US20060174691A1 - Method of controlling degradation of trace gas sensors - Google Patents
Method of controlling degradation of trace gas sensors Download PDFInfo
- Publication number
- US20060174691A1 US20060174691A1 US11/053,046 US5304605A US2006174691A1 US 20060174691 A1 US20060174691 A1 US 20060174691A1 US 5304605 A US5304605 A US 5304605A US 2006174691 A1 US2006174691 A1 US 2006174691A1
- Authority
- US
- United States
- Prior art keywords
- sensor
- oxygen
- transduction molecule
- matrix
- sensor housing
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
Images
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N33/00—Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
- G01N33/48—Biological material, e.g. blood, urine; Haemocytometers
- G01N33/483—Physical analysis of biological material
- G01N33/497—Physical analysis of biological material of gaseous biological material, e.g. breath
Definitions
- This invention relates to methods for controlling the degradation of transduction molecules in trace gas sensors.
- Trace gas analysis is a promising tool for many applications. For instance, in the medical field, changes in exhaled nitric oxide (NO) concentration in exhaled breath can indicate a change in the level of inflammation in the airway of an asthmatic, indicating an increase in the likelihood of an asthma attack. Trace gas analysis may also be useful in measuring other trace constituents of exhaled breath, such as carbon monoxide. Also, there is a need for means to measure trace gases in the atmosphere, for environmental assessment, and to measure trace gases in manufacturing and industrial settings.
- NO nitric oxide
- xerogel stabilized sol-gel
- cytochrome-c nitric oxide
- degradation is defined to include any loss in the sensor's functionality, including the sensor's loss in responsivity to the analyte of interest (e.g. NO) in both magnitude and time-course. It is also defined in the case of cytochrome-c/NO as the loss in the soret peak, which is the spectral peak of the iron porphyrin (the active part of the heme-protein). Thus, one can measure the loss in reactivity to NO or the loss in the magnitude of the soret peak centered around 400 nm.
- the technology of this application is designed to work with sensors that have sensing elements with transduction molecules, where such molecules undergo optical or electrical changes in response to the analyte.
- the present invention is a method of reducing the degradation of a transduction molecule in a trace gas sensor by controlling the exposure of the protein to oxygen.
- FIG. 1 is a graph showing the degradation of a cytochrome-c NO sensor over time.
- the y-axis on this graph represents the change in absorbance in a NO sensor in 90 seconds when the humidity surrounding the sensor is fixed at 200 ppm water and the sensor is reacted with 500 ppb NO.
- FIG. 2 is a graph comparing the NO response after 7 days at 70° C. for sensors aged in an ambient environment, and those aged in an oxygen free environment.
- a sensor was taken from an initial ambient environment with 6% relative humidity and then placed in an environment with ambient oxygen and salt at 6% relative humidity for a period equivalent to 220 days at room temperature.
- the 6% RH was maintained by a saturated solution of LiBr.
- a degradation of 78% in sensor performance was observed, meaning that this sensor was 78% less sensitive to NO after exposure to the tested environment.
- the applicants first made a baseline measurement of the reactivity of the sensor to 500 ppb NO in air, and then measured the degree to which the reactivity was lost after exposure to the testing environment.
- the applicant's sensing element is especially sensitive to oxygen degradation because it is has a high surface area, and this increases the susceptibility of the device to oxygen.
- the applicant's sensing element is cytochrome-c in a sol-gel with a surface area of approximately 400 m2/g.
- nitrogen or another suitable substance can be used to purge oxygen from the sensor housing, and then the sensor housing can be sealed in an oxygen-free (i.e. oxygen-purged) packaging environment.
- oxygen-free packaging environment i.e. oxygen-purged
- the purging can be accomplished with five cycles of nitrogen, based on sensor volume and sensor housing volume.
- a vacuum can be created within the housing, either with our without nitrogen purging.
- an oxygen absorber can be used to remove oxygen from a sealed sensor housing.
