KR20060004003A - Precision chopping device for diagnostic instrument for helicobacter pylori with photoacoustic spectroscopy - Google Patents

Abstract

The present invention relates to a 60 Hz, 5 V square wave signal generation circuit, a sinusoidal conversion and voltage amplification circuit, a synchronous motor, a chopper device comprising a chopper vane and a method of shielding light at exactly 10.16 Hz. This device can be applied to the photoacoustic spectroscopy device which requires high sensitivity by shielding light very accurately for the diagnosis of Helicobacter pylori infection.

Signal conversion, frequency amplification, precision

Description

Precise chopping device for diagnostic instrument for helicobacter pylori with photoacoustic spectroscopy             

1 is a signal conversion circuit diagram according to an embodiment of the present invention;

2 is an amplifier circuit diagram according to one embodiment of the present invention;

3 is a schematic view showing a chopper drive device according to an embodiment of the present invention;

4 is a schematic diagram of a performance comparison device according to an embodiment of the present invention;

5 is a graph showing a comparison between the error using the existing signal generator and the error of the device according to an embodiment of the present invention

The present invention relates to a 60 Hz, 5 V square wave signal generation circuit, a sine wave conversion and voltage amplification circuit, a synchronous motor, a chopper device comprising a chopper blade and a method of shielding light at exactly 10 Hz.                         

Helicobacter pylori is a Gram-negative bacterium with a spiral torso and flagella, first identified by Dr. Warren and Dr. Marshell in 1983. , 127-1275, 1983).

To date, Helicobacter pylori has been recognized as a causative agent of gastric cancer, including gastritis, gastric ulcer and duodenal ulcer, and is known to be involved in the development and recurrence of chronic gastritis and peptic ulcer (Lancet 1984, 1, 1311-1314, Gastroenterology Vol.92 , No5, Part 2, 1518, J. Clin Pathol 1986, 39, 353-365, Gastroeterology 1987, 93, 371-383). In addition, according to Blasser (Reviews of Infectious Diseases 1991, 13 (Suppl 8), S704-708), Helicobacter pylori infection is closely related to duodenal ulcer and gastric ulcer, and Schubertt Helicobacter pylori infection was reported in 85% of duodenal ulcers, 53% of gastric ulcers, 50% of duodenitis, 28% of reflux esophagitis, 29% of gastritis, and 43% of non-ulcer dyspepsia (Am. J. Gastroenterol, 1989, 84 , 637-642).

As described above, as Helicobacter pylori has been found to be closely related to gastrointestinal diseases, the importance of Helicobacter pylori infection diagnosis is increasing.

In general, a test for diagnosing a disease should be fully utilized in a clinic, and thus, it should be an easy and convenient method of high sensitivity and specificity, economical, and pain-free. In this way, Helicobacter pylori infection diagnosis is largely used by invasive and non-invasive tests.

Invasive methods include bacteriological test, biopsy, rapid urease test (RUT test), etc. Noninvasive methods include serological test and urea breath test (13C-urea breath test). It is used.

However, in order to implement an invasive method, there is a difficulty in performing endoscopy in all patients, and a disadvantage in that the examination process is complicated and expensive. In particular, the bacterial culture test has a difficulty in culturing the biopsy tissue under difficult conditions, the biopsy has the difficulty of requiring an experienced, skilled experimenter.

On the other hand, the non-invasive serological test of the patient is better than the invasive method, but the antibody does not form early in the early stages of Helicobacter pylori infection can come out negative, and serum titers of antibodies after the bactericidal therapy Stomach instability may be due to instability. In addition, it takes more than six months before the antibody titer falls after treatment, and there is some difficulty in clinical application to confirm the success after Helicobacter pylori eradication treatment.

Accordingly, research on urea breath test has been actively conducted in recent years as a diagnostic method that is excellent in sensitivity and specificity without causing discomfort to a test subject.

For example, the method described in US Pat. No. 4,830,010 (January 1, 1989), as described above, produces a carbon dioxide and ammonia by hydrolyzing the surrounding elements to produce carbon dioxide and ammonia by releasing urease that is not present in mammals. It uses the surviving trait. That is, a method of analyzing the presence of ammonia and carbon dioxide, which are hydrolysis products of the urea, has been proposed after administering urea to a test subject. The document also discloses a method for detecting hydrolysis products of urea by using urea labeled ¹³ C, ¹⁴ C, ¹⁵ N or by measuring pH changes due to the production of ammonia. . However, the method described in this document makes it difficult for the solution used to administer the labeled urea to change the conditions of the gastrointestinal tract, resulting in a reliable result, and also inconvenient because the amount of the labeled urea administered depends on the weight to be administered. However, the amount is also excessive, which may cause toxicity or adverse effects on the subject to be administered.

