Relevant Levels Research Articles

Accelerated Continuous Flow Depolymerization of Poly(Methyl Methacrylate).

A continuous flow setup comprising an inline dialysis unit for immediate monomer removal is used for the depolymerization of poly(methyl methacrylate) (pMMA), synthesized via reversible addition-fragmentation chain transfer (RAFT) polymerization. The approach used allows one to carry out solution depolymerizations at much higher polymer content compared to batch processes while maintaining high depolymerization conversions. pMMA is efficiently depolymerized in the flow reactor, yielding up to 68% monomer recovery under catalyst-free reaction conditions at 160 °C, starting from a 1 molar repeat unit concentration, which is a 20-fold improvement compared to previous batch studies. This was achieved by using the inline dialysis to continuously remove monomer from the depolymerization solution and hence continuously shifting of the depolymerization equilibrium to the recycling side. Depolymerizations at various temperatures, starting polymer concentrations, and reactor setup modifications are investigated, clearly showing the highly advantageous effect of the monomer removal on the reaction. The employed approach represents a significant advancement toward the industrial feasibility of depolymerization of methacrylates by lowering the solvent use, expanding its temperature operation window, and bringing polymer contents to a practically relevant level.

Factors influencing clinical supervision of undergraduate occupational therapy students during practice learning in the Global South: A rapid review

Background. Clinical practice learning is an important aspect of educating undergraduate occupational therapy (OT) students to understand the profession and for professional identity. Practice learning could be hampered by several factors including the lack of proficient clinical supervisors, coupled with a burgeoning number of students. To ensure the success of the programme, the expectations of lecturers and supervisors should be compatible. Objective. To investigate the factors influencing clinical supervision of undergraduate OT students during practice learning in the Global South. Methods. A rapid review of the literature was conducted between 2017 and 2022 with searches in EBSCOhost and PubMed databases. Mendeley Reference Manager was used as a tool for database storage, and the literature found was screened and documented according to the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) statement and guidelines. A hierarchy of evidence was formed using Tomlin and Borgetto’s (2011) research pyramid. Articles within the three most trustworthy and relevant levels of the qualitative hierarchy were appraised using the clinical appraisal skills programme (CASP) tool. Results. Five main themes emerged from a thematic analysis of 20 records: quality assurance; roles and relationships; hegemonies in and out of context; context of clinical practice; and teaching how. Conclusion. The key aspects influencing clinical supervision in undergraduate OT programmes are interconnected. The findings emphasise the importance of having a protocol, sequence of preparation and procedure, and training of personnel in informing quality of supervision. Quality individualised support for learners is best achieved when there is structure and proficient supervision.

Developing a Flow-Resistance Module for Elucidating Cell Mechanotransduction on Multiple Shear Stresses.

Fluid shear stress plays a pivotal role in regulating cellular behaviors, maintaining tissue homeostasis, and driving disease progression. Cells in various tissues are specifically adapted to physiological levels of shear stress and exhibit sensitivity to variations in its magnitude, highlighting the requirement for a comprehensive understanding of cellular responses to both physiologically and pathologically relevant levels of shear stress. In this study, we developed an independent upstream flow-resistance module with high fluidic resistances comprising three microchannels. The validity of the flow-resistance module was confirmed via computational fluid dynamics (CFD) simulations and flow calibration experiments, resulting in the generation of steady wall shear stresses ranging from 0.06 to 11.57 dyn/cm2 within the interconnected cell culture chips. Gene expression profiles, cytoskeletal remodeling, and morphological changes, as well as Yes-associated protein (YAP) nuclear translocation, were investigated in response to various shear stresses to authenticate the reliability of our experimental platform, indicating an increasing trend as the shear stress increases, reaching its maximum at various shear stresses. Our findings suggest that this flow-resistance module can be readily employed for precise characterization of cellular responses under various shear stresses.