- the oxygen absorber could be OS film from Cryovac of Cerritos, Calif., or one of the oxygen absorbers (such as PharmaKeep®) from Sud-Chemie of Belen, New Mexico, or any other suitable oxygen absorber.
- the oxygen absorber could be placed in the packaging with the sensor.
- the sealed sensor housing could be made of permeable material that allows the exit of oxygen into the packaging environment and from there into the oxygen absorber. Purging of oxygen from the sensor housing is optional in this embodiment.
- an oxygen absorber can be used to remove oxygen from an unsealed sensor housing.
- This embodiment is similar to the second embodiment, except that the sensor housing is unsealed to facilitate diffusion of oxygen to the absorber. Purging of oxygen from the sensor housing is also optional in this embodiment.
Landscapes
- Life Sciences & Earth Sciences (AREA)
- Health & Medical Sciences (AREA)
- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Molecular Biology (AREA)
- Physics & Mathematics (AREA)
- Biomedical Technology (AREA)
- Food Science & Technology (AREA)
- General Health & Medical Sciences (AREA)
- Hematology (AREA)
- Biophysics (AREA)
- Medicinal Chemistry (AREA)
- Analytical Chemistry (AREA)
- Biochemistry (AREA)
- Urology & Nephrology (AREA)
- General Physics & Mathematics (AREA)
- Immunology (AREA)
- Pathology (AREA)
- Investigating Or Analysing Materials By The Use Of Chemical Reactions (AREA)
- Investigating Or Analyzing Non-Biological Materials By The Use Of Chemical Means (AREA)
- Investigating Or Analysing Biological Materials (AREA)
- Investigating Or Analyzing Materials By The Use Of Fluid Adsorption Or Reactions (AREA)
Abstract
Description
- 1. Field of the Invention
- This invention relates to methods for controlling the degradation of transduction molecules in trace gas sensors.
- 2. General Background
- Trace gas analysis is a promising tool for many applications. For instance, in the medical field, changes in exhaled nitric oxide (NO) concentration in exhaled breath can indicate a change in the level of inflammation in the airway of an asthmatic, indicating an increase in the likelihood of an asthma attack. Trace gas analysis may also be useful in measuring other trace constituents of exhaled breath, such as carbon monoxide. Also, there is a need for means to measure trace gases in the atmosphere, for environmental assessment, and to measure trace gases in manufacturing and industrial settings.
- To quantify the concentration of trace gases, various sensors have been developed. Some of these sensors detect and measure changes in substances in response to the trace gas analyte. For instance, a sensor developed by the present inventors measures the optically-quantifiable changes in xerogel (stabilized sol-gel) encapsulated cytochrome-c in response to nitric oxide (NO). This sensor and related technology are disclosed in the following U.S. patent applications, the disclosures of which are hereby incorporated herein by reference: Ser. No. 10/334,625, filed 30 Dec. 2003, and Ser. No. 10/767,709, filed 28 Jan. 2004.
- However, previous work with transduction molecule trace gas sensors has revealed a potential vulnerability: rapid degradation of the sensor. In particular, the applicants have found that in normal circumstances (when attempting to measure trace concentrations) their cytochrome-c sensor would degrade rapidly. The degradation time depends on many parameters, such as temperature, etc., but this unpredictability would make such a sensor impracticable for commercial use, since the sensor may not be usable by the time it reached the end user.
- For purposes of this patent, degradation is defined to include any loss in the sensor's functionality, including the sensor's loss in responsivity to the analyte of interest (e.g. NO) in both magnitude and time-course. It is also defined in the case of cytochrome-c/NO as the loss in the soret peak, which is the spectral peak of the iron porphyrin (the active part of the heme-protein). Thus, one can measure the loss in reactivity to NO or the loss in the magnitude of the soret peak centered around 400 nm. The technology of this application is designed to work with sensors that have sensing elements with transduction molecules, where such molecules undergo optical or electrical changes in response to the analyte.
