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Abstract In this paper, the floating body effect (FBE) in indium-gallium-zinc-oxide (IGZO) thin-film transistor (TFT) and the mechanism of device failure caused by that are reported for the first time. If the toggle AC pulses are applied to the gate and drain simultaneously for the switching operation, the drain current of IGZO TFT increases dramatically and cannot show the on/off switching characteristics. This phenomenon was not reported before, and our study reveals that the main cause is the formation of a conductive path between the source and drain: short failure. It is attributed in part to the donor creation at the drain region during the high voltage (V high) condition and in part to the donor creation at the source region during the falling edge and low voltage (V low) conditions. Donor creation is attributed to the peroxide formation in the IGZO layer induced by the electrons under the high lateral field. Because the donor creation features positive charges, it lowers the threshold voltage of IGZO TFT. In detail, during the V high condition, the donor creation is generated by accumulated electrons with a high lateral field at the drain region. On the other hand, the floating electrons remaining at the short falling edge (i.e., FBE of the IGZO TFT) are affected by the high lateral field at the source region during the V low condition. As a result, the donor creation is generated at the source region. Therefore, the short failure occurs because the donor creations are generated and expanded to channel from the drain and source region as the AC stress accumulates. In summary, the FBE in IGZO TFT is reported, and its effect on the electrical characteristics of IGZO TFT (i.e., the short failure) is rigorously analyzed for the first time.

Abstract Carbon nanotube networks (CNTs)-based devices are well suited for the physically unclonable function (PUF) due to the inherent randomness of the CNT network, but CNT networks can vary significantly during manufacturing due to various controllable process conditions, which have a significant impact on PUF performance. Therefore, optimization of process conditions is essential to have a PUF with excellent performance. However, because it is time-consuming and costly to fabricate directly under various conditions, we implement randomly formed CNT network using simulation and confirm the variable correlation of the CNT network optimized for PUF performance. At the same time, by implementing an analog PUF through simulation, we present a 2D patterned PUF that has excellent security and can compensate for error occurrence problems. To evaluate the performance of analog PUF, a new evaluation method different from the existing digital PUF is proposed, and the PUF performance is compared according to two process variables, CNT density and metallic CNT ratio, and the correlation with PUF performance is confirmed. This study can serve as a basis for research to produce optimized CNT PUF by applying simulation according to the needs of the process of forming a CNT network.

Abstract Background Petersen’s hernia, which occurs after Billroth-II (B-II) or Roux-en-Y (REY) anastomosis, can be reduced by defect closure. This study aims to compare the incidence of bowel obstruction above Clavien–Dindo classification grade III due to Petersen’s hernia between the mesenteric fixation method and the conventional methods after laparoscopic or robotic gastrectomy. Methods This study was designed as prospective, single-blind, non-inferiority randomized controlled multicenter trial in Korea. Patients with histologically diagnosed gastric cancer of clinical stages I, II, or III who underwent B-II or REY anastomosis after laparoscopic or robotic gastrectomy are enrolled in this study. Participants who meet the inclusion criteria are randomly assigned to two groups: a CLOSURE group that underwent conventional Petersen’s defect closure method and a MEFIX group that underwent the mesenteric fixation method. The primary endpoint is the number of patients who underwent surgery for bowel obstruction caused by Petersen’s hernia within 3 years after laparoscopic or robotic gastrectomy. Discussion This trial is expected to provide high-level evidence showing that the MEFIX method can quickly and easily close Petersen’s defect without increased postoperative complications compared to the conventional method. Trial registration ClinicalTrials.gov NCT05105360. Registered on November 3, 2021.

Obtaining symmetrical and highly linear synapse weight update characteristics of analog resistive switching devices is critical for attaining high performance and energy efficiency of the neural network system. In this work, based on the two-terminal one transistor-one memristor (1T1M) block, the improvement of the symmetry and linearity of synaptic weight update is demonstrated by combining the InGaZnO synaptic transistor and memristor. Due to the symmetric and linear weight update characteristic, a pattern recognition accuracy of 88% is achieved after 50 epochs in the on-chip learning simulation of the hand-written digit images (MNIST) data set. The proposed 1T1M device saves the hardware burden and additional power consumption required to implement non-identical programming pulses.

