Solvent Treatment of Wet-Spun PEDOT: PSS Fibers for Fiber-Based Wearable pH Sensing

There is a growing desire for wearable sensors in health applications. Fibers are inherently flexible and as such can be used as the electrodes of flexible sensors. Fiber-based electrodes are an ideal format to allow incorporation into fabrics and clothing and for use in wearable devices. Electrically conducting fibers were produced from a dispersion of poly (3,4-ethylenedioxythiophene)-poly (styrenesulfonate) (PEDOT: PSS). Fibers were wet spun from two PEDOT: PSS sources, in three fiber diameters. The effect of three different chemical treatments on the fibers were investigated and compared. Short 5 min treatment times with dimethyl sulfoxide (DMSO) on 20 μm fibers produced from Clevios PH1000 were found to produce the best overall treatment. Up to a six-fold increase in electrical conductivity was achieved, reaching 800 S cm−1, with no loss of mechanical strength (150 MPa). With a pH-sensitive polyaniline coating, these fibers displayed a Nernstian response across a pH range of 3.0 to 7.0, which covers the physiologically critical pH range for skin. These results provide opportunities for future wearable, fiber-based sensors including real-time, on-body pH sensing to monitor skin disease.

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Technology assessment framework for precision health applications

International Journal of Technology Assessment in Health Care ◽

10.1017/s0266462321000350 ◽

2021 ◽

Vol 37 (1) ◽

Author(s):

M. Sazzad Hussain ◽

David Silvera-Tawil ◽

Geremy Farr-Wharton

Keyword(s):

Emerging Technologies ◽

Mobile Apps ◽

Scientific Evidence ◽

Wearable Sensors ◽

Assessment Process ◽

Assessment Framework ◽

Response Options ◽

Regulatory Standards ◽

Precision Health ◽

Health Applications

Abstract Objective Established and emerging technologies—such as wearable sensors, smartphones, mobile apps, and artificial intelligence—are shaping positive healthcare models and patient outcomes. These technologies have the potential to become precision health (PH) innovations. However, not all innovations meet regulatory standards or have the required scientific evidence to be used for health applications. In response, an assessment framework was developed to facilitate and standardize the assessment of innovations deemed suitable for PH. Methods A scoping literature review undertaken through PubMed and Google Scholar identified approximately 100 relevant articles. These were then shortlisted (n = 12) to those that included specific metrics, criteria, or frameworks for assessing technologies that could be applied to the PH context. Results The proposed framework identified nine core criteria with subcriteria and grouped them into four categories for assessment: technical, clinical, human factors, and implementation. Guiding statements with response options and recommendations were used as metrics against each criterion. Conclusion The proposed framework supports health services, health technology innovators, and researchers in leveraging current and emerging technologies for PH innovations. It covers a comprehensive set of criteria as part of the assessment process of these technologies.

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Common Loon, Gavia immer, Breeding Success in Relation to Lake pH and Lake Size Over 25 Years

The Canadian Field-Naturalist ◽

10.22621/cfn.v123i2.693 ◽

2009 ◽

Vol 123 (2) ◽

pp. 146 ◽

Cited By ~ 5

Author(s):

Robert Alvo

Keyword(s):

Breeding Success ◽

Low Ph ◽

Single Pair ◽

Gavia Immer ◽

Common Loon ◽

Sulphur Deposition ◽

Acidic Lakes ◽

Ph Range ◽

Lake Size ◽

Critical Ph

I monitored Common Loon (Gavia immer) breeding success in relation to lake pH (range 4.0–8.5) between 1982 and 2007 on 38 single-pair lakes (5–88 ha) in the Sudbury, Ontario, area. No chicks fledged on lakes with pH < 4.4. Chicks fledged on lakes with slightly higher pH only if the lakes were relatively large. Acidic lakes became less acidic as sulphur dioxide emissions from the Sudbury smelters and sulphur deposition from other long-range sources decreased. Two lakes initially too acidic to support successful loon reproduction eventually had successful reproduction. One loon pair used two large acidic lakes (combined area 140 ha) connected by shallow rapids, and one of the adults made extremely long dives (average = 99 s) while foraging for the chicks. One chick died on that lake after apparently ingesting a very large food item; the lack of smaller items was attributed to the lake’s acidity. My results suggest that a shortage of food for chicks is the main reason why low pH reduces breeding success. I suggest that, for lakes without high levels of dissolved organic carbon (DOC), the critical pH for loon breeding success is approximately 4.3, and the suboptimal pH is approximately 4.4–6.0.

