• Journal of Veterinary Clinics
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• v.33 no.6
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• pp.381-384
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• 2016

A 7-year-old intact female Maltese dog was referred to the hospital with a history of paresis in the hind limbs, left head turn, and a loss of balance that persisted for 2 weeks. Her condition was initially managed with steroids, prescribed by the referring veterinarian, but her neurological symptoms were not alleviated. Physical and neurological examinations, radiography, computed tomography, and magnetic resonance imaging were performed. Based on the findings on these examinations, caudal occipital malformation syndrome (COMS) with syringohydromyelia was diagnosed. Medical treatment was not effective in the previous trial; therefore, foramen magnum decompression, durotomy, and free autogenous adipose tissue grafting were performed. After 3 days, an improvement was observed in the clinical symptoms and was maintained for 8 months postoperatively. Based on the results, it is suggested that the decompression method with a fat graft may be considered an effective surgical treatment for the management of COMS that did not respond well to previous medical treatment.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.11 no.8
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• pp.1465-1471
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• 2007

The electro-magnetic wave propagates through the air in the terrestrial communications, but the acoustic wave propagates through the seawater in the underwater acoustic communication(UAC). It makes the differences between the UAC link and the well hon air communication links. In this paper, we have studied path loss, absorption and ambient noise of the ocean as a medium for UAC. We have analyzed the absorption coefficient and ambient noise level of the coastal area of South Korea and suggested a strategy for the selection of the frequency band by considering the absorption coefficient and ambient noise level. Also, we present an illustrative example of a link budget for the QPSK UAC system which has carrier frequency 25kHz, bit rate 10kbps, range 1km and BER $10^{-3}$ in the shallow water environment with an ideal AWGN assumption.

• The Korean Journal of Pain
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• v.34 no.4
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• pp.471-478
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• 2021

Background: The effect of lumbar spinal stenosis (LSS) and peripheral vascular disease (PVD), which occurs with similar degenerative conditions, when seen together, has not been studied. The aim of this study is to examine and compare the relationship between pain, balance, disability, fear of falling, and kinesiophobia in LSS patients with intermittent vascular claudication (IVC). Methods: Seventy-two patients diagnosed with LSS using magnetic resonance imaging participated in this study. Thirty-five patients with IVC symptoms and showing vascular lesions by lower extremity venous and arterial Doppler ultrasonography imaging were included in the IVC-LSS group. The pain, static balance, dynamic balance, disability, fear of falling, and kinesiophobia were evaluated using the numeric rating scale, single leg stance test, Time Up and Go (TUG), the Oswestry Disability Index (ODI), Fall Efficacy Scale-International (FES-I), and Tampa Scale for Kinesiophobia (TSK), respectively. Results: Age and female sex were found to be higher in the IVC-LSS group (P = 0.024; P = 0.012). The IVC-LSS group had a shorter single leg stance time and TUG test duration, pain intensity, ODI, FES-I, and TSK scores were higher than patients with LSS (P = 0.001). Pain, fear of falling, and kinesiophobia were moderately correlated with disability in the IVC-LSS group. No relationship was found between pain and dynamic balance. Also, the pain was not related to kinesiophobia. Conclusions: The findings indicated that IVC causes loss of balance and an increase in pain, disability, fear of falling, and kinesophobia in patients with LSS.

• Nano
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• v.13 no.11
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• pp.1850125.1-1850125.12
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• 2018

To reduce the imbalance of impedance matching between the magnetic metal nanowires and free space, $Fe/TiO_2$ core/shell nanowire arrays with different diameters were fabricated in the templates of anodic aluminum oxide membranes by electrodeposition. The influences of the microstructure on the microwave absorption properties of the $Fe/TiO_2/Al_2O_3$ composites were studied by the transmission/reflection waveguide method. It was demonstrated experimentally that both the interfacial polarization and the diameter of the $Fe/TiO_2$ core/shell nanowires have critical effects on the microwave absorption properties. We also investigated the angle dependence of the microwave absorption properties. Due to the interfacial polarization and associated relaxation, the $Fe/TiO_2/Al_2O_3$ composites exhibited optimal microwave absorption properties when microwave propagation direction was accordant with the axis of the nanowires. Finally, we managed to obtain an optimal reflection loss of below -10 dB (90% absorption) over 10.2-14.8 GHz, with a thickness of 3.0 mm and the minimum value of -39.4 dB at 11.7 GHz.

