The Experts below are selected from a list of 267 Experts worldwide ranked by ideXlab platform

C. Van Katwijk - One of the best experts on this subject based on the ideXlab platform.

Andrew Mills - One of the best experts on this subject based on the ideXlab platform.

  • A general-purpose colourimetric air Pressure Indicator
    Sensors and Actuators B: Chemical, 2020
    Co-Authors: Dilidaer Yusufu, Andrew Mills
    Abstract:

    Abstract A general-purpose air Pressure colourimetric Indicator is described based on a sensitive CO2 Indicator, which responds to the change in partial Pressure of CO2 in air. The Indicator uses the pH Indicator dye thymol blue (TB) and is green in ambient air (at 1 atm), bright blue under high vacuum ( 10 atm). The TB Indicator is cast from an ink and its change in colour monitored mainly using digital photography coupled with colour analysis and quantitatively related to air Pressure. The response of the TB Indicator is initially probed using different Ar/CO2 gas mixtures at 1 atm Pressure and then used to monitor: (i) sub-ambient air Pressures, P, over the range 0.1−1 atm and (ii) super ambient air Pressures over the range 1−14 atm. Colour analysis of all the photographic images taken in the two studies reveals a consistent data set that is readily related quantitatively to P, with a typical 50 % colour change at 1.02 ± 0.03 atm of air, i.e. or (4.2 ± 0.1)×10−4 atm of CO2. The 90 % response and recovery times of the Indicator to sudden changes in Pressure are fast,

  • A colourimetric vacuum air-Pressure Indicator
    The Analyst, 2019
    Co-Authors: Dilidaer Yusufu, Andrew Mills
    Abstract:

    A colourimetric vacuum air Pressure Indicator is described, based on the very low level of CO2 in air. The Indicator uses the pH Indicator dye, ortho-cresolphthalein, OCP, which is violet coloured in its deprotonated form and colourless when protonated. When the violet coloured OCP anion is ion-paired with the tetrabutylammonium cation, the product is readily dissolved in a non-aqueous solution containing the polymer ethyl cellulose to create an ink which, when cast and allowed to dry, responds to levels of CO2 well below that in air, i.e.≪0.041%; the Indicator's halfway colour changing point is at 0.062 atm of air at 22 °C, which is interesting in that in food vacuum packaging the Pressure in the pack is usually ca. 0.04 atm. The Indicator can be used as a qualitative and quantitative Indicator of vacuum air Pressure. The latter requires the use of digital photography, coupled to RGB colour analysis, in the analysis of the Indicator's colour. As with most CO2 Indicators, the Indicator's response is temperature sensitive, with ΔH = 78 ± 5 kJ mol-1. The Indicator's 90% response and recovery times to a cycle of vacuum and air are 16.2 and 2.7 min, respectively. The efficacy of the Indicator as a vacuum-package integrity Indicator for food packaging is illustrated and other potential applications are discussed briefly. This is the first reported example of an ink-based, inexpensive, colourimetric vacuum air Pressure Indicator.

Chingyi Lee - One of the best experts on this subject based on the ideXlab platform.

  • the intracranial volume Pressure response in increased intracranial Pressure patients clinical significance of the volume Pressure Indicator
    PLOS ONE, 2016
    Co-Authors: Hungyi Lai, Chinghsin Lee, Chingyi Lee
    Abstract:

    Background For patients suffering from primary brain injury, monitoring intracranial Pressure alone is not enough to reflect the dynamic intracranial condition. In our previous study, a segment of the Pressure-volume curve can be expressed by the parabolic regression model with single Indicator “a”. The aim of this study is to evaluate if the Indicator “a” can reflect intracranial conditions. Methods Patients with traumatic brain injury, spontaneous intracranial hemorrhage, and/or hydrocephalus who had external ventricular drainage from January 2009 to February 2010 were included. The successive volume Pressure response values were obtained by successive drainage of cerebral spinal fluid from intracranial Pressure 20–25 mm Hg to 10 mm Hg. The relationship between withdrawn cerebral spinal fluid volume and intracranial Pressure was analyzed by the parabolic regression model with single parameter “a”. Results The overall mean for Indicator “a” was 0.422 ± 0.046. The mean of “a” in hydrocephalus was 0.173 ± 0.024 and in severe intracranial mass with slender ventricle, it was 0.663 ± 0.062. The two extreme intracranial conditions had a statistical significant difference (p<0.001). Conclusion The Indicator “a” of a Pressure-volume curve can reflect the dynamic intracranial condition and is comparable in different situations. A significantly larger Indicator “a” with increased intracranial Pressure is always observed in severe intracranial mass lesions with cerebral edema. A significantly smaller Indicator “a” with increased intracranial Pressure is observed in hydrocephalus. Brain computed tomography should be performed early if a rapid elevation of Indicator “a” is detected, as it can reveal some ongoing intracranial pathology prior to clinical deterioration. Increased intracranial Pressure was frequently observed in patients with intracranial pathology. The progression can be differentiated using the pattern of the volume Pressure Indicator.