Mindfulness and the Judging Mind in the Context of Buddhist Models of Mind

AbstractPsychological research on mindfulness has often focused on the effects of mindfulness training, such as clinical application, rather than on the meaning of mindfulness itself as taught in various spiritual, philosophical, and medical traditions. Mindfulness is often seen as a general training in attentional awareness. From a Buddhist perspective, this approach does not allow for the effective solution of deep-rooted problems arising from a deluded state of mind, which requires insight into the nature of mind. In order to apply the practice of mindfulness as a soteriological path, a precise understanding of the full range of functions of mindfulness and the judgmental mind is essential. To this end, this study explores the relevant definitions and levels of this practice in the context of Buddhist models of mind. This paper provides a profound analysis of early Indian Buddhist sources such as the Four Foundations of Mindfulness and later Tibetan Buddhist presentations, in particular those of the Kagyu lineage, such as the Distinction between Consciousness and Wisdom by the 3rd Karmapa Rangjung Dorje (1284–1339). Buddhist epistemology and meditation instructions offer various mind maps and discuss the steps in the process of perception, based on the application of mindfulness, to overcome deluded states of mind and develop highest wisdom. The theoretical and practical findings are intended to be helpful in integrating traditional Buddhist models of mindfulness and the judging mind, including issues of health and happiness, with our modern understanding of cognitive processes as described in applied psychology.

Sex Differences in the Anxiolytic Properties of Common Cannabis Terpenes, Linalool and β-Myrcene, in Mice

Volatile organic compounds, colloquially referred to as “terpenes”, have been proposed to impact the therapeutic qualities that are traditionally ascribed to cannabis. However, the contribution of these terpenes in anxiety, at relevant levels and exposure methods common with cannabis use, is lacking empirical assessment. We tested the anxiolytic properties of two prominent cannabis terpenes, linalool and β-myrcene, in male and female mice using short duration vapor pulls to model human inhalation when combusting flower or vaping cannabis oil. We observed sex differences in the locomotor effects in the open field and anxiolytic properties in the elevated plus maze of these terpenes that depended on their exposure characteristics. Both linalool and β-myrcene had anxiolytic effects in female mice when delivered in discrete vapor pulls over the course of 30 min. In male mice, only a single vapor hit containing linalool or β-myrcene had anxiolytic effects. The combination of sub-effective levels of linalool and the phytocannabinoid, cannabidiol (CBD), had synergistic anxiolytic effects in females, but these entourage effects between CBD and terpenes were absent with β-myrcene for females and for either terpene in males. Together, our findings reveal sex differences in the anxiolytic properties of common cannabis terpenes and highlight the potential benefits of unique combinations of CBD and terpenes in expanding the therapeutic dose window.

UV Sensitivities of Two Littoral and Two Deep-Freshwater Amphipods (Amphipoda, Crustacea) Reflect Their Preferred Depths in the Ancient Lake Baikal

Solar ultraviolet (UV) is among the most important ecological factors shaping the composition of biota on the planet’s surface, including the upper layers of waterbodies. Inhabitants of dark environments recently evolving from surface organisms provide natural opportunities to study the evolutionary losses of UV adaptation mechanisms and better understand how those mechanisms function at the biochemical level. The ancient Lake Baikal is the only freshwater reservoir where deep-water fauna emerged, and its diverse endemic amphipods (Amphipoda, Crustacea) now inhabit the whole range from highly transparent littoral to dark depths of over 1600 m, which makes them a convenient model to study UV adaptation. With 10-day-long laboratory exposures, we show that adults of deep-water Baikal amphipods Ommatogammarus flavus and O. albinus indeed have high sensitivity to environmentally relevant UV levels in contrast to littoral species Eulimnogammarus cyaneus and E. verrucosus. The UV intolerance was more pronounced in deeper-dwelling O. albinus and was partially explainable by lower levels of carotenoids and carotenoid-binding proteins. Signs of oxidative stress were not found but UV-B specifically seemingly led to the accumulation of toxic compounds. Overall, the obtained results demonstrate that UV is an important factor limiting the distribution of deep-water amphipods into the littoral zone of Lake Baikal.

