• Journal of Korean Society of Forest Science
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• v.85 no.2
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• pp.329-339
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• 1996

This study is to investigate the effect of mycorrhizal development, growth, nutrient absorption of P. thunbergii seedlings inoculated with Pisolithus tinctorius(Pt. KJ-1) in relation to toxic materials in soil. The concentrations on copper solution applied to the soils were 0, 40, 120, 260, 430ppm. The results are summarized as follows : 1. The germination of P. thunbergii with Pt. increased greater than without ectomycorrhizal fungi. Mycorrhizal development showed a significant decreasing trend at high concentration, and tolerant Cu test with Pt. in agar plate media showed a decreasing trend at a high level. 2. P. thunbergii seedlings inoculated with Pt. showed that the shoot length was significantly promoted at 40, 120ppm copper levels, and that of noninoculated seedlings had the lowest effect in 430ppm copper level. 3. The outer shape of ectomycorrhizal root tips after inoculating Pt. on P. thunbergii seedlings appeared as a monopodial type, a fern-like type, and a cluster-like type at 0ppm, 40ppm levels, but only monopodial type came out at 260ppm, 430ppm copper levels. 4. Root length, no. of juvenile leaves, total length of juvenile leaves, total dry weight, no. of needles and total length of needles of P. thunbergii with Pt. increased greater than those of noninoculated seedling. Growth response of P. thunbergii seedling inoculated with Pt. increased significantly at 40ppm, 120ppm Cu levels. 5. As a result of analysis of growth medium, pH, Na, CEC increased at higher Cu level, and total nitrogen, organic matters, available phosphorous, K, Ca and Mg decreased at 40ppm, 120ppm Cu levels. As a result of an analysis about a copper within soils, it appeared having high Cu-concentration at 0ppm level of an inoculated Pt. and high Cu-concentration in noninoculated Pt. than in inoculated Pt. at higher level. 6. As a result of an analysis of shoot, N, P, and K-concentration were higher in noninoculated seedlings than in inoculated seedlings, and Cu-concentration was higher in inoculated seedlings than in noninoculated seedlings. The analysis of root resulted in a high N-concentration at 40ppm, 120ppm levels, in a high P-concentration in inoculated seedlings and in a high Cu-concentration in noninoculated seedlings. Cu-concentration was significantly higher at root than at shoot.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2000.11a
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• pp.3-4
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• 2000

Many researchers are interested in the synthesis and characterization of carbon nitride and diamond-like carbon (DLq because they show excellent mechanical properties such as low friction and high wear resistance and excellent electrical properties such as controllable electical resistivity and good field electron emission. We have deposited amorphous carbon nitride (a-C:N) thin films and DLC thin films by shielded arc ion plating (SAIP) and evaluated the structural and tribological properties. The application of appropriate negative bias on substrates is effective to increase the film hardness and wear resistance. This paper reports on the deposition and tribological OLC films in relation to the substrate bias voltage (Vs). films are compared with those of the OLC films. A high purity sintered graphite target was mounted on a cathode as a carbon source. Nitrogen or argon was introduced into a deposition chamber through each mass flow controller. After the initiation of an arc plasma at 60 A and 1 Pa, the target surface was heated and evaporated by the plasma. Carbon atoms and clusters evaporated from the target were ionized partially and reacted with activated nitrogen species, and a carbon nitride film was deposited onto a Si (100) substrate when we used nitrogen as a reactant gas. The surface of the growing film also reacted with activated nitrogen species. Carbon macropartic1es (0.1 -100 maicro-m) evaporated from the target at the same time were not ionized and did not react fully with nitrogen species. These macroparticles interfered with the formation of the carbon nitride film. Therefore we set a shielding plate made of stainless steel between the target and the substrate to trap the macropartic1es. This shielding method is very effective to prepare smooth a-CN films. We, therefore, call this method "shielded arc ion plating (SAIP)". For the deposition of DLC films we used argon instead of nitrogen. Films of about 150 nm in thickness were deposited onto Si substrates. Their structures, chemical compositions and chemical bonding states were analyzed by using X-ray diffraction, Raman spectroscopy, X-ray photoelectron spectroscopy and infrared spectroscopy. Hardness of the films was measured with a nanointender interfaced with an atomic force microscope (AFM). A Berkovich-type diamond tip whose radius was less than 100 nm was used for the measurement. A force-displacement curve of each film was measured at a peak load force of 250 maicro-N. Load, hold and unload times for each indentation were 2.5, 0 and 2.5 s, respectively. Hardness of each film was determined from five force-displacement curves. Wear resistance of the films was analyzed as follows. First, each film surface was scanned with the diamond tip at a constant load force of 20 maicro-N. The tip scanning was repeated 30 times in a 1 urn-square region with 512 lines at a scanning rate of 2 um/ s. After this tip-scanning, the film surface was observed in the AFM mode at a constant force of 5 maicro-N with the same Berkovich-type tip. The hardness of a-CN films was less dependent on Vs. The hardness of the film deposited at Vs=O V in a nitrogen plasma was about 10 GPa and almost similar to that of Si. It slightly increased to 12 - 15 GPa when a bias voltage of -100 - -500 V was applied to the substrate with showing its maximum at Vs=-300 V. The film deposited at Vs=O V was least wear resistant which was consistent with its lowest hardness. The biased films became more wear resistant. Particularly the film deposited at Vs=-300 V showed remarkable wear resistance. Its wear depth was too shallow to be measured with AFM. On the other hand, the DLC film, deposited at Vs=-l00 V in an argon plasma, whose hardness was 35 GPa was obviously worn under the same wear test conditions. The a-C:N films show higher wear resistance than DLC films and are useful for wear resistant coatings on various mechanical and electronic parts.nic parts.

