Artificial Intelligence for Global Health: Learning From a Decade of Digital Transformation in Health Care

The health needs of those living in resource-limited settings are a vastly overlooked and understudied area in the intersection of machine learning (ML) and health care. While the use of ML in health care is more recently popularized over the last few years from the advancement of deep learning, low-and-middle income countries (LMICs) have already been undergoing a digital transformation of their own in health care over the last decade, leapfrogging milestones due to the adoption of mobile health (mHealth). With the introduction of new technologies, it is common to start afresh with a top-down approach, and implement these technologies in isolation, leading to lack of use and a waste of resources. In this paper, we outline the necessary considerations both from the perspective of current gaps in research, as well as from the lived experiences of health care professionals in resource-limited settings. We also outline briefly several key components of successful implementation and deployment of technologies within health systems in LMICs, including technical and cultural considerations in the development process relevant to the building of machine learning solutions. We then draw on these experiences to address where key opportunities for impact exist in resource-limited settings, and where AI/ML can provide the most benefit.Comment: Accepted Paper at ICLR 2020 Workshop on Practical ML for Developing Countrie

Direct Coupling of Dispersive Extractions with Magnetic Particles to Mass Spectrometry via Microfluidic Open Interface

Microextraction coupled to mass spectrometry (MS) has great potential in analytical chemistry laboratories operating in a variety of fields. Indeed, microextraction methods directly coupled to MS can be of large value given that they can provide not only analyte extraction and enrichment but also effective sample cleanup. In recent years, the practicality in handling high active surface area, versatility, and environmentally friendly features of magnetic dispersive microextraction technologies has contributed to an explosion in the number of methods and technologies reported in the literature for a wide range of applications. However, to the best of our knowledge, no technology to date has been capable of efficiently merging these two rising concepts in a simple and integrated analytical workflow. In this context, the microfluidic open interface is presented for the direct coupling of dispersive magnetic extraction to mass spectrometry. This technology operates under the concept of a flow-isolated desorption volume, which generates a stagnant droplet open to ambient conditions while continuously feeding the ionization source with solvent by means of the self-aspiration process intrinsic of the electrospray ionization (ESI) interface. To improve the efficiency of the final analytical workflow, a novel dispersive magnetic micro- and nanoparticle extraction protocol for biofluid droplets was developed. The final methodology entailed the dispersion of a small amount of magnetic particles (20-70 μg) in a droplet of biofluid (≤40 μL) for extraction, followed by a particle collection step using a homemade 3D-printed holder containing an embedded rare-earth magnet. In the final step, the holder is set on top of the microfluidic open interface (MOI) for desorption in the isolated droplet. Switching the valve transfers the desorbed analytes to the ESI source in less than 5 s. As proof of concept, the completely new setup was applied to the determination of prohibited substances from phosphate-buffered saline (PBS) and human urine using Fe 2 O 3 magnetic nanoparticles (50 nm) functionalized with C 18 . The limits of quantitation (LOQs) obtained were in the low-ppb range in all cases, and acceptable precision (≤20%) and accuracy (80-120%) were attained. Also, taking advantage of the fast extraction kinetics provided by the radial diffusion associated with small particles, we employed the methodology for the selective extraction of phosphopeptides from 40 μL of tryptic β-casein digest using 70 μg of magnetic Ti-IMAC microparticles. To conclude, the technology and methodology herein presented provided excellent capabilities comparable to those of other solid-phase microextraction (SPME-MS) approaches while dramatically minimizing the amount of sample and sorbent required per analysis, as well as affording significantly fast extraction times due to the enhanced kinetics of extraction.Fil: Tascon, Marcos. University of Waterloo; Canadá. Universidad Nacional de San Martín. Instituto de Investigación e Ingeniería Ambiental. - Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigación e Ingeniería Ambiental; ArgentinaFil: Singh, Varoon. University of Waterloo; CanadáFil: Huq, Mohammad. University of Waterloo; CanadáFil: Pawliszyn, Janusz. University of Waterloo; Canad

Direct Coupling of Dispersive Extractions with Magnetic Particles to Mass Spectrometry via Microfluidic Open Interface