On the other hand, the element labeled with ¹⁴ C can be easily detected by using a device such as a beta radiation detector, while the safety of the radioactivity controversy, although the amount is small, but the use is limited to children or pregnant women Repeated administration to the same patient is prohibited.

In an improved process for the method of the problems described in the above-mentioned document EP 0881491 A1 Lake to hold the similar conditions, i.e. pH in the gastrointestinal tract and the living conditions of Helicobacter pylori present in the gastrointestinal tract, an element labeled with ¹³ C A method of confirming the presence of Helicobacter pylori has been proposed by administering citric acid together with and measuring ¹³ CO ₂ from urea therefrom.

Generally, oral administration of a ¹³ C-labeled urea to a subject suspected of a Helicobacter pylori infection results in hydrolysis of urea administered by urease secreted by Helicobacter pylori to produce ¹³ CO ₂ in Helicobacter pylori infection. ¹³ CO ₂ is released through exhalation. Thereby ¹³ CO _^2/12 CO ₂ ratio is increased in the breath. On the other hand, since the urease is not secreted in the case of non-infected people, orally administered urea is excreted as it is. Accordingly element breath test is to determine whether the infection of Helicobacter pylori by determining the CO ₂ of the ¹³ CO _^2/12 CO ₂ ratio being discharged by breathing as described above as a non-invasive method. This isotope ratio is calculated according to Equation 1 below and represented as per millimeter (‰) with δ ¹³ CO ₂ value.

In the formula, R sample is the carbon dioxide isotope ratio of the sample, and R control represents the isotope ratio of the reference carbon dioxide.

In addition, the determination of infection of Helicobacter pylori is determined using a value calculated according to Equation 2 below.

In general, δ ¹³ CO ₂ (after urea administration) means the value measured at 30 minutes after urea administration, and δ ¹³ CO ₂ (prior to urea administration) is expressed as 0 minutes before the administration. In addition, if the criterion value (excess δ ¹³ CO ₂ value) is greater than δ ¹³ CO ₂ > A (wherein A is greater than the mean δ ¹³ CO ₂ value + 3 X standard deviation of the Helicobacter pylori negative subject), it is judged to be Helicobacter pylori positive. do. (Eur. J. of Gastroenterology & Hepatology 1991, 3, 915-921).

In the urea breath test, the criteria for Helicobacter pylori infection are the factors and measurement devices based on the experimental conditions such as the age and condition of the subject and the type and amount of experimental feeding used to delay the gastrointestinal tract movement during the test. Although somewhat variable by a number of factors, excess δ ¹³ CO ₂ values are generally chosen from about 2 to 7 degrees. (Eur. J. of Gastroenterol Hepatol, 1991, 3, 915-921, Eur. J. of Gastroenterol Hepatol 1998, 10, 7, 569-572, Eur. J. of Gastroenterol Hepatol, 1999, 11, 10, 1135- 1138, J. Pediatr Gastroenterol Nutr. 1999, 29, 3, 297-301).

Therefore, in order to diagnose the infection of Helicobacter pylori, such as the information to be very accurately measured to the ¹³ CO _^2/12 CO ₂ ratio the per mille (‰) unit. For this purpose, an isotope ratio mass spectrometer is used to accurately measure the molecular weights m / z 45 and m / z 44 of ¹³ CO ₂ and ¹² CO ₂ . The device can very accurately measure the ratios of ¹³ CO ₂ / CO ₂ ¹² Since the measure, discrete and separate by molecular ion with a magnetic field after ionization of CO ₂ molecules in the ionizer to the detector. However, the isotope mass spectrometer uses a high vacuum pump because it ionizes CO ₂ molecules under high vacuum conditions and separates them by molecular weight using a magnetic field, and a high voltage generator for ionizing CO ₂ is required. Due to the complexity of the device, high cost, and difficult operation of the equipment, sufficient use in clinical practice has been limited.

Complementing these shortcomings is photoacoustic spectroscopy (PAS). This method was designed by Bell in 1880 to use the phenomenon that sound waves are generated in a container when gas is put into a sealed container and irradiated with light. ¹³ CO ₂ and ¹² CO ₂ are linear molecules with the same binding force between atoms, but have different converted mass (μ) and moment of inertia, so vibration and rotation energy are different. Total when using the absorbed light energy microphone using the photoacoustic method switching to the sound signal it is possible to measure the ratio of ¹³ CO _^2/12 CO _2. This method consists of a light source, a chopper, a sample cell, an optoacoustic detector, and a lock-in amp. The light irradiated from the light source is shielded by the chopper at regular intervals and passes through the sample cell to reach the detector. Periodically, the light reaching the detector causes the pressure of the gas contained in the detector to rise and fall repeatedly. This pressure change is converted into an electric signal by the microphone, and the signal and the chopper's periodic shielding signal are used to remove and amplify the noise included in the detection signal with the lock-in amplifier.

