DE2162063A1 - Anticoagulant moldings and processes for their production - Google Patents

Description

PATENT LAWYERS

DR. E. WIEGAND DIPL-ING. W. NIEMANN 21620 63

DR. M. KÖHLER DIPL-ING. C. GERNHARDT

MÖNCHEN HAMBURG

TELEPHONE: 5554 76 8000 MD N CHEN 15,

TELEGRAMS: KARPATENT NUSSBAUMSTRASSE 10

. December 1971

W. 4-0 933/71

Kureha Kagaku Kogyo Kabushiki Kaisha Tokyo (Japan)

Anticoagulant moldings and processes for their production

The invention relates to an anticoagulant Shaped body comprising an electret. In particular, the invention relates to a material for use as a replacement for a living organ of an animal's body or for Use in a device for using a plastic material in the treatment of (animal blood.

Due to a number of useful properties such as good workability, toughness and flexibility, Plastic is capable of sterilization and reduced reactivity with tissues within an animal body. materials particularly suitable for use in the manufacture of artificial organs or artificial blood vessels; however, they have the serious disadvantage that they coagulate blood on their surfaces. Nonetheless to trol; ζ find different plastic materials Use for purposes in which they are associated with the

and blood from l'iuren in premature gelsmgen., j especially with blood " from Menschon

209828/0945 ÖAD ORiölNAL

Human (eg artificial blood vessels and artificial organs such as artificial hearts or artificial kidneys) _T or during storage or transport of blood, 'with the proviso that one anticoagulant compound, for example Heperin, the blood is incorporated to prevent its coagulation.

Process for improving the coagulation properties of plastic materials that are currently practiced include kneading an anticoagulant Connection into the plastics, a grafting of the same onto the surface of the plastics, a coating the surface of the plastics with graphite, the formation of a new artificial tissue (e.g. formation through Tissue culture), on the surface of the plastics, or a negative charging of the surface of the plastics. The use of an electret is one embodiment of the method for negatively charging the surface of plastics. ■ "-

The present invention relates to an anticoagulant plastic molded body, such as pipes or vessels, which are suitable for transport or storage, and which comprise an electret of a fluorine body which is obtained by irradiation with electrons. ^:

Electrets _; which have hitherto been used frequently in the field of acoustic transducers and the like are of the type of so-called thermoelectrets and are generated by heating dielectric materials above their glass transition temperature under high DC voltage. ; -and subsequent cooling produced. However, this method of making electrets has the following shortcomings. One such disadvantage is the need to use two electrodes, one positive and one negative, "suggesting the application of high-voltage direct current.

209 828/0945. BATH

-3- 2162Q63

voltage is due. Veiters is, apart from additional problem of contact with a base material, what is believed to be most important for obtaining an electret of good repeatability is the shape of the Electrodes limited, making it extremely difficult can be considered a material with a special shape, such as tubes, bottles or balls directly into a To convert electret. Also the appropriate devices are limited due to the high temperatures, which are necessary for the production of electret. Furthermore Electrification production takes a long time due to the need to make dielectric materials from to cool at high temperatures.

The electrical potential of the surface of the resulting electret is useful when used in air becomes, but decreases rapidly, at high temperatures and in the presence of water, e.g. in water, humid atmosphere, Einger's solution or blood. Therefore such electrets are unsuitable for use under such conditions.

Longstanding research and development work by Inventors of the present application in the field of "electrets have shown that by

Impingement of electrons in a riuorliarzformkörper the electret of it in any desired form immediately

. . ,,. of a period. ο / ^ · -u · ·· remotely inside from a few seconds to a few Minutes ^ without the need for electrodes and heat, can be produced. These electrets have an electrical potential that moisture, like Water, humidity, Ringer's solution or blood and is stable at clearing scraper, and even after "The course of a year did not deteriorate at all. This is in "considering the fact that electrets". . the conventional type in ■. Presence of moisture ii are easily vented and have a short lifespan ", · 3 · ί'.Γ5θ1ιοηΟ.

■■ 20982870945 BAD ORIGINAL

Shaped bodies made of fluororesin are known to coagulate less. It is surprising that electrets, which are produced from such shaped bodies, have much less coagulating properties.