Microextraction coupled to mass spectrometry (MS) has great potential in analytical chemistry laboratories operating in a variety of fields. Indeed, microextraction methods directly coupled to MS can be of large value given that they can provide not only analyte extraction and enrichment but also effective sample cleanup. In recent years, the practicality in handling high active surface area, versatility, and environmentally friendly features of magnetic dispersive microextraction technologies has contributed to an explosion in the number of methods and technologies reported in the literature for a wide range of applications. However, to the best of our knowledge, no technology to date has been capable of efficiently merging these two rising concepts in a simple and integrated analytical workflow. In this context, the microfluidic open interface is presented for the direct coupling of dispersive magnetic extraction to mass spectrometry. This technology operates under the concept of a flow-isolated desorption volume, which generates a stagnant droplet open to ambient conditions while continuously feeding the ionization source with solvent by means of the self-aspiration process intrinsic of the electrospray ionization (ESI) interface. To improve the efficiency of the final analytical workflow, a novel dispersive magnetic micro- and nanoparticle extraction protocol for biofluid droplets was developed. The final methodology entailed the dispersion of a small amount of magnetic particles (20-70 μg) in a droplet of biofluid (≤40 μL) for extraction, followed by a particle collection step using a homemade 3D-printed holder containing an embedded rare-earth magnet. In the final step, the holder is set on top of the microfluidic open interface (MOI) for desorption in the isolated droplet. Switching the valve transfers the desorbed analytes to the ESI source in less than 5 s. As proof of concept, the completely new setup was applied to the determination of prohibited substances from phosphate-buffered saline (PBS) and human urine using Fe 2 O 3 magnetic nanoparticles (50 nm) functionalized with C 18 . The limits of quantitation (LOQs) obtained were in the low-ppb range in all cases, and acceptable precision (≤20%) and accuracy (80-120%) were attained. Also, taking advantage of the fast extraction kinetics provided by the radial diffusion associated with small particles, we employed the methodology for the selective extraction of phosphopeptides from 40 μL of tryptic β-casein digest using 70 μg of magnetic Ti-IMAC microparticles. To conclude, the technology and methodology herein presented provided excellent capabilities comparable to those of other solid-phase microextraction (SPME-MS) approaches while dramatically minimizing the amount of sample and sorbent required per analysis, as well as affording significantly fast extraction times due to the enhanced kinetics of extraction.Fil: Tascon, Marcos. University of Waterloo; Canadá. Universidad Nacional de San Martín. Instituto de Investigación e Ingeniería Ambiental. - Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigación e Ingeniería Ambiental; ArgentinaFil: Singh, Varoon. University of Waterloo; CanadáFil: Huq, Mohammad. University of Waterloo; CanadáFil: Pawliszyn, Janusz. University of Waterloo; Canad

Advancing Molecular Sieving via Å-Scale Pore Tuning in Bottom-Up Graphene Synthesis

Porous graphene films are attractive as a gas separation membrane given that the selective layer can be just one atom thick, allowing high-flux separation. A favorable aspect of porous graphene is that the pore size, essentially gaps created by lattice defects, can be tuned. While this has been demonstrated for postsynthetic, top-down pore etching in graphene, it does not exist in the more scalable, bottom-up synthesis of porous graphene. Inspired by the mechanism of precipitation-based synthesis of porous graphene over catalytic nickel foil, we herein conceive an extremely simple way to tune the pore size. This is implemented by increasing the cooling rate by over 100-fold from −1 °C min-1 to over −5 °C s-1. Rapid cooling restricts carbon diffusion, resulting in a higher availability of dissolved carbon for precipitation, as evidenced by quantitative carbon-diffusion simulation, measurement of carbon concentration as a function of nickel depth, and imaging of the graphene nanostructure. The resulting enhanced grain (inter)growth reduces the effective pore size which leads to an increase of the H2/CH4 separation factor from 6.2 up to 53.3.</p

Development and validation of a fully automated solid phase microextraction high throughput method for quantitative analysis of multiresidue veterinary drugs in chicken tissue

The final publication is available at Elsevier via https://doi.org/10.1016/j.aca.2018.12.044. © 2018. This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/This paper presents the development and validation of a fully automated, high-throughput multiclass, multiresidue method for quantitative analysis of 77 veterinary drugs in chicken muscle via direct immersion solid phase microextraction (DI-SPME) and ultra-high pressure liquid chromatography-electrospray ionization - tandem mass spectrometry (UHPLC-ESI-MS/MS). The selected drugs represent more than 12 different classes of drugs characterized by varying physical and chemical properties. A Hydrophilic–lipophilic balance (HLB)/polyacrylonitrile (PAN) extraction phase, prepared using HLB particles synthesized in-house, yielded the best extraction/desorption performance among four different SPME extraction phases evaluated in the current work. The developed SPME method was optimized in terms of SPME coating and geometry, desorption solvent, extraction and rinsing conditions, and extraction and desorption times. Multivariate analysis was performed to determine the optimal desorption solvent for the proposed application. The developed method was validated according to the Food and Drug Administration (FDA) guidelines, taking into account Canadian maximum residue limits (MRLs) and US maximum tolerance levels for veterinary drugs in meat. Method accuracy ranged from 80 to 120% for at least 73 compounds, with relative standard deviation of 1–15%. Inter-day precision ranged from 4 to 15% for 70 compounds. Determination coefficients values were higher than 0.991 for all compounds under study with no significant lack of fit (p > 0.05) at the 5% level. In terms of limits of quantitation, the method was able to meet both Canadian and US regulatory levels for all compounds under study.The authors would like to acknowledge Perkin Elmer for the financial support and the staff at the University of Waterloo's Science Technical Services for their exceptional technical support and collaboration to improve the SPME brush of the high-throughput system. V.A.J.thanks FAPESP, process 2016/16180e6 for his scholarship