Accurate current-voltage (I-V) modeling based on the Berkeley short-channel insulated-gate field-effect transistor model (BSIM) is pivotal for integrated circuit simulation. However, the current BSIM model does not support a buried-channel-array transistor (BCAT), which is the structure of the state-of-the-art commercial dynamic random access memory (DRAM) cell transistor. In this work, we propose an intelligent I-V modeling technique that combines genetic algorithm (GA) and deep learning (DL). This hybrid technique facilitates both optimization of BSIM parameter and accurate I-V modeling, even for devices not originally supported by BSIM. Additionally, we extended application of the DL to model one of the principal degradation mechanisms of transistor, the hot-carrier degradation (HCD). The successful modeling results of I-V characteristic and device degradation demonstrated that devices not supported by BSIM can be accurately modeled for integrated circuit simulations.

Abstract Oxide semiconductor thin-film transistors (TFTs) are used in the pixel array and gate driver circuits of organic light emitting diode (OLED) display panels. Long-term reliability characteristics of the TFTs are a barometer of the lifetime of OLED display panels. The long-term reliability of the driver TFTs is evaluated in a short time under high voltages and high temperature for an accelerated degradation test. If reliability parameters from the power law or stretched-exponential functions are the same for individual devices and devices in an operating panel, the lifetime of the panel can be accurately estimated. However, since compensation circuits are designed into operating panels, an environmental discrepancy exists between the accelerated test of single devices and the operation of devices in the panel. Herein, we propose a novel compensation stretched-exponential function (CSEF) model which captures the effect of the threshold voltage compensation circuit in the panel. The CSEF model not only bridges the discrepancy between individual devices and panel devices, but also provides a method to accurately and efficiently estimate the long-term lifetime of all display panels that utilize compensation circuits.

With the recent increase in imaging tests, coexisting abdominal aortic aneurysms (AAAs) and thoracic aortic aneurysms (TAAs) are being discovered accidentally. We report two cases of simultaneous endovascular aortic repair (EVAR) and thoracic endovascular aortic repair (TEVAR) for AAA and TAA. Both 74-year-old and 79-year-old male with infrarenal AAA and saccular TAA were treated simultaneously with EVAR and TEVAR. Saccular TAAs were identified in the upper thoracic aorta during the evaluation of AAA. During endograft placement, carotid-subclavian bypass and cerebrospinal fluid (CSF) drainage were performed. Both patients were successfully discharged without spinal cord ischemia. Simultaneous EVAR and TEVAR can be considered for patients with AAA and saccular TAA in the upper thoracic aorta. Moreover, CSF drainage may be necessary to protect the spinal cord.

Desmoid tumours are rare tumours originating from fibroblasts, and are characterised by local infiltration and no metastasis. When complete resection is possible, surgical resection is considered a first-line treatment. In the case of large desmoid tumours, it is mainly performed by laparotomy, not laparoscopy. We report a case of a 43-year-old female patient presenting with a hypodense mass of approximately 5 cm in the posterior wall of the gastric antrum on computed tomography. There was no history of familial adenomatous polyposis, trauma or abdominal surgery. The patient underwent laparoscopic gastric wedge resection and spleen-preserving distal pancreatectomy without peri-operative complications. Pathological analysis revealed a desmoid tumour, which originated from the stomach and invaded the pancreas. Despite the large size and the locally infiltrative characteristics of these tumours, laparoscopic surgery can be an optimal treatment option due to its advantages.

Short- and long-term neuroplasticity behaviors are key mechanisms for various activities. In this paper, we propose a synaptic transistor with a floating-gate (FG) node and an amorphous InGaZnO (IGZO) channel layer. The proposed device emulates the neuroplasticity functions of both short-term memory (STM) and long-term memory (LTM) through the control of the amplitude and the number of input pulses. The STM operated by ion movement in the gate dielectrics occurs when the input amplitude is relatively small (< 9 V). The LTM operated through the storage of electrons in the FG occurs when the input amplitude is relatively large (>10 V). In addition, as the number of input pulses increases, information is stored for a longer time. Our FG IGZO synaptic transistor could be a promising device solution for brain-inspired computing systems.

