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OBJECTIVE Magnetic resonance imaging (MRI) is the gold-standard tool for diagnosing lumbar spinal stenosis (LSS), but it is difficult to promptly examine all suspected cases with MRI considering the modality’s high cost and limited accessibility. Although radiography is an efficient screening technique owing to its low cost, rapid operability, and wide availability, its diagnostic accuracy is relatively poor. In this study, the authors aimed to develop a deep learning model with a convolutional neural network (CNN) for diagnosing severe central LSS using radiography and to evaluate radiological diagnostic features using gradient-weighted class activation mapping (Grad-CAM). METHODS Patients who had undergone both spinal MRI and radiography in the period from May 1, 2005, to December 31, 2017, were screened. According to the formal MRI report, participants were consecutively included in the severe central LSS or healthy control group, and radiographs for both groups were collected. A CNN-based transfer learning algorithm was developed to classify radiographic findings as LSS or normal (binary classification). The proposed models were evaluated using six performance metrics: area under the receiver operating characteristic curve (AUROC), accuracy, sensitivity, specificity, and positive and negative predictive values. RESULTS The VGG19 model achieved the highest accuracy with an AUROC of 90.0% (95% CI 89.8%–90.3%) by training 12,442 images. Accuracy was 82.8% (95% CI 82.5%–83.1%) by averaging 5-fold models. Feature points on Grad-CAM were reasonable, and the features could be categorized into reduced disc height, narrow foramina, short pedicle, and hyperdense facet joint. The AUROC in the extra validation was 89.3% (95% CI 88.7%–90.0%). Accuracy was 81.8% (95% CI 80.6%–83.0%) by averaging 5-fold models. Multivariate logistic regression analysis showed that a combination of demographic factors (age and sex) did not improve the model performance. CONCLUSIONS The algorithm trained by a CNN to identify central LSS on radiographs showed high diagnostic accuracy and is expected to be useful as a triage tool. The algorithm could accurately localize the stenotic lesion to assist physicians in the identification of LSS.

The plasma healing of acute wound on 56 hairless mice is examined and initiated by several externally controlled physical parameters such as driving frequency and power, duration and interval of plasma treatment, a fraction of air mixture, the gap distance between plasma and wound, and others. The variation of these physical parameters results in a different amount of reactive oxygen and nitrogen species (RONS), which stimulate the regulation of RONS in mouse tissue before revealing several important bioindicators in the process of wound healing. While focusing on an important physical indicator such as the wound size, the limited examination with 56 mice showed promising results [much improved over the previous mice experiments by single-frequency plasma (SP)] by Dual-frequency plasma (DP) with 2% air mixture to argon, which effectively correlates with the observation of optical emission spectra. Circular acute wounds treated by DP (2%) were reduced to 24% in just 8 h after the treatment and further reduced to 5% within a few days.

BACKGROUND A lifestyle characterized by poor eating habits and physical inactivity is a risk factor for multiple lifestyle diseases in young adults. This study assessed the effects of implementing an intensive 10-day health promotion program combining diet and physical activities on body composition, physical fitness, and biochemical parameters of young adults. MATERIAL AND METHODS In this randomized pilot study, 30 female undergraduate students were randomly allocated to an intervention and a control group. The health promotion program consisted of unlimited amounts of vegetarian food; aerobic, flexibility, and strength exercises (3 hours/day); lectures on health (3 hours/day); massage practice (2 hours/day); and healthy cooking practice (1 hour/day). The effects of the intervention were analyzed using the Mann-Whitney U test and the Wilcoxon signed-rank test. RESULTS The intensive 10-day health promotion program significantly reduced body weight, body mass index, triglyceride, total cholesterol, low-density lipoprotein cholesterol, blood glucose, and the homeostasis model assessment of insulin resistance. At the same time, participants demonstrated increased back muscle, leg muscle, and grip strength; waist and shoulder flexibility; balance; and cardiorespiratory endurance. CONCLUSIONS The intensive 10-day health promotion program is a viable intervention for improving body composition, physical fitness, glycemic control, and blood lipid levels in young adults.

