• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.10a
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• pp.231-234
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• 2002

Ultrasonic machining technology has been developed over recent years for the manufacture of cost-effective and quality-assured precision parts for several industrial application such as optics, semiconductors, aerospace, and automobile. Ultrasonic machining process is an efficient and economical means of precision machining of ceramic materials. The process is non-thermal, non-chemical and non-electric and hardly creates changes to the mechanical properties of the brittle materials machined. This paper describes the characteristics of the micro-hole of $\textrm{Al}_2\textrm{O}_3$ by ultrasonic machining with tungsten carbide tool. The effects of various parameters of ultrasonic machining, including abrasives, machining force and pressure, on the material removal rate, hole quality, and tool wear presented and discussed. The ultrasonic Machining of micro-holes in ceramics has been under taken and the machining mechanism in the ultrasonic machining of ceramics based on the fracture-mechanics concept has been analyzed.

• Korean Journal of Veterinary Research
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• v.34 no.2
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• pp.395-406
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• 1994

To study the conditions to enhance success of embryo transfer in the dog, 20 mixed-breed bitches were used for the experiment along with 4 male dogs for mating. The bitches were paired according to synchronism of natural estrus, or the counterpart as donor or recipient was treated with gonadotropin as FSH (follicular stimulating hormone) or PMSG (pregnant mare serum gonadotropin) for induction of estrus to be synchronized with estrus of the other bitch in natural estrus. Embryo recovery was performed in two ways for comparison, either by flushing each uterine horn after ovariohysterectomy or by flushing each horn in the state of non-ovariohysterectomy. In addition, the result of pregnancy according to the embryo stage and the repeatability of the experimental animals as donor or recipient were also investigated. FSH or PMSG was administered to the bitches which had passed over 4 months from last estrus, resulting in estrus-positive in 3 dogs of 6 FSH-treated dogs (50.0%), and in 5 dogs of 9 PMSG-treated dogs (55.6%), determined by proestrus signs and vaginal smear test. Estrus-positive bitches induced with gonadotropin were used as donor or recipient resulting in one embryo-recovered bitch as donor and one offspring-delivered bitch as recipient in 5 PMSG-treated dogs, whereas no result was obtained from 3 FSH-treated dogs. The rate of embryo recovery to be compared with number of corpus luteum was 68.2% in ovariohysterectomized dogs and 55.2% in non-ovariohysterectomized dogs, respectively. The number of dogs from which embryo was collected were 4 dogs of 6 ovariohysterectomized dogs (66.7%) and 6 dogs of 7 non-ovariohysterectomized dogs (85.7%), respectively. The result of parturition was obtained from one dog of 5 estrus-induced recipients, whereas no result was obtained from 3 natural-estrus recipients. The only dog which delivered a male puppy had been transferred 3 morulae and 2 blastocysts. Of 6 repeat-used bitches in canine embryo transfer, 3 dogs showed repeatability either as donor or recipient. These results indicated that inducing estrus of a dog with gonadotropin is feasible in canine embryo transfer to be synchronized with that of a natural-estrus dog, that embryo recovery is also possible in non-hysterectomized dogs, that the estrus-induced dog is also usable as recipient to result in parturition, and that repeat-use of a bitch as donor or(and) recipient is possible in canine embryo transfer.

• Korean Journal of Veterinary Research
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• v.12 no.1
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• pp.133-139
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• 1972

Estrous and non-estrous rabbits were inoculated with E. coli or Streptococcus pyogenes, and the mixture of the two organisms, and bacterial count and histopathological studies of uterine horns were made to observe the effects of estrogen on the resistance of the uterus to bacterial infection. The results obtained were summarized as followings; 1. Four hours after inoculation of bactoria into uterine horn, the number of organisms was significantly lower in estrous rabbits than in non-estrous regardless of the kind of organisms inoculated. 2. The highest reduction rate of the organisms among the three bacterial inoculation groups was found in estrous rabbits inoculated with E. coli, and the lowest reduction rate was with Streptococcus pyogenes. 3. Histopathological changes of uterine horns induced five days after bacterial inoculation were observed. In estrous rabbits, a mild inflammatory reaction was found in Streptococcus pyogenes group, but a slight inflammatory reaction and only a negligible inflammatory reaction were observed in mixed bacteria group, and in E. coli group respectively. In non-estrous group, however, a marked inflammatory reaction was observed in Streptococcus pyogenes group, a moderate inflammatory reaction and a slight inflammatory reaction were observed in the mixed bacterial group and E. coli group, respectively.