• Journal of Korean Society of Environmental Engineers
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• v.31 no.1
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• pp.51-57
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• 2009

Biofouling in seawater reverse osmosis (SWRO) desalination process causes many problems such as flux decline, biodegradation of membrane, increased cleaning time, and increased energy consumption and operational cost. Therefore biofouling is considered as the most critical problem in system operation. To control biofouling in early stage, detection of the most problematic bacteria causing biofouling is required. In this study, six model bacteria were chosen; Bacillus sp., Flavobacterium sp., Mycobacterium sp., Pseudomonas aeruginosa, Pseudomonas fluorescens, and Rhodobacter sp. based on report in the literature and phylogenetic analysis of seawater intake and fouled RO membrane. The adhesion to RO membrane, the high pressure resistance, and the hydrophobicity of the six model bacteria were examined to find out their fouling potential. Rhodobacter sp. and Mycobacterium sp. were found to attach very well to RO membrane surface compared to others used in this study. The test of hydrophobicity revealed that the bacteria which have high hydrophobicity or similar contact angle with RO membrane ($63^{\circ}$ of contact angle) easily attached to RO membrane surface. P. aeruginosa which is highly hydrophilic ($23.07^{\circ}$ of contact angle) showed the least adhesion characteristic among six model bacteria. After applying a pressure of 800 psi to the sample, Rhodobacter sp. was found to show the highest reduction rate; with 59-73% of the cells removed from the membrane under pressure. P. fluorescens on the other hand analyzed as the most pressure resistant bacteria among six model bacteria. The difference between reduction rates using direct counting and plate counting indicates that the viability of each model bacteria was affected significantly from the high pressure. Most cells subjected to high pressure were unable to form colonies even thought they maintained their structural integrity.

• Journal of the Korean Wood Science and Technology
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• v.36 no.3
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• pp.1-8
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• 2008

The lateral strength test of bending type was done to investigate the lateral capacity of the double bolt connection of domestic larix glulam according to bolt spacing. In the shear specimen, which is bolted connection in the inserted plate type, the hole of bolt was made, changing the diameter of bolt (12 mm and 16 mm), the number of bolt (single bolt : control and double bolt), the direction of bolt row (in parallel to grain : Type-A and in perpendicular to grain : Type-B) and the bolt spacing (Type-A : 4 d and 7 d and Type-B : 3 d and 5 d). Lateral capacity and failure mode of bolt connection were compared according to conditions. In prototype design (KBCS, 2000), the reduction factor of the allowable shear resistance that the bolt spacing is reduced was calculated. The results were as follows. 1) Bearing stress per bolt in the single and double bolt connection of Type-A was directly proportional to bolt diameter and bolt spacing. Bearing stress of Type-B decreased as bolt diameter was increased, and decreased by 2~10% when bolt diameter was increased. 2) In the single bolt connection and the double bolt connection of Type-A, the splitted failure was formed in the edge direction. When the bolt spacing was 3 d in Type-B, bolt was yielded more in the part of tension than in the part of compression, and the splitted failure started at the bolt in the part of tension. In the 5 d spacing specimen, the bolt in the part of tension was yielded similarly to bolt in the part of compression, and the splitted failure started in the part of compression. 3) In the prototype design, the reduction factor was calculated by non-dimensionizing the yielding load in the standard of bolt spacing (Type A : 7 d and Type B : 5 d). In 12 mm bolt connection, the reduction factor of bolt spacing 4 d (type-A) and single bolt connection was 0.87 and 0.55, respectively, and the reduction factor of bolt spacing 3 d (Type-B) and single bolt connection was 0.91 and 0.55, respectively. In 16 mm bolt connection, the reduction factor of bolt spacing 4 d (type-A) and single bolt connection was 0.96 and 0.76, respectively, and the reduction factor of bolt spacing 3 d (Type-B) and single bolt connection was 0.91 and 0.77, respectively.