Cross-culture adaptation and validation of Indonesian language version of Pittsburgh Sleep Quality Index

Hemodialysis (HD) patients have a high rate of poor sleep. The Pittsburgh Sleep Quality Index (PSQI) is the most popular self-reported instrument to measure sleep quality. No study has tested the psychometric efficiency of the Bahasa (Indonesian language) PSQI in hemodialysis (HD) patients, and no cross-cultural adaptation has been done. The purpose of this research was to translate the PSQI into Bahasa and improve its psychometric properties for use in evaluating HD patients in Indonesia. This study used instrument translation, cultural adaptation, content validation, and equivalence to crossculturally validate and adapt an instrument. The hemodialysis center at a West Java medical facility served as a source of potential HD patients throughout the period of October 2022 to February 2023. A content validity index (CVI) was calculated for each item and the entire scale. The factor structure of the Bahasa PSQI has been evaluated by confirmatory factor analysis and internal consistency was calculated using Cronbach's alpha. The online survey received a response rate of 62.8% from a total of 220 patient with HD (about ten responders each item). The level of language clarity was 87.8%, and the level of cultural relevance was 84.5%. The CVI varied from 0.92 to 1.00. Each factor had factor loading ranging from 0.51 to 0.62. that Cronbach alpha for total score was 0.803, and the subscale ranged from 0.771 to 0.863. Our research provides preliminary evidence of the validity and reliability of the translated and adapted tool using data from HD patients in Indonesian hospitals.

LabEmbryoCam: An opensource phenotyping system for developing aquatic animals

Phenomics is the acquisition of high-dimensional data on an individual-wide scale and is proving transformational in areas of biological research related to human health including medicine and the crop sciences. However, more broadly, a lack of accessible transferrable technologies and research approaches is significantly hindering the uptake of phenomics, in contrast to molecular-omics for which transferrable technologies have been a significant enabler. Aquatic embryos are natural models for phenomics, due to their small size, taxonomic diversity, ecological relevance, and high levels of temporal, spatial and functional change. Here, we present LabEmbryoCam, an autonomous phenotyping platform for timelapse imaging of developing aquatic embryos cultured in a multiwell plate format, and while optimised for embryos, the instrument is extremely versatile. The LabEmbryoCam capitalises on 3D printing, single board computers, consumer electronics and stepper motor enabled motion. These provide autonomous X, Y and Z motion, a web application streamlined for rapid setup of experiments, user email notifications and a humidification chamber to reduce evaporation over prolonged acquisitions. Downstream analyses are provided, enabling automated embryo segmentation, heartbeat detection, motion tracking, and energy proxy trait (EPT) measurement. LabEmbryoCam is a scalable, and flexible laboratory instrument, that leverages embryonic and early life stage organisms to tackle key global challenges including biological sensitivity assessment, toxicological screening, but also to support broader engagement with the earliest stages of life.

Cyclic Removal and Destruction of Per- and Polyfluoroalkyl Substances from Water Using Ion Exchange, Resin Regeneration, and UV/Sulfite Reduction