• Asian-Australasian Journal of Animal Sciences
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• v.17 no.7
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• pp.919-923
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• 2004

Ultrasonographic study was undertaken to establish the echogenecity and size of reproductive organs of 18 cycling buffaloes of different parities and compared with the sizes measured by palpation per rectum at estrus (day 0), met estrus (day 2), mid diestrus (day 10) and late diestrus (day 16). The overall mean size of cervix, uterine body, right horn, left horn, right ovary and left ovary measured by palpation per rectum were 2.70$\pm$0.43, 2.36$\pm$0.36, 2.17$\pm$0.37, 2.12$\pm$0.38, 2.63$\pm$0.41 and 2.72$\pm$0.37 cm, respectively. The corresponding ultrasonographic observations were 2.10$\pm$0.40, 1.85$\pm$0.30, 1.73$\pm$0.36, 1.64$\pm$0.37, 2.16$\pm$0.36 and 2.29$\pm$0.38 cm respectively. Variations in the size of genitalia due to stages of estrous cycle were non-significant. The size of genitalia measured by palpation per rectum was significantly higher (p<0.05) than by ultrasonography. However, there was linear positive correlation (r=+0.87) in the measurements by the two techniques. The ultrasonographic characteristics of tubular genitalia revealed different echogenic gray shades around the nonechogenic (black) central area of lumen depending upon the stage of cycle. The ovarian stroma appeared as hyperechoic (white) area with nonechogenic (black) follicle. The corpus luteum (CL) exhibited different echogenic texture viz. grayish black, grayish granular and grayish white at met estrus, mid diestrus and late diestrus, respectively. Therefore, ltrasonography can be effectively employed to record the exact size and echotexture of the buffalo genitalia during different stages of estrous cycle.

• International Journal of Oral Biology
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• v.39 no.1
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• pp.49-56
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• 2014

We investigated the role of central P2X receptors in inflammatory pain transmission in the orofacial area in rats. Experiments were carried out using male Sprague-Dawley rats weighing 230-280g. Complete Freund's adjuvant (CFA, $40{\mu}L$) was applied subcutaneously to the vibrissa pad to produce inflammatory pain. The intracisternal administration of iso-PPADS tetrasodium salt, a non-selective P2X receptor antagonist, A317491 sodium salt hydrate, a $P2X_{2/3}$ receptor antagonist, 5-BDBD, a $P2X_4$ receptor antagonist, or A438079 hydrochloride, a $P2X_7$ receptor antagonist, was performed 5 days after CFA injection. Subcutaneous injections of CFA produced increases in thermal hypersensitivity. Intracisternal injections of iso-PPADS ($25{\mu}g$) or A438079 (25 or $50{\mu}g$) produced significant anti-hyperalgesic effects against thermal stimuli compared to the vehicle group. A317491 or 5-BDBD did not affect the head withdrawal latency times in rats showing an inflammatory response. Subcutaneous injections of CFA resulted in the up-regulation of OX-42, a microglia marker, and GFAP, an astrocyte marker, in the medullary dorsal horn. The intracisternal administration of A438079 reduced the numbers of activated microglia and astrocytes in the medullary dorsal horn. These results suggest that a blockade of the central $P2X_7$ receptor produces antinociceptive effects, mediated by inhibition of glial cell function in the medullary dorsal horn. These data also indicate that central $P2X_7$ receptors are potential targets for future therapeutic approaches to inflammatory pain in the orofacial area.