Kinetic theory of electron acoustic waves (EAWs) in the presence of wave angular momentum has been derived to study the effect of wave angular momentum on the propagation of EAWs in a non-Maxwellian plasma. Both types of electrons (hot and cool) are modeled as Kappa distributed velocity distribution functions. The theory is also applied to Saturn's magnetosphere where these kinds of distribution functions are commonly found. It is seen that the presence of wave angular momentum in the model has a significant effect on the existence of the regions where EAWs are weakly damped. The effect of wave angular momentum on EAWs is studied by defining a parameter η = k/(lqθ), which is the ratio of the planar wave number to the azimuthal wave number. The wave is purely planar if η→∞. The weakly damped region of EAWs depends strongly on this parameter in addition to other parameters such as hot electron spectral index κh, cool electron spectral index κc, the fraction of hot electrons, and hot to cool electrons temperature ratio. The results also show the effect of η on the propagation of EAWs in various region of the Saturn's magnetosphere.

Using Ar/Air mixture microwave plasma, we investigated the effects of air and gas temperature on the generation of electrons, ozone (O3), and nitric oxide (NO) through experiments and chemical kinetics simulation. The global model (GM) chemical kinetics simulation was used to validate and complement experimental observations. As the air percentages in Ar plasma increase, electrons are mainly generated by reactive oxygen species (ROS), but electron densities decrease. This is why plasma jet length becomes shorter with the mixture of air to Ar plasma at the same power. The profile of O3 densities has a maximum point because these are affected by oxygen (O2) molecules and gas temperature. O3 densities increase because these are generated via recombination of atomic oxygen (O) and O2 radicals as the air percentages increase. As the gas temperature increases, O3 densities decrease and O3 radicals are mainly destroyed by ROS such as O2−, excited O2, and O, although air percentages increase. NO radicals increase continually with the addition of air mixture and increase in gas temperature. With respect to biomedical applications, in the case of Ar/Air plasma treatment, it takes just 2 d, which has reduced the wound area to 30% because of faster scab formation over the wound and mRNA activation. Abundant NO radicals with ROS in Ar/aAir plasma strongly enhance IL-6 and TGF-β1, which facilitate collagen remodeling and wound recovery effectively.

To show the long-term fate of the herbicide mefenacet in rice paddies, [aniline-14C]mefenacet was applied to a lysimeter of loamy soil with a depth of 1 m, and rice plants were cultivated for 6 consecutive years according to the conventional methods in Korea. Mineralization of [14C]mefenacet to 14CO2 and volatilization from the soil surface were 12.01 and 0.02 %, respectively, of the originally applied amount during the first 23 weeks following application. Throughout the 6-year period, the total proportion of 14C-radioactivity that leached through the lysimeter soil was 0.778 % of the original radioactivity. The total 14C-radioactivity absorbed and translocated by rice plants throughout the 6 years was 2.46 % of the applied 14C. Measurement of the 14C-radioactivity distributed in each part of the rice plant (the straw, the ears without rice grain, the chaff, and the brown rice grain) indicated that the amount of 14C in straw was 25.87 times higher than that in brown rice grain over the 6 years. The 14C-radioactivity remaining in the soil layer after 6 years was 44.58 % of that applied, 91.45 % of which was distributed in the upper 0–20-cm layer. These results strongly indicate that mefenacet moved downward very slowly and more than half of the herbicide applied was released into the air, mainly through mineralization to CO2 in soil during the experimental period.

Non-thermal atmospheric pressure plasma (NTP) has been shown to induce cell death in various mammalian cancer cells. Accumulated evidence also shows that NTP could be clinically used in cancer therapy. However, the current NTP-based applications lack target specificity. Here, a novel method in NTP-mediated cancer therapeutics was described with enhanced target specificity by treating EGF (epidermal growth factor)-conjugated GNP (gold nanoparticle). The treatment with EGF-conjugated GNP complex, followed by NTP irradiation showed selective apoptosis of cells having receptor-mediated endocytosis. NTP triggered γ–H2AX elevation which is a typical response elicited by DNA damage. These results suggest that EGF-conjugated GNP functions as an important adjuvant which gives target specificity in applications of conventional plasma therapy.

