JP6293500B2 - Method for evaluating the degree of occurrence of redness of the skin at the site where the absorbent article is worn - Google Patents

Description

  The present invention relates to a method for evaluating the quality of a skin condition in a wet environment at a site where an absorbent article is worn.

  Various proposals have been made to keep the skin condition well at the site where the absorbent article is worn. As one means for improving the condition of the skin, a technique of applying a skin care agent to a skin facing surface such as a surface sheet in an absorbent article is known (see, for example, Patent Document 1).

  Regarding the improvement effect of the skin condition by the absorbent article in which the skin care agent is applied to the skin facing surface such as the surface sheet, Patent Document 2 may be affected by the vapor permeability of the back sheet and the collagen rewetting value of the absorbent core. Have been described. In Patent Document 3, the contact angle of water with respect to the skin of the wearer in a state where the absorbent article is worn and the skin care agent has transferred, and the contact angle of water with respect to the skin of the wearer before wearing the absorbent article, And a method for evaluating the skin care effect based on the magnitude relationship has been proposed.

JP 2002-065727 A JP-T-2001-515754 JP 2013-111396 A

  The evaluation methods described in Patent Documents 2 and 3 are basically performed in a state where the absorbent article does not absorb the liquid and the topsheet is not wet. Therefore, the evaluation methods described in these patent documents are useful as methods for suppressing the transpiration of moisture from the skin, that is, for evaluating the moisture barrier property. However, the evaluation methods described in these patent documents cannot be said to be evaluated in the actual wearing environment of the absorbent article, that is, in an environment where the liquid is absorbed and held and moistened. It is unfamiliar with the evaluation of the quality of the skin condition in a moist environment, such as the likelihood of redness of the skin that may occur due to the skin.

  Therefore, the subject of this invention is providing the method of evaluating the quality of the skin condition in the wet environment in the site | part which worn the absorbent article.

  According to the present invention, an absorbent article having a topsheet and an absorbent body is made to absorb artificial urine to wet the topsheet, and the topsheet and skin are brought into contact with each other. The skin at the site where the absorbent article is worn, which measures the coefficient of friction against the skin and evaluates the quality of the skin condition at the site where the absorbent article is worn based on the magnitude of the measured coefficient of friction. It provides a condition evaluation method.

  ADVANTAGE OF THE INVENTION According to this invention, the quality of the skin condition in the wet environment in the site | part which worn the absorbent article can be evaluated accurately. Therefore, the evaluation method of the present invention is one of the guidelines for designing an absorbent article that is unlikely to cause skin irritation or the like even when the absorbent article in a wet state is worn for a long time.

FIG. 1 is a perspective view showing a main part of a surface sheet in an absorbent article which is an object of measurement of a friction coefficient in the present invention. FIG. 2 is a perspective view showing a main part in another embodiment of the top sheet of the absorbent article that is the object of measurement of the friction coefficient in the present invention. 3 (a) to 3 (c) are cross-sectional views showing the main parts of still another embodiment of the top sheet of the absorbent article that is the object of measurement of the coefficient of friction in the present invention. FIG. 4 is a perspective view showing a main part in still another embodiment of the topsheet in the absorbent article that is the object of measurement of the friction coefficient in the present invention. FIG. 5 is a perspective view showing a main part of still another embodiment of the top sheet of the absorbent article that is the object of measurement of the friction coefficient in the present invention. FIG. 6 is a schematic diagram illustrating a state in which the coefficient of friction of the absorbent article with respect to the skin is measured. FIG. 7 is a schematic view showing a state where the absorbent article is rubbed against the skin and the stratum corneum is peeled off. FIG. 8 is a graph showing the correlation between the friction coefficient measured in the example and the stratum corneum peeling amount.

  The present invention will be described below based on preferred embodiments with reference to the drawings. In the present invention, the absorbent article used for the evaluation of skin condition has at least a surface sheet and an absorbent body. This absorbent article may further include a back sheet. The top sheet is located on the side close to the wearer's skin and is arranged to face the wearer's skin. The back sheet is located on the side far from the wearer's skin. The absorber is disposed between the top sheet and the back sheet. The absorber is liquid retaining. Furthermore, a pair of leak-proof cuffs may be disposed on the left and right sides on the top sheet of the absorbent article as necessary.

