Method for detecting residual blood through object surface disinfection wet tissue

Abstract

The invention provides a method for detecting residual blood through object surface disinfection wet tissue, and relates to the technical field of medical environment, medical equipment and equipment surface cleaning detection. After the object surface disinfection wet tissue with the residual blood detection function is used for collecting surface samples of a medical environment, a medical instrument and equipment, the residual blood pollution degree of the surfaces of the medical environment, the medical instrument and the equipment is qualitatively, semi-quantitatively and quantitatively judged according to the color change of the object surface disinfection wet tissue with the residual blood detection function. The semi-quantitative detection calibrator comprises multiple stages of color blocks and subdivision grids, and the residual blood volume is calculated by counting the area proportion of different color blocks through visual inspection; according to the quantitative detection AI rule, wet tissue images are scanned through photography and analysis equipment, software analyzes the mapping relation between pixel RGB values and standard concentration, the method is easy and convenient to operate, large-batch data can be rapidly processed, the cost is remarkably reduced, and the method is particularly suitable for rapid pollution evaluation of medical environments, medical instruments and equipment surfaces. Meanwhile, the pirameton can generate a composite reaction with other components in the object surface disinfection wet tissue with the residual blood detection function, so that the sterilization and disinfection capability of the product is improved; through detection, the killing rate of the object surface disinfection wet tissue with the residual blood detection function on microorganisms such as staphylococcus aureus, escherichia coli and pseudomonas aeruginosa within one minute is as high as 99.999%, and the killing rate of the object surface disinfection wet tissue on poliovirus is as high as 99.99%.

Description

Technical Field

[0001] This invention belongs to the field of medical environment, medical device and equipment surface cleaning, disinfection, decontamination and detection technology, and more specifically, it relates to a method for detecting residual blood with disinfectant wipes on object surfaces. Background Technology

[0002] In the medical field, ensuring thorough and highly compliant cleaning and disinfection of complex, reusable medical surfaces, equipment, and devices by healthcare workers is a pressing issue. Residual blood is the most common form of medical contamination on medical device surfaces. Hemoglobin, being colorless, is difficult to observe on surfaces and even harder to detect quickly and accurately with instruments. Unremoved residual blood on device surfaces severely impacts subsequent disinfection and sterilization, affecting not only device usability but also, more seriously, the transmission of pathogens such as hepatitis B, HIV, and syphilis, seriously affecting the health of healthcare workers and patients. Currently, there is an urgent need for a cost-effective, efficient, rapid, and convenient detection method to address the lack of compliance among healthcare workers in cleaning, decontamination, and disinfection, especially since cleaning and disinfection in medical institutions are often outsourced to third-party personnel. According to data from the World Health Organization (WHO), healthcare workers are 4-10 times more likely to contract hepatitis B due to occupational exposure than the general population. Inadequate cleaning, disinfection, and sterilization of medical surfaces, medical devices, and medical equipment used repeatedly in clinical settings is a significant factor contributing to hospital-acquired infections and endangering patients' lives.

[0003] According to my country's "Disinfection Technical Specifications (2002 Edition)" and a series of related regulatory documents, organic matter (such as blood and protein) on the surface of instruments must be thoroughly cleaned before sterilization. Even if the sterilization procedure meets the requirements, there may still be surviving microorganisms.

[0004] In particular, residual blood contamination during the reuse of medical devices poses a significant risk to hospital infection control, and existing methods for detecting residual blood have obvious shortcomings: Immunoassay: High specificity but expensive; false negatives are common when blood volume is too large. Traditional chemical methods lack standardized quantitative means, can only make qualitative judgments, and are complex to operate, making them difficult to implement. There is an urgent need to develop a safe, low-cost, and rapid detection technology that can assess the degree of pollution in both semi-quantitative and fully quantitative ways. Summary of the Invention

[0005] To address the aforementioned technical problems, this invention provides a method for detecting residual blood on object surface disinfectant wipes, thereby resolving the aforementioned issues.

[0006] S1: Method for detecting residual blood on disinfectant wipes for object surfaces, including the following steps: S2: Wipe the surface of the object to be tested with a surface disinfection wipe with residual blood detection function; S3: Observe the color reaction within 10 minutes of standing; The presence of residual blood is determined qualitatively by the intensity of the color change: purple indicates a positive result, while no change indicates a negative result.