• Journal of Veterinary Clinics
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• v.15 no.1
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• pp.94-99
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• 1998

This study was carried out to determine the effects of uterus shortening on the duration required for estrus, the number of ovulation and the level of serum progesterone and prostaglandin $F_{2}{\alpha} (PGF_{2}{\alpha} $). The duration required for estrus after the surgical shortening of uterine horns and the interval between the following estrus was not affected by the surgical treatment but affected by luteal and follicular phase. The number of ovulations were increased by induction of superovulation to gilts with shortened uterine horns compared to the control. Serum progesterone concentration during the luteal phase was higher than that during the follicular phase with no difference between the control and me horns than that of the control. Findings of this study indicate that luteal formation and regressions and estrus cycle were normal when the unconnected parts of uterine horns were left in abdominal cavity. Therefore surgical shortening of uterine horns of sows helps embryo collections by non-surgical methods.

• Journal of Hospice and Palliative Care
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• v.1 no.1
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• pp.65-68
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• 1998

The neuropathic pains are not well controlled by common analgesics and opioid drugs in terminal cancer patients. The types of these pains are divided within the two cages, one is due to continuous central sensitization and the other is due to paroxymal peripheral sensitization. The mechanism of continuous central sensitization is the activity of dorsal horn neurones that are activated by C-fiber input. The tricyclic antidepressants, non-tricyclic antidepressants, and oral local anaesthesia probably produce analgesic effects in neuropathic pains through suppression of this activity. The mechanism of paroxymal peripheral sensitization is the hyper-excitability of peripheral neurones. The neuropathic pains due to peripheral sensitization respond relatively the anticonvulsants and baclofen that stabilize membranes and suppress paroxymal electrical discharge. The patients was a 38-year-old female who complained of hyperthemia on upper right extremity. The symptom of this patient was improved with anticonvulsant(dilantin 600mg).

• The Korean Journal of Physiology
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• v.30 no.2
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• pp.289-297
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• 1996

Excitatory amino acids (EAA) are thought to play an important role in producing cell death associated with ischemic and traumatic spinal cord injury. The present study was carried out to determine if the response characteristics of spinal sensory neurons in segments adjacent to degeneration sites induced by EAA are altered following these morphological changes. Intraspinal injections of quisqualic acid (QA) produced neuronal degeneration and spinal cavitation of gray matter. The severity of lesions was significantly attenuated by pretreatment with a non-NMDA antagonist NBQX. In extracellular single unit recordings, dorsal horn neurons in QA injected animal showed the increased mechanosensitivity, which included a shift to the left in the stimulus-response relationship, an increased background activity and an increase in the duration of after-discharge responses. Neuronal responses, especially the C-fiber response, to suprathreshold electrical stimulation of sciatic nerve also increased in most cases. These results suggest that altered functional states of neurons may be responsible for sensory abnormalities, e.g. allodynia and hyperalgesia, associated with syringomyolia and spinal cord injury.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.4 no.5
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• pp.931-936
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• 2000

A novel CPFDTD algorithm for modeling the smooth curved surfaces is presented. This scheme subdivides electric fields on the distorted grid into the extended contour field, the non-distorted field, and the quasi-available field to avoid the collinear borrowing approximation. Several preceding methods are applied to the I-plane sectoral horn antenna to get far-field patterns. The accuracy of the presented method is demonstrated by comparison with measured values.

• Journal of Veterinary Clinics
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• v.14 no.2
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• pp.223-229
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• 1997

This study was carried out to determine the effect of uterus shortening on the pvaries, the length of uterine horn and the recovery of embryos. The length of the shortened uterine horns increased more in part of uterine tip from connecting part for shortening than in base (P<0.05), and collection of embryos was also difficult in gilts because of its narrow pelvis. The embryos collected surgically from gilts with shortened uterine horns were developed into 2~8cells (87.5%) 3days and 4cell~morula (88.9%) 5days after mating.