- The cause or causes of this degradation were previously unknown, but the applicants have now discovered the primary mechanism that causes the degradation, and therefore have created the present invention which preserves transduction molecule trace gas sensors for a sufficient period of time to allow for the creation of a viable commercial product.
- The present invention is a method of reducing the degradation of a transduction molecule in a trace gas sensor by controlling the exposure of the protein to oxygen. Through their research, the applicants have discovered that oxidation is responsible for the rapid degradation of the sensor. To combat this degradation, the sensor can be stored in a low-oxygen or a substantially oxygen-free environment.
-
FIG. 1 is a graph showing the degradation of a cytochrome-c NO sensor over time. The y-axis on this graph represents the change in absorbance in a NO sensor in 90 seconds when the humidity surrounding the sensor is fixed at 200 ppm water and the sensor is reacted with 500 ppb NO. -
FIG. 2 is a graph comparing the NO response after 7 days at 70° C. for sensors aged in an ambient environment, and those aged in an oxygen free environment. - The applicants discovered that oxidation was causing the unacceptable degradation of the sensor. The applicants made this discovery in the context of developing a transduction sensor comprised of cytochrome-c encapsulated in a sol-gel matrix. The applicants left sensors in the ambient air, and the sensors had a detectable loss in optical density within 24 hours. When the sensors were left in a nitrogen purged environment, the sensors retained all optical density and substantially all responsivity. This indicated that a constituent in the atmosphere besides nitrogen caused the degradation.
- Next, the applicants performed experiments to isolate the cause of the degradation. The applicants measured percentage of degradation in various environmental conditions, as shown below.
Experimental Groups Stability (% degradation) 1. Initial @ 6% RH −> −78% O2, salt @ 6% RH (control) 2. Initial @ 6% RH −> −10% No O2, 16% 3A @ <0.1% RH - In the first experimental group, which is the control, a sensor was taken from an initial ambient environment with 6% relative humidity and then placed in an environment with ambient oxygen and salt at 6% relative humidity for a period equivalent to 220 days at room temperature. The 6% RH was maintained by a saturated solution of LiBr. Under these storage conditions a degradation of 78% in sensor performance was observed, meaning that this sensor was 78% less sensitive to NO after exposure to the tested environment. To determine percentage of degradation, the applicants first made a baseline measurement of the reactivity of the sensor to 500 ppb NO in air, and then measured the degree to which the reactivity was lost after exposure to the testing environment.
- In the second experimental group, a sensor was placed in an environment with no oxygen and a relative humidity of 0.1% and a 3 A molecular sieve for the equivalent to 220 room temperature days. This sensor experienced a 10% degradation rate. This confirms that oxygen is the primary cause of the degradation, and that RH also contributes to the problem.
- The discovery that oxygen is a major cause of degradation is surprising, since the applicants are aware of no prior art teaching that protein-based gas sensors need to be stored in an oxygen-deprived environment. For instance, to the applicants' knowledge, previous protein based sensors have not been stored in oxygen-deprived environments, but instead typically only require removal of moisture for storage.
- The applicants believe that their sensing element is especially sensitive to oxygen degradation because it is has a high surface area, and this increases the susceptibility of the device to oxygen. In one embodiment, the applicant's sensing element is cytochrome-c in a sol-gel with a surface area of approximately 400 m2/g.
- A number of different techniques can be used to control the degradative effects of oxygen. In one embodiment of the present invention, nitrogen or another suitable substance can be used to purge oxygen from the sensor housing, and then the sensor housing can be sealed in an oxygen-free (i.e. oxygen-purged) packaging environment. For instance, the purging can be accomplished with five cycles of nitrogen, based on sensor volume and sensor housing volume. Or a vacuum can be created within the housing, either with our without nitrogen purging.