[0007] Preferably, the semi-quantitative detection adopts a visual inspection method, comparing the color-developed disinfectant wipes with residual blood detection function to a colorimetric card of a calibrator. The calibrator has multiple standard color blocks, each corresponding to a specific hemoglobin concentration range. The calibrator contains 255 1cm×1cm grids, and below the grids are 6 levels of standard color blocks, representing hemoglobin concentrations of 0μg, 1μg, 5μg, 10μg, 15μg, and 20μg, respectively. The visual inspection method calculates the total residue by statistically analyzing the area ratio of different concentration color blocks on the disinfectant wipes with residual blood detection function. The formula is: Total residue = Σ (color block area / standard color block area × corresponding concentration value).

[0008] Preferably, the quantitative detection employs an AI analysis method, including: acquiring wet images using photographic and analytical equipment; identifying the RGB values ​​of each pixel in the image; and calculating the total residual amount based on the RGB values ​​and a preset hemoglobin concentration function. The AI ​​algorithm calculation formula is: residual amount = Σ (pixel percentage × RGB mapping concentration value × total area of ​​the disinfectant wipes for object surfaces with residual blood detection function). A positive control experiment is required before detection to verify the effectiveness of the residual blood detection function of the disinfectant wipes for object surfaces with residual blood detection function by simulating hemoglobin spray. The object surface to be tested is the surface of a medical environment, medical device, or equipment.

[0009] Preferably, the residual blood semi-quantitative calibrator divides each grid into 4 sub-grids by dashed lines for fine-grained statistical analysis of the area of ​​the colorimetric region.

[0010] Preferably, piramycin is selected as the chromogenic substance. This type of substance can undergo a complex reaction with the components of surface disinfectant wipes with residual blood detection function to produce compounds containing amines. These compounds then react with aldehyde-containing components in the surface disinfectant wipe solution to form Schiff bases. Schiff bases are also important antibacterial agents. Their hydrophobic aromatic rings or long-chain alkyl groups can insert into the cell membrane, disrupting the lipid bilayer structure, leading to increased membrane permeability and leakage of contents. Positively charged Schiff bases can also bind to negatively charged bacterial membranes (such as phospholipid head groups), disrupting the membrane potential and inducing cell lysis. Schiff bases can also act as ligands with Fe 3+ Cu 2+When metal ions form stable complexes, they deprive bacteria of essential metal nutrients. Schiff bases can also generate reactive oxygen species (such as ·OH, H2O2) through redox cycles (e.g., quinone structures), triggering lipid peroxidation, DNA breakage, and protein oxidation, leading to bacterial death.

[0011] Based on the color development characteristics of the Pilamy hole and its corresponding substrate, this invention can detect hemoglobin content using a special calibrator and related AI software according to the depth of color development. At the same time, the Pilamy hole can also react with the components in the surface disinfection wipes with residual blood detection function to generate substances with stronger bactericidal and disinfecting capabilities, thereby improving the bactericidal and disinfecting capabilities of the surface disinfection wipes with residual blood detection function.

[0012] This method of hemoglobin determination is simpler, more convenient, safer, and more economical compared to traditional methods. Ordinary healthcare workers only need to wipe surfaces with disinfectant wipes equipped with residual blood detection capabilities to quickly determine the presence of blood contamination. Simultaneously, a semi-quantitative residual blood calibrator can be used to rapidly and semi-quantitatively determine the hemoglobin content, thus assessing the degree of blood contamination. This not only improves the efficiency of blood contamination detection and reduces related costs and time, but also reduces the risk of pathogen infection for healthcare workers and patients.

[0013] Compared with the prior art, the present invention has the following beneficial effects: This invention is based on the colorimetric reaction between the pilamyde hole and a corresponding substrate. By judging the intensity of the color development and combining it with a specially designed calibrator or related AI software, semi-quantitative or quantitative detection of hemoglobin content can be achieved. Compared with traditional detection methods, this method is simpler to operate, more convenient to use, and has higher safety and economy. Furthermore, this invention cleverly utilizes the ability of the chromogenic substance—pilamyde hole—to react with components in surface disinfectant wipes with residual blood detection function, generating substances with stronger bactericidal and disinfecting capabilities, thus improving the bactericidal and disinfecting ability of the surface disinfectant wipes with residual blood detection function.