• Journal of IKEEE
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• v.22 no.4
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• pp.1068-1072
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• 2018

In underwater communications, there are many challenges due to energy limitations, long propagation delay, low data rate, and high power loss, unlike terrestrial RF communications. Especially, the propagation delay of underwater acoustic channel is five orders of magnitude higher than in electro-magnetic terrestrial channels due to the low speed of sound(1,500m/s). Thus, the MAC protocols for terrestrial communications are not suitable for underwater network. In this paper, we studied the considerations for MAC protocol in underwater acoustic channel. Here, we concentrated on CSMA based MAC protocols. From the results, we confirmed that the number of control packets has an important effect on the performance in underwater environment. These results would be useful in designing MAC protocols for underwater acoustic communications.

• The Korean Journal of Pain
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• v.32 no.4
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• pp.271-279
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• 2019

Background: We utilized diffusion tensor imaging (DTI) to evaluate the cerebral white matter changes that are associated with phantom limb pain in patients with unilateral arm amputation. It was anticipated that this would complement previous research in which we had shown that changes in cerebral blood volume were associated with the cerebral pain network. Methods: Ten patients with phantom limb pain due to unilateral arm amputation and sixteen healthy age-matched controls were enrolled. The intensity of phantom limb pain was measured by the visual analogue scale (VAS) and depressive mood was assessed by the Hamilton depression rating scale. Diffusion tensor-derived parameters, including fractional anisotropy, mean diffusivity, axial diffusivity (AD), and radial diffusivity (RD), were computed from the DTI. Results: Compared with controls, the cases had alterations in the cerebral white matter as a consequence of phantom limb pain, manifesting a higher AD of white matter in both hemispheres symmetrically after adjusting for individual depressive moods. In addition, there were associations between the RD of white matter and VAS scores primarily in the hemispheres related to the missing hand and in the corpus callosum. Conclusions: The phantom limb pain after unilateral arm amputation induced plasticity in the white matter. We conclude that loss of white matter integrity, particularly in the hemisphere connected with the missing hand, is significantly correlated with phantom limb pain.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.21 no.2
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• pp.143-149
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• 2021

BLDC motors are getting better performance due to the improvement of material technology including high performance of permanent magnets, advancement of driving IC technology with high integration and high functionality, and improvement of assembly technology such as high point ratio. While having the advantage of such a square wave driven BLDC motor, interest in the design and development of a square wave driven BLDC permanent magnet motor and development of a position detection circuit and driver is increasing in order to more meet the needs of users. However, in spite of the cost and functional advantages due to reduced efficiency, switching loss and vibration, noise, etc., the application is somewhat limited. Therefore, in this paper, we study a position detection circuit that generates a sinusoidal signal in proportion to the magnetic flux of a BLDC motor rotor using a Hall Effect Sensor that generates a sinusoidal wave to increase the efficiency of the motor, reduce ripple, and drive a sinusoidal current with excellent speed and torque characteristics.

• Journal of Genetic Medicine
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• v.18 no.2
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• pp.127-131
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• 2021