• Korean Journal of Organic Agriculture
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• v.23 no.3
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• pp.549-565
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• 2015

This study was conducted to investigate the growth characteristics and functional materials of baby vegetables as affected by different LEDs and luminous intensity at Anseongsi, Gyeonggi Province, in 2014. Test crops were beet, chicory, spinach, red leaf lettuce, crown daisy and red mustard purchased from the seed company of Dongbu Hannong and Jinheung. Growth characteristics were measured and the content of functional materials was analyzed 40 days after seeding at plug plate. Treatment of Red+Blue (4:1) at $150{\mu}mol\;m^{-2}s^{-1}$ luminous intensity showed the highest number of leaves in five baby vegetables of beet, chicory, red leaf lettuce, crown daisy and red mustard. The highest shoot length of chicory, spinach, red leaf lettuce, crown daisy and red mustard was obtained from the treatment of Red+Blue (4:1) at $150{\mu}mol\;m^{-2}s^{-1}$ luminous intensity. Fresh weight and dry weight of all six baby vegetables were the highest in treatment of Red+Blue (4:1) at $150{\mu}mol\;m^{-2}s^{-1}$ luminous intensity. Content of chlorophyll a and chlorophyll b of spinach, red leaf lettuce and red mustard showed the highest in Fluorescent lamp at $150{\mu}mol\;m^{-2}s^{-1}$ luminous intensity whereas other crops did not show definite trend under different LEDs lights and luminous intensity. The highest total content of anthocyanins and polyphenol were obtained from the treatment of Red+Blue (4:1) at $150{\mu}mol\;m^{-2}s^{-1}$ luminous intensity in all six baby vegetables. Free radical scavenging activity was highest in all six vegetable crops at $150{\mu}mol\;m^{-2}s^{-1}$ luminous intensity, but it was not different significantly between LEDs. As a result, the growth and the content of functional material of baby vegetables are generally to be increased in Red+Blue (4:1) at $150{\mu}mol\;m^{-2}s^{-1}$ luminous intensity. Mixed light of Red+Blue is thought to give good effect on the growth and the content of functional material in baby vegetable crops. Because there are many differences in regard of LED lights, crop varieties, cultivation and experimental methods in their impact on the growth and functional materials of baby vegetables among researchers, it is considered that a more precise studies are needed for the crop responses to LED light and luminous intensity.

• Korean Journal of Microbiology
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• v.55 no.3
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• pp.234-241
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• 2019

An intensive interaction between yeasts and insects has highlighted their relevance for attraction to food and for the insect's development and behavior. Yeast associated in the gut of insects secretes cellulase which aided in the food digestion (cellulose degradation). Three strains of cellulose-degrading yeast were isolated from the gut of adult grasshoppers collected in Gyeonggi Province, South Korea. The strains $ON22^T$, $G10^T$, and $G15^T$, showed positive cellulolytic activity in the carboxymethyl cellulose (CMC)-plate assay. The phylogenetic tree based on sequence analysis of D1/D2 domains of the large subunit rRNA gene and the internal transcribed spacer (ITS) regions revealed that the strains $ON22^T$ (100 and 98.4% sequence similarities in D1/D2 domains and ITS) and $G10^T$ (99.8 and 99.5% in D1/D2 domain and ITS region) were most closely related to the species Moesziomyces aphidis JCM $10318^T$; $G15^T$ (100% in D1/D2 domains and ITS) belongs to the species Moesziomyces antarcticus JCM $10317^T$, respectively. Morphology and biochemical test results are provided in the species description. Cellulase with its massive applicability has been used in various industrial processes such as biofuels like bioethanol productions. Therefore, this is the first report of the cellulolytic yeast strains $ON22^T$, $G10^T$, and $G15^T$ related to the genus Moesziomyces in the family Ustilaginaceae (Ustilaginales), in Korea.