Large aspect ratio plasma jets with sub-mm diameter are produced by a microwave coaxial resonator electrode. The jet length shows a sharp asymmetric dependence on the drive frequency: the plasma jet suddenly turns off below a critical frequency while the jet length slowly decreases above the frequency. A general mechanism is proposed to explain the asymmetry based on a universal feedback relation among the plasma impedance, the power coupling efficiency and the plasma dimension in resonator type electrodes. The input impedance of the resonator electrode changes depending on the plasma size formed in the electrode. The degree of the impedance mismatch between the electrode-plasma and the power source determines the power coupling efficiency and the resistive loss in the electrode which in turn affects the plasma size. The asymmetric dependence on the drive frequency is a consequence of the fact that the resonance frequency decreases for increasing plasma size. The feedback model shows a good agreement with the experimental measurements, providing essential information for the plasma control.

The breakdown transition mechanism, scaling law for transition frequency, and universal law for breakdown voltage of a Ramsauer gas Ar with various ranges of neutral gas pressure and micron gap distance between parallel electrodes are examined. The electron kinetics in argon gas is analyzed to understand the reason of the abrupt transition of breakdown voltage partitioning γ- and α-regimes. The quiver motion of electron in high frequency source implies that the breakdown voltage drastically drops when the oscillating amplitude of an electron becomes smaller than its critical value. The scaling law, which reveals that the transition frequency is inversely proportional to the neutral gas pressure and the gap distance to the fractional power, supports the conjecture about the transition mechanism, and this is confirmed by particle-in-cell incorporating Monte Carlo collision (PIC/MCC) simulations. Breakdown voltage as a function of the product of the neutral gas pressure and gap distance, the ratio of the driving frequency and neutral gas pressure, secondary electron emission coefficient induced by the ion bombardment, and the ratio of gap distance over the radius of electrodes is expressed by the universal law which, as well, are confirmed by the PIC/MCC and fluid simulations. Furthermore, no universality is observed at the plasma size of 3 μm with field emission under diversified neutral gas pressure.

Using surface type air atmospheric pressure plasma, we investigated the amount of ozone and other reactive species generation with variations of the surface temperature of an electrode through an optical emission spectrum and a tube type gas detector. Reduced version of global model (GM) was employed to complement these experimental observations. The results of the model matched well with the experimental data. The amount of ozone generated from the surface type air plasma device was dramatically reduced with increasing temperature. Atomic oxygen (O) and nitric oxide (NO) radicals, which are important agents for biomedical applications, proportionally increased with increasing temperature. We also elucidated the dominant reaction related to the generation or loss of these radicals based on temperature variation through our GM.

Oral cavity and teeth are important organs of human body. The attention and cost for dental treatments increase every year. In dental clinics, the most common diseases are dental caries, periodontal disease, and stomatitis. Dental aesthetics such as tooth whitening is one of important part of dental clinics. However, conventional treatment methods in dental clinics have limitations by pain and long-time treatment. Nonthermal plasmas have shown great potential as noble techniques to dental applications due to safety and multi-functional effects achieved by the abundant plasma components including charged particles, radiation, and reactive species. Reactive oxygen species generated from plasmas can effectively inhibit pathogen activity. The use of nonthermal plasmas is efficient in treating oral diseases because the construction of the plasma devices allows easy access to the oral cavity. However, few studies have been conducted on the use of plasmas in oral disease. Tooth aesthetics, as well as treatment of oral diseases, are important in determining the quality of human life. Recent studies have shown nonthermal plasmas to have strong tooth-bleaching effects. Studies on oral care using nonthermal plasmas will significantly contribute to oral health in the future.