  As the top sheet and the back sheet, the same sheets as used so far in the technical field can be used. As the surface sheet, for example, a hydrophilic nonwoven fabric or a perforated film having liquid permeability can be used. These nonwoven fabrics and films are generally composed of a thermoplastic resin. Specific examples of the topsheet will be described in more detail with reference to FIGS. 1 to 5 described later. As the back sheet, for example, a liquid-impermeable film or a liquid-impermeable nonwoven fabric can be used. The liquid-impermeable film may have moisture permeability.

  As the absorbent body, it is possible to use a laminated product of flap pulp or a mixed product of fluff pulp and superabsorbent polymer. The absorbent body may have the same thickness over the entire area of the article, or a part thereof, for example, a part facing the excretion part of the wearer may be thicker than the other part. The same applies to the basis weight of the absorbent body, which may have the same basis weight over the entire area of the article, or a part, for example, the part facing the excretion part of the wearer has a higher basis weight than the other part. It may be. Moreover, the absorber which consists of a block structure in which many high basic weight parts were divided by the low basic weight part can also be used.

  In the evaluation method of the present invention, the friction sheet is measured by bringing the surface sheet of the absorbent article into contact with the skin. Therefore, the friction coefficient of the absorbent article measured in the present invention mainly depends on the properties of the topsheet. The property of the surface sheet is the surface shape (for example, a flat shape or uneven shape) of the surface sheet facing the wearer's skin (hereinafter also referred to as “wearer facing surface”) and the fibers constituting the surface sheet. The type (for example, fiber thickness (dtex), etc.).

  As the surface shape of the wearer facing surface of the topsheet, various types have been proposed so far in the technical field. For example, as shown in FIG. 1, the most common surface sheet 1a has a wearer facing surface 2 that is flat. As for the surface sheet 1b shown in FIG. 2, the wearer facing surface 2 has a grooving shape. Specifically, the top sheet 1b is composed of a single liquid-permeable sheet. The liquid-permeable sheet has a flange 3a extending in one direction and a groove 3b extending in the same direction as the flange 3a. Alternatingly arranged. Thereby, the wearer facing surface 2 of the topsheet 1b has a corrugated shape when viewed in a direction orthogonal to the extending direction of the flange 3a and the groove 3b.

  Similar to the topsheet 1b shown in FIG. 2, the topsheet 1c shown in FIGS. 3A to 3C has a flange 3a and a groove 3b. In the surface sheet 1b shown in FIG. 2, the flange 3a and the groove 3b have the same thickness, but in the surface sheet 1c shown in FIGS. 3 (a) to 3 (c), the flange 3a is It is comprised from the site | part with relatively large thickness in the surface sheet 1c, and the groove part 3b is comprised from the site | part with relatively small thickness in the surface sheet 1c. Moreover, in Fig.3 (a), in the cross section in the direction (direction shown by X in the figure) orthogonal to the extending direction, the collar part 3a has a smooth curve in which the wearer facing surface 2 is convex upward. It has a contour to draw. On the other hand, a surface 2 ′ opposite to the wearer facing surface 2 has a contour that draws a smooth and gentle curve convex downward. In FIG. 3 (b), the surface 2 'opposite to the wearer facing surface 2 has a contour that forms a smooth and gentle curve that is convex upward. In FIG. 3C, the surface 2 'opposite to the wearer facing surface 2 is a flat surface.

  The topsheet 1d shown in FIG. 4 has a plurality of first protrusions 4a that protrude to the wearer facing surface 2 side. The first projecting portion 4a has a space formed by opening the absorber facing surface 2 'side. The topsheet 1d has a plurality of second protrusions 4b that protrude toward the absorber-facing surface 2 '. As for the 2nd protrusion part 4b, the wearer opposing surface 2 side is open | released and the space is formed. The first and second projecting portions 4a and 4b are arranged alternately and continuously along each of two different directions intersecting each other in plan view, for example, over the entire surface sheet 1d. The two different directions are, as a specific example, an X direction that is one direction of a different direction and a Y direction that is another direction different from the X direction. In the form shown in FIG. 4, the convex part seen from the wearer facing surface 2 side is the first projecting part 4a, and the concave part is the second projecting part 4b. Conversely, the convex portion viewed from the absorber facing surface 2 ′ is the second protruding portion 4 b, and the concave portion is the first protruding portion 4 a. Therefore, a part is shared by the 1st protrusion part 4a and the 2nd protrusion part 4b. The first and second projecting portions 4a and 4b have top portions 4aT and 4bT, respectively. The top portions 4aT and 4bT are formed in a round truncated cone shape or a hemispherical shape.