Since the electret molded article according to the present invention can be manufactured in a short time without the need for electrodes and heat, any specially shaped article can be directly molded into an electret. Furthermore, the electret according to the present earth's extension due to the high stability of its electric potential and due ψ its extremely low coagulation at its with, find · on Blood the contacted surface of an extremely wide range of applications, including for artificial organs, the specific forms

require
and high accuracy /, ader transportation and storage

of blood. -..... "

The shaped bodies according to the present invention are described in more detail below.

In the accompanying drawings, FIG. 1 shows the change in the surface electrical voltage in water at JO ⁰ G of one. Electret ,, that-through

Irradiation with electron beams of 50 KeV and 100 / uA ν ajcuum and. / . · /

/ Using an electron microscope was obtained $

Fig. 2 shows the change in surface tension in the surrounding air of 4-0 ⁰ C and a relative humidity of 90% of an artificial heart valve, which obtained by irradiation with electron beams of ^l j0 KeV and 100 / uA under vacuum and using an electron microscope was4

Fig. 3 shows the distribution of the load and the change in the surface tension of an electret obtained by irradiation with electron beam of p_ en HoV and 1 mA at a Abfiorptionsdoaiy of 6 Mrad a Anor <.i · -. 16 superimposed gelatinised plates under

BATH ORIGINAL

Turn of an electron accelerator made in air was after this 30 days in the air of 80 ° C was left.

Pig. 4- shows the change in the surface tension in water at 30 ^° C. of an electret similar to a test tube, which was produced by irradiation with electron beams at 2 MeY and 1 mA at an absorption dose of 2 Mrad and using an electron accelerator in air.

The electret material used according to the invention is a fluororesin that is a homopolymer of tetrafluoroethylene or a copolymer of tetrafluoroethylene with at least one comonomer. such as vinylidene fluoride, hexafluoropropylene or trifluoromonochlorethylene.

The electret formation according to the present invention is achieved by exposing the material to irradiation with - ^ - rays, x-rays or ytf-rays, whereby electrons penetrate into the material. . If the irradiation source used is 4 "rays or X-rays are '-' the electrons penetrate the material through the Compton effect. In case of use from / 3 rays are accelerated electrons ■ used, where ^ -rays emitted directly from a radioactive isotope are used, or an electron accelerator is used.

The energy intensity of the radiation source used in accordance with the present invention is at least 10 KeV. When electron beams of relatively low energy are used, the irradiation is carried out in a vacuum. Since the electron beams have a low energy, the range of the electron beams is short, and even if the material is directly irradiated with the electron beams, the electrons do not pass through the material but are distributed in the material as electric space charge.

2 0 9 8 2 8/9 k 0 5 BAD ORJQINAi

2162053

The surface tension of the obtained electret is negative on the irradiated surface and positive on the back. Some electrets are among these Conditions stable and others will be monopolar electrets, in which the positive charge on the back decreases to a negative charge, so that both surfaces are negatively charged. Thickness. plates are converted into electrets of the former type, for example, and thin foils often become electrets of the latter type.

There is also a method in which high-energy electron beams are indirectly used will. In this case, the irradiation is carried out in air and electron beams can be used of high energy with more than 1 MeV can be used with practical advantage ^. According to this method, the Material is not directly exposed to electron beams, but rather before it is exposed to electron beams low energy produced by reducing the energies of high energies electrons to one or the other V / can be obtained to use. According to one of these proposals (Belgian patent 74-4-594-) a absorbent body of a thickness which is about the practical range given by the Feather equation is expressed, corresponds, placed between the radiation source and the material, to the greatest part of high energy electron beams, and the low energy electron beams

out of this. energy that is / are retained by the secondary emission, Another method is used./ Another dielectric method is used Body placed under the z \ i irradiating material, whereby the secondary of the material and the dielectric Body . electrons released onto the material by means of single-electric Fcld / pdas by (irradiating the dielectric body generated with electron beams is, steers back. According to these methods, stable · ■ "". ·

2 0.9 J 1 8/0945. BATH ORIGINAL

Electret achieved especially in the case of thin foils. Initially, the electret obtained by the former method polarizes into a negative charge on the irradiated surface and a positive charge on the back. On the other hand, the electret obtained by the second method polarizes into a positive charge on the irradiated surface and a negative charge on the rear side. both surfaces of which are negatively charged. It has been reported that in this way good electrets made of thin foils of about 10 ax. are thick, can be manufactured. It is not known, however, whether good electrets are made of flat-shaped. Material / of a thickness of more than 50 / U can be produced.