Ion exchange (IX) can effectively remove per- and poly-fluoroalkyl substances (PFAS) from drinking water sources at ng/L to µg/L levels. However, adsorbed PFAS on spent resins should be further destructed for detoxification. Traditional resin incineration or landfilling may cause secondary pollution to the surrounding environment and cannot achieve resin reuse. This study explored three variations of a PFAS treatment train, aiming to completely defluorinate PFAS with different chain lengths and functional groups at environmentally relevant levels (ng/L) and to reuse the resins and solvents. The optimized treatment train includes IX, resin regeneration with 5wt% NaCl and 60% v/v methanol, distillation of waste regenerant, and advanced reduction by hydrated electrons (eaq−) generated during the ultraviolet/sulfite (UV/sulfite) treatment of still bottoms. Such a treatment train achieved nearly 100% PFAS removal from surface water and groundwater using either PFAS-specific or generic resins, and almost 100% defluorination of PFAS except a few short-chain fluorinated sulfonates and ethers. Regenerated resins had comparable PFAS removal to the pristine resins over three cycles. The generic resins (e.g., Dupont AmberLite™ IRA910) are easier to regenerate and thus are recommended for the treatment train over PFAS-selective resins (e.g., Purofine® PFA694E). Direct heterogenous defluorination on resins loaded with perfluorooctane sulfonate (PFOS) was ineffective, potentially due to the consumption of UV light/eaq− by the resins and insufficient contact between the UV light/eaq− with PFOS on the resin surface. Distillation of the waste regenerant successfully concentrated PFAS in the still bottoms, reduced the waste volume, and removed excess methanol, all essential for effective UV/sulfite treatment. Meanwhile, the produced condensate with high methanol contents and low PFAS levels can be reused for the next regeneration cycle. Findings from this study provide a timely and sustainable solution to the stringent and evolving regulations on PFAS and the resultant production of PFAS-laden resins as hazardous wastes.

The analytical evaluation threshold for inorganic metal extractables and leachables analysis of medical devices

Chemical characterization of medical devices uses the analytical evaluation threshold (AET) to determine reportable organic extractables, as these chemicals may be of toxicological concern and should be addressed via toxicological risk assessment. The AET is not applicable to metal extractables due to the exclusion of toxicity data on inorganics from the dataset used to derive dose-based threshold (DBT) values. This results in minimal guidance for reporting metal extractables. Herein, an AET for metals, or mAET, is proposed as a reporting threshold for individual metal extractables. The mAET can ensure metals are reported that are at quantities that may present a patient safety risk. This may reduce the number of metals reported in a chemical characterization report, improving the efficiency of the overall biocompatibility evaluation by removing unneeded effort and resource time. Conversely, an analytical method’s ability to report all metals at toxicologically relevant levels can be confirmed by comparing method sensitivity to mAET values. DBTs were developed for 70 metals, permitting mAET values to be determined. These mAET values were then compared to metal reporting limits from 13 previously conducted chemical characterization studies, which used varying extraction designs and analytical methods, to determine the impact of the mAET.

Chronic toxicity and intergenerational effects of N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine (6PPD) exposure alone and in combination with Zn2+ on Daphnia magna (Cladocera).

N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine (6PPD) and Zn2+, extensively used in the tire manufacturing process, are frequently detected in freshwater environments. However, the intergenerational effects of isolated 6PPD exposure and joint 6PPD and Zn2+ exposure at concentrations approximating environmental levels remain unknown. This study assessed the chronic toxicity and intergenerational effects of 6PPD (0.02-20 μg/L) and a mixture of 6PPD and Zn2+ (5 μg/L) over three generations in Daphnia magna bioassays. In the F0 generation, a dose-dependent decline in total offspring number was observed with 6PPD exposure alone, while co-exposure with Zn2+ exacerbated the reproductive toxicity of 6PPD. Across three generations, low-dose (0.02 µg/L) 6PPD alone and combined with Zn2+ induced a cumulative degenerative maternal effect. Conversely, high-dose (20 µg/L) 6PPD, both independently and in combination with Zn2+, exhibited an adaptive maternal effect. Notably, the grandmaternal effect emerged exclusively in the co-exposure group treated with 20 μg/L 6PPD and 5 μg/L Zn2+, with no such effect in the group exposed to 20 μg/L 6PPD alone, suggesting that Zn2+ may enhance the potential toxicity of 6PPD. Overall, this study provides novel insight into the intergenerational impacts of environmentally relevant levels of 6PPD alone and in combination with a heavy metal, elucidating the environmental risks posed by tire-derived chemicals through their synergistic effects on transgenerational toxicity.