  Unlike the conventional surface sheets, the surface sheet 1e shown in FIG. 5 is composed of a laminate of two sheets. Specifically, in the topsheet 1e, the laminated first sheet 5a and second sheet 5b are partially joined to form a plurality of joints 6, and the first sheet 5a is composed of the plurality of joints. 6 is a composite sheet that protrudes in a direction away from the second sheet at the non-joined portion surrounded by 6 and has a large number of hollow convex portions 7 inside. The convex part 7 protrudes to the wearer facing surface 2 side of the topsheet 1e. The absorber facing surface 2 'side of the topsheet 1e is substantially flat. The inside of the convex part 7 is hollow. The convex portion 7 has a rectangular bottom surface. Moreover, the convex part 7 is a flat rectangular parallelepiped or a truncated quadrangular pyramid whose ridgeline is rounded as a whole. On the other hand, the junction 6 is also rectangular. The convex portions 7 and the joint portions 6 are arranged alternately and in a row in one direction. Specifically, in FIG. 5, the convex portions 7 and the joint portions 6 are alternately arranged along the X direction to form a row. The same applies to the Y direction, and the convex portions 7 and the joint portions 6 are alternately arranged along the Y direction to form a row.

  Any absorptive article which has each above-mentioned surface sheet 1a-1e is used for the evaluation method of the present invention. In the present invention, an absorbent article provided with a surface sheet having various surface shapes is used, and the friction coefficient between the absorbent article and the skin is measured. In the present invention, prior to the measurement of the friction coefficient, it is important that the absorbent sheet absorbs artificial urine to keep the surface sheet wet. Thus, the friction coefficient between the absorbent article and the skin can be measured in a state closer to the actual wearing environment. As a result, the skin condition can be accurately evaluated.

  Known artificial urine can be used as artificial urine to be absorbed by the absorbent article. For example, artificial urine having the composition described in paragraph [0025] lines 11 to 16 of JP2009-178411A can be used. This artificial urine is 1.94% by mass of urea, 0.795% by mass of sodium chloride, 0.11% by mass of magnesium sulfate, 0.062% by mass of calcium chloride, 0.197% by mass of potassium sulfate, Red No. 2 (dye) 0.010% by mass, water 96.88% by mass and polyoxyethylene lauryl ether (about 0.07% by mass), and the surface tension was adjusted to 53 ± 1 dyne / cm (23 ° C.).

  For artificial urine, the absorbent article is spread horizontally in a flat state with the top sheet facing upward, and 120 g is injected in a lump in that state, and left for 10 minutes after the injection is completed. An injection amount of 120 g is particularly preferred when the absorbent article is a disposable diaper, typically for the M size.

  When the artificial urine is absorbed by the absorbent article, the artificial urine is supplied to a position at a substantially central portion in the longitudinal direction and the width direction of the absorbent body in a state where the top sheet is directed upward in the vertical direction. Once the total amount of artificial urine is absorbed, in order to acclimatize the absorbent article, it is allowed to acclimate by leaving it in an environment of 15 ° C to 25 ° C and 30% RH to 70% RH for 5 minutes to 30 minutes. I do.

  As described above, after the artificial urine is absorbed by the absorbent article to make the surface sheet wet, the coefficient of friction with the skin is measured. Considering that the evaluation method of the present invention relates to the quality of the skin condition at the wearing site when the absorbent article is worn, the body part used for measuring the friction coefficient is absorbent. Most preferably, the site where the article is worn is used. That is, it is most preferable to select a human waist, buttocks, groin, lower abdomen, etc. as the body part and measure the friction coefficient with the skin of the part. However, it often takes time to measure the coefficient of friction between the skin at these sites and the absorbent article. Therefore, as a result of intensive studies by the inventor, it has been found that when a human adult forearm is used as an alternative part of these parts, the reproducibility of the evaluation result is high and the evaluation can be performed with high accuracy. In particular, the inner side of the human forearm is advantageous in that the accuracy of the evaluation method of the present invention is further improved because the state of the lumbar region, the buttocks, and the skin are similar.