According to the methods mentioned above, electron beams become of high energy are not used directly, but • electron beams are relatively lower Energy .used, or the "speed of electron beams." high energy is degraded by some method prior to its use. But when such electron beams of relatively low energy or decelerated electron beams for irradiation of .. formed hollow bodies, such as pipes, bottles or spherical shapes, are used, there is a tendency to uneven irradiation, because the rays in at least need to penetrate two walls of the body. Tubular For example, bodies could be irradiated while rotating, but this will Complicated process. In fact, it's practically un-. possible to have a body of complicated shape, like a artificial heart, to be irradiated evenly.

It has now been found that excellent electrets Can be made by making a molded article in-air-directly from the irradiation with electron beam- "

209828 / .Q945 bad ORIGINAL

len of high energy. This method is very simple and works great for that practical use. According to this method, you can Electron beams of high energy directly on only one orbit

ttev

or pia / cfb if sheet-like. materials be used as basic materials, but this has not been found to be expedient. By stacking two or more web-shaped materials, which are subjected to irradiation at the same time - electrets with a high surface tension can be obtained. According to this method the unique effect of stacking the base material

\ or plates /
achieved. If spells of the same strength are used, then electrets with a higher surface tension are obtained if they are stacked in divided portions of the same strength, and these - \ parts are then subjected to irradiation with electron beams. Furthermore, base materials with a larger area result in electrets with a higher surface tension and better repeatability.

Excellent electrets are becoming increasingly popular

\ or Ρίο11en / number of stacked lanes / achieved, i.e. with increasing Thickness of the entire stack of sheets. However, if the thickness goes beyond a certain value, then the electric charge in this part decreases, and it can either no electrets with high surface tension obtained or such electrets cannot be obtained with good repeatability.

The thickness of the material that gives a high surface tension electret with good repeatability should be within the practical range of the electron beams used. J) The practical range of e.g. 2 McV electron beams is calculated using Feather's equation

2 0 9 H 2 Π / () y 4 B

BAD ORIGfNAL

Ry = 0.526 Eo - O ₇ 094 (g / cm ² )

where j> is the density and

E is the energy of the electron beams in MeV,

2
• and obtained with 0.958 g / cm. In the case of using E ¹ EP Teflon, the calculated thickness is about 0.48 cm, assuming its specific gravity is 2. With changing radiation doses, good electrets are obtained with PEP Teflon about 0.35 cm or less thick, and this thickness is about 70% of the practical range. Within such a range, it is considered that there are sufficient amounts of high energy electron beams, and the same phenomenon is observed when the amount of the absorbed rays is varied.

It can therefore be seen that the formation of good electrets

the

with high surface tension does not respond to / dose of electron beams but due to the energy of the electron beams.

This method is characterized in that in the event

direct
the / application of high energy electron beams, the secondary emission electrons are not specifically used, although this process has not yet been clarified. According to the invention, it is also possible to produce an artificial organ from a plate-like or sheet-like electret of high performance obtained by the above-mentioned method.

When using materials of the desired final shape for the production of electrets, the invention can Method can be used with particular advantage on hollow bodies. There were hollow bodies, like Tubes, bottles or balls directly with electron beams high energy irradiated, preferably within the practical pool Range of the K electroncunirahlen. Body with one that goes beyond a predetermined value Thickness were- transient Elekl, ret; e, which is in a

&, - .. 7 0 -9 8 ? f \ I 0 S) U & BAD ORIGINAL

negative charge on the surface irradiated with electrons and one- positive ^. Polarized charge on the back. It was therefore assumed that the inner surface of the molded hollow body was positively charged would be. However, when the hollow body was cut open was, and the surface tension of the inner part was also measured, surprisingly found that the body had been formed into an electret, which from the outset had a high surface tension had, and both surfaces of which were negatively charged. This means that if such a Electret is actually used as an artificial organ, the hollow portion that directly contacts blood comes, has a high negative surface tension