Background We previously showed that cervical pedicle screw (CPS) placement is safe even with the freehand technique. The posterolateral fusion rate 1 year after CPS placement, as measured by computed tomography (CT), is reported here. The graft resorption rates when different graft materials were used were also analyzed. Methods Between 2012 and 2015, 93 patients underwent posterior cervical fusion surgery with the CPS from C2 to C7. Of these patients, 56 consented to CT scans immediately and 1 year after surgery. These patients formed the present study group. The patients were categorized according to whether the graft material was local bone, allograft, or a mixture. Graft volume was measured at both CT scans. Graft resorption rate was determined by comparing the 2 scans. Radiologic fusion was assessed on the 1 year postoperative CT scan and radiography. Results The reason for surgery was trauma ( n = 19), degenerative disease ( n = 35), tumor ( n = 1), and spondylitis ( n = 1). Surgery was performed with CPS fixation and decompression. Even although iliac bone grafting was not performed, the overall fusion rate was 98.2% (55/56). The single fusion failure case received a mixture of local bone and allograft. Although the allograft group showed the greatest graft resorption rate (91.5%), all patients in this group had a bony bridge that crossed the facet joint on the 1 year CT scan. Conclusions CPS placement yielded a posterolateral cervical fusion rate of 98.2%. Despite the high resorption rate of allograft only, this material yielded fusion rates that were similar to those of the other materials. Thus, the strong fixation power of CPS might compensate for the delayed fusion and high resorption rates of allograft bone chips.

Energy-based surgical devices are widely used to fuse tissues and seal vessels, but tissue adhesion to the instrument complicates the procedure. We deposit a robust non-stick coating on the jaws of LigaSure tissue fusion devices by employing an atmospheric pressure RFdriven plasma with hexamethyldisiloxane (HMDSO) entrained in argon carrier gas. The hydrophobicity, surface energy, surface topography, and chemical characteristics of deposited films are characterized by water contact angle measurements, surface energy test pens, atomic force microscopy, and Fourier transform infrared spectroscopy, respectively. We demonstrate significantly reduced tissue adhesion to HMDSO polymer film-coated instruments during the tissue fusion procedure in comparison with uncoated and chromium nitride-coated instruments.

Radio frequency (RF) driven hybrid gaswater plasma for tooth whitening was developed and the plasma chemical reactions with de-ionized (DI) water were studied. Plasma operating conditions, such as RF input power and argon flow rate were correlated with plasma lengths. The operation of hybrid gaswater plasma changed both the electrical conductivity and pH concentration of the DI water. OH and H2O2 densities were measured to determine the dominant species generated by plasma. The major chemical reaction pathways and known rate constants are given in support of the analysis of major chemical reaction pathways. Finally, we demonstrated that the hybrid gaswater configuration achieved porcine tooth whitening.

Unique atmospheric pressure plasma devices are designed to investigate the plasma characteristics for various driving frequencies under the same operating conditions. Electrical properties of the plasma, gas temperature, formation of plasma jets, and sterilization efficiency are studied for two different driving frequencies of 13 kHz (low frequency) and 877 MHz (microwave frequency). When compared with low frequency plasma, microwave plasma is found to have better electrical properties such as no electric shock for safety, high discharge current for effective chemical reactions, clean waveform for homogenous plasma, and high power coupling efficiency. Furthermore, microwave plasma leads to effective sterilization which is related to the high intensity of atomic oxygen. One-dimensional particle-in-cell simulation reveals that microwave plasma has substantial electrons in the energy range 2–5 eV (bond dissociation energy), thus electrons in this energy range can produce more atomic oxygen. It shows that the probability of producing high energy ions, which can damage the electrode, is low in microwave plasma.

