Yun-Tae Kim

Implementation of FlexRay protocol with an automotive application

FlexRay is a high-speed communications protocol with high flexibility and reliability. It was devised by automotive manufacturers and semiconductor vendors. FlexRay provides a high speed serial communication, time triggered bus and fault tolerant communication between electronic devices for automotive applications. In this paper, we first design the FlexRay communication controller, bus guardian protocol specification and function parts using SDL (specification and description language). Then, the system is re-designed using Verilog HDL based on the SDL source. The FlexRay system is synthesized using Samsung 0.35 muml technology. It is shown that the designed system can operate in the frequency range up to 76 MHz. In addition, the FlexRay system is implemented using ALTERA excalibur ARM EPXA4F672C3 with a bus driver chip AS8211. It is shown that the implemented system operates successfully in automobile advance alarm system in vehicle applications.

Factors Affecting the Postoperative Outcome in Adult Cardiac Surgery with Cardiopulmonary Bypass

We defined factors affecting the postoperative outcome in adult cardiac surgery with cardiopulmonary bypass (CPB). Thirty-two adult patients scheduled for elective cardiac surgery participated in this study. Levels of leukocyte, glutamic oxaloacetic transaminase (GOT), troponin-I (cTNI), interleukin-6 (IL-6), D-dimer and neuron-specific enolase (NSE) were significantly elevated, whereas platelet count declined in cardiac surgery with CPB. GOT and D-dimer levels at CPB-off each had a positive significant correlation significantly with 24 hrs-bleeding, total bleeding, mechanical ventilatory assist time, ICU stay time and length of hospitalization. BUN levels at CPB-off were directly related to total bleeding, mechanical ventilatory assist time, ICU stay time and length of hospitalization. Platelet count at CPB-off was inversely related to mechanical ventilatory assist time, ICU stay time and length of hospitalization. Creatinine concentration at CPB-off interrelated positively with mechanical ventilatory assist time and ICU stay time. NSE levels at CPB-off had a positive relationship with postoperative 24 hrs-bleeding. The length of hospitalization was prolonged proportionally to the elevation of cTNI levels in cardiac surgery. Aortic cross-clamping and total CPB times also related with increase of 24 hrs and total bleeding volumes and the length of hospitalization. IL-6 and ET-1 had no mutual relation with any postoperative outcome. These data suggest that GOT, BUN, creatinine, D-dimer and platelet levels are the most important factors affecting postoperative outcomes and patients recovery in adult cardiac surgery with CPB.

Prevalence of Human Papillomavirus by DNA Chip Test in Women

We determined the prevalence of human papillomavirus (HPV) by DNA chip test in 549 women and cytologic diagnosis. 237 of 549 women (43.17%) subjected with HPV DNA Chip examination were found positive for HPV. 210 (88.60%, High group) were infected with high-risk HPV types. 17 (7.17%, Low group) were infected with low-risk HPV types (6, 11, 40, 44, 70) and 17 (7.17%, Mixed group) were infected with mixed types. According to age, in their twenties, thirties, forties, fifties and over sixties, the prevalence of infection with high-risk HPV types were 1.26% (3/237), 15.61% (37/237), 31.65% (75/237), 23.21% (55/237), and 13.92% (33/237), respectively. In the Low and Mixed group, percentages of infection with HPV were significantly lower than that of the High group. On the comparison of cytologic diagnosis (224 women) by Pap smear and DNA chip positive (237 women) for HPV, 132 out of 194 cases in the High group (68.04%) suffered cervical lesions with ASCUS (atypical squamous cells of undetermined significance, 7.22%), LSIL (low grade squamous intraepithelial lesion, 15.98%), HSIL (high grade SIL, 23.20%) and ICC (invasive cervical cancer, 21.65%). The Low group (14/224 women) showed 1 case of ASCUS and 6 cases of LSIL, whereas the Mixed group (4/224 women) had only 2 cases of ASCUS. According to the HPV subtypes, the high-risk types 16 and 18 induced 26 and 7 cases of ICC, respectively, whereas other HPV subtypes induced lower or no ICC incidence. In conclusion, the present data imply that the prevalence of HPV was 43.17%, high-risk HPV type 16 is a major factor, which causes precancerous and/or cervical cancer in woman and that HPV DNA chip is an accurate and useful tool for detecting HPV.

Analysis of the Correlations between the Serum Levels of Cytokines and Postoperative Outcomes in Valvular Heart Surgery with Cardiopulmonary Bypass

Cytokines play a pivotal role in systemic inflammatory response following cardiac surgery with cardiopulmonary bypass (CPB). The purpose of this study was to investigate the perioperative changes in proinflammatory [tumor necrosis factor- (TNF-) and interleukin-6 (IL-6)] and antiinflammatory cytokines [interleukin-10 (IL-10)], and each correlation between the cytokines and other variables in valvular heart surgery with CPB. Serum IL-6 and IL-10 levels and leukocyte counts significantly increased following CPB. CPB caused hepatic, renal and myocardial dysfunctions. IL-6 levels had positive correlations with IL-10 levels at postoperative periods. TNF- levels had correlations with leukocyte counts and myocardial marker levels at postoperative 24 hr (PO-24 h). Furthermore, IL-6 or IL-10 levels had positive correlations with other variable such as hepatic, renal or myocardial marker at postoperative periods. These results showed that balance between proinflammatory and antiinflammatory cytokines is maintained during cardiac surgery with CPB, and that these cytokines exert postoperatively inflammatory and antiinflammatory reactions.