Autosomal recessive spinocerebellar ataxia 20 (SCAR20; OMIM #616354) is a recently described disorder that is characterized by ataxia, intellectual disability, cerebellar atrophy, macrocephaly, coarse face, and absent speech. It is caused by loss-of-function mutations in SNX14. To date, all cases with homozygous pathogenic variants have been identified in consanguineous families. This report describes the first Korean cases of SCAR20 family caused by homozygous variants in SNX14. Two siblings were referred to our clinic because of severe global developmental delay. They presented similar facial features, including a high forehead, long philtrum, thick lips, telecanthus, depressed nasal bridge, and broad base of the nose. Because the older sibling was unable to walk and newly developed ataxia, repeated brain magnetic resonance imaging (MRI) was performed at the age of 4 years, revealing progressive cerebellar atrophy compared with MRI performed at the age of 2 years. The younger sibling's MRI revealed a normal cerebellum at the age of 2 years. Whole-exome sequencing was performed, and homozygous variants, such as c.2746-2A>G, were identified in SNX14 from the older sibling. Sanger sequencing confirmed homozygous SNX14 variants in the two siblings as well as a heterozygous variant in both parents. This report extends our knowledge of the phenotypic and mutational spectrum of SCAR20. We also highlight the importance of deep phenotyping for the diagnosis of SCAR20 in individuals with developmental delay, ataxia, cerebellar atrophy, and distinct facial features.

• Clinics in Shoulder and Elbow
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• v.25 no.1
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• pp.22-27
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• 2022

Background: In some patients with rotator cuff tear (RCT), the axial view of magnetic resonance imaging (MRI) shows subtle posterior decentering (PD) of the humeral head from the glenoid fossa. This is considered to result from a loss of centralization that is typically produced by rotator cuff function. There are few reports on PD in RCT despite the common occurrence of posterior subluxation in degenerative joint disease. In this study, we investigated the effect of PD in arthroscopic rotator cuff repair (ARCR). Methods: We conducted a retrospective study of consecutive patients who underwent ARCR at our institute and were followed-up for at least 1 year. PD was identified as a 2-mm posterior shift of the humeral head relative to the glenoid fossa in the axial MRI view preoperatively. The tear size and fatty degeneration (FD, Goutallier classification) were also evaluated using preoperative MRI. Retears were evaluated through MRI at 1 year postoperatively. Results: We included 135 shoulders in this study. Ten instances of PD (including seven retears) were observed preoperatively. Fifteen retears (three and 12 retears in the small/medium and large/massive tear groups, respectively) were observed postoperatively. PD was significantly correlated with tear size, FD, and retear occurrence (p<0.01 each). The odds ratio for PD in retears was 34.1, which was greater than that for tear size ≥3 cm and FD grade ≥3. Conclusions: We concluded that large tear size and FD contribute to the occurrence of PD. Furthermore, PD could be a predictor of retear after ARCR.

• Korean Journal of Veterinary Service
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• v.45 no.2
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• pp.139-143
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• 2022

A 10-year-old, spayed female miniature schnauzer was referred to the Veterinary Medical Teaching Hospital of Chungnam National University due to evaluation of sudden polyuria (PU) and, polydipsia (PD) (540 mL/kg/day) with severe anemia and weight loss. Blood examination results were normal except for severe anemia (hematocrit, [HCT]: 11.8%). Urinalysis revealed a urine specific gravity (USG) of 1.003, whereas urine sediment was not specific. Urine osmolality was 90 mOsm (reference range: 800~2500 mOsm), and plasma osmolality was 303 mOsm. No specific lesions were found using diagnostic imaging including radiography, ultrasonography and magnetic resonance imaging (MRI). The serum cortisol level was normal in cosyntropin stimulation test. Plasma arginine vasopressin (AVP) concentration was <0.4 pg/mL (reference range: 3.49~5.45 pg/mL). Blood transfusion was initiated in addition to an oral prescription of desmopressin acetate (DDAVP, 0.1 mg/head) thrice a day for one week. The patient was rechecked for clinical signs, urine osmolality, and USG; the clinical signs of PU/PD were resolved, urine osmolality increased to 1106 mOsm, and, USG increased to 1.021. Considering the improved clinical signs, and increased urine osmolality, and USG after DDAVP treatment, the dog was diagnosed with central diabetes insipidus. USG and urine osmolality increased to >1.030 and 2200 mOsm, respectively. Anemia also gradually improved and HCT increased to >37%. DDAVP was tapered to 0.1 mg/head twice a day and all clinical signs in the patient have completely resolved.