resulting from PPBs was the primary reason for flow delay. Our results suggest that increasing the penetration depth of the barriers is more efficient in delaying flow than increasing the PPB length. Finally, devices with four inlet channels and 0-6 PPBs across each channel were successfully applied in flow delay for sequential fluid delivery. These results improve the understanding of the major factors, affecting the 3D PDMS barrier fabrication and the resulting flow control in paper microfluidics, providing practical implications for applications in various fields.

Paper aging and protection processes play an essential function in the preservation of library collections and archives. In this study, some physical-mechanical properties of paper samples from XXth century books (private collections), such as pH acidity, tensile strength, and modulus of elasticity, as well as optical properties, such as absolute change in yellowness, were examined before and after treating them with hydroxyapatite nanoparticles (HAp). Accelerated light aging was also evaluated and discussed. The treatment with HAp nanoparticles increased the paper’s pH to slightly alkaline values (approximately pH 8). Washing and treating the paper improved its mechanical properties compared to untreated paper; the tear length increased by 35% and the modulus of elasticity increased by 56%. That the treated and aged samples are more elastic than the original samples demonstrates that HAp nanoparticles consolidated the cellulose fibers. Additionally, particle morphology, size, composition and size distribution were assessed via image analysis using scanning electron microscopy (SEM-EDX), atomic force microscopy (AFM), and the ImageJ processing program.

Flexible inkjet-printed antenna is presented. The proposed antenna is designed on a synthetic paper substrate with an area of 35 × 40 mm2 to provide frequency bands for many popular wireless applications. Simulation and measurement are used to study the performances, including the frequency bands, radiation patterns, peak gains and efficiency, of the antenna in two severely bending conditions with a curvature radius of 20 mm in the forward and backward directions. The antenna printed in photo papers material could not be fully flexible due to cracks introduced to the coating material on the surface of the photo paper. Hence, the resin coated material was only suitable for curved devices. The synthetic paper material used in this paper does not have a resin coating, therefore, the antenna does not lose its flexibility and can be bent in both the forward and backward directions without any cracks. Results show that bending in these two conditions has insignificant effects on the performances of the antenna. With a curvature radius of 20 mm in the forward direction, the measured peak gain and efficiency of the antenna are in the ranges from −3 to +2 dBi and 40% to 60%, respectively. The results together with the low cost make the antenna most suitable for many flexible 5G communications devices.

Recognising the relevance of learning Geometry, and in particular 3D Geometry, this study aims to discuss the contributions that digital technology and paper and pencil approaches can bring to students’ learning. We seek, therefore, to identify the differences between the two approaches, and specifically: What factors are relevant in one and the other approach? What does one approach facilitate over the other? A quantitative and a qualitative and interpretive methodology was adopted, and based on a didactic intervention, the students' resolutions of the proposed tasks were analysed. The results obtained show that the experience and prior knowledge of the students with each of the solids involved seems to be decisive in the approach with paper and pencil. However, technology emerges as an enhancing resource when prior knowledge is more fragile. The study also shows differences between the representations supported by the two resources, suggesting the mobilisation of different knowledge by the students in relation to each of the resources., This work was partially funded by CIEd – Centro de Investigação em Educação, Instituto de Educação, Universidade do Minho, projects UIDB/01661/2020 and UIDP/01661/2020, through national funds of FCT/MCTES-PT; and by national funds through FCT – Foundation for Science and Technology, I.P., within the scope of the project PTDC/CED-EDG/32422/2017.

The use of paper dry strength additives is one of the methods for producing packaging boards with a lower grammage while maintaining mechanical properties. In the present work, papers were formed using dissolving grade kraft fibres, kraft fibres and carboxymethylated cellulose (CMC) modified kraft fibres (C-kraft fibres), with either cationic starch (CS), anionic polyacrylamide (APAM) or anionic polyelectrolyte complexes (PECs). Fibres and sheets were characterized to evaluate how the saturation adsorption of the different strength additives influences the properties of the treated fibres and the final handsheets. The tensile index of papers made from C-kraft fibres was the highest due to the highest adsorption capacity of strength additives. Moreover, the strength additives increased the tensile index by 33–84 %, while z-directional tensile strength was increased dramatically by 46–139 %. Bending stiffness was improved by 2.6–25 %, and the combination of CS and APAM or PECs resulted in a significant improvement in bending stiffness compared to the addition of CS alone. Importantly, the strength improvement did not sacrifice the density significantly. In summary, the knowledge gained from the current study expands the understanding of strength additives and their relationship with fibres of different surface charge and the overall paper properties.

The email that is indicated on an academic paper usually reflects that of the corresponding author (CA). In some cases, there may be more than one CA, and thus emails. It stands to reason that the email, especially if its is an institutional email, should obligatorily match that of the CA’s affiliation. This report highlights 47 papers, all in Wiley (Hindawi) open access journals, in which the institutional email address suffix does not match or correspond to the stated affiliation indicated as the CA’s affiliation. All papers, except for one, have a stated Chinese academic affiliation. One possibility is that such papers are associated with paper mills, i.e., third party paid services providing content, and possibly even emails to CAs. Editors of the journals in which these papers have been published have the responsibility to investigate.

Ubiquitous nature, versatility, and durability enabled paper to maintain its importance in the digital age. It is not surprising there have been numerous attempts to combine paper with the digital content. One way to do so is to place paper on a horizontal interactive display (e.g. tabletop or tablet). The paper thus becomes "the screen" on which the digital content is viewed, yet it also acts as a barrier that degrades the quality of the perceived image. This research tries to address this problem by proposing and evaluating a novel paper display concept called Dynamic pinhole paper. The concept is based on perforating the paper (to decrease its opacity) and moving digital content beneath the perforated area (to increase the resolution). To evaluate this novel concept, we fabricated the pinhole paper and implemented the software in order to run multiple user studies exploring the concept’s viability, optimal movement trajectory (amount, direction and velocity), and the effect of perforation on printing, writing and reading. The results show that the movement of digital content is a highly effective strategy for improving the resolution of the digital content through perforation where the optimal velocity is independent from trajectory direction (e.g. horizontal or circular) and amount of movement. Results also show the concept is viable on of the shelf hardware and that it is possible to write and print on perforated paper.