Cutting-balloon angioplasty before drug-eluting stent implantation for the treatment of severely calcified coronary lesions

Background Severely calcified coronary lesions respond poorly to balloon angioplasty, resulting in incomplete and asymmetrical stent expansion. Therefore, adequate plaque modification prior to drug-eluting stent （DES） implantation is the key for calcified lesion treat- ment. This study was to evaluate the safety and efficacy of cutting balloon angioplasty for severely calcified coronary lesions. Methods Ninety-two consecutive patients with severely calcified lesions （defined as calcium arc 〉 180% calcium length ratio 〉 0.5） treated with bal- loon dilatation before DES implantation were randomly divided into two groups based on the balloon type： 45 patients in the conventional balloon angioplasty （BA） group and 47 patients in the cutting balloon angioplasty （CB） group. Seven cases in BA group did not satisfactorily achieve dilatation and were transferred into the CB group. Intravascular ultrasound （IVUS） was performed before balloon dilatation and after stent implantation to obtain qualitative and quantitative lesion characteristics and evaluate the stent, including minimum lumen cross-sectional area （CSA）, calcified arc and length, minimum stent CSA, stent apposition, stent symmetry, stent expansion, vessel dissection, and branch vessel jail. In-hospital, 1-month, and 6-month major adverse cardiac events （MACE） were reported. Results There were no statistical differences in clinical characteristics between the two groups, including calcium arc （222.2° ± 22.2° vs. 235.0° ± 22.1 °, p=0.570）, calcium length ratio （0.67 ± 0.06 vs. 0.77± 0.05, P = 0.130）, and minimum lumen CSA before PCI （2.59 ±0.08 mm2 vs. 2.52 ± 0.08 mm2, P = 0.550）. After stent implantation, the final minimum stent CSA （6.26 ± 0.40 mm2 vs. 5.03 ± 0.33 mm2; P = 0.031） and acute lumen gain （3.74 ±0.38 mm2 w. 2.44 ± 0.29 mm2, P = 0.015） were significantly larger ila the CB group than that of the BA group. There were not statis tically differences in stent expansion, stent symmetry, incomplete stent apposition, vessel dissection and branch vessel jail between two groups. The 30-day and 6-month MACE rates were also not different. Conclusions Cutting balloon angioplasty before DES implantation in severely calcified lesions appears to be more efficacies including significantly larger final stent CSA and larger acute lumen gain, without increasing complications during operations and the MACE rate in 6-month.

Effects of Total-Ionizing-Dose Irradiation on Single-Event Burnout for Commercial Enhancement-Mode AlGaN/GaN High-Electron Mobility Transistors

We investigate the synergism effect of total ionizing dose(TID)on single-event burnout(SEB)for commercial enhancement-mode AlGaN/GaN high-electron mobility transistors.Our experimental results show that the slight degradation of devices caused by gamma rays can affect the stability of the devices during the impact of high energy particles.During heavy ion irradiation,the safe working values of drain voltage are significantly reduced for devices which have already been irradiated by 60Co gamma rays before.This could be attributed to more charges trapped caused by 60Co gamma rays,which make GaN devices more vulnerable to SEB.Moreover,the electrical parameters of GaN devices after 60Co gamma and heavy-ion irradiations are presented,such as the output characteristic curve,effective threshold voltages,and leakage current of drain.These results demonstrate that the synergistic effect of TID on SEB for GaN power devices does in fact exist.

Simulation of Synergism Effect Using Temperature Switching Irradiation on Bipolar Comparator

The synergism effect of total ionizing dose（TID） on a single event transient（SET） in a bipolar comparator is investigated. Experimental results show that the shapes of the SET are considerably influenced by the TID accumulated in low dose rates. The variation tendency of SET shapes can be accurately simulated by temperature switching irradiation. The mechanism of this synergism effect is also analyzed in brief via the operating schematic of a comparator. After the accumulation of 100 krad（Si）, the lower tendency of negative SET can be attributed to the degeneration of . The change tendency of a positive SET, either lower or higher, is dependent on the load condition that limits the output range of the comparator.

Estimation of enhanced low dose rate sensitivity mechanisms using temperature switching irradiation on gate-controlled lateral PNP transistor

The mechanisms occurring when the switched temperature technique is applied,as an accelerated enhanced low dose rate sensitivity(ELDRS)test technique,are investigated in terms of a specially designed gate-controlled lateral PNP transistor(GLPNP)that used to extract the interface traps(Nit)and oxide trapped charges(Not).Electrical characteristics in GLPNP transistors induced by ^(60)Co gamma irradiation are measured in situ as a function of total dose,showing that generation of Nit in the oxide is the primary cause of base current variations for the GLPNP.Based on the analysis of the variations of Nit and Not,with switching the temperature,the properties of accelerated protons release and suppressed protons loss play critical roles in determining the increased Nit formation leading to the base current degradation with dose accumulation.Simultaneously the hydrogen cracking mechanisms responsible for additional protons release are related to the neutralization of Not extending enhanced Nit buildup.In this study the switched temperature irradiation has been employed to conservatively estimate the ELDRS of GLPNP,which provides us with a new insight into the test technique for ELDRS.