scholarly journals Covalent Linking of pH-Sensitive Dye to Fumed Silica

2010 ◽  
Vol 4 (2) ◽  
Author(s):  
Matthew Nielsen ◽  
Megan C. Frost
Keyword(s):  
Nitric Oxide ◽  
Fumed Silica ◽  
Thrombus Formation ◽  
Sol Gel ◽  
Ph Sensor ◽  
Healthcare Providers ◽  
Blood Gases ◽  
Blood Gas ◽  
Sensor Surface ◽  
Deprotonated Form

Measuring the blood gases of patients in the intensive care unit or undergoing major surgical procedures in real time would help healthcare providers diagnose and manage base excess and base deficient disorders. Optical fibers provide a platform upon which an intravascular blood gas sensor may be built and has been by various companies. Unfortunately, thrombosis on the sensor surface interferes with the blood gas measurements and also poses the risk of creating emboli. Nitric oxide inhibits platelet adhesion and activation, which can reduce thrombus formation on the sensor surface. An optically based pH sensor is fabricated as a first step to show that nitric oxide can be used with blood gas sensors to reduce thrombosis and not interfere with the measurements. pH sensors fabricated using glass microscope slides suffered from leaching of the dye from the sol-gel matrix. The dye readily leached out when the dye was in its appropriate protonated or deprotonated form. To reduce the leaching of the dye, methods of covalently linking the dye to fumed silica have been investigated, and one is presented here.

scholarly journals Novel Photoinitiated Nitric Oxide Releasing Compounds for More Biocompatible Coatings on Blood and Tissue Contacting Medical Devices

2009 ◽  
Vol 3 (2) ◽  
Author(s):  
B. M. Burgess ◽  
G. E. Gierke ◽  
M. C. Frost
Keyword(s):  
Nitric Oxide ◽  
Thrombus Formation ◽  
Neointimal Hyperplasia ◽  
Vascular Grafts ◽  
Blood Gases ◽  
Surface Fluxes ◽  
Biomedical Devices ◽  
Polymer Fillers ◽  
Nitric Oxide Releasing

Biomedical devices that contact blood and tissue universally inspire a host response that often compromises the function of the device (i.e., intravascular sensors become coated with thrombi, artificial vascular grafts become coated with thrombi, artificial vascular grafts become occluded with thrombus formation and neointimal hyperplasia). Nitric oxide (NO) has been shown to be a potent inhibitor of platelet adhesion and activation and has been implicated in mediating the inflammatory response and promoting would healing. We are currently developing NO-releasing compounds based on S-nitrosothiols derived from substituted aromatic compounds that utilize light as an external on/off trigger capable of releasing precisely controlled surface fluxes of NO. The level of NO generated is dependent on the wavelength and intensity of light shown on the compounds. Data will be presented that show the synthesis and NO-release properties of three novel compounds, S-nitroso-2-methoxybenzene, S-nitroso-3-methoxybenzene and S-nitroso-2-chlorobenzene. Ultimately, these compounds will be tethered to the surface of polymer fillers that will then be blended into hydrophobic polymers and used as coatings on biomedical devices. A model system that will be used to demonstrate the utility of this approach will be a multi-element fiber optic sensors that will contain sensing elements capable of measuring blood gases and NO-releasing fibers that locally generate enough NO to inhibit clot formation on the sensor surface, thus allowing the sensor to function reliably in vivo.

scholarly journals Novel Photoinitiated Nitric Oxide Releasing Compounds for More Biocompatible Coatings on Blood and Tissue Contacting Medical Devices

2009 ◽  
Vol 3 (2) ◽  
Author(s):  
B. M. Burgess ◽  
M. C. Frost
Keyword(s):  
Nitric Oxide ◽  
Thrombus Formation ◽  
Neointimal Hyperplasia ◽  
Blood Gases ◽  
Surface Fluxes ◽  
Biomedical Devices ◽  
Hydrophobic Polymers ◽  
Polymer Fillers ◽  
Nitric Oxide Releasing

Biomedical devices that contact blood and tissue universally inspire a host response that often compromises the function of the device (i.e., intravascular sensors become coated with thrombi, artificial vascular grafts become occluded with thrombus formation and neointimal hyperplasia). Nitric oxide (NO) has been shown to be a potent inhibitor of platelet adhesion and activation and has been implicated in mediating the inflammatory response and promoting wound healing. We are currently developing NO-releasing compounds based on S-nitrosothiols derived from substituted aromatic compounds that utilize light as an external on/off trigger capable of releasing precisely controlled surface fluxes of NO. The level of NO generated is dependent on the wavelength and intensity of light shown on the compounds. Data will be presented that show the synthesis and NO-release properties of three novel compounds, S-nitroso-2-methoxybenzene, S-nitroso-3-methoxybenzene and S-nitroso-2-chlorobenzene. Ultimately, these compounds will be tethered to the surface of polymer fillers that will then be blended into hydrophobic polymers and used as coatings on biomedical devices. A model system that will be used to demonstrate the utility of this approach will be a multi-element fiber optic sensors that will contain sensing elements capable of measuring blood gases and NO-releasing fibers that locally generate enough NO to inhibit clot formation on the sensor surface, thus allowing the sensor to function reliably in vivo.