Therefore, the accuracy of the chopper greatly affects the accuracy of the entire device. Therefore, the chopper used for the diagnosis should have a very high accuracy unlike the general chopper.

The present invention is to provide a chopper drive device that can be used in the Helicobacter pylori infection diagnosis as described above and a drive method to have an accurate shielding period 10Hz.

The drive device of the present invention has a 60 Hz square wave signal generator having a 5 V voltage and an amplifier for changing and boosting the voltage of the 60 Hz square wave signal to a 24 V AC sine wave, and a synchronous motor operated by the sinusoidal wave and two perforated chopper vanes. Characterized in that it comprises a.

Signal generator

The signal generator circuit of the present invention is shown in FIG.

The frequency generator circuit receives 500KHz square wave which periodically changes 0V and 5V output from the programmable ROM into the 7th terminal of the first division circuit and changes it to 490Hz at the 1st terminal. The second division circuit converts the 490Hz square wave input to the 10th terminal into a 60Hz squared wave which periodically changes 0V and 5V to the 6th terminal.

amplifier

The amplifier circuit of the present invention is shown in FIG.

The amplifying circuit converts the 60Hz square wave input from the second frequency divider circuit into an AC sine wave of 60Hz and 2.4V. The signal converted into an AC sine wave passes through a high frequency filter circuit for removing high frequency noise and is introduced into a first order amplifying circuit. In the primary amplification circuit, the AC voltage was amplified to 3.6 V and introduced into the secondary amplification circuit through an offset control circuit. The secondary amplification circuit is driven by DC voltage of ± 40V, and 60Hz and AC 40V are applied to the synchronous motor.

Chopper Drive

One embodiment of the chopper drive and drive confirmation device of the present invention is shown in FIG. 3. The signal generator was used by receiving ± 5V from the DC power supply, and the secondary amplification circuit was driven by receiving DC power of ± 40V from the DC power supply.

In order to confirm the driving of the chopper, a photocoupler driven by receiving 5V power from a DC power supply was used, and an output signal was detected using an oscilloscope. In order to check the accuracy of the chopper drive, the signal deviation was checked through the oscilloscope (HP 54616C (500MHz), Hewlett-Packard) connected to the photocoupler (PM-K44, SUNX), and the signal generator (FG-8002, LG Electronics) To verify the accuracy of the signal generator, we connected a signal generator.

The present invention will be described in detail through the following examples.

Example 1

Measure the accuracy of the device

In order to check the accuracy of the chopper drive by connecting the signal generator and the existing signal generator of the chopper drive device of the present invention to the amplifier, the error according to the driving frequency was measured. The chopper drive device of the present invention has a fixed drive frequency of 10.16 Hz for use in a Helicobacter pylori infection diagnostic apparatus. One embodiment of the produced device is shown in FIG. The driving frequency and the error of the chopper according to the signal inputted by the existing signal generator were prepared together with the result of the invented signal generator, which is shown in FIG. 5.

As can be seen in Figure 5, the existing signal generator showed an average error of 18.7usec, and thus the drive frequency of the chopper showed an error of 284usec on average. However, when using the invented signal generator, no signal error occurred, and the error of the chopper drive frequency was measured to be 40usec. This error corresponds to 0.41 ‰ of 10.16Hz, which can be applied to the Helicobacter pylori infection diagnosis device.

As described above, the chopper drive device according to the present invention was able to obtain a chopper drive frequency of 10.16 Hz with an error of 0.41 ‰ by using a signal generator made of a programmable ROM and a divider circuit.

In addition, in the present invention, when a synchronous motor used for driving a chopper is changed, a chopper of a frequency other than 10.16 Hz can be driven. In other words, if a synchronous motor with 100, 150, 200, or 250 revolutions per minute is used, a divider circuit can be added to the signal generator to generate signals of 20 Hz, 30 Hz, 40 Hz, and 50 Hz, from which the drive frequency of the chopper is 3.34 Hz. You can get 5Hz, 6.67Hz and 8.33Hz to shield the light at various frequencies.

Claims (5)

A chopper drive device operating at 10.16 Hz, including a programmable ROM as a signal generator and a voltage amplification circuit for driving a synchronous motor as a signal converter. The chopper drive device according to claim 1, wherein the frequency divider circuit has two frequency divider circuits connected in series. The chopper drive device according to claim 1, wherein the amplifying circuit receives a 5V square wave and outputs an AC 40V sine wave. The precision chopper device of claim 1, wherein the precision chopper device exhibits a fixed frequency after replacing a synchronous motor among the driving devices. A method of driving a precision chopper using the device of claim 1.

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