[0014] Ordinary medical staff only need to wipe the surface to be tested with disinfectant wipes that have residual blood detection function to quickly determine whether the surface is contaminated with blood. When combined with a semi-quantitative residual blood calibrator or related AI software, the hemoglobin content can be quickly measured semi-quantitatively or quantitatively, thus clarifying the degree of blood contamination. This invention not only effectively reduces the cost of blood contamination detection, shortens the detection time, and improves detection efficiency, but also significantly improves medical staff's compliance with the cleaning and disinfection procedures for medical environments, medical devices, and equipment, reducing the risk of pathogen infection of medical staff and patients, and has high practical application value.

[0015] Meanwhile, this method also provides new tools and perspectives for studying blood-borne diseases (such as hepatitis B and HIV). Precise assessment of residual blood on the surfaces of medical devices and equipment helps to deepen our understanding of the transmission mechanisms and pathways of these diseases, and provides crucial scientific evidence for tracing the source of outbreaks and developing effective prevention and control strategies. Attached Figure Description

[0016] Figure 1 This is a graph showing the residual blood protein content and OD value of the present invention; Figure 2 This invention provides a quantitative colorimetric method for obtaining RGB value diagrams corresponding to semi-quantitative amounts of different residual blood proteins. Figure 3 This is a schematic diagram of the measurement using the lattice calibrator of the present invention; Figure 4 This is a schematic diagram of an example of the calibrator of the present invention; Figure 5 This invention aims to display and detect RGB values ​​of hemoglobin. Figure 6 This is a schematic diagram of the detection value structure of the AI ​​software of this invention.

[0017] Figure 7 This is a schematic diagram of the microbial killing index of the surface disinfection wipes with residual blood detection function of the present invention. Detailed Implementation

[0018] The embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples. The following examples are for illustrative purposes only and should not be construed as limiting the scope of the invention.

[0019] Please see Figure 1 - Figure 7 This invention provides a method for detecting residual blood on object surfaces using disinfectant wipes, comprising the following steps: Wipe the surface of the object to be tested with a surface disinfectant wipe that has a residual blood detection function. Observe the color reaction within 10 minutes; The presence of residual blood is determined qualitatively by the intensity of the color change: purple indicates a positive result, while no change indicates a negative result.

[0020] Semi-quantitative detection uses a visual method, comparing the color-developed disinfectant wipes with residual blood detection function to a colorimetric card from a calibrator. The calibrator has multiple standard color blocks, each corresponding to a specific hemoglobin concentration range. The calibrator contains 255 1cm×1cm grids, with 6 levels of standard color blocks below the grids, representing hemoglobin concentrations of 0μg, 1μg, 5μg, 10μg, 15μg, and 20μg, respectively. The visual method calculates the total residue by statistically analyzing the area ratio of different concentration color blocks on the disinfectant wipes with residual blood detection function. The formula is: Total residue = Σ (color block area / standard color block area × corresponding concentration value).

[0021] Quantitative detection employs AI analysis, including: acquiring images of disinfectant wipes with residual blood detection function on object surfaces using photographic and analytical equipment; identifying the RGB values ​​of each pixel in the image; and calculating the total residual amount based on the RGB values ​​and a preset hemoglobin concentration function. The AI ​​algorithm calculation formula is: Residual amount = Σ (pixel percentage × RGB mapping concentration value × total area of ​​disinfectant wipes with residual blood detection function on object surfaces). A positive control experiment is required before detection to verify the effectiveness of the residual blood detection function of the disinfectant wipes on object surfaces using residual blood detection function by simulating hemoglobin spray. The object surfaces to be tested are medical object surfaces, equipment surfaces, and instrument surfaces.

[0022] The residual blood semi-quantitative calibrator divides each grid into four sub-grids by dashed lines, which is used to refine the statistical analysis of the area of ​​the colored region.

[0023] Experimental materials: 1) Surface disinfectant wipes with residual blood detection function; 3) Positive control solution – simulated hemoglobin spray; 4) Residual blood semi-quantitative calibrator.

[0024] (I) Positive control experiment: Purpose of testing: To determine the effectiveness of surface disinfectant wipes with residual blood detection function.

