• The Korean Journal of Physiology
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• v.26 no.1
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• pp.75-88
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• 1992

It is well established that neurons in ventrolateral medulla play a key role in determining the vasomotor tone. The purpose of present study is to identify sympathetic related, medullospinal tract neurons in ventrolateral medulla and to show that these mediate somato-sympathetic reflex. Medullospinal tract cells were identified by antidromic stimulation to intermediolateral nucleus (IML) of the second thoracic ($T_2$) spinal cord in anesthetized cats. Peripheral nerves were stimulated for orthodromic activation of these cells and peripheral receptive fields were determined. Post R wave histogram of unit and spike triggered averaging of sympathetic nerve discharge (SND) were used to define sympathetic related cell. A total of 113 neurons was recorded in ventrolateral medulla that had the axonal projections to $T_2$ spinal cord. Thirty four of these medullospinal cells showed spontaneous discharges and the others not. Between these two groups, rostro-caudal coordinate of the distribution from obex [$4.7{\pm}0.2\;$ (mean S.E.) mm, 4.1 0.1 mm], depth from dorsal surface ($5.5{\pm}0.2mm,\;4.9{\pm}0.1mm$ and conduction velocity ($9.9{\pm}1.7m/sec,\;16.7{\pm}1.9\;m/sec$) were significantly different (p<0.05). In spontaneously discharging group, characteristics of rostral and caudal groups were significantly different and we demonstrated that cells in rostral group mediate somatosympathetic reflex. From these results, we conclude that a certain portion of spontaneously discharging medullospinal tract cells in rostral ventrolateral medulla comprise the efferent outputs of somatosympathetic reflex to sympathetic preganglion neurons.

• The Journal of Korean Physical Therapy
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• v.14 no.4
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• pp.266-273
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• 2002

Carpal Tunnel Syndrome(CTS) is a common entrapment neuropathy of the median nerve at the wrist. An Electrophysiologic study has been widely used for the diagnosis of carpal tunnel syndrome. The subjects of this study were 48 cases (88 hands) with clinically suspected carpal tunnel syndrome who underwent electrodiagnostic examination from Jan 1, 2001 to Sep 30, 2001, The results were as follows: 1. Among 48 persons with a clinically suspected carpal tunnel syndrome, 40 patients were female 83.33$\%$ and the patients who are above 60 years old were 37.50$\%$. 2. Electrodiagnostic results were 22 cases (45.84$\%$) with bilateral carpal tunnel syndrome and 10 cases (20.83$\%$) with normal. 3. Physical findings consisted of tingling sensation in 48.86$\%$ of the involved hands, positive Phalen's Sign in 20.46$\%$ of them, thenar atrophy in 15.91$\%$ of them, and weakness in 14.77$\%$ of them. 4. Electrophysiologic studies showed a decreased sensory conduction velocity in 20 cases (22.73$\%$) of total hands, a prolonged latency in 3 cases (3.41$\%$) of them, abnormal sensory and motor fiber in 33 cases (37.50$\%$) of them, and normal in 27 cases (30.68$\%$) of them. Considering above results, we had better make a diagnosis precisely the patients with clinically suspected carpal tunnel syndrome through subjective symtoms, physical examinations, and electrophysiologic studies.

• The Journal of Korean Physical Therapy
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• v.11 no.3
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• pp.1-12
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• 1999