CO2 protects cells from iron-Fenton oxidative DNA damage in Escherichia coli and humans

While hydroxyl radical is commonly named as the Fenton product responsible for DNA and RNA damage in cells, here we demonstrate that the cellular reaction generates carbonate radical anion due to physiological bicarbonate levels. In human and Escherichia coli models, their transcriptomes were analyzed by RNA direct nanopore sequencing of ribosomal RNA and chromatography coupled to electrochemical detection to quantify oxidation products in order to follow the bicarbonate dependency in H2O2-induced oxidation. These transcriptomic studies identified physiologically relevant levels of bicarbonate focused oxidation on the guanine base favorably yielding 8-oxo-7,8-dihydroguanine (OG). In human cells, the bicarbonate-dependent oxidation was further analyzed in the metabolome by mass spectrometry, and a glycosylase-dependent qPCR assay to quantify oxidation sites in telomeres. These analyses further identify guanine as the site of oxidation when bicarbonate is present upon H2O2 exposure. Labile iron as the catalyst for forming carbonate radical anion was demonstrated by repeating the bicarbonate-dependent oxidations in cells experiencing ferroptosis, which had a >fivefold increase in redox-active iron, to find enhanced overall guanine-specific oxidation when bicarbonate was present. The complete profiling of nucleic acid oxidation in the genome, transcriptome, and metabolome supports the conclusion that a cellular Fe(II)-carbonate complex redirects the Fenton reaction to yield carbonate radical anion. Focusing H2O2-induced oxidative modification on one pathway is consistent with the highly evolved base excision repair suite of enzymes to locate G-oxidation sites for repair and gene regulation in response to oxidative stress.

Multi-Professional Family Support Programme: A Collective Development at the Neonatal Intensive Care Unit

This study was undertaken to structure and validate a Multi-Professional Family Support Programme that was collectively developed at a Neonatal Intensive Care Unit (NICU). This is participative research of the action-research category with a qualitative–quantitative approach conducted at a University Hospital in the southeast of Brazil with the participation of their multi-professional staff. The study was done in four interdependent stages, adapted from the method proposed by Thiollent (2011): organisation, structuring, validation, and diffusion. Qualitative data were analysed following Bardin’s (2016) Content Analysis Technique and presented in categories and sub-categories. The evaluation instruments followed the evaluation criteria proposed by Pasquali (2010). In the analysis of quantitative data, Cronbach’s Alpha coefficient was used to verify reliability, Fleiss’ Kappa coefficient for measuring agreement, and the Content Validity Index for relevance and representativeness. The programme was built collectively and is based on the Family-Centred Care model. Cronbach’s Alpha reached values above 0.90, which is excellent reliability. There was varying agreement between substantial/perfect and significant (k = 0.68–1.00; p < 0.001), and all the evaluation criteria were considered relevant and representative (CVI > 90.0%). The programme and its guiding technologies were structured and validated with high levels of reliability, agreement, relevance, and representativeness.

Design, Evaluation, and Implementation of a Novel Magnetic Resonance Imaging-Compatible Physiologic Loading Simulator for Ex-Vivo Joints.

Quantitative magnetic resonance imaging (qMRI), in combination with mechanical testing, offers potential to investigate how loading (e.g., from daily physical exercise) is related to joint and tissue function. However, current testing devices compatible with magnetic resonance imaging (MRI) are often limited to uniaxial compression, often applying low loads, or loading individual tissues (instead of multiple), while more complex simulators do not facilitate MRI. Hence, in this work, we designed, built and tested (N = 1) an MRI-compatible multi-axial load-control system, which enables scanning cadaveric joints (healthy or pathologic) loaded to physiologically relevant levels. Testing involved estimating and validating physiologic loading conditions before implementing them experimentally on cadaver knees to simulate and image gait loading (stance and swing). The resulting design consisted of a portable loading device featuring pneumatic actuators to reach a combined loading scenario, including axial compression (≤2.5 kN), shear (≤1 kN), bending (≤30 N·m) and muscle tension. Initial laboratory testing was carried out; specifically, the device was instrumented with force and pressure sensors to evaluate loading and contact response repeatability in one cadaver knee specimen. This loading system was able to simulate healthy or pathologic gait with reasonable repeatability (e.g., 1.23-2.91% coefficient of variation for axial compression), comparable to current state-of-the-art simulators, leading to generally consistent contact responses. Contact measurements demonstrated a tibiofemoral to patellofemoral load transfer with knee flexion and large contact pressures concentrated over small sites between the femoral cartilage and menisci, agreeing with experimental studies and numerical simulations in the literature.