[0025] Detection method: Take a surface disinfectant wipe with residual blood detection function, and spray 1-2 sprays of positive control solution—simulated hemoglobin spray—on the wipe. Observe the color change of the wipe within 10 minutes. If purple appears on the wipe, it is a positive result, indicating that the colorimetric reaction of the wipe is effective.

[0026] (II) Qualitative and semi-quantitative detection methods for surface disinfection wipes with residue detection function: A. The sampling and testing method for surface disinfectant wipes with residual blood detection function involves wiping the area to be tested with the surface disinfectant wipes with residual blood detection function and observing the color change within 10 minutes. The target objects for sampling with surface disinfectant wipes with residual blood detection function are all medical object surfaces, equipment and instrument surfaces.

[0027] B. Qualitative determination: When the color of the disinfectant wipes with residual blood detection function appears as any color on the standard colorimetric card on the residual blood semi-quantitative calibrator, the object being tested is determined to be positive for residual blood; when the color of the disinfectant wipes with residual blood detection function does not change significantly, the residual blood content of the object being tested is determined to be less than the minimum detection limit, and the residual blood test is negative.

[0028] C. Semi-quantitative visual inspection method: The color of the surface disinfectant wipes with residual blood detection function is visually compared with the semi-quantitative color block on the colorimetric card of the semi-quantitative residual blood calibrator. The total residual blood content of the surface disinfectant wipes with residual blood detection function can be calculated according to the following calculation logic formula: The range of residual blood content on the test site is the range of residual blood content where the purple color depth on the surface disinfectant wipes with residual blood detection function is similar to that on the colorimetric card of the semi-quantitative residual blood visual calibrator. The number of each color depth range is accumulated and multiplied by the residual blood content of this range. Finally, the total residual blood protein content of each different range is accumulated, which is the total residual blood protein content of the sample taken by the surface disinfectant wipes with residual blood detection function.

[0029] D. Quantitative AI software calculation method: When the sample size is large and the contamination level is high, the workload of visual inspection is huge. Based on the same logic as visual inspection, the calculation logic formula can be used to automatically calculate the RGB values ​​of the color blocks of the disinfectant wipes with residual blood detection function on the object surface through electronic scanning and AI software, and automatically and semi-quantitatively calculate the total amount of residual blood of the disinfectant wipes with residual blood detection function on the object surface.

[0030] E. This AI software incorporates RGB value functions for samples of different hemoglobin standard concentrations. Using photographic and analytical equipment, images of disinfectant wipes with residual blood detection capabilities are acquired. The software statistically analyzes the proportion (Xi) of pixels with different RGB values ​​in the image and correlates the RGB value of each pixel with the RGB function of the standard concentration sample to obtain the hemoglobin concentration (Yi) corresponding to different pixels. The area of ​​the disinfectant wipes with residual blood detection capability is known to be 255 cm². 2 The formula for residual blood protein content in surface disinfectant wipes with residual blood detection function is as follows: HGB (μg) = .

[0031] F. The system automatically calculates the quantitative value of residual blood clots, and the error is about 5% to 8% after comparison with the actual weighing.

[0032] Semi-quantitative visual inspection of residual blood: The semi-quantitative visual calibrator for residual blood (hereinafter referred to as the calibrator) consists of 255 calibrators, each measuring 1.0cm × 1.0cm = 1.00cm. 2 It consists of a grid pattern, with six standard color charts of different color systems below the grid. The area of ​​each standard color patch on the color chart is 1.0cm × 1.0cm = 1.00cm. 2 .

[0033] A. Correlation analysis between residual blood content and OD value: like Figure 1 Disinfectant solution A for surface disinfection wipes with residual blood detection function was divided into 10 groups of 15ml each. Different masses of hemoglobin were added to each group, and the OD value (wavelength 510nm) was measured using a spectrophotometer. The hemoglobin content corresponding to the OD values ​​of the 10 samples was obtained, and the relevant regression analysis data and curves were compiled (see...). Figure 1 (R=0.99, P<0.01) B. Determine the color patch range and RGB value of the color patch corresponding to the residual blood content: like Figure 2 While measuring the OD value and hemoglobin of 10 15ml samples, 15μl of the mixed colorimetric solution of sample 1 (1μg hemoglobin), sample 5 (5μg hemoglobin), sample 8 (10μg hemoglobin), sample 9 (15μg hemoglobin), and sample 10 (20μg hemoglobin) were respectively pipetted and added to 5 1cm tablets. 2 Five corresponding color patches were obtained on the dry and wet wipes. After drying with hot air, the color changes were observed within 1 to 5 minutes, and photos were taken to record the results. Finally, the color system of the photos was printed into a semi-quantitative colorimetric card for residual blood, and the corresponding RGB values ​​were obtained. Based on the RGB values, semi-quantitative colorimetric cards for residual hemoglobin in different ranges can be prepared or printed. This allows observers to visually and semi-quantitatively determine the residual content on the surface disinfection wipes with residual blood detection function by looking at the color patches on the colorimetric card. Alternatively, the residual blood content can be automatically identified and quantitatively calculated by AI software through electronic photography or scanning.