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Introducing a Thermo-Alkali-Stable, Metallic Ion-Tolerant Laccase Purified From White Rot Fungus Trametes hirsuta

Frontiers in Microbiology ◽

10.3389/fmicb.2021.670163 ◽

2021 ◽

Vol 12 ◽

Author(s):

Jing Si ◽

Hongfei Ma ◽

Yongjia Cao ◽

Baokai Cui ◽

Yucheng Dai

Keyword(s):

Specific Activity ◽

Endocrine Disrupting Chemicals ◽

Environmental Pollutants ◽

Fold Increase ◽

Industrial Applications ◽

White Rot ◽

White Rot Fungus ◽

Metallic Ions ◽

Trametes Hirsuta ◽

Ph Range

This study introduces a valuable laccase, designated ThLacc-S, purified from white rot fungus Trametes hirsuta. ThLacc-S is a monomeric protein in nature with a molecular weight of 57.0 kDa and can efficiently metabolize endocrine disrupting chemicals. The enzyme was successfully purified to homogeneity via three consecutive steps consisting of salt precipitation and column chromatography, resulting in a 20.76-fold increase in purity and 46.79% yield, with specific activity of 22.111 U/mg protein. ThLacc-S was deciphered as a novel member of the laccase family and is a rare metalloenzyme that contains cysteine, serine, histidine, and tyrosine residues in its catalytic site, and follows Michaelis-Menten kinetic behavior with a Km and a kcat/Km of 87.466 μM and 1.479 s–1μM–1, respectively. ThLacc-S exerted excellent thermo-alkali stability, since it was markedly active after a 2-h incubation at temperatures ranging from 20 to 70°C and retained more than 50% of its activity after incubation for 72 h in a broad pH range of 5.0–10.0. Enzymatic activities of ThLacc-S were enhanced and preserved when exposed to metallic ions, surfactants, and organic solvents, rendering this novel enzyme of interest as a green catalyst for versatile biotechnological and industrial applications that require these singularities of laccases, particularly biodegradation and bioremediation of environmental pollutants.

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TiO2 Nano Flowers Based EGFET Sensor for pH Sensing

Coatings ◽

10.3390/coatings9040251 ◽

2019 ◽

Vol 9 (4) ◽

pp. 251

Author(s):

Chih-Chiang Yang ◽

Kuan-Yu Chen ◽

Yan-Kuin Su

Keyword(s):

Ph Value ◽

Ph Sensor ◽

High Sensitivity ◽

Experimental Result ◽

Ph Sensing ◽

Voltage Reference ◽

Ph Sensors ◽

Oxide Substrate ◽

Ph Range ◽

The Relationship

In this study, pH sensors were successfully fabricated on a fluorine-doped tin oxide substrate and grown via hydrothermal methods for 8 h for pH sensing characteristics. The morphology was obtained by high-resolution scanning electron microscopy and showed randomly oriented flower-like nanostructures. The TiO2 nanoflower pH sensors were measured over a pH range of 2–12. Results showed a high sensitivity of the TiO2 nano-flowers pH sensor, 2.7 (μA)1/2/pH, and a linear relationship between IDS and pH (regression of 0.9991). The relationship between voltage reference and pH displayed a sensitivity of a 46 mV/pH and a linear regression of 0.9989. The experimental result indicated that a flower-like TiO2 nanostructure extended gate field effect transistor (EGFET) pH sensor effectively detected the pH value.

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Near-Infrared pH Sensor Based on a SPEEK–Polyaniline Polyelectrolyte Complex Membrane

Proceedings ◽

10.3390/iocn_2018-1-05493 ◽

2018 ◽

Vol 3 (1) ◽

pp. 11 ◽

Cited By ~ 1

Author(s):

Nedal Y. Abu-Thabit

Keyword(s):

Polyelectrolyte Complex ◽

Near Infrared ◽

Response Times ◽

Oxidative Polymerization ◽

Ph Sensor ◽

Ph Sensing ◽

Ph Values ◽

Sensing Applications ◽

Ph Range ◽

Speek Membrane

A polyelectrolyte complex (PEC) membrane based on sulfonated poly (ether ether ketone) and polyaniline (SPEEK-PANI) was developed for pH sensing applications. Aniline was polymerized in the presence of the SPEEK membrane by using in situ chemical oxidative polymerization to yield an ionically crosslinked SPEEK-PANI membrane. The fabricated membrane exhibited sensitivity in the physiological pH range of 2–8. The PEC membrane pH sensor showed good absorption properties in the near-infrared region (NIR). The membrane showed fast response during a de-doping process (≈90 s), while longer response times are essential for doping processes from the alkaline/neutral pH region to the acidic pH region, which is attributed to the presence of highly acidic sulfonic acid groups with a high buffering capacity in the PEC membrane. The SPEEK-PANI membrane exhibited slightly higher water uptake compared to the neat SPEEK membrane. The membrane exhibited good stability, as it was stored in 1M HCl solution for more than 2 years without physical or visual deterioration. A preconditioning step in 1M HCl ensured that the results were reproducible and allows the pH sensor to be used repeatedly. The PEC sensor membranes are suitable for applications that start at low pH values and move upwards to higher pH values in the 2–8 pH range.