Abstract Amorphous oxide semiconductor (AOS) field-effect transistors (FETs) have been integrated with complementary metal-oxide-semiconductor (CMOS) circuitry in the back end of line (BEOL) CMOS process; they are promising devices creating new and various functionalities. Therefore, it is urgent to understand the physics determining their scalability and establish a physics-based model for a robust device design of AOS BEOL FETs. However, the advantage emphasized to date has been mainly an ultralow leakage current of these devices. A device modeling that comprehensively optimizes the threshold voltage (V T), the short-channel effect (SCE), the subthreshold swing (SS), and the field-effect mobility (µFE) of short-channel AOS FETs has been rarely reported. In this study, the device modeling of two-steps oxygen anneal-based submicron indium-gallium-zinc-oxide (IGZO) BEOL FET enabling short-channel effects suppression is proposed and experimentally demonstrated. Both the process parameters determining the SCE and the device physics related to the SCE are elucidated through our modeling and a technology computer-aided design (TCAD) simulation. In addition, the procedure of extracting the model parameters is concretely supplied. Noticeably, the proposed device model and simulation framework reproduce all of the measured current–voltage (I–V), V T roll-off, and drain-induced barrier lowering (DIBL) characteristics according to the changes in the oxygen (O) partial pressure during the deposition of IGZO film, device structure, and channel length. Moreover, the results of an analysis based on the proposed model and the extracted parameters indicate that the SCE of submicron AOS FETs is effectively suppressed when the locally high oxygen-concentration region is used. Applying the two-step oxygen annealing to the double-gate (DG) FET can form this region, the beneficial effect of which is also proven through experimental results; the immunity to SCE is improved as the O-content controlled according to the partial O pressure during oxygen annealing increases. Furthermore, it is found that the essential factors in the device optimization are the subgap density of states (DOS), the oxygen content-dependent diffusion length of either the oxygen vacancy (V O) or O, and the separation between the top-gate edge and the source-drain contact hole. Our modeling and simulation results make it feasible to comprehensively optimize the device characteristic parameters, such as V T, SCE, SS, and µFE, of the submicron AOS BEOL FETs by independently controlling the lateral profile of the concentrations of V O and O in two-step oxygen anneal process.

We demonstrate the reliable resistive switching performance of nanocrystalline-HfO2 inside amorphous-HfOx in TaN/nc-HfO2/ITO memristor structure. Transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS) were utilized to confirm the presence of nc-HfO2 and non-stoichiometric HfOx in the switching layer. In presence of nc-HfO2, quantized conductance was controlled by the narrowing of conductive filaments in an atomic scale applying a very slow voltage sweep. Conductance change under DC voltage shows the quantized conductance states with integer and half-integer multiples of G0 (77.5 μS). Enhanced resistive switching performances with multilevel resistance states behavior were investigated under different current compliance and RESET stop voltages. Short-term plasticity and long-term potentiation, pulse number, and spike rate-dependent plasticity by controlling the magnitude and duration of the input stimulus play a critical role in modulating the post-synaptic conductivity. The combination of nc-HfO2 and amorphous-HfOx in the memristor structure provide promising scope for neuromorphic system applications.

Due to the short storage period, large quantities of platelet concentrate (PC) are expiring. The expired PC cannot be injected into a blood vessel, but the activity of bioactive molecules, especially growth factors, is still preserved. In this paper, we organized a process to obtain a growth factor-rich bioproduct for use as a supplement in human cell culture by optimizing freezing, thawing, and sterilization conditions. Each unit of PC displayed visual differences, diverse biochemical values, and growth factor concentrations. To minimize lot-to-lot variation, we pooled a minimum of 10 PC units. The concentrations of growth factors were maximized through five freeze–thaw cycles for 12 h at −80 °C for freezing and for 5 min at 36 °C for thawing. We used a cell strainer with 40 µm pores, followed by a 0.45 μm filter and a 0.22 μm filter sequentially to sterilize the bioproduct with minimizing loss. The obtained growth factors remained stable for 4–6 h at room temperature (23 °C), 24 h at 4 °C, and 12 months at −80 °C. Cellular responses to the growth factor-rich bioproduct were tested with primary human renal proximal tubule epithelial cells. The cells exhibited a significantly increased growth rate, compared to the fetal bovine serum (FBS)-treated control group. The cells maintained their characteristic cuboidal shape, and stem cells and renal progenitor cells also preserved their genetic characteristics during culture. Therefore, the growth factor-rich bioproduct isolated from expired PC through our process can be used as a medium supplement to replace FBS in human cell culture for clinical application.

Abstract Oxide semiconductor transistors control the brightness and color of organic light‐emitting diode (OLED) displays in large‐screen televisions to portable telecommunications devices. Oxide semiconductor thin‐film transistors under driving conditions are required to maintain a steady current through the OLED for constant illuminance. Interestingly, for driving conditions under strong saturation where both gate and drain bias are high, a boosting phenomenon of the drain current is discovered, even with compensation of the threshold voltage. In this paper, the current boosting effect of self‐aligned InGaZnO transistors under driving conditions is comprehensively investigated. Based on experimental extraction methods, two distinct regions within the device are identified: an electron‐capture‐dominant region including electron trapping in the gate insulator and O–O dimer bond‐breaking, and an electron‐emission‐dominant region caused by peroxide formation. A dual‐transistor‐in‐series model is proposed, where each region is modeled as a local transistor. The current boosting phenomena as a function of time are well‐reproduced for various channel length devices, which validate the accuracy of the model. Better understanding of the underlying mechanisms enables increased effectiveness of compensation schemes for transistors under long‐term current‐driving conditions.