The radiation source used in this case is a high energy electron beam of more than 300 KeV. From the standpoint of cost in terms of the necessary devices, electron beams are from less than 10 MeV is desirable. The appropriate dose of electron beams to be absorbed is between 0.1 Mrad and 50 Mrad. Appropriate irradiation should be with an energy content within the practical range of the electron beams, and outside the practical range, electrets with good Properties cannot always be obtained with good reproducibility. So the energy strength will be according to the size and thickness of the body is determined. if Short practical range electron beams are used, the electret formation must be at the same. early rotation and movement of the irradiated Surface of the lOrmkörper made. The one for electret formation The time required ranges from a few seconds to a few minutes. Compared to the Methods for making founderen electret is required the invention very short periods of time for electret formation. In addition, the obtained Kektrebe have have a high surface tension and are stable towards moisture. __

2 0 9fl;> n / n <U6 bad original

The materials used to form electrets can be of a shape that is "suitable for the end use." is, ■ have, e.g. pipes or vessels, such as artificial Blood vessels, artificial hearts, tubes for blood transfusion or blood storage vessels. Plate-shaped Materials can be "irradiated and converted into electrets, and then processed into molded articles that are suitable for the end use, and zvrar so that the negatively charged surface is always the inner surface that comes into contact with the blood.

The properties of the electrets according to the invention in relation to blood were tested using animal blood. The blood coagulation test was carried out in vitro by the following two methods.

1. A simplified form of the Sahli-Fonio method: The blood of a rabbit is poured onto a bullet-shaped Electret with a diameter of 100 mm

of the blood, and it becomes what is needed for coagulation Time measured.

2. The Lee-White method:

One cubic centimeter of dog venous blood is put into a reagent tube-like electret with an inner diameter of 9-10 mm is brought, and the blood is inclined at a 45 ° angle every 30 seconds. the The time required for the blood to coagulate is measured.

This experiment clearly confirmed the superiority of the electret body.

According to the manufacturing conditions and the post-treatment the electrets obtained have either polarized positively charged and negatively charged surfaces (with a homogeneous or heterogeneous charge), or both surfaces have charges of the same polarity (Monoladun [- ·;). Egg; roicht however our :, if the inner ο '·

? ü 9 R UWI Cj 9 U 5

BATH ORIGINAL

Surface of the body is negatively charged.

As already shown, the production of the molded body is done s very simple according to the invention. The surface tension of the obtained electret is high and behaves like in the presence of moisture Blood, stable. Another advantage of the molded body © according to the invention is its lower tendency for blood coagulation and its lower reactivity within an animal's body. The molded body according to the invention also has a high level of resistance to Chemicals and heat, and does not need to be sterilized due to exposure to electron beams will. Even if sterilization is necessary, it can

they can be done very easily. Based on these Because of their superior properties, the molded bodies according to the invention will have a very large area of application for parts that come into contact with blood, such as artificial organs such as replacement blood vessels, artificial hearts and heart valves, vessels for blood storage, tubes or tubes for transport of blood or disposable syringes for drawing blood, and - are very promising.

The invention will now be explained in more detail with the aid of the following examples. .

example 1

A copolymer of tetrafluoroethylene and hexafluoropropylene (FEP Teflon ^ 100, trade name, Du Pont) became a shell-shaped object with a thickness of 0.5 mm, a diameter of 100 mm and an

209828/0946

1 mm diameter compression molded. Using an electron microscope was the subject of a Bestrah lung with electron beams of 100 KeV and O ^ AiA vacuum at JO subjected seconds.

The electret obtained initially had a surface tension (which with a potentiometer of the rotary sec- • fcorarfc measured at a distance between sample and electrode of 1 cm) of about 1000 V on both the positive as well as on the negatively charged surface. When the electret was placed in water of 30 ° C, they returned the charges on both surfaces change within 7 days. Then an electret was obtained with a Surface tension of about - $ 00 V on one surface (Fig. 1, A-1) and about -100 to -200 V on the other Surface (Fig. 1, A-II).

When this electret was kept in water at 30 ° C _; Even after half a year it showed hardly any signs of wear and tear, but demonstrated great stability and a long service life.

The relationship between time and the surface of the
shown.

The voltage of the electret in water of $ 0 C is shown in Fig.

The electret was then used for the blood coagulation test.

The samples used were the negatively charged ones Surface of the obtained above.gem according to the invention Electrets, a glass bowl, and the same shaped body as above, which is not converted into an electret became.