Helium (He) and Argon (Ar) atmospheric pressure plasma jets operated with low-frequency power source are designed and studied. The current and voltage waveforms, formation of plasma jets, estimated rotational and vibrational temperatures, optical emission spectra, and numerical simulations for He and Ar gases are investigated to analyze the plasma characteristics. Ar plasma shows higher discharge current and many instantaneous current peaks compared with He plasma. For gas flow between 1 and 7 L/min and applied voltage between 3 and 10 kV, no significant changes in Ar plasma are observed. He plasma is found to be sensitive as far as gas flow rate and applied voltage are concerned. This sensitivity is associated with a transition from laminar to turbulent mode of gas flow. The estimated gas temperatures show higher values for Ar plasma than those of He plasma. Ar plasma jet emits extremely high intensity of OH (305 nm ~312 nm) and O (777 nm) compared with that emitted from He plasma jet. High concentration of OH and O in Ar plasma is related with high density of electrons with 4-5 eV, which is in the range of the dissociation energy of H-H, O-H, and O=O bonds. As a result, wider sterilization area and higher sterilization efficacy in indirect treatment are observed for Ar plasma than He plasma.

A low-power palm-size microwave power module for portable microwave-excited plasma applicable to biomedicine is integrated on a single printed circuit board for the first time. The designed board includes a power amplifier chip, a phase-locked loop (PLL) chip, and an impedance matching network with microstrip lines. In addition, as a part of the true one-chip integration of the plasma power module, the PLL is designed and fabricated in a semiconductor chip with a 0.18-μm CMOS technology for dedicated use to our plasma source. For the plasma generator, a 900-MHz coaxial transmission line resonator is used with argon gas flow. The designed plasma source is applied to the inactivation of S. mutans, showing three-log reduction within 180-s treatment. Measurements for the different initial concentrations (from 105 to 10 9 CFU/mL) are also conducted, and the outcomes are discussed. The results verify the feasibility of the proposed integrated microplasma source for use in dental treatments.

Atmospheric pressure plasmas have attracted great interests and been widely used in biomedical applications such as sterilization, coagulation, wound healing, and cancer cells treatment. The reactive oxygen species (ROS) generated in atmospheric pressure plasmas have been believed to play a crucial role in these biomedical applications. The experimental measurement of the atomic oxygen density showed that the highest density was measured at an admixture of 0.5% of O2. The similar trend of the atomic oxygen density varying the concentration of O2 was reproduced through a global model of He/O2 in atmospheric pressure plasmas. The evolution of the dominant production and loss reactions for the atomic oxygen was analyzed. With increase in the concentration of O2, the atomic oxygen was produced mainly by the dissociation of O2 and lost through the recombinations with themselves and oxygen molecules.

Three-electrode plasma jet system consisting of a perforated dielectric tube with two outer and one floating inner electrodes was developed and employed for tooth bleaching. Lowered gas breakdown voltage and increased discharge current were achieved by using the floating inner electrode. Optical emission spectra analysis showed that the rotational temperature of the second positive nitrogen bands was ≈290 K and vibrational temperature was ≈2 500 K, which means this plasma is in highly non-quilibrium state and nonthermal. The presence of excited He, N2, N and O in the plasma plume was revealed. The plasma jet was used in combination with hydrogen peroxide (H2O2) to remove stains from extracted teeth stained by either coffee or red wine. Combining the plasma jet and H2O2 improved the bleaching efficacy by a factor of 3.1 (coffee) and 3.7 (red wine) compared with using H2O2 alone.

To enhance the sensitivity of an ELISA developed for the acaricide/insecticide fenazaquin, the length of the spacer arm attached to the 7-position of the quinazoline ring in the hapten (H-I) used previously as an immunogen was shortened, and this modified hapten (H-IV) was then used as an immunogen. The new immunogen used to raise polyclonal antibodies was designated 3-(4-(4-tert-butylbenzyloxy)quinazolin-7-ylcarbamoyl)propanoic acid. Under optimized conditions of a competitive indirect ELISA (ciELISA), the former IC50 value of 96.97 ng/mL was reduced to 42.13 ng/mL, and the detection range was 10.96–161.91 ng/mL, the lowest detection limit being 1.8 ng/mL. HPLC was run to compare with and to validate the ELISA with fortified fruit and water samples; the correlation was 0.997–1.000 (n=4-5) with a slope of 0.905–1.112. The recoveries of fenazaquin from fortified samples by the ELISA ranged from 90.61 to 115.12%, which is acceptable as an ELISA for residue analysis.