• Journal of the Korean Wood Science and Technology
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• v.32 no.4
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• pp.8-17
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• 2004

Antifungal, antibacterial, and antioxidative activities of ethanol extracts from 65 families 263 species were investigated to select tree species for the utilization of natural fungicide or preservative resources. The antifungal activities of extracts from wood, leaf and bark were measured as hyphal growth inhibition rate using four plant pathogenic and five wood rotting fungi. High inhibitory effect on the fungi growth was found in five species of Pinaceae (Pinus koraiensis, P. rigida, P. densiflora, P. banksiana. Cedrus deodara), three species of Cupressaceae (Juniperus rigida, J. chinensis, Chamaecyparis obtusa) and three species of Leguminosae (Albizzia julibrisssin, Sophora japonica, Maackia amurensis), respectively. Antibacterial activities of ethanol extracts were determined by means of disc-agar plate diffusion method using three gram-positive and five gram-negative bacteria. The ethanol extracts, which showed prominent effect on the suppression of bacteria growth, were six species of Betulaceae (Carpinus tschonoskii, C. coreana, C. laxiflora, Alnus hirsuta, A. firma, Betula schmidtii), five species of Fagaceae (Castanopsis cuspidata var. sieboldii, Quercus serrata, Q. mongolica, Q aliena, C crenata), four species of Euphorbiaceae (Aleurites fordii, Sapium sebiferum, S japonicum Mallotus japonicus) and three species of Elaeagnaceae (Elaeagnus umbellata, Elaeagnus glanbra, Elaeagnus macrophylla). According to these results, the extracts from Zelkova serrata, Pinus densiflora, Maackia amurensis, Chamaecyparis obtusa and Juniperus chinensis could be available for natural fungicide or food preservatives, because ethanol extracts from these species indicated excellent antifungal and antibacterial activities. In order to test antioxidative activities of ethanol extracts, free radical scavenging method was adopted with 1,1-diphenyl-2-picrylhydrohydrazyl (DPPH). Free radical scavenging activity was proved very high in the extracts of eight species of Rosaceae (Eriobotrya japonica, Prunus takesimensis, P yedoensis, P padus, P armeniaca var. ansu, Chaenomeles sinensis, Stephanandra incisa, Rosa multiflora) and five species of Ericaceae (Rhododenron mucronulatum, R. scblippenbacbii, R. yedoense var. poukhanense, Vaccinium bracteatum, V oldbami), resvectively. It turned out from this study that only six species among 48 species of Rosaceae showed less than 80% free radical scavenging activity. As a consequences, it could be deduced that the components effective on antioxidative activity commonly exist in Rosaceae plant family.

• Korean Journal of Agricultural Science
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• v.13 no.1
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• pp.113-122
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• 1986

In order to promote mechanization of corn harvesting in Korea, this study was conducted to find out the effect of moisture content on compressive properties such as force, deformation, energy and modulus of stiffness to the bioyield and the rupture point for Korean corn kernel. In this study, the loading positions of corn were flat, edge, longitude and the moisture contents were about 13, 17, 21, 25% in wet basis. The compression test was carreied out with flat plate by use of dynamic straingage for three varieties of Korean corn under quasi-static force when the loading rate was 1.125mm/min. The results of this study are summarized as follows; 1. When the moisture content of corn ranged from 12.5 to 24.5 percent, at flat position, the bioyied force was in the range of 13.63-26.73 kg and the maximum compressive strength was in the range of 21.55-47.65kg. Their values were reached minimum at about 17% and maximum at about 21% moisture content. The bioyield force was in the range of 13.58-6.70kg at edge position and the maximum compressive strength which was 16.42 to 7.82kg at edge position was lower than that which was 18.55-9.05kg at longitudinal position. 2. Deformation of corn varied from 0.43 to 1.37 mm at bioyield point and from 0.70 to 2.66mm at rupture point between 12.5 to 24.5% moisture content. As the moisture content increased, deformation was increased. 3. The moduli of resilience and toughness of corn ranged from 2.60 to 8.57kg. mm and from 6.41 to 34.36kg. mm when the moisture content ranged from 12.5 to 24.5 percent, respectively. As the moisture content increased, the modulus of toughness was increased at edge position and decreased at longitudinal position. And their values were equal each other at 22-23% moisture content. 4. The modulus of stiffness was decreased with increase in the moisture content. Its values ranged from 32.07 to 5.86 kg/mm at edge position and from 42.12 to 18.68kg/mm at flat position, respectively. Also, the values of Suweon 19 were higher than those of Buyeo. 5. It was considered that the compressive properties of corn at flat position were more important on the design data for corn harvesting and processing machinery than those of edge or longitudinal position. Also, grinding energy would be minimized when a corn was processed between about 12.5 to 17% moisture content and corn damage would be reduced when a corn was handled between about 19 to 24% moisture content in wet basis.