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CONSTITUENTS OF ELEMENTARY BODIES OF VACCINIA

Journal of Experimental Medicine ◽

10.1084/jem.74.1.69 ◽

1941 ◽

Vol 74 (1) ◽

pp. 69-80 ◽

Cited By ~ 28

Author(s):

Charles L. Hoagland ◽

S. M. Ward ◽

Joseph E. Smadel ◽

Thomas M. Rivers

Keyword(s):

Cytochrome Oxidase ◽

Potassium Cyanide ◽

Emission Spectra ◽

Fold Increase ◽

Dry Weight ◽

Copper Component ◽

Ph Range

A search by means of spectroscopic and enzymatic techniques has failed to demonstrate either cytochrome or cytochrome oxidase in purified elementary bodies of vaccinia. A constituent of the virus which catalyzes the oxidation of cystein has been found and identified as copper in a concentration amounting to 0.05 per cent of the dry weight of the virus. The copper constituent was not removed by repeated washing, ultrafiltration, dialysis against 0.1 molar potassium cyanide, or by electrodialysis over a pH range which did not inactivate the virus. During the process of purification of the virus a 25-fold increase of the copper constituent was observed. Emission spectra obtained from the dry virus also revealed copper but no significant traces of other metallic substances. No biological rôle can yet be ascribed to the copper component of virus.

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Fiber optic pH sensing with long wavelength excitable Schiff bases in the pH range of 7.0–12.0

Analytica Chimica Acta ◽

10.1016/j.aca.2007.01.070 ◽

2007 ◽

Vol 588 (1) ◽

pp. 42-49 ◽

Cited By ~ 47

Author(s):

Sibel Derinkuyu ◽

Kadriye Ertekin ◽

Ozlem Oter ◽

Serpil Denizalti ◽

Engin Cetinkaya

Keyword(s):

Schiff Bases ◽

Fiber Optic ◽

Ph Sensing ◽

Long Wavelength ◽

Ph Range

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Heat stability of milk: influence of colloidal calcium phosphate and β-lactoglobulin

Journal of Dairy Research ◽

10.1017/s0022029900015466 ◽

1975 ◽

Vol 42 (3) ◽

pp. 427-435 ◽

Cited By ~ 64

Author(s):

P. F. Fox ◽

M. C. T. Hoynes

Keyword(s):

Calcium Phosphate ◽

Fold Increase ◽

Heat Stability ◽

Protein Charge ◽

Ph Values ◽

Colloidal Calcium Phosphate ◽

Maximum Stability ◽

Ph Range ◽

Ph Curve ◽

Β Lactoglobulin

SummaryReduction of the level of colloidal calcium phosphate (CCP) progressively increased the heat stability of milk at pH values <~7·0 and increased the pH of maximum stability. Removal of 40% CCP also stabilized the system at the pH of minimum stability, but removal of ≥60% CCP rendered milk very unstable at pH values >7·2, an effect not offset by a 4-fold increase in κ-casein concentration. Doubling CCP had a slight destabilizing effect in the pH range 6·5–7·5.Addition of β-lactoglobulin to serum protein-free casein micelles had a marked destabilizing effect at pH values > ~6·8, but increased stability in the pH range 6·4–6·8. β-Lactoglobulin had a similar and more apparent effect on the heat stability of Na caseinate dissolved in milk diffusate.It is suggested that rather than being a stabilizing factor responsible for the maximum in the heat stability-pH curve, the true effect of β-lactoglobulin is to shift the curve to more acid pH values (reason unknown) and to sensitize the caseinate system to heat-induced Ca phosphate precipitation at pH values > ~7·0. Low stability at ~pH 7·0 introduces an apparent maximum in the heat stability-pH curve at ~pH 6·8, but this has no independent existence. At pH values >7·2, increased protein charge more than off-sets the influence of heat-precipitated CCP and stability again increases in micellar but not in soluble casein systems.