  When a human forearm is used to measure the coefficient of friction between the absorbent article and the skin, the forearm is washed before measurement, and the part that comes into contact with the absorbent article is cleaned, and then the part is acclimated. Washing is performed, for example, by lathering a commercially available mild facial cleanser to thoroughly wash the forearm and thoroughly rinsing with water. Thereafter, the measurement site is lightly wiped with Kim Towel (registered trademark) manufactured by Nippon Paper Crecia Co., Ltd. Then, it is made to acclimatize for 20 minutes or more and 60 minutes or less in an environmental variable room of 15 degreeC or more and 25 degrees C or less and 30% RH or more and 70% RH or less.

  For measurement of the coefficient of friction between the absorbent article and the skin, for example, a commercially available tactile meter equipped with a strain gauge can be used. Specifically, “Tribogear Series Portable Tactile Meter Type 33” available from Shinto Scientific Co., Ltd. can be used. However, the present invention is not limited to this apparatus, and it is not impeded to measure the coefficient of friction using another apparatus.

  FIG. 6 schematically shows the measurement state of the coefficient of friction using the portable tactile meter. The tactile meter 100 includes a measurement unit main body 101 and a movable stage 102 disposed on the upper side thereof. The movable stage 102 has a structure capable of uniaxial or biaxial movement. On the movable stage 102, the absorbent article A to be measured is placed. Absorbent article A is fixed to movable stage 102 with its top sheet oriented vertically upward. Therefore, the absorbent article A operates together with the operation of the movable stage 102.

  When the absorbent article A is fixed on the movable stage 102 in this way, the human forearm B is placed on the surface sheet of the absorbent article A. At this time, as shown in FIG. 6, it is reliable to place the forearm B on the absorbent article A so that the inner part of the forearm and the central part of the elbow and the wrist are in contact with the absorbent article A. It is preferable from the viewpoint that high evaluation can be performed. At this time, the forearm B is kept in a state of being simply placed on the absorbent article A.

  In a state where the forearm B is placed on the absorbent article A, it is preferable to keep the forearm B as horizontal as possible from the viewpoint of performing highly reliable evaluation. For this purpose, a jack (not shown) is used, and the height of the movable stage 102 of the tactile meter 100 is adjusted to be approximately the same. The part may be supported. A skilled subject often does not need to support his hand with a jack.

As described above, the absorbent article A is placed and fixed on the movable stage 102 of the tactile meter 100. In contrast, the forearm B placed on the absorbent article A is: The absorbent article A is in an unfixed state. That is, the forearm B is simply placed on the absorbent article A. The reason for this is to make the relationship between the absorbent article A and the forearm B as close as possible to the relationship between the absorbent article in the actual wearing state and the skin at the wearing site. For this purpose, it is preferable that the degree of pressure applied to the absorbent article A by placing the forearm B is 196 Pa ( ² gf / cm ² ) or more, particularly 245 Pa (2.5 gf / cm ² ) or more. . Specifically, the degree of pressure is 196Pa (2gf / cm ²⁾ or more 392Pa (4gf / cm ²⁾ or less, particularly 245Pa (2.5gf / cm ²⁾ or more 294Pa (3gf / cm ²⁾ forearm as to become less It is preferable to place B on the absorbent article A.

  When the absorbent article A and the forearm B are set in the above state, the movable stage 102 of the tactile meter 100 is operated to move the absorbent article A on the movable stage 102 with respect to the forearm B. Note that the forearm B is not moved at this time. The direction of movement of the absorbent article A relative to the forearm B may be uniaxial or biaxial in accordance with the movement direction of the movable stage 102. As a result of the inventor's study, when the absorbent article A is reciprocated back and forth along the longitudinal direction of the forearm B, that is, along the direction connecting the wrist and the elbow, it is relatively simple and has high reliability. It was found that the evaluation can be performed.

  When the absorbent article B is reciprocated in the uniaxial direction along the longitudinal direction of the forearm B, the vibration width of the reciprocating movement, that is, the state in which the absorbent article A has moved to the most wrist side and the absorbent article A has the most elbow The vibration width, which is the amount of movement in the state of moving to the side, is preferably 15 mm or more and 30 mm or less, and particularly preferably 20 mm or more and 25 mm or less.