Graphene membranes with pyridinic nitrogen at pore edges for high-performance CO₂ capture

Membranes based on a porous two-dimensional selective layer offer the potential to achieve exceptional performance to improve energy efficiency and reduce the cost for carbon capture. So far, separation from two-dimensional pores has exploited differences in molecular mass or size. However, competitive sorption of CO2 with the potential to yield high permeance and selectivity has remained elusive. Here we show that a simple exposure of ammonia to oxidized single-layer graphene at room temperature incorporates pyridinic nitrogen at the pore edges. This leads to a highly competitive but quantitatively reversible binding of CO2 with the pore. An attractive combination of CO2/N2 separation factor (average of 53) and CO2 permeance (average of 10,420) from a stream containing 20 vol% CO2 is obtained. Separation factors above 1,000 are achieved for dilute (~1 vol%) CO2 stream, making the membrane promising for carbon capture from diverse point emission sources. Thanks to the uniform and scalable chemistry, high-performance centimetre-scale membranes are demonstrated. The scalable preparation of high-performance two-dimensional membranes opens new directions in membrane science.</p

Metal organic framework nanosheets in polymer composite materials for gas separation

[EN] Composites incorporating two-dimensional nanostructures within polymeric matrices have potential as functional components for several technologies, including gas separation. Prospectively, employing metal-organic frameworks (MOFs) as versatile nanofillers would notably broaden the scope of functionalities. However, synthesizing MOFs in the form of freestanding nanosheets has proved challenging. We present a bottom-up synthesis strategy for dispersible copper 1,4-benzenedicarboxylate MOF lamellae of micrometre lateral dimensions and nanometre thickness. Incorporating MOF nanosheets into polymer matrices endows the resultant composites with outstanding CO2 separation performance from CO2/CH4 gas mixtures, together with an unusual and highly desired increase in the separation selectivity with pressure. As revealed by tomographic focused ion beam scanning electron microscopy, the unique separation behaviour stems from a superior occupation of the membrane cross-section by the MOF nanosheets as compared with isotropic crystals, which improves the efficiency of molecular discrimination and eliminates unselective permeation pathways. This approach opens the door to ultrathin MOF-polymer composites for various applications.The research leading to these results has received funding (J.G., B.S.) from the European Research Council under the European Union’s Seventh Framework Programme (FP/2007-2013)/ERC Grant Agreement no. 335746, CrystEng-MOF-MMM. T.R. is grateful to TUDelft for funding. G.P. acknowledges the A. von Humboldt Foundation for a research grant. A.C., I.L. and F.X.L.i.X. thank Consolider-Ingenio 2010 (project MULTICAT) and the ‘Severo Ochoa’ programme for support. 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Zeolites with continuously tuneable porosity

Funding: Royal Society for provision of an industry fellowship and the EPSRC for funding (EP/K025112/1 and EP/L014475/1) (R.E.M.); Czech Science Foundation for (P106/12/G015) (J.Cˇ.); European Community under a Marie Curie Intra-European Fellowship (A.B.P.).Zeolites are important materials whose utility in industry depends on the nature of their porous structure. Control over microporosity is therefore a vitally important target. Unfortunately, traditional methods for controlling porosity, in particular the use of organic structure-directing agents, are relatively coarse and provide almost no opportunity to tune the porosity as required. Here we show how zeolites with a continuously tuneable surface area and micropore volume over a wide range can be prepared. This means that a particular surface area or micropore volume can be precisely tuned. The range of porosity we can target covers the whole range of useful zeolite porosity: from small pores consisting of 8-rings all the way to extra-large pores consisting of 14-rings.Publisher PDFPeer reviewe