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Quantification of kinetic rate law parameters of uranium release from sodium autunite as a function of aqueous bicarbonate concentrations

Environmental Chemistry ◽

10.1071/en13117 ◽

2013 ◽

Vol 10 (6) ◽

pp. 475 ◽

Cited By ~ 2

Author(s):

Ravi Gudavalli ◽

Yelena Katsenovich ◽

Dawn Wellman ◽

Leonel Lagos ◽

Berrin Tansel

Keyword(s):

Dissolution Kinetics ◽

Fold Increase ◽

Activation Energies ◽

Complexing Agent ◽

Dissolution Mechanism ◽

Rate Law ◽

Ph Conditions ◽

Bicarbonate Solutions ◽

Ph Range ◽

Relationship Of

Environmental context Uranium is a key contaminant of concern because of its high persistence in the environment and toxicity to organisms. The bicarbonate ion is an important complexing agent for uranyl ions and one of the main variables affecting its dissolution. Results from this investigation provide rate law parameters for the dissolution kinetics of synthetic sodium autunite that can influence uranium mobility in the subsurface. Abstract Hydrogen carbonate (also known as bicarbonate) is one of the most significant components within the uranium geochemical cycle. In aqueous solutions, bicarbonate forms strong complexes with uranium. As such, aqueous bicarbonate may significantly increase the rate of uranium release from uranium minerals. Quantifying the relationship of aqueous bicarbonate solutions to the rate of uranium release during dissolution is critical to understanding the long-term fate of uranium within the environment. Single-pass flow-through experiments were conducted to estimate the rate of uranium release from Na meta-autunite as a function of bicarbonate solutions (0.0005–0.003M) over the pH range of 6–11 and temperatures of 5–60°C. Consistent with the results of previous investigations, the rate of uranium release from sodium autunite exhibited minimal dependency on temperature, but was strongly dependent on pH and increasing concentrations of bicarbonate solutions. Most notably at pH 7, the rate of uranium release exhibited a 370-fold increase relative to the rate of uranium release in the absence of bicarbonate. However, the effect of increasing concentrations of bicarbonate solutions on the release of uranium was significantly less under higher pH conditions. It is postulated that at high pH values, surface sites are saturated with carbonate, thus the addition of more bicarbonate would have less effect on uranium release. Results indicate that the activation energies were unaffected by temperature and bicarbonate concentration variations, but were strongly dependent on pH conditions. As the pH increased from 6 to 11, the activation energy values were observed to decrease from 29.94 to 13.07kJmol–1. The calculated activation energies suggest a surface controlled dissolution mechanism.

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The evolution and mechanism of GPCR proton sensing

Journal of Biological Chemistry ◽

10.1074/jbc.ra120.016352 ◽

2020 ◽

pp. jbc.RA120.016352

Author(s):

Jacob B. Rowe ◽

Nicholas J. Kapolka ◽

Geoffrey J. Taghon ◽

William M. Morgan ◽

Daniel G. Isom

Keyword(s):

Therapeutic Potential ◽

G Protein Coupled Receptors ◽

Hek293 Cells ◽

Ph Sensing ◽

Physiological Importance ◽

Class A ◽

Acidic Residues ◽

Ph Range ◽

G Protein Coupled ◽

Direct Regulation

Of the 800 G protein-coupled receptors (GPCRs) in humans, only three (GPR4, GPR65, and GPR68) regulate signaling in acidified microenvironments by sensing protons (H+). How these receptors have uniquely obtained this ability is unknown. Here we show these receptors evolved the capability to sense H+ signals by acquiring buried acidic residues. Using our informatics platform pHinder, we identified a triad of buried acidic residues shared by all three receptors, a feature distinct from all other human GPCRs. Phylogenetic analysis shows the triad emerged in GPR65, the immediate ancestor of GPR4 and GPR68. To understand the evolutionary and mechanistic importance of these triad residues, we developed Deep Variant Profiling (DVP), a yeast-based technology that utilizes high-throughput CRISPR to build and profile large libraries of GPCR variants. Using DVP and GPCR assays in HEK293 cells, we assessed the pH-sensing contributions of each triad residue in all three receptors. As predicted by our calculations, most triad mutations had profound effects consistent with direct regulation of receptor pH sensing. Additionally, we found that an allosteric modulator of many class A GPCRs, Na+, synergistically regulated pH sensing by maintaining the pKa values of triad residues within the physiologically relevant pH range. As such, we show that all three receptors function as coincidence detectors of H+ and Na+. Taken together, these findings elucidate the molecular evolution and long-sought mechanism of GPR4, GPR65, and GPR68 pH sensing, and provide pH-insensitive variants that should be valuable for assessing the therapeutic potential and (patho)physiological importance of GPCR pH sensing.

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