  • The Intracranial Volume Pressure Response in Increased Intracranial Pressure Patients: Clinical Significance of the Volume Pressure Indicator.
    PloS one, 2016
    Co-Authors: Hungyi Lai, Chinghsin Lee, Chingyi Lee
    Abstract:

    Background For patients suffering from primary brain injury, monitoring intracranial Pressure alone is not enough to reflect the dynamic intracranial condition. In our previous study, a segment of the Pressure-volume curve can be expressed by the parabolic regression model with single Indicator “a”. The aim of this study is to evaluate if the Indicator “a” can reflect intracranial conditions. Methods Patients with traumatic brain injury, spontaneous intracranial hemorrhage, and/or hydrocephalus who had external ventricular drainage from January 2009 to February 2010 were included. The successive volume Pressure response values were obtained by successive drainage of cerebral spinal fluid from intracranial Pressure 20–25 mm Hg to 10 mm Hg. The relationship between withdrawn cerebral spinal fluid volume and intracranial Pressure was analyzed by the parabolic regression model with single parameter “a”. Results The overall mean for Indicator “a” was 0.422 ± 0.046. The mean of “a” in hydrocephalus was 0.173 ± 0.024 and in severe intracranial mass with slender ventricle, it was 0.663 ± 0.062. The two extreme intracranial conditions had a statistical significant difference (p

  • The intracranial volume Pressure response in increased intracranial Pressure patients: Part 1. Calculation of the volume Pressure Indicator.
    Acta neurochirurgica, 2010
    Co-Authors: Hungyi Lai, Chingyi Lee, Hsun Hui Hsu, Shih Tseng Lee
    Abstract:

    Background The intracranial Pressure (ICP) is usually continuously monitored in the management of patients with increased ICP. The aim of this study was to discover a mathematic equation to express the intracranial Pressure–volume (P–V) curve and a single Indicator to reflect the status of the curve.

Hungyi Lai - One of the best experts on this subject based on the ideXlab platform.

  • the intracranial volume Pressure response in increased intracranial Pressure patients clinical significance of the volume Pressure Indicator
    PLOS ONE, 2016
    Co-Authors: Hungyi Lai, Chinghsin Lee, Chingyi Lee
    Abstract:

    Background For patients suffering from primary brain injury, monitoring intracranial Pressure alone is not enough to reflect the dynamic intracranial condition. In our previous study, a segment of the Pressure-volume curve can be expressed by the parabolic regression model with single Indicator “a”. The aim of this study is to evaluate if the Indicator “a” can reflect intracranial conditions. Methods Patients with traumatic brain injury, spontaneous intracranial hemorrhage, and/or hydrocephalus who had external ventricular drainage from January 2009 to February 2010 were included. The successive volume Pressure response values were obtained by successive drainage of cerebral spinal fluid from intracranial Pressure 20–25 mm Hg to 10 mm Hg. The relationship between withdrawn cerebral spinal fluid volume and intracranial Pressure was analyzed by the parabolic regression model with single parameter “a”. Results The overall mean for Indicator “a” was 0.422 ± 0.046. The mean of “a” in hydrocephalus was 0.173 ± 0.024 and in severe intracranial mass with slender ventricle, it was 0.663 ± 0.062. The two extreme intracranial conditions had a statistical significant difference (p<0.001). Conclusion The Indicator “a” of a Pressure-volume curve can reflect the dynamic intracranial condition and is comparable in different situations. A significantly larger Indicator “a” with increased intracranial Pressure is always observed in severe intracranial mass lesions with cerebral edema. A significantly smaller Indicator “a” with increased intracranial Pressure is observed in hydrocephalus. Brain computed tomography should be performed early if a rapid elevation of Indicator “a” is detected, as it can reveal some ongoing intracranial pathology prior to clinical deterioration. Increased intracranial Pressure was frequently observed in patients with intracranial pathology. The progression can be differentiated using the pattern of the volume Pressure Indicator.