The aim of this study is to examine the sensitivity and characteristics of electromyography abnormalities detected by using various paramenters in patients with lumbosacral radiculopathies. EMG is widely used for disgnosing and localizing the level of radiculopathy. The results of the study were as follow : 1. In electromyography, L5 radiculopathy usa 95 cases(51.690). S1 radiculopathy was $45m(24.5\%)$ L4 radiculopathy was 18cases $(9.8\%)$, and L2, 3 radiculopathy was 8cases$(4.3\%)$. Remains 18cases$(9.8\%)$ had no definite radiculopathy. 2. Peroneal and tibial motor nerve conduction velocity studies were not significant as compared to the side to side. 3. Latency of H-reflex in L5 radiculopathy was $30.55\pm2.47$ in affected side, $29.47\pm2.29$ in unaffected side, in S1 radiculopathy was $33.00\pm2.03$ in affected side, R30.18\pm2.21$ in unaffected side. It was statistically significant(p<0.01). H-reflex mean difference of S1 radiculopathy group was significantly prolonged as compared to the L5 and S1 radiculopathies(p<0.001). 4. In L2, 3 radiculopathy, abnormal spontaneous activities and motor unit action potentials were showed high sensitivity in upper lumber paraspinal, hip adductors, quadriceps and iliopsoas muscles. 5. In L4 radiculopathy, lower lumbar paraspinal, tibialis anterior, quadriceps muscles were showed high sensitivity. 6. In L5 radiculopathy, lower lumbar paraspinal, extensor hallucis longus, extensor digitorum longus, peroneus longus, extensor digitorum brevis, gluteus maximus, tensor fasciae latae muscles were showed high sensitivity. 7. In S1 radiculopathy, lower lumbar paraspinal, gluteus maximus, peroneus longus, soleus, abductor hallucis, hamstrings, extensor digitorum brevis, extensor hallucis lognus, gastrocnemius muscles were showed high sensitivity.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.17 no.2
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• pp.101-109
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• 2005

The purpose of this study is to investigate the performance of outdoor heat exchanger for heat pump using carbon dioxide. Two types of fin and tube heat exchangers (2 rows for type A and 3 rows for B) are tested. Both heat exchangers have counter-cross flow and 1-circuit arrangement. Test results such as heat transfer rate, pressure drop characteristics and temperature distribution in the heat exchanger are shown with respect to mass flow rate of refrigerant and frontal air velocity For cooling mode, the minimum temperature difference between air and refrigerant of type B is smaller than that of type A by $1^{circ}C$, but the pressure loss of air side is much higher for type B by $29\%$. It is found that a large temperature gradient of carbon dioxide during gas cooling Process Promotes thermal conduction through tube wall and fins which results in degradation of heat transfer performance. For heating mode operation, type B heat exchanger shows higher heat transfer performance compared to type A. However, because pressure loss of refrigerant side of type B is much greater than that of type A, the refrigerant outlet pressure of type B becomes lower than that of type A.

• Restorative Dentistry and Endodontics
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• v.20 no.2
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• pp.527-537
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• 1995

The effect of calcitonin gene-related peptide (CGRP), substance P (SP) and electrical stimulation of the tooth on the intradental nerve activtiy (INA) was investigated in anesthetized cats. The INA was recorded from single pulp nerve units dissected from the inferior alveolar nerve under stereomicroscope. The INA elicited by 3 minute application of 4M NaCl in deep dentinal cavity was compared before and after stimulation at 10 minute intervals. The magnitude of INA was calculated as the total number of nerve impulses produced in given period, and the changes of INA are expressed as % of control INA. The results obtained were as follows. 1. 16 single pulp nerve units were classified as 14 $A{\delta}$-fibers (3.4~19.4m/sec) and 2-fibers (1.5~1.7m/sec) according to the conduction velocity. 2. 4M NaCl evoked an irregular bursts of spikes which continued until washing out. Isotonic saline did not affect INA to subsequent applications of the hypertonic NaCl solution (P>0.05). 3. Local application of CGRP ($200{\mu}g$/ml) in deep dentinal cavity reduced the INA induced by 4M NaCl in $A{\delta}$-fiber units (P<0.01) and some units of those responded to CGRP during application. 4. Local application of SP ($100{\mu}g$/ml) in deep dentinal cavity reduced the INA induced by 4M NaCl in AS-fiber units (p<0.05), but increased the INA in C-fiber unit coincided with large reduction of the INA of $A{\delta}$-fiber units. 5. Monopolar electrical stimulation applied to the crown at intensities high enough to excite C-fibers (12V, 5ms, 10Hz, 10~30min) decreased the INA in $A{\delta}$-fiber units (P<0.01) and systemic pretreatment with phenoxybenzamine (3mg/kg, i.v.) enhanced this inhibitory effect (P<0.01). On the contrary, electrical stimulation increased the INA in C-fiber unit.

