Experimental Study on the Dielectric Breakdown Voltage of the Insulating Oil Mixed with Magnetic Nanoparticles

AbstractIn this study, we have measured the dielectric breakdown voltage of transformer oil-based nanofluids in accordance with IEC 156 standard and have investigated the dielectric breakdown performance with the application of an external magnetic field and different volume concentrations of magnetic nanoparticles. It is confirmed that the dielectric breakdown voltage of pure transformer oil is about 10kV with a gap distance of 1mm between electrodes. In the case of our transformer oil-based nanofluids with 0.08% < Φ < 0.39% (Φ means the volume concentration of magnetic nanoparticles in the fluid), the dielectric breakdown voltage is three times higher than that of pure transformer oil. Furthermore, when the external magnetic field is applied under the experimental vessel, the dielectric breakdown voltage of the nanofluids is above 40kV, which is 30% higher than that without the external magnetic field

Clinical disease characteristics according to karyotype in Turner syndrome

Purpose : Turner syndrome (TS) is a disorder in which various anomalies can be accompanied, especially cardiovascular, renal, thyroid and auditory problems. The aim of this study is to identify the incidence of these disorders in patients with TS according to karyotype. Methods : We reviewed medical records of 90 patients with TS diagnosed by chromosomal analysis in 4 hospitals from Jan 1998 to Dec 2007. We evaluated these cases by prepared protocol of 4 medical problems. Results : The distribution of karyotype was 45,X (47.8&#37;), mosaic pattern (34.4&#37;) and structural aberration group (17.8 &#37;). Renal anomalies, cardiovascular anomalies, thyroid disorders and auditory problems are accompanied in 4.4&#37;, 10.0 &#37;, 11.1&#37; and 5.6&#37;, respectively. 45,X group had renal anomalies (7.0&#37;), cardiovascular anomalies (18.6&#37;), thyroid disorders (9.3&#37;) and auditory problems (11.6&#37;). Mosaic group had renal anomalies (3.2&#37;), thyroid disorders (12.9&#37;), no cardiovascular anomalies and auditory problems. Structural aberration group had cardiovascular anomalies (6.3&#37;), thyroid disorders (12.5&#37;) and no other 2 problems. Patients with 45,X group had a significant higher incidence of cardiovascular anomalies (P&#61;0.025). Conclusion : Our results indicate that there are differences clinically according to karyotype of TS, especially in incidence of cardiovascular anomalies

Favored serum albumin level and ICF volume after use of 1.1% aminoacid based peritoneal dialysis(PD) solution

Aminoacid based PD solution (AAD) has been shown to induce positive nitrogen balance and improve nutritional markers of malnourished patients. But its effcets on body fluid composition and various nutritional markers are contradictory. Nutritional markers may influenced by patient's ECF volume status. So we evaluate effects of AAD on nutritional markers and body composition by analysis using multi-frequency bioimpedance analyzer. 35 PD patients(>6months duration of CAPD) were prospectively randomized to 17 AAD(Nutrineal, one time use/day) and 18 GD group(keep their glucose based PD solution). After 3 months follow up, AAD group showed marginally increased body weight and fat mass, decreased ECF volume(12.45±0.54Lvs 12.10±0.57L, p=0.06), no changed ICF volume(22.2±0.9Lvs 22.3±0.9L, p>0.05) and marginally increased drainage volume(8.77±0.76Lvs 9.12±0.83L, p=0.09). AAD group also showed favored several markers include nPCR(1.59±0.07vs 1.98±0.08, p=0.00), BUN and albumin level (3.54±0.11 vs 3.74±0.11, p=0.02). Although serum albumin level was increased, correction with ECF volume(albumin level X ECF volume) makes it no difference (43.45±2.13vs 44.80±2.28, p=0.14). Furthermore △albumin vs △ECF showed negative correlation pattern(r=-0.46, p=0.07) that means serum albumin change was influenced by ECF volume change. In conclusion, AAD treatment improved markers of better nutritional status. However the change in serum albumin level was influenced by patient's ECF volume status, which can partially explain contradictory effect of aminoacid based PD solution on serum albumin level