scholarly journals Ex-Vivo Measurement of the pH in Aqueous Humor Samples by a Tapered Fiber-Optic Sensor

Sensors ◽  
2021 ◽  
Vol 21 (15) ◽  
pp. 5075
Author(s):  
Ondřej Podrazký ◽  
Jan Mrázek ◽  
Jana Proboštová ◽  
Soňa Vytykáčová ◽  
Ivan Kašík ◽  
...  
Keyword(s):  
Cataract Surgery ◽  
Aqueous Humor ◽  
Fiber Optic ◽  
Ex Vivo ◽  
Sol Gel ◽  
Ph Sensor ◽  
Fiber Optic Sensor ◽  
Optic Sensor ◽  
Tapered Optical Fiber ◽  
Practical Demonstration

A practical demonstration of pH measurement in real biological samples with an in-house developed fiber-optic pH sensor system is presented. The sensor uses 8-hydroxypyrene-1,3,6-trisulfonate (HPTS) fluorescent dye as the opto-chemical transducer. The dye is immobilized in a hybrid sol-gel matrix at the tip of a tapered optical fiber. We used 405 nm and 450 nm laser diodes for the dye excitation and a photomultiplier tube as a detector. The sensor was used for the measurement of pH in human aqueous humor samples during cataract surgery. Two groups of patients were tested, one underwent conventional phacoemulsification removal of the lens while the other was subjected to femtosecond laser assisted cataract surgery (FLACS). The precision of the measurement was ±0.04 pH units. The average pH of the aqueous humor of patients subjected to FLACS and those subjected to phacoemulsification were 7.24 ± 0.17 and 7.31 ± 0.20 respectively.

StatPal II pH and Blood Gas Analysis System evaluated

1994 ◽  
Vol 40 (1) ◽  
pp. 124-129 ◽  
Author(s):  
R J Wong ◽  
J J Mahoney ◽  
J A Harvey ◽  
A L Van Kessel
Keyword(s):  
Point Of Care ◽  
Blood Gases ◽  
Blood Gas Analysis ◽  
Gas Analysis ◽  
Portable Instrument ◽  
Blood Gas ◽  
Target Value ◽  
Analysis System

Abstract We evaluated a new portable instrument, the PPG StatPal II pH and Blood Gas Analysis System, designed for "point-of-care" measurements of blood gases and pH. Inaccuracy (% of target value) and imprecision (CV%) were assessed by blood tonometry and comparison with a Corning 178. Within-day results for PCO2 inaccuracy and imprecision ranged from 98.2% to 102.9% and 3.3% to 3.9%, respectively; for PO2, these were 95.5% to 102.3% and 2.3% to 3.0%, respectively. Between-day results for PCO2 inaccuracy and imprecision ranged from 99.2% to 99.3% and from 2.9% to 3.2%, respectively; for PO2, the ranges were 96.2% to 98.2% and 2.6% to 3.0%, respectively. Two PCO2 outliers (in 645 samples = 0.3%) were observed. In general, tonometry recovery, measurement stability, and pH bias results for the StatPal II and Corning 178 were comparable. We conclude that the StatPal II performs within acceptable ranges of inaccuracy and imprecision.

Miniaturization of organically doped sol-gel materials: a microns-size fluorescent pH sensor

1994 ◽  
Vol 21 (5-6) ◽  
pp. 431-434 ◽  
Author(s):  
Joshua Samuel ◽  
Allina Strinkovski ◽  
Shmuel Shalom ◽  
Klony Lieberman ◽  
Michael Ottolenghi ◽  
...  
Keyword(s):  
Sol Gel ◽  
Ph Sensor

A luminescent pH sensor based on a sol–gel film functionalized with a luminescent organometallic complex

2000 ◽  
Vol 10 (8) ◽  
pp. 1825-1828 ◽  
Author(s):  
Michael H. W. Lam ◽  
Derek Y. K. Lee ◽  
K. W. Man ◽  
Cindy S. W. Lau
Keyword(s):  
Sol Gel ◽  
Ph Sensor ◽  
Organometallic Complex ◽  
Gel Film

Performance of Polishing Slurries containing Silica Particles grown by Sol-Gel Method

2000 ◽  
Vol 613 ◽  
Author(s):  
Sun Hyuk Bae ◽  
Jae-Hyun So ◽  
Seung-Man Yang ◽  
Do Hyun Kim
Keyword(s):  
Fumed Silica ◽  
Sol Gel ◽  
Particle Growth ◽  
Silica Particles ◽  
Gel Method ◽  
Sol Gel Method ◽  
Irregular Shapes ◽  
Wafer Polishing ◽  
Transmission Electron ◽  
Silica Slurry

ABSTRACTSilica slurry used as abrasives in wafer polishing process is made by dispersing silica particles in an alkali solution. Since commercially available colloidal or fumed silica particles need some modifications to be directly used as abrasive slurry due to their small sizes, irregular shapes or broad size distribution, we have prepared silica abrasives by particle growth of fumed silica or colloidal silica as seeds by sol-gel method. Silica slurries prepared by this step-wise growth from commercial seeds were tested using one-armed polisher for the comparison with commercial slurries and showed the performance comparable to commercial slurries. Microstructures of polishing slurries were investigated using transmission electron microscopy and ARES rheometer. From the result, stability of the slurry was found to be more important than the primary particle sizes for the polishing performance.