• Korean Journal of Cleft Lip And Palate
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• v.9 no.2
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• pp.85-92
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• 2006

Korean Cleft Lip and Palate Association (KCLPA) was founded in 1996. The first overseas charity operation was in Karachi, Pakistan, 2002 and our association has visited fourteen times in six countries for the free cleft surgery: Pakistan, Egypt, Kenya, Morocco, Jordan and Vietnam. The cumulated number of operated patients reaches to 280. Before our association, many Korean oral and maxillofacial surgeons have performed charity operations individually since 1964. It was started from Vietnam but the activity is now carried on in Africa, middle-east Asia, south-east Asia, China, and Korea as an official team. LG electronics, a Korean company helped to propagate our team's activity to middle-east Asia to Africa. This paper is a report concerning about the results of our association's charity activities especially in Kenya, east Africa. We provided free cleft surgery for 30 patients in 2004 and 27 patients in 2005, in Nairobi. As the blood test for HIV of the cleft patients was not allowed before and during surgery, our surgeons and nurses were cautious about every movement during the surgeries. Thus the operation time for each patient was longer than any other time. The attitude of the local hospital and the doctors seemed to be accustomed to this situation. They helped us in case of needle injuries. Safety of medical staff and patients is more important than the number of the patients operated in charity operation. This belief should be approached being parallel and multidisciplinary as an international cooperation, focusing on international funding for medical support and continuous education for local doctors who are willing to devote to their people.

• Korean Journal of Agricultural Science
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• v.2 no.1
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• pp.199-231
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• 1975

It is well known fact that antibiotic residues in milk of cows create significant problem for the fermented dairy industry and public health because of inhibition of starter activity and of creation of allergic disease. It can be assumed that antibiotic residues in milk of other aniimals also can create some problems for their infants as in the case of humen. For the above mentioned reasons, present studies were undertaken to determine concentration and duration of antibiotic residues in milk of cows, goats and dogs following intramuscular or intravenous injection and intramammary infusion of penicillin, streptomycin and oxytetracycline at usual dosage. The cylinder-plate method was used for their assay. The results obtained were summerized as follows: 1) Following the intramuscular injection of penicillin, the antibiotic was detected in milk of cows up to 72 hours, in milk of goats 48 hours and in milk of dogs 60 hours of postinjection. The mean peak concentrations were recorded at 12 hours as 0.136 I.U./ml in cows. 6 hours as 0.773 I.U./ml in goats and 3 hours as 1.192 I.U./ml in dogs. 2) Following the intramuscular injection of streptomycin, the antibiotic was detected in milk of cows and goats up to 36 hours and in milk of dogs 24 hours of post-injection. The mean peak concentration were recorded at 6 hours as $0.26{\mu}g/ml$ in cows and at 3 hours in goats and dogs $0.45{\mu}g/ml$ and $0.36{\mu}g/ml$ respectively. 3) Following the intra venous injection of oxytetracycline, the antibiotic was detectable in milk of all the test animals up to 48 hours of postinjection. The mean peak concentrations were recorded at 6 hours as $3.5{\mu}g/ml$ in cows $2.4{\mu}g/ml$ in goats and $2.0{\mu}g/ml$ in dogs respectively. 4) Following intrarnammary infusion of penicillin in amounts of 100,000 I.U. for cows, 20.000 I.U. for goats and 10,000 I.U. for dogs, the penicillin residues in milk of the infused quarter perssisted to 72 hours in cows and 84 hours in goats and dogs. 5) Following intramammary infusion of streptomycin in amount of 500mg for cows, 100mg for goats and 25mg for dogs, the streptomycin residues in milk of the infused quarter persisted to 72 hours in cows and goats and 60 hours in dogs. 6) Following intramammary infusion of oxytetracycline in amount of 500mg for cows, 100mg for goats and 25mg for dogs, the oxytetracycline residues in milk of the infused quarter persisted to 72 hours in cows and 60 hours in goats and dogs. 7) A corelation between the residual antibiotic concentration and milk yield in cows and goats was observed; That is, the lower in the milk production showed a higher the concentration of an antibiotic residues and a longer the time in persistance. 8) Intramammary transfer of the antibiotic from an infused to non infused quarters, in dogs, was observed following the intramammary infusion of penicillin. streptomycin and oxytetracyclne in amounts of 10.000 I.U. 25mg and 25mg respectively. However, no transfer by 100.000 I.U. or 20.000 I.U. of penicillin. 500mg of streptomycin and 100mg of oxytetracyline was observed in cows and goats. 9) In dogs, minimum dosage of antibiotics for transfer fro in treated to untreated quarters following intramammary infusion were 2,500 I.U. of penicillin and 5mg each of streptomycin and oxytetracycline.