- In a second embodiment, an oxygen absorber can be used to remove oxygen from a sealed sensor housing. The oxygen absorber could be OS film from Cryovac of Cerritos, Calif., or one of the oxygen absorbers (such as PharmaKeep®) from Sud-Chemie of Belen, New Mexico, or any other suitable oxygen absorber. In this embodiment, the oxygen absorber could be placed in the packaging with the sensor. The sealed sensor housing could be made of permeable material that allows the exit of oxygen into the packaging environment and from there into the oxygen absorber. Purging of oxygen from the sensor housing is optional in this embodiment.
- In a third embodiment, an oxygen absorber can be used to remove oxygen from an unsealed sensor housing. This embodiment is similar to the second embodiment, except that the sensor housing is unsealed to facilitate diffusion of oxygen to the absorber. Purging of oxygen from the sensor housing is also optional in this embodiment.
- One skilled in the art will appreciate that the present invention can be practiced by other than the preferred embodiments, which are presented for purposes of illustration and not of limitation.
Claims (27)
Priority Applications (8)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US11/053,046 US20060174691A1 (en) | 2005-02-07 | 2005-02-07 | Method of controlling degradation of trace gas sensors |
US11/348,925 US7278291B2 (en) | 2005-02-07 | 2006-02-06 | Trace gas sensor with reduced degradation |
AU2006212799A AU2006212799A1 (en) | 2005-02-07 | 2006-02-06 | Trace gas sensor with reduced degradation |
EP06720442A EP1851526A4 (en) | 2005-02-07 | 2006-02-06 | Trace gas sensor with reduced degradation |
JP2007554327A JP2008530534A (en) | 2005-02-07 | 2006-02-06 | Trace gas sensor with reduced degradation |
PCT/US2006/004292 WO2006086388A2 (en) | 2005-02-07 | 2006-02-06 | Trace gas sensor with reduced degradation |
CA002596488A CA2596488A1 (en) | 2005-02-07 | 2006-02-06 | Trace gas sensor with reduced degradation |
NO20074074A NO20074074L (en) | 2005-02-07 | 2007-08-07 | Tracer sensor with reduced degradation |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US11/053,046 US20060174691A1 (en) | 2005-02-07 | 2005-02-07 | Method of controlling degradation of trace gas sensors |
Related Child Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US11/348,925 Continuation-In-Part US7278291B2 (en) | 2005-02-07 | 2006-02-06 | Trace gas sensor with reduced degradation |
Publications (1)
Publication Number | Publication Date |
---|---|
US20060174691A1 true US20060174691A1 (en) | 2006-08-10 |
Family
ID=36778560
Family Applications (2)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US11/053,046 Abandoned US20060174691A1 (en) | 2005-02-07 | 2005-02-07 | Method of controlling degradation of trace gas sensors |
US11/348,925 Active US7278291B2 (en) | 2005-02-07 | 2006-02-06 | Trace gas sensor with reduced degradation |
Family Applications After (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US11/348,925 Active US7278291B2 (en) | 2005-02-07 | 2006-02-06 | Trace gas sensor with reduced degradation |
Country Status (7)
Country | Link |
---|---|
US (2) | US20060174691A1 (en) |
EP (1) | EP1851526A4 (en) |
JP (1) | JP2008530534A (en) |
AU (1) | AU2006212799A1 (en) |
CA (1) | CA2596488A1 (en) |
NO (1) | NO20074074L (en) |
WO (1) | WO2006086388A2 (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20110208081A1 (en) * | 2007-09-07 | 2011-08-25 | Smith Trevor | Apparatus and method |
Families Citing this family (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP5240954B2 (en) | 2010-08-03 | 2013-07-17 | パナソニックヘルスケア株式会社 | Nitric oxide detection element |
Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5421981A (en) * | 1991-06-26 | 1995-06-06 | Ppg Industries, Inc. | Electrochemical sensor storage device |
US20040104114A1 (en) * | 1999-12-15 | 2004-06-03 | Thomas Schulte | Gas sensor for determining the concentration of gas components in gas mixtures and use thereof |
Family Cites Families (11)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS56152417A (en) * | 1980-04-28 | 1981-11-26 | Furointo Sangyo Kk | Preparation of cytochrome c pharamaceutical for internal use |
JPS5721315A (en) * | 1980-07-15 | 1982-02-04 | Ookura Seiyaku Kk | Stable solid preparation of cytochrome c and its preparation |
US5096813A (en) * | 1988-07-18 | 1992-03-17 | Massachusetts Institute Of Technology | Visual indicator system |
JPH0298669A (en) | 1988-10-04 | 1990-04-11 | Fujikura Ltd | Semiconductor acceleration sensor |
US5520545A (en) | 1994-11-21 | 1996-05-28 | The Whitaker Corporation | Variable orientation, surface mounted hermaphroditic connector |
CA2252024C (en) | 1996-04-09 | 2006-09-19 | Sievers Instruments, Inc. | Method and apparatus for the measurement of components of exhaled breath in humans |
US6787366B1 (en) * | 1996-12-11 | 2004-09-07 | The United States Of America As Represented By The Secretary Of The Army | Microspot test kit and method for chemical testing |
US20040017570A1 (en) | 2002-07-23 | 2004-01-29 | Bhairavi Parikh | Device and system for the quantification of breath gases |
US7220387B2 (en) | 2002-07-23 | 2007-05-22 | Apieron Biosystems Corp. | Disposable sensor for use in measuring an analyte in a gaseous sample |
US20050053549A1 (en) | 2003-09-10 | 2005-03-10 | Aperon Biosystems Corp. | Method for treating airway disorders |
US7325409B2 (en) * | 2004-03-24 | 2008-02-05 | Espinosa Edward P | Vacuum storage apparatus with sliding drawers |
-
2005
- 2005-02-07 US US11/053,046 patent/US20060174691A1/en not_active Abandoned
-
2006
- 2006-02-06 US US11/348,925 patent/US7278291B2/en active Active
- 2006-02-06 WO PCT/US2006/004292 patent/WO2006086388A2/en active Application Filing
- 2006-02-06 CA CA002596488A patent/CA2596488A1/en not_active Abandoned
- 2006-02-06 EP EP06720442A patent/EP1851526A4/en not_active Withdrawn
- 2006-02-06 AU AU2006212799A patent/AU2006212799A1/en not_active Abandoned
- 2006-02-06 JP JP2007554327A patent/JP2008530534A/en active Pending
-
2007
- 2007-08-07 NO NO20074074A patent/NO20074074L/en not_active Application Discontinuation
Patent Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5421981A (en) * | 1991-06-26 | 1995-06-06 | Ppg Industries, Inc. | Electrochemical sensor storage device |
US20040104114A1 (en) * | 1999-12-15 | 2004-06-03 | Thomas Schulte | Gas sensor for determining the concentration of gas components in gas mixtures and use thereof |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20110208081A1 (en) * | 2007-09-07 | 2011-08-25 | Smith Trevor | Apparatus and method |
Also Published As
Publication number | Publication date |
---|---|
EP1851526A4 (en) | 2009-06-17 |
JP2008530534A (en) | 2008-08-07 |
US20060191321A1 (en) | 2006-08-31 |
WO2006086388A3 (en) | 2007-03-15 |
CA2596488A1 (en) | 2006-08-17 |
AU2006212799A1 (en) | 2006-08-17 |
WO2006086388A2 (en) | 2006-08-17 |
US7278291B2 (en) | 2007-10-09 |
NO20074074L (en) | 2007-09-05 |
EP1851526A2 (en) | 2007-11-07 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US10775338B2 (en) | Electrochemical gas sensor, filter and methods | |
US7533558B2 (en) | Disposable sensor for use in measuring an analyte in a gaseous sample | |
US4772560A (en) | Laminated wafer for sensing and monitoring exposure to gases | |