LEGALITY OF TRADITIONAL OIL MINING EXPLORATION IN RANTO PEUREULAK, EAST ACEH: AN ANALYSIS OF THE ISLAMIC ECONOMIC LAW PERSPECTIVE

This article aims to examine the legality of oil mining resulting from traditional mining exploitation by the Ranto Pereulak community, East Aceh. This research uses descriptive qualitative research methods and the approach used in this research is a sociological normative approach. This research was located in Ranto Peureulak District, which is one of the sub-districts in East Aceh Regency. The results of this research show that the East Aceh Government through Qanun Number 6 of 2009 provides space for the community to manage mining products, in this case oil, by obtaining an IUP issued by the East Aceh government and going through all the conditions therein. The IUP is granted by the Regent after obtaining principle permission or approval from the Governor through the relevant provincial and district level agencies. However, in practice, many people in Ranto Peureulak District, East Aceh Regency, in managing illegal wells traditionally do not follow the applicable SOPs or regulations. Then the oil drilling carried out can endanger the health of workers and the surrounding community. This can also have an impact on the environment, because it does not pay attention to health standards or Health Safety and Environment or abbreviated as (HSE), which is the main priority for mining. In terms of safety too, it often catches fire and causes casualties, both workers and residents. Because drilling oil and gas wells is a very complex process and at each step procedures, requirements and important decisions are required that must be considered and implemented very carefully.

Protocol for Therapeutic Drug Monitoring Within the Clinical Range Using Mid-infrared Spectroscopy.

Therapeutic drug monitoring (TDM), which involves measuring drug levels in patients' body fluids, is an important procedure in clinical practice. However, the analysis technique currently used, i.e. liquid chromatography-tandem mass spectrometry (LC-MS/MS), is laboratory-based, so does not offer the short response time that is often required by clinicians. We suggest that techniques based on Fourier transform infrared spectroscopy (FTIR) offer a promising alternative for TDM. FTIR is rapid, highly specific and can be miniaturized for near-patient applications. The challenge, however, is that FTIR for TDM is limited by the strong mid-IR absorption of endogenous serum constituents. Here, we address this issue and introduce a versatile approach for removing the background of serum lipids, proteins and small water-soluble substances. Using phenytoin, an antiepileptic drug, as an example, we show that our approach enables FTIR to precisely quantify drug molecules in human serum at clinically relevant levels (10 μg/mL), providing an efficient analysis method for TDM. Beyond mid-IR spectroscopy, our study is applicable to other drug sensing techniques that suffer from the large background of serum samples.

Perceived support for climate policy in Australia: The asymmetrical influence of voting behaviour

A comprehensive policy response from wealthy nations is a necessary step to limiting catastrophic climate change. Community attitudes toward policy, and polarisation along political lines, may threaten this response. Using two representative cross-sectional survey studies of Australian voters (N = 2013; N = 3834), we test levels of support for a range of climate policies, levels of partisan polarisation, and whether people misperceive support among other partisans (false polarisation). Importantly, we investigate how perceptions differ across voting groups spanning left-wing, centre-left-wing, centre-right-wing, and right-wing voting orientations. In Study 1, we find support for climate policy across the political spectrum. However, assumed support from others is routinely underestimated, with support estimates decreasing the less socially proximal the group being estimated is. Meanwhile, perceptions of others’ support relates positively to perceptions of policy legitimacy. While policy support is associated with partisanship, in Study 2 we find left-wing voters perceive partisan polarisation to be greater than it actually is (false polarisation), while right-wing voters underestimate actual polarisation. We also find perceived polarisation is associated with higher levels of issue relevance. We discuss our findings with respect to intergroup processes, and recommend that community consensus regarding support for climate policy action be emphasised.

