The single particle motion analysis and particle-in-cell merged with Monte Carlo collision (PIC/MCC) simulations are compared to explain substantial breakdown voltage reduction for helium microwave discharge above a critical frequency corresponding to the transition from the drift-dominant to the diffusion-dominant electron loss regime. The single particle analysis suggests that the transition frequency is proportional to the product ofp m and ( )where p is the neutral gas pressure, d is the gap distance, and m is a numerical parameter, which is confirmed by the PIC simulation. In the low-frequency or drift-dominant regime, i.e., -g regime, the secondary electron emission induced by ion drift motion is the key parameter for determining the breakdown voltage. The fluid analysis including the secondary emission coefficient, g, induces the extended Paschen law that implies the breakdown voltage is determined by pd, f p, g, and d R where f is the frequency of the radio or microwave frequency source, and R is the diameter of electrode. The extended Paschen law reproduces the same scaling law for the transition frequency and is confirmed by the independent PIC and fluid simulations.

Pulsed microwave driven microplasma at atmospheric pressure is proposed as an efficient source of energetic electrons for low-temperature biomedical applications. Energetic electrons are required to break the covalent bonds of nitrogen, oxygen, and water molecules in humid air and produce reactive species. Particle-in-cell (PIC) simulations demonstrate that the energetic electrons with energy greater than 10 eV (capable of breaking the bond of nitrogen molecules) can be produced much more efficiently in pulsed microwave helium plasmas than in pulsed DC or continuous microwave plasmas.In particular, fast heating and cooling of electrons are observed at the rising edge and the falling edge of the pulse, respectively. This phenomenon is consistent with the fluid analysis showing the electrons' energy gain via collective motion and collisional loss to the neutral particles.

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Epidemiologic studies of pediatric bone and joint infection have been done mostly by developed Western countries, and such results could be expected to be biased. Therefore, an epidemiologic study to identify the distinct features of an Eastern country would be beneficial to improve their health outcomes and to reduce health care cost. A study was planned to investigate the epidemiology of pediatric osteomyelitis and septic arthritis in South Korea and to find out epidemiologic factors related with the occurrence of surgery.We conducted a cross-sectional study among hospitalized pediatric patients (<18 years old) with osteomyelitis and septic arthritis using nationwide cohort based on the Health Insurance Review and Assessment Service (HIRA) from 2008 to 2016. Percentage of hospitalization was additionally calculated according to several epidemiologic factors including age, month, site of infection, and region of residence. Logistic regression analysis was performed to find out the association between epidemiologic factors and occurrence of surgeryAnnual hospitalization rates (per 100,000) in our country were 7.8 to 9.1 for osteomyelitis, and 11.9 to 20.8 for septic arthritis. Frequent sites of osteomyelitis and septic arthritis were pelvis and lower extremity. The hospitalization rates of osteomyelitis and septic arthritis showed increasing trend with age. After multivariate logistic regression analysis, female gender, children, and adolescents rather than infants, rural area rather than urban area were associated with significantly increased odd ratios for surgery.The hospitalization rate of septic arthritis (11.9 to 20.8 per 100,000) in South Korea was higher than the Western countries (1.1 to 11 per 100,000), and the hospitalization rate of osteomyelitis (peak at 12 years) and septic arthritis (peak at 17 years) showed increasing trend with age, which was different from those of the developed Western countries showing higher incidence in children aged under 5 years. After multivariate logistic regression analysis, our study identified female gender, higher age group including children, and adolescents, and rural residence as epidemiologic risk factors associated with surgery.

For patients with kyphosis of the cervical spine, laminoplasty is usually incapable of improving neurological symptoms as it worsens kyphotic alignment. Thus, laminoplasty is not recommended in the presence of kyphotic alignment. Nevertheless, laminoplasty may be selected for myelopathy due to multiple-segment intervertebral disc herniation or ossification of posterior longitudinal ligament despite kyphotic alignment. This study examined whether cervical alignment influences surgical outcomes. Cervical alignment before the surgery was classified into lordosis and non-lordosis, and the non-lordosis group was subclassified into reducible and non-reducible groups to determine the change in cervical alignment before and after the surgery and to analyze its relationship with spinopelvic parameters. The lordosis group showed an increase in upper cervical motion (C0-2 Range of Motion (ROM), C0-2ROM/C0-7ROM) after surgery, while the non-lordosis group exhibited a decrease in C2-7ROM and C0-7ROM. The C0-2ROM was maintained without any reduction in the reducible group, while there was no significant change in cervical alignment and ROM of the non-reducible group. None of these changes showed significant association with the spinopelvic parameters of other sites. However, having a non-reducible type non-lordosis is not a proper indication for laminoplasty, as it does not change the alignment after surgery. Therefore, cervical alignment and reducibility should be identified before surgery.