  • The Intracranial Volume Pressure Response in Increased Intracranial Pressure Patients: Clinical Significance of the Volume Pressure Indicator.
    PloS one, 2016
    Co-Authors: Hungyi Lai, Chinghsin Lee, Chingyi Lee
    Abstract:

    Background For patients suffering from primary brain injury, monitoring intracranial Pressure alone is not enough to reflect the dynamic intracranial condition. In our previous study, a segment of the Pressure-volume curve can be expressed by the parabolic regression model with single Indicator “a”. The aim of this study is to evaluate if the Indicator “a” can reflect intracranial conditions. Methods Patients with traumatic brain injury, spontaneous intracranial hemorrhage, and/or hydrocephalus who had external ventricular drainage from January 2009 to February 2010 were included. The successive volume Pressure response values were obtained by successive drainage of cerebral spinal fluid from intracranial Pressure 20–25 mm Hg to 10 mm Hg. The relationship between withdrawn cerebral spinal fluid volume and intracranial Pressure was analyzed by the parabolic regression model with single parameter “a”. Results The overall mean for Indicator “a” was 0.422 ± 0.046. The mean of “a” in hydrocephalus was 0.173 ± 0.024 and in severe intracranial mass with slender ventricle, it was 0.663 ± 0.062. The two extreme intracranial conditions had a statistical significant difference (p

  • The intracranial volume Pressure response in increased intracranial Pressure patients: Part 1. Calculation of the volume Pressure Indicator.
    Acta neurochirurgica, 2010
    Co-Authors: Hungyi Lai, Chingyi Lee, Hsun Hui Hsu, Shih Tseng Lee
    Abstract:

    Background The intracranial Pressure (ICP) is usually continuously monitored in the management of patients with increased ICP. The aim of this study was to discover a mathematic equation to express the intracranial Pressure–volume (P–V) curve and a single Indicator to reflect the status of the curve.

Dilidaer Yusufu - One of the best experts on this subject based on the ideXlab platform.

  • A general-purpose colourimetric air Pressure Indicator
    Sensors and Actuators B: Chemical, 2020
    Co-Authors: Dilidaer Yusufu, Andrew Mills
    Abstract:

    Abstract A general-purpose air Pressure colourimetric Indicator is described based on a sensitive CO2 Indicator, which responds to the change in partial Pressure of CO2 in air. The Indicator uses the pH Indicator dye thymol blue (TB) and is green in ambient air (at 1 atm), bright blue under high vacuum ( 10 atm). The TB Indicator is cast from an ink and its change in colour monitored mainly using digital photography coupled with colour analysis and quantitatively related to air Pressure. The response of the TB Indicator is initially probed using different Ar/CO2 gas mixtures at 1 atm Pressure and then used to monitor: (i) sub-ambient air Pressures, P, over the range 0.1−1 atm and (ii) super ambient air Pressures over the range 1−14 atm. Colour analysis of all the photographic images taken in the two studies reveals a consistent data set that is readily related quantitatively to P, with a typical 50 % colour change at 1.02 ± 0.03 atm of air, i.e. or (4.2 ± 0.1)×10−4 atm of CO2. The 90 % response and recovery times of the Indicator to sudden changes in Pressure are fast,

  • A colourimetric vacuum air-Pressure Indicator
    The Analyst, 2019
    Co-Authors: Dilidaer Yusufu, Andrew Mills
    Abstract:

    A colourimetric vacuum air Pressure Indicator is described, based on the very low level of CO2 in air. The Indicator uses the pH Indicator dye, ortho-cresolphthalein, OCP, which is violet coloured in its deprotonated form and colourless when protonated. When the violet coloured OCP anion is ion-paired with the tetrabutylammonium cation, the product is readily dissolved in a non-aqueous solution containing the polymer ethyl cellulose to create an ink which, when cast and allowed to dry, responds to levels of CO2 well below that in air, i.e.≪0.041%; the Indicator's halfway colour changing point is at 0.062 atm of air at 22 °C, which is interesting in that in food vacuum packaging the Pressure in the pack is usually ca. 0.04 atm. The Indicator can be used as a qualitative and quantitative Indicator of vacuum air Pressure. The latter requires the use of digital photography, coupled to RGB colour analysis, in the analysis of the Indicator's colour. As with most CO2 Indicators, the Indicator's response is temperature sensitive, with ΔH = 78 ± 5 kJ mol-1. The Indicator's 90% response and recovery times to a cycle of vacuum and air are 16.2 and 2.7 min, respectively. The efficacy of the Indicator as a vacuum-package integrity Indicator for food packaging is illustrated and other potential applications are discussed briefly. This is the first reported example of an ink-based, inexpensive, colourimetric vacuum air Pressure Indicator.