[0034] Table 1. Semi-quantitative analysis of different residual blood proteins in different color patches of disinfectant wipes with residual blood detection function on object surfaces using quantitative colorimetry, and comparison of corresponding RGB values.

[0035] C. Fabrication of the lattice calibrator: Figure 3 The total area of ​​the grid is 15cm × 17cm = 255cm². 2 The length and width of the surface disinfectant wipes with residual blood detection function are the same, as is the total area. The total number of grids is 15 × 17 = 255, and the area of ​​each grid is 1 cm². 2 To facilitate visual observation, the total amount of residual blood detected on disinfectant wipes with residual blood detection function was manually and semi-quantitatively counted per 1cm. 2 The grid is further subdivided into four smaller grids by dotted lines to facilitate visual identification and accumulation of smaller color blocks. Below the 255 grids are six 1cm blocks. 2 The different shades of purple in the squares represent 0μg, 1μg, 5μg, 10μg, 15μg, and 20μg, respectively.

[0036] D. Semi-quantitative calculation method for residual blood See Figure 4 The semi-quantitative sampling method for surface disinfectant wipes with residual blood detection function is as follows: After wiping and developing the surface with the disinfectant wipes, place the colored wipes under a calibrator and compare them with the different colored patches on the colorimetric card indicating different amounts of residual blood protein. Count the number of different colored patches on the wipes and semi-quantitatively calculate the amount of residual hemoglobin. The formula for the residual blood protein content of surface disinfectant wipes with residual blood detection function is as follows: HGB(μg) = + .

[0037] E. Semi-quantitative calculation method using AI software The AI ​​software incorporates RGB value functions for samples of different hemoglobin standard concentrations. It acquires images of disinfectant wipes with residual blood detection capabilities from object surfaces using camera and analysis equipment. The software then calculates the proportion (Xi) of pixels with different RGB values ​​in the image and correlates the RGB value of each pixel with the RGB function of the standard concentration sample to obtain the hemoglobin concentration (Yi) corresponding to different pixels. The area of ​​the disinfectant wipes with residual blood detection capability is known to be 255 m². 2 The formula for residual blood protein content in surface disinfectant wipes with residual blood detection function is as follows: HGB (μg) = .

[0038] Example 1. When comparing the surface disinfectant wipes with residual blood detection function and the colorimetric card, the surface disinfectant wipes with residual blood detection function had a 1cm colorimetric patch indicating 1μg of residual blood protein on the colorimetric card. 2When using color blocks, the semi-quantitative amount of residual blood on the surface disinfectant wipes with residual blood detection function is 1 μg. If there are two such color blocks, the semi-quantitative amount of residual blood on the surface disinfectant wipes with residual blood detection function, HGB (μg), is = 1 × 1 (μg) + 1 × 1 (μg) = 2 μg. However, if the surface disinfectant wipes with residual blood detection function have a color chart showing 1 μg, but the area is less than one grid, only 1 / 4 of a grid (the small grid with dotted lines), and there are a total of 8 such color blocks, then the semi-quantitative amount of residual blood on the surface disinfectant wipes with residual blood detection function is: HGB(μg)=0.25×1(μg)+0.25×1(μg)+0.25×1(μg)+0.25×1(μg)+0.25×1(μg)+0.25×1(μg)+0.25×1(μg)+0.25×1(μg) =2μg.