  On the other hand, the period of movement of the absorbent article A in the uniaxial direction is preferable on the condition that the vibration width of movement is within the above range. Specifically, this period is preferably 2 seconds or more and 4 seconds or less, and particularly preferably 2 seconds or more and 3 seconds or less.

  The reciprocating motion in the uniaxial direction with the above cycle is preferably performed 10 times or more and 20 times or less, particularly preferably 10 times or more and 15 times or less.

  The physical quantity measured by the tactile meter 100 is a frictional force. The coefficient of friction is determined by dividing this value by the load. The friction coefficient is measured by preparing six different types of absorbent articles and targeting six different subjects. The arithmetic average value is used as the friction coefficient value.

  Based on the magnitude of the value of the friction coefficient obtained by the above procedure, the quality of the skin condition at the wearing site is evaluated when it is assumed that the absorbent article used for the measurement is worn. As a specific example of the quality of the skin condition, it is possible to determine how much redness is likely to occur on the skin when the absorbent article is attached. When a wet absorbent article is worn for a long time, the amount of moisture in the skin increases and the skin tends to become over-hydrated. In such a state, the foreign substance permeability of the skin is high. When rubbing by the absorbent article occurs on the skin in such a state, the skin is likely to be reddish. In the case of an absorbent article that hardly rubs, redness is unlikely to occur on the skin. Since the degree of ease of rubbing with the skin is caused by the magnitude of the coefficient of friction of the absorbent article, the fact that the coefficient of friction of the absorbent article is small means that the wearing site is assumed when the absorbent article is worn. This means that the skin condition can be evaluated as being good. Conversely, a large coefficient of friction of the absorbent article means that it can be evaluated that the skin condition at the wearing site is not good.

  According to the present inventors, the quality of the skin condition at the site where the absorbent article is worn can be evaluated more accurately based on the correlation with the amount of exfoliation of the skin when the absorbent article is rubbed against the skin. It became clear as a result of examination. The larger the value of the stratum corneum peeling amount, the larger the value, the more the stratum corneum peels, the skin foreign matter permeability increases, and the redness of the skin increases. And since there is a correlation between the amount of exfoliation of the stratum corneum and the degree of skin redness, if a calibration curve representing the correlation between the coefficient of friction and the amount of exfoliation of the stratum corneum is prepared in advance, the coefficient of friction of a certain absorbent article is By measuring by the above method, it is possible to quantitatively predict the degree of occurrence of redness, which is the condition of the skin when the absorbent article is worn, without actually putting the absorbent article on the subject. it can.

  The stratum corneum peeling amount is measured by the following method. First, artificial urine is absorbed into the absorbent article by the same procedure as the absorbent article wetting operation performed at the time of measuring the coefficient of friction, and then acclimated. In addition, the skin is habituated by the same operation as the skin habituation operation performed at the time of measuring the friction coefficient. The target skin is preferably the site where the absorbent article is worn, as in the measurement of the coefficient of friction, but from the viewpoint of ease of measurement, it is preferable to acclimate the skin of the human forearm, for example. Next, as shown in FIG. 7, the acclimatized absorbent article A is attached to the bottom surface of the cylindrical weight 110 so that the surface sheet faces outward, and the absorbent article A is attached to the side surface of the weight 110. Clamp with rubber 111 and fix. The diameter of the bottom surface of the weight 110 is 50 mm. The absorbent article in this state is brought into contact with the inner side of the forearm of a human adult, and under this state, the weight 110 is moved by hand along the longitudinal direction of the forearm, and the range of 5 cm is reciprocated 30 times. Do. Next, the absorbent article A is removed from the weight 110, and the stratum corneum scraped off by the topsheet is extracted to perform protein quantification. This determines the amount of stratum corneum peeling. For protein quantification, for example, protein hydrolyzed amino acid analysis can be used.

  As described above, according to the evaluation method of the present invention, when it is assumed that the absorbent article is attached without actually attaching the absorbent article to the subject, the skin condition at the attachment site is predicted with high reliability. can do. Therefore, the evaluation method of the present invention is one of the guidelines for designing an absorbent article that is unlikely to cause skin troubles such as skin irritation.

  Absorbent articles for which the coefficient of friction is to be measured in the present invention include a wide range of products in the technical field such as disposable diapers, incontinence pads, auxiliary pads, sanitary napkins, panty liners, orimono sheets.