On each of these three specimens there was 0.3 cm of venous Given rabbit blood. During the coagulation state

209823/0948

of the blood on the sample was observed, the surface of the blood was streaked with an iron needle. The time to coagulation of the blood was measured, which was indicated by the adherence of a fibrous mass to the needle after it was removed from the blood and the subsequent failure of the blood to flow even when the sample was tilted. The measurement was made at 22 C and a relative humidity of 4-2%. The results are shown in Table 1.

Table 1

Sample No. Samples · ■ Surface. time to

Tension to coagulation

Glass jar 12 min.

not converted into an electret
Rehearsal 15 min.

Electret according to
the invention
(negatively charged
Surface) - - 300 V 24- Min ..

The table shows that the electret according to the invention with a negative charge has a much better anticoagulant effect compared to the glass dish and the material not converted into an electret (not charged) (samples ITr. 1 and 2).

The electret according to the invention was sterilized for one hour using a medical device Sterilizer, and then the blood coagulation experiment carried out in the same way as above. The results are in Table 2

9823/0945

Table 2

Sample Mr. rehearse surfaces
tension Time to
Coagulation 1 Glass vessel 12 min. 2 not in an elec
kick converted
sample 15 Hin.

Electret according to the

Invention (negative

charged surface)

sterilized -250 V 23 min.

The results obtained show that even after heat sterilization, the surface tension hardly decreases, and that the electret works very well as an anti-coagulant

Ii c Ii GH rend material with essentially the same ability as Preventing blood coagulation is appropriate.

dps of blood The time to coagulate / the above

was measured in relation to fresh whole blood under static conditions. In relation to fMeasuring, total blood, i.e. blood under dynamic Conditions, a large increase in the time to coagulation was observed.

Example 2

A heart valve with a diameter of 15 which is now used in an artificial heart, made from Teflon, has been irradiated with , Electron beams of 50 KeV and 100 vuA in a vacuum during a minute, using an electron microscope. When measuring the surface tension xL'es obtained electrets (using /

09823/0945

of a surface electropotentiometer of the erosion sector type) at a distance between electrode and sample of 1 cm, it was found that both the irradiated surface and the rear side had a negative mono charge. When the electret was stored in air at 40 ° C. and a relative humidity of 90%, no reduction in the electrical voltage could be determined after one year. In addition, the anti-coagulant properties of the electret on the surface in contact with blood were much better than those of the starting material before electret formation. "■.

The changes in electret surface tension

in an environment of 40 ° C and 90% relative Humidity of the above-mentioned Teflon artificial heart valve is shown in FIG.

Example 3 -

Sixteen press plates as used ⁱⁿ Example 1 were closely stacked and subjected to electron beam irradiation of 1.0 mA from above for about 60 seconds in air at room temperature using a resonance converting electron beam accelerator (from General Electric) . The sample was set up 40 cm from the radiation source and moved using a conveyor device.

The dose of the electron beam was approximately 6.0 Mrad calculated as the mean within the effective range of the electron beams. It was the surface tension of the obtained electret must. The results are shown in Fig. 3.

81 ^ / 09

Ho represents the initial electrical. Voltage of the irradiated surface, and 11 ™ i- ^s ^ & i- ^e electrical surface tension measured after storage of the sample for 30 days in air at 80 ^° C. Pig. 3 shows that the surface tension hardly decreased and the electret was very stable.

It can also be seen that the first seven of a total of 16 plates have electrets with very high electrical surface tension are. The fourth electret counted from the irradiated surface was used for the blood coagulation test. For comparison purposes, a glass dish and the same molded article were used such as the electret according to the invention used in this example.

Using these three samples, the blood coagulation test was carried out carried out in the same manner as described in Example 1. The results are shown in Table 3.

table 3

Sample Mr. rehearse surfaces
tension time to
to the
Coagulation 1 Glass vessel 13 min. 2 Not in an El
ectret converted
3rd sample 17 min.

Electret straight of the invention (negative ["olaxlene Surface)

-700 V

26 min.

2 0-9 8 2 8/0 9 A B

BAD OR »G * N ^At

The results obtained show that the elec-. , According to the invention, a negatively charged surface has a much better anticoagulant effect opposite has blood.

of the blood .. The time to coagulation / the above

was measured on fresh whole blood under static conditions. With whole blood flowing, namely blood under dynamic conditions, a drastic increase in the time required for coagulation was observed.