[0039] Example 2. When comparing the color patches on a surface disinfectant wipe with residual blood detection function and a colorimetric card, if the surface disinfectant wipe with residual blood detection function has a 1cm² color patch indicating 1μg of residual blood protein from the colorimetric card, the semi-quantitative amount of residual blood on the surface disinfectant wipe with residual blood detection function is 1μg. If there are two such color patches, and the surface disinfectant wipe with residual blood detection function also has a 1μg color patch from the colorimetric card, but the area is less than one square, only 1 / 4 of a square (the small square with the dotted line), and there are a total of 4 such color patches, the semi-quantitative amount of residual blood on the surface disinfectant wipe with residual blood detection function is: HGB(μg)=0.25×1(μg)+0.25×1(μg)+0.25×1(μg)+0.25×1(μg)=2μg.

[0040] Example 3. (As follows) Figure 4 Place the surface disinfectant wipes with residual blood detection function into the designated squares on the calibrator. By comparison: the surface disinfectant wipes with residual blood detection function have 19 complete color patches and 14 quarter-size color patches on the colorimetric card for 1ug residual blood protein; 4 complete color patches for 5ug residual blood protein on the colorimetric card; 7 complete color patches and 15 quarter-size color patches for 10ug residual blood protein on the colorimetric card; and 2 complete color patches and 5 quarter-size color patches for 15ug residual blood protein on the colorimetric card.

[0041] At this point, the residual blood in the surface disinfectant wipes with residual blood detection function is semi-quantitatively measured: HGB(μg)=19×1(μg)+14×0.25×1(μg)+4×5(μg)+7×10(ug)+15×0.25×10(ug)+2×15(ug) =180(μg).

[0042] The embodiments of the present invention are given for illustrative and descriptive purposes only, and are not intended to be exhaustive or to limit the invention to the forms disclosed. Many modifications and variations will be apparent to those skilled in the art. The embodiments were chosen and described in order to better illustrate the principles and practical application of the invention, and to enable those skilled in the art to understand the invention and to design various embodiments with various modifications suitable for a particular purpose.

Claims

1. A method for detecting residual blood on a surface disinfectant wipe of an object, the method comprising: The method comprises the following steps: S1: using the object surface disinfection wet wipes with residual blood detection function to wipe the surface of the object to be tested; S2: standing and observing the color reaction; S3: qualitatively determining the presence of residual blood by the presence or absence of color development: positive if purple appears, and negative if there is no change; semi-quantitatively or quantitatively determining the content of residual blood by the color depth.

2. The method of claim 1, wherein: The semi-quantitative detection uses visual inspection method, comparing the colored object surface disinfection wet wipes with residual blood detection function with the colorimetric card of the calibration device, the calibration device is provided with a plurality of standard color blocks, each color block corresponds to a specific hemoglobin concentration interval.

3. The method of claim 2, wherein: The calibration device contains 255 1cm×1cm grids, and 6 standard color blocks are arranged below the grids, representing 0μg, 1μg, 5μg, 10μg, 15μg and 20μg hemoglobin concentration respectively.

4. The method of claim 3, wherein: The visual inspection method calculates the total residual amount by counting the area ratio of different concentration color blocks on the object surface disinfection wet wipes with residual blood detection function, the formula is: total residual amount = Σ(color block area / standard color block area×corresponding concentration value).

5. The method of claim 1, wherein: The quantitative detection uses AI analysis method, which comprises: 1): obtaining the image of the object surface disinfection wet wipes with residual blood detection function through photography and analysis equipment; 2): identifying the RGB value of each pixel point in the image; 3): calculating the total amount of residual blood based on the RGB value and the preset hemoglobin concentration function relationship.

6. The method of claim 5, wherein: The AI algorithm calculation formula is: residual amount = Σ(pixel point ratio×RGB mapping concentration value×total area of object surface disinfection wet wipes with residual blood detection function).

7. The method of claim 1, wherein: Positive control test is required before detection, which verifies the effectiveness of the object surface disinfection wet wipes with residual blood detection function in detecting residual blood by simulating hemoglobin spray.

8. The method of claim 1, wherein: The surface of the object to be tested is the surface of medical environment, medical equipment and devices.

9. A residual blood semi-quantitative calibrator according to claim 3, characterized in that: Each grid is divided into four sub-grids by dotted lines for fine statistical color development area.

10. The use of the method according to any one of claims 1-9 in evaluating the cleaning effect of the surface of medical environment, medical equipment and devices.

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