• Journal of the Korea Institute of Military Science and Technology
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• v.17 no.4
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• pp.463-470
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• 2014

Stealth technology of combat aircraft is most significant capability in recent air battlefield. As the detector of IR missiles is being developed, IR stealth capability which is evaluated by IR signature level become more important than it was in previous generation. Among IR signature of aircraft from various sources, aerodynamic heating dominates in long-wavelength IR spectrum of $8{\sim}12{\mu}m$. Skin temperature change by aerodynamic heating which is derived by effects of Mach number and structure. The 4th and 5th generation aircraft are selected for calculation of the skin temperature, and its height and velocity in numerical conditions are 10,000 m and Ma 0.9~1.9 respectively. Aircraft skin temperature is calculated by computing convection of fluid and conduction, convection and radiation of surface. As the aircraft accelerates to higher Mach number, maximum skin temperature increases more rapidly than average temperature and temperature distribution changes in more sharp, interactive ways. The 4th generation aircraft whose shape is more complex than that of the 5th generation aircraft have complicated temperature distribution. On the other hand, the 5th generation aircraft whose shape is relatively simple shows plain temperature distribution and lower skin temperature in terms of both average and maximum value.

• Restorative Dentistry and Endodontics
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• v.17 no.1
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• pp.1-9
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• 1992

The intradental nerve activity was recorded from single pulp nerve unit dissected from the inferior alveolar nerve in canine teeth of anesthetized cats. The effects of various test solutions on intradental nerve activity evoked by 4M NaCl applied to the deep dentinal cavities were investigated. 1. Total 15 single pulp nerve units were recorded. Of these 9 were Mi - fibers and 6 were C -fibers. The mean conduction velocity and electrical threshold of $A{\delta}$ - fiber were $6.3{\pm}3.7m/sec$, $1.2{\pm}0.7V$ and those of C - fiber were $1.0{\pm}0.2m/sec$, $2.3{\pm}1.3V$, respectively. The response to cold stimuli of $A{\delta}$ - fiber began immediately and that of C - fiber began after a latency. 2. When applied to deep dentinal cavity, 4M NaCl induced irregular bursts of action potential in 4 $A{\delta}$ - fibers and 3 C - fibers, which continued until the solution was washed away. 3. In the $A{\delta}$ - fiber, histamine failed to induce any nerve acitivity and did not produce an increase in intradental nerve activity evoked by 4M NaCl. However following the application of 1M KCl, the response to 4M NaCl was eliminated. 4. In the C - fiber, histamine generated some nerve activity and produced a significant increase in intradental nerve activity evoked by 4M NaCl, but 5M $CaCl_2$ did not abolish this enhandced response.

• Archives of Plastic Surgery
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• v.32 no.5
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• pp.613-618
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• 2005

When a large peripheral nerve defect occurs, an autologous nerve graft is the most ideal method of recinstruction. But an autologous nerve graft has many limitations due to donor site morbidities. Many previous focused on finding the ideal nerve conduit. Among them, $Gore-Tex^{(R)}$ has several advantages over other conduits. It can be manipulated to a suitable size, does not collapse easily, and it is a semi- permeable material that contain pores. A round shaped nerve can be newly formed because of its smooth inner surface. The purpose of this study was to evaluate the availability of $Gore-Tex^{(R)}$ tube as a nerve conduit at the peripheral nerve defect in the rat sciatic nerve. The 10 mm nerve gap was made in each group. A $Gore-Tex^{(R)}$ tube filled with skeletal muscle was inserted and autologous nerve graft was harvested, respectively. In the experimental group, we placed a 0.5 mm thickness, $30{\mu}m$ pored, 1.8 mm in diameter and 14 mm length tube with skeletal muscle inserted inside. In the control group, the nerve gap was inserted with a rat sciatic nerve. We estimated the results electrophysiologically and histologically to 16 weeks postoperatively. Results in the nerve conduction velocity, total myelinated axon count, myelin sheath thickness and mean nerve fiber diameter, the experimental group was substantially lower than that of the control group, but the statistic difference was not significant (p<0.05). The morphology was very similar in both groups, microscopically. From the above results, We conclude that $Gore-Tex^{(R)}$ qualifies as an ideal nerve conduit. It is suggested that $Gore-Tex^{(R)}$ tube filled with skeletal muscle may, substitute for an autologous nerve graft.