Dimly illuminated nights alter behavior and negatively affect fat metabolism in adult male zebra finches.

This experiment investigated the effects of an ecologically relevant level of dim light at night (dLAN) on behavior, physiology and fat metabolism associated gene expressions in central and peripheral tissues of adult male zebra finches that were hatched and raised in 12:12h LD cycle (Ev, day = 150 ± 5lx; Ev, night = 0lx) at 22 ± 2°C temperature. Half of the birds (n = 8) were maintained on LD cycle and temperature, as before (control), to the other half of birds the 12h dark period was dimly illuminated at ~ 5lx (dim light at night, dLAN; Ev, day = 150 ± 5lx; Ev, night = ~ 5lx) for 6weeks. The exposure to dLAN altered the 24h activity and feeding patterns with enhanced activity and feeding at night. Birds under dLAN fattened and gained weight, and had higher night glucose levels. Concurrently, a negative effect of dLAN was found on mRNA expression of ppar-alpha and cd36 genes involved in the fat metabolism in the hypothalamus, intestine, liver and muscle. These results suggest a more global effect of dLAN exposure on obesity and perhaps long-term health risks due to obesity-related complications to diurnal animals including humans inhabiting an urbanized environment.

Prenatal Arsenic Exposure and Gene Expression in Fetal Liver, Heart, Lung, and Placenta.

This is the first study comparing alterations in gene expression across multiple organs following prenatal exposure to environmentally relevant levels of arsenic. These findings, elucidating the multi-organ impact of prenatal arsenic exposure on predominantly immune-related pathways, further our mechanistic understanding of the long-term health effects observed in early-life arsenic-exposed populations.

A paper-based analytical device for the on-site multiplexed monitoring of soil nutrients extracted with a cafetière

Sustainable agricultural production has the aim to maximise the yield and quality of harvests. For that, farmers need to monitor nutrient levels within soils to apply fertilizers accordingly and to prevent land degradation and soil exhaustion. Current methods involve time-consuming sampling and transport to a laboratory; and most farmers do not have the resources to measure frequently at multiple locations, limiting their sustainable production. In order to address this challenge, a paper-based analytical device (PAD) for the multiplexed detection of soil nutrients, i.e. phosphate, nitrate and pH, extracted with a cafetière-based method, is developed in this work. The compact and easy-to-use platform enables an accurate soil analysis in less than 20 min; 3 min for extraction and 15 min for readout. Two detection channels for nitrate and phosphate analysis, and one circular detection area for pH, including the selective reagents to each analyte, are defined within the PAD. Upon contact with the specific nutrients, the platform produces a colorimetric response that is easily readable by naked eye and smartphone camera. The detection reactions were optimized in the range 1 − 22.5 mg L−1, 10 −100 mg L−1 and 5.0 – 8.5 for phosphate, nitrate and pH, respectively, in agreement with the relevant levels in soils. The volume of water, the number of pushes of the plunger, the extraction time and the mass of soil were also optimized for the nutrient extraction method with the cafetière. The optimal workflow was validated with commercial soils and compared with the conventional UV-Vis method and the labels from the soil package, showing excellent agreement. This paper-based platform provides the possibility of a cheap, sensitive and specific monitoring of soil nutrients by minimally trained operators, such as farmers, enabling in-the-field analyses of multiple key soil nutrients in resource-limited settings and therefore addressing the challenge of routine monitoring for sustainable agriculture.