Blood gas changes during panting in a small East African antelope, the dik-dik

1978 ◽  
Vol 44 (4) ◽  
pp. 534-537 ◽  
Author(s):  
M. Maskrey ◽  
P. P. Hoppe ◽  
O. S. Bamford
Keyword(s):  
Heat Stress ◽  
Heat Exposure ◽  
Blood Gases ◽  
Respiratory Alkalosis ◽  
Second Phase ◽  
Blood Gas ◽  
Climatic Chamber ◽  
East African ◽  
Blood Samples ◽  
Arterial Blood

Five adult male dik-dik (Madoqua kirkii) were exposed in a climatic chamber to an air temperature of 45 degrees C. Measurements were made of rectal temperature (Tre) and respiratory frequency (f) and arterial blood samples taken before and during heat exposure were analyzed for pH, PCO2 and PO2. During exposure, Tre and f increased in all animals. In the first 80 min dik-dik displayed thermal tachypnea and minor changes in blood gases. Continued exposure lead to hyperpnea accompanied by a fall in PaCO2 and a rise in pH. PaCO2 at first fell and then increased toward or above control levels. The dik-dik did not display second phase breathing. This observation confirms that second phase breathing is not essential to the development of respiratory alkalosis. The main conclusion of the study is that the dik-dik, unlike another heat-adapted antelope, the wildebeest (Taylor, Robertshaw, and Hoffmann. Am. J. Physiol. 217:907–910, 1969), is unable to resist alkalosis during heat stress.

Standardized Evaluation of Cord Gases in Neonates at Risk for Hypoxic Ischemic Encephalopathy

2021 ◽  
Author(s):  
Elizabeth Blecharczyk ◽  
Lucy Lee ◽  
Krista Birnie ◽  
Arun Gupta ◽  
Alexis Davis ◽  
...  
Keyword(s):  
At Risk ◽  
Cord Blood ◽  
Umbilical Cord ◽  
Care Pathway ◽  
Clinical Care ◽  
Blood Gases ◽  
Hypoxic Ischemic Encephalopathy ◽  
Blood Gas ◽  
Clinical Care Pathway ◽  
Ischemic Encephalopathy

BACKGROUND: Umbilical-cord acidemia may indicate perinatal asphyxia and places a neonate at increased risk for hypoxic ischemic encephalopathy (HIE). Our specific aim was to develop a standardized clinical care pathway, ensuring timely identification and evaluation of neonates with umbilical-cord acidemia at risk for HIE. METHODS: A standardized clinical care pathway to screen inborn neonates ≥36 weeks with abnormal cord blood gases (a pH of ≤7.0 or base deficit of ≥10) for HIE was implemented in January 2016. Abnormal cord blood gases resulted in a direct notification from the laboratory to an on-call physician. Evaluation included a modified Sarnat examination, postnatal blood gas, and standardized documentation. The percentage of neonates in which physician notification, documented Sarnat examination, and postnatal blood gas occurred was examined for 6 months before and 35 months after implementation. RESULTS: Of 203 neonates with abnormal cord gases in the post–quality improvement (QI) period, physician notification occurred in 92%. In the post-QI period, 94% had a documented Sarnat examination, and 94% had postnatal blood gas, compared with 16% and 11%, respectively, of 87 neonates in the pre-QI period. In the post-QI period, of those evaluated, >96% were documented within 4 hours of birth. In the post-QI period, 15 (7.4%) neonates were cooled; 13 were in the NICU at time of identification, but 2 were identified in the newborn nursery and redirected to the NICU for cooling. CONCLUSIONS: A standardized screening pathway in neonates with umbilical-cord acidemia led to timely identification and evaluation of neonates at risk for HIE.

Arterial blood gases

2007 ◽  
pp. 319-326
Keyword(s):  
Decision Making ◽  
Pulse Oximetry ◽  
Respiratory Rate ◽  
Management Strategy ◽  
Blood Gases ◽  
Capillary Blood ◽  
Blood Gas ◽  
Arterial Blood Gas ◽  
Arterial Blood ◽  
Gas Measurements

Arterial blood gas (ABGs) analysis forms the cornerstone of emergency respiratory investigation. In many situations values obtained dictate management strategy and facilitate decision-making. It is an uncomfortable procedure for the patients and if repeated ABGs are required, consider whether less invasive measures, such as respiratory rate, pulse oximetry or capillary blood gas measurements could be used....

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