  As mentioned above, although this invention was demonstrated based on the preferable embodiment, this invention is not restrict | limited to the said embodiment. For example, in the above-described embodiment, a case where a plurality of types of absorbent articles mainly having different types of the surface sheet is used as an object of measurement of the friction coefficient has been described as an example, but instead of or in addition to this, Prepare the same type of absorbent article with different types and amount of skin care agent applied to it, application pattern, etc., and use these absorbent articles as objects of friction coefficient measurement. You can also evaluate the condition.

  In relation to the above-described embodiment, the present invention further discloses the following skin condition evaluation method.

  Hereinafter, the present invention will be described in more detail with reference to examples. However, the scope of the present invention is not limited to such examples.

[Example 1]
As a measurement object of the coefficient of friction, a disposable diaper made by Kao Corporation, Merry's (registered trademark) Myokyo Shunsui Air Size M (made in China) was used. The surface sheet of this diaper has many uneven | corrugated shape in one nonwoven fabric, as shown in FIG. About this diaper, the friction coefficient with respect to the forearm of a human adult was measured by the above-mentioned method. For the measurement, “Tribogear Series Portable Tactile Meter (model“ 33 fixed base type ”) manufactured by Shinto Kagaku Co., Ltd. was used. Separately from the measurement of the coefficient of friction, the amount of stratum corneum peeling of the forearm of a human adult was measured for this diaper by the method described above. The measurement was performed by 6 panelists. One diaper was measured for one panelist. The results are shown in Table 1 below. The measurement of the friction coefficient and the stratum corneum peeling amount was mainly performed using the central region of the surface sheet in the longitudinal direction and the width direction.

[Examples 2 and 3]
Instead of the diaper used in Example 1, Pampers (registered trademark) M size, which is a disposable diaper of Procter & Gamble Japan, was used (Example 2). The top sheet of the diaper has the form shown in FIG. Moreover, Mummy Poco (registered trademark) M size which is a disposable diaper of Unicharm Corporation was used (Example 3). The top sheet of the diaper has the form shown in FIG. Except this, it carried out similarly to Example 1, and measured the friction coefficient and the stratum corneum peeling amount. The results are shown in Table 1 below.

[Comparative Examples 1 and 2]
Measurement was carried out in the same manner as in Examples 1 and 2 except that artificial urine was not included in the topsheet. The results are shown in Table 1 below.

  FIG. 8 shows a graph of the results of the examples shown in Table 1. The diaper of Example 1 has a low coefficient of friction when wet and a good amount of stratum corneum peeling. As is clear from the results shown in Table 1 and FIG. 8, it is recognized that there is a positive and positive correlation between the coefficient of friction during wetting and the amount of stratum corneum peeling. When measured without wetting (comparative example), no clear correlation is seen and it is difficult to discriminate. Therefore, it can be seen that the evaluation method of the present invention is a highly reliable method.

100 Tactile meter 101 Measuring unit main body 102 Movable stage A Absorbent article B Human forearm

Claims (3)

The coefficient of friction of the absorbent article with respect to the skin by contacting the surface sheet with the skin in a state in which artificial urine is absorbed by the absorbent article having the surface sheet and the absorbent body and the surface sheet is wetted with measuring the,
Measuring the amount of exfoliation of the stratum corneum of the skin when the surface sheet in a state where artificial urine is absorbed and moistened in the absorbent article is rubbed against the skin;
Create a calibration curve representing the correlation between the stratum corneum peeling amount and the friction coefficient,
Based on the calibration curve, the more said measured friction coefficient is less absorbent article, when wearing the absorbent article, evaluates and hardly occurs redness of the skin at the wearing site, under wearing site of the absorbent article To evaluate the degree of occurrence of redness in the skin.   The evaluation method according to claim 1, wherein the friction coefficient is measured by bringing the surface sheet of the absorbent article into contact with a human forearm. With the top sheet oriented vertically upward, the absorbent article is fixed on a movable stage of a friction coefficient measuring device, and a human forearm is placed on the absorbent article,
3. The evaluation method according to claim 2, wherein the human forearm is not moved, and the absorbent article is reciprocated back and forth along the longitudinal direction of the human forearm together with the movable stage to measure the friction coefficient.

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