Example 4-

A tube of the test tube type 9 mm Large 0 0 10 mm χ χ 10 cm of a copolymer of tetrafluoroethylene and hexafluoropropylene (FEP Teflon 100, trade name, Du Pont) was irradiated with electric _w's rays about 2 MeV and 1.0 mA Subjected for 20 seconds in room temperature air using a resonance transducer type electron beam accelerator (manufactured by General Electric). The sample was placed 40 cm from the radiation source and moved using a conveyor. The dose of the electron beams was about 2.0

Mrad calculated as the mean value within the effective range of the electron beams.

One was made of aluminum foil Electrode placed in the electret tube and the surface tension the outer surface was determined by a rotary sector type potentiometer a distance between sample and electrode of 1 cm. The initial surface electrical tension was found to be about -JOOV. Then the pipe cut open and the surface tension of the

209828/0945

surface was measured to be about - 3 ^ 0 V. The electret obtained was charge an electret having mono, whose "both surfaces were negatively charged Die." Changes in surface tension when immersed in water of 3O ⁰ C are shown in Figure 4. from which it can be seen that the electret obtained is very stable.

A test tube type electret sample was used for the blood coagulation test; with an electric voltage to "the outer surface of about. -300 Y, the ^NAC & iner similar method was prepared. were purposes For comparison two Glasreagenzrohre, silicone-coated Glasreagenzrohre and the same materials / accordance · s of the invention are used and not converted into electrets.

The venous blood of a dog was used and the experiment was carried out in a 37 ° ^C constant temperature water bath. A dog's forelegs were stretched slightly and a hypodermic needle was quickly inserted into the elbow vein to draw approximately 2.5 ml of blood, taking care that the needle tip was properly positioned within the blood vessel. As soon as the blood flowed into the thread, the time was measured with the help of a stop watch. One millimeter of blood was poured into each of the reagent tubes. One of the two reagent tubes for each sample, which are placed in the water bath with constant

every 3p seconds temperature was raised / was at an angle of

inclined to see if

the blood in the pipe flowed. "The other sample was not moved. As soon as the blood in the first reagent tube stopped flowing at all, the second reagent tube was tilted at an angle of 45 ° every 30 seconds, and ^{the blood's 1 '1} Ii es si ability

2098 2 8 / 0.94 p

observed. The time required was measured until the blood coagulated and its ability to flow completely lost. With regard to the measured values, fractions of less than a minute were added Be careful. The results are shown in Table 4. '"..

Table 4

rehearse

charge

Time until onset of coagulation (min.)

Time until the end of coagulation (min.)

Glass 1
2

12 18

Silicone 1
ized
Glass 2

25th

PEP body, 1
who is not in
an electret
converted
became 2

Electret ge 1 -320 V according to the invention 2 - -540 V

27 50

The results obtained show that the electret according to the invention is much better in preventing coagulation Has an effect on blood compared to the glass tube, the silicone-coated glass tube and the same molded body, which has not been converted into an electret.

The time to coagulation of the blood given above was based on fresh whole blood measured under static conditions. Regarding flowing whole blood, namely blood under dynamic Conditions, became a "drastic Krhöhuii {;; the Time have been observed for coagulation.

2098287-0945

BATH

Claims (1)

Claims 1 1 ./Anticoagulant moldings that contain an electret characterized in that the electret is formed by irradiating a molded article made of a fluororesin with electrons, the negatively charged surface of the electret being in contact with it bring with blood is appropriate. 2. Anticoagulant moldings which comprise an electret, characterized in that the electret by direct irradiation of a shaped object from a Fluororesin obtained with electron beams having an energy within the practical range of electron beams was, the negatively charged surface of said electret suitable for being brought into contact with blood is. 3 ". Anticoagulant moldings according to claim 2, characterized in that they contain hollow molded objects, like pipes, bottles or balls are. 4-. Process for the preparation of anticoagulant Shaped bodies which comprise an electret, characterized in that a shaped object from a Fluororesin of direct electron beam irradiation of an energy within the practical range of Subjects to electron beams. 5 · Process for the preparation of anticoagulant Shaped bodies which comprise an electret, characterized in that a shaped object from a Fluororesin of direct irradiation with electron beams of 0.1 - 50 Mrad in the energy range within the practical range of electron beams. 209 8 2 B / Ό9