• Restorative Dentistry and Endodontics
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• v.21 no.2
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• pp.505-516
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• 1996

The effects of application of dentin desensitizer containing glutaraldehyde (Gluma Desensitizer) and dentin adhesive system (All Bond 2) to the exposed dentin on the intradental nerve activity (INA) and the occluding aspects of dentinal tubules were investigated in cat canine teeth. Single pulp nerve units were dissected from the inferior alveolar nerve and indentified as $A{\delta}$-fiber units. The INAs elicited by 4M NaCl before and after the application of each experimental agent were compared. The morphological changes of exposed dentin surfaces and dentinal tubules in the dentin specimens used to record INAs were observed by SEM. The results obtained were as follows. 1. Eight $A{\delta}$-fiber units (conduction velocity: $8.0{\pm}4.0m$/sec) were identified. 4M NaCl evoked an irregular burst of action potentials which ceased immediately after washing. 2. In 4 $A{\delta}$-fiber units, the change of INA after the application of Gluma Desensitizer was $133.9{\pm}80.7%$ when it was compared with the INA before the application of the same agent. 3. In 4 $A{\delta}$-fiber units, application of All Bond 2 completely abolished the INA induced by 4M NaCl. 4. In specimens applied with Gluma Desensitizer, the formation of hybrid layer as well as the identification of resin penetration and reaction products with proteins in dentinal tubules were not clearly observed in interface between dentin and adhesive resin. In specimens applied with All Bond 2, the gap width of 2-$3{\mu}m$ was formed between exposed dentin and adhesive resin, and the hybrid layer and resin tags were not clearly formed either.

• Journal of Korean Neurosurgical Society
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• v.55 no.3
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• pp.148-151
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• 2014

Objective : Posture-induced radial neuropathy, known as Saturday night palsy, occurs because of compression of the radial nerve. The clinical symptoms of radial neuropathy are similar to stroke or a herniated cervical disk, which makes it difficult to diagnose and sometimes leads to inappropriate evaluations. The purpose of our study was to establish the clinical characteristics and diagnostic assessment of compressive radial neuropathy. Methods : Retrospectively, we reviewed neurophysiologic studies on 25 patients diagnosed with radial nerve palsy, who experienced wrist drop after maintaining a certain posture for an extended period. The neurologic presentations, clinical prognosis, and electrophysiology of the patients were obtained from medical records. Results : Subjects were 19 males and 6 females. The median age at diagnosis was 46 years. The right arm was affected in 13 patients and the left arm in 12 patients. The condition was induced by sleeping with the arms hanging over the armrest of a chair because of drunkenness, sleeping while bending the arm under the pillow, during drinking, and unknown. The most common clinical presentation was a wrist drop and paresthesia on the dorsum of the 1st to 3rd fingers. Improvement began after a mean of 2.4 weeks. Electrophysiologic evaluation was performed after 2 weeks that revealed delayed nerve conduction velocity in all patients. Conclusion : Wrist drop is an entrapment syndrome that has a good prognosis within several weeks. Awareness of its clinical characteristics and diagnostic assessment methods may help clinicians make diagnosis of radial neuropathy and exclude irrelevant evaluations.