US7352465B2 (en) | Sample conditioning and environmental control techniques for gas sensor | |
US6338266B1 (en) | Method of identifying a gas and associated apparatus | |
JP2014528594A (en) | Method for inspecting a gas sensor | |
US8537020B2 (en) | Visual indicator of gas sensor impairment | |
US8916037B1 (en) | Instrument and method for measuring high concentrations of carbon monoxide in a gaseous sample | |
US20060174691A1 (en) | Method of controlling degradation of trace gas sensors | |
JP5734109B2 (en) | Measuring apparatus and measuring method | |
US20020020208A1 (en) | Instrument for combustible gas detection | |
Mirmohseni et al. | Determination of chlorinated aliphatic hydrocarbons in air using a polymer coated quartz crystal microbalance sensor | |
Magori et al. | Fractional exhaled nitric oxide measurement with a handheld device | |
EP3893748B1 (en) | Hydrogen breath analyzer and breath test method | |
EP1866432B1 (en) | Rapid-response gas sensing element | |
RU2132551C1 (en) | Gas sensor operating process | |
Deng et al. | Unraveling fabrication and calibration of wearable gas monitor for use under free-living conditions | |
US20060175208A1 (en) | Water-conductivity CO2 sensor | |
Alexy et al. | Disposable optochemical sensor chip for nitrogen dioxide detection based on oxidation of N, N′-diphenyl-1, 4-phenylenediamine | |
EP1326075A1 (en) | Device and method for measuring alcohol vapour concentration | |
US20020131898A1 (en) | Alcohol sensor using the work function measurement principle | |
AP1310A (en) | Measuring probe and method for measuring the concentration of agents in gases and/or liquids. | |
JPH10513554A (en) | Method for extending the shelf life of a colorimetric device for indicating carbon dioxide and a package containing the device | |
Hassan et al. | Potentiometric gas sensor for the selective determination of azides | |
CN112740032B (en) | Method and apparatus for calibrating a fluid detector having a preconcentrator |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
AS | Assignment |
Owner name: APERON BIOSYSTEMS CORP., CALIFORNIA Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:CHAZAN, DAVID;ANVAR, DAVID;TALBOTT, AUTUMN;REEL/FRAME:017439/0282;SIGNING DATES FROM 20051213 TO 20051218 |
|
AS | Assignment |
Owner name: APERON BIOSYSTEMS CORP., CALIFORNIA Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:CHAZAN, DAVID J.;ANVAR, DAVID J.;TALBOTT, AUTUMN;REEL/FRAME:017865/0477 Effective date: 20060417 |
|
STCB | Information on status: application discontinuation |
Free format text: ABANDONED -- FAILURE TO RESPOND TO AN OFFICE ACTION |
|
AS | Assignment |
Owner name: SILICON VALLEY BANK, CALIFORNIA Free format text: SECURITY AGREEMENT;ASSIGNOR:APIERON, INC.;REEL/FRAME:023319/0669 Effective date: 20090911 |
|
AS | Assignment |
Owner name: APIERON, INC. F/K/A APERON BIOSYSTEMS CORP.,CALIFO Free format text: RELEASE BY SECURED PARTY;ASSIGNOR:SILICON VALLEY BANK;REEL/FRAME:024445/0943 Effective date: 20100525 Owner name: AEROCRINE AB,SWEDEN Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:APIERON, INC., F/K/A APERON BIOSYSTEMS CORP., BY AND THROUGH ITS CHAPTER 7 TRUSTEE, JANINA M. ELDER;REEL/FRAME:024456/0478 Effective date: 20100519 Owner name: AEROCRINE AB, SWEDEN Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:APIERON, INC., F/K/A APERON BIOSYSTEMS CORP., BY AND THROUGH ITS CHAPTER 7 TRUSTEE, JANINA M. ELDER;REEL/FRAME:024456/0478 Effective date: 20100519 Owner name: APIERON, INC. F/K/A APERON BIOSYSTEMS CORP., CALIF Free format text: RELEASE BY SECURED PARTY;ASSIGNOR:SILICON VALLEY BANK;REEL/FRAME:024445/0943 Effective date: 20100525 |