Lipofibromatous hamartoma, first reported in 1953, is a rare, slowly progressive soft tissue tumor, the characteristics of which include the enlargement of the affected nerve via the epineurial and perineurial proliferation of adipose and fibrous tissues. Out of 200 previously reported cases of lipofibromatous hamartoma of the median nerve, there have been approximately 25 pediatric cases under the age of 18. Herein, we report a case of lipofibromatous hamatoma of the median nerve in a 3-year-old female patient who was surgically decompressed via carpal tunnel release and epineurolysis. The patient was followed-up on an outpatient clinic basis annually with sonographic evaluations, and the postoperative 10th-year follow-up did not show recurrence or any deficits in motor and sensory functions.

Ulcerative colitis is an inflammatory bowel disease characterized by inflammation in the mucosal and submucosal layers of the colon. Obesity is closely related to the occurrence and progression of colitis. The most plausible mechanism linking obesity and colitis is an excessive adipogenesis-related inflammatory response, which causes mucosal dysfunction. Obesity and colitis are linked by several etiologic mechanisms, including excessive adipogenesis, lipotoxicity, pro-inflammatory adipokines/cytokines, macrophage polarization, oxidative stress, endoplasmic reticulum (ER) stress, and gut microbiota. These low-grade enteric inflammations cause mucosal layer damage, especially goblet cell dysfunction through mucin 2 (MUC2) misfolding, ultimately leading to colitis. Inhibiting the inflammatory response can be the most effective approach for treating obesity-related colitis. We focused on the anti-inflammatory effects of polyphenols in Protaectia brevitas larvae. The P. brevitas was prepared as a low molecular protein hydrolysate (PHPB) to increase the concentration of anti-inflammatory molecules. In the current study, we investigated the anti-inflammatory effect of PHPB in an obesity-induced colitis mouse model. Compared with the high-fat diet (HFD) group, the group treated with PHPB exhibited reduced body/organ/fat weight, appetite/food intake inhibition, hypolipidemic effect on ectopic fat, and anti-adipogenic mechanism through the AMPK signaling pathway. Furthermore, we observed attenuated expression of PPARγ and C/EBPα, inhibition of pro-inflammatory molecules, stimulation of anti-inflammatory molecules, probiotic-like effect against obesogenic gut microbiota, inhibition of macrophage polarization into M1, suppression of oxidative/ER stress, and reduction of Muc2 protein misfolding in colon. These diverse anti-inflammatory responses caused histological and functional recovery of goblet cells, eventually improving colitis. Therefore, our findings suggest that the protein hydrolysate of Protaetia brevitarsis can improve obesity-related colitis through its anti-inflammatory activities.

Since the most of three dimensional (3D) NAND devices’ channel is composed of polysilicon grain, the actual 3D NAND channel has a wave-shaped channel, not uniform shape. In this study, we defined the curvature of the channel as a ‘Wave Factor (WF)’ parameter, and simulated 3D NAND device with the WF applied channel. Various effects of the curvature in the channel on the program and erase operation of the device have been investigated. When the channel is wave-shaped, the electric field tends to be concentrated on the corner region of the blocking oxide during the program operation, which causes increase of the electron back tunneling to the gate. Therefore, program speed degraded as the WF value higher. During the erase operation, the same with program operation, the electric field concentrated on the corner of the blocking oxide increased, enhanced electron back tunneling from the metal gate occurred while less amount of hole charge trapped. As a result, $\text{V}_{\mathrm {TH}}$ shift after the erase operation decreased according to increased WF. This phenomenon becomes more serious on the short channel condition. In addition, the result shows that degradation of erase characteristic by WF can be prevented by applying thicker blocking oxide.

Objective Posterior endoscopic cervical foraminotomy (PECF) is a well-established, minimally invasive surgery for cervical radiculopathy, but have the more chances of neural structure damage due to the limited visibility and steeper learning curve. So, the anatomical understanding of the nerve associated with the bony structure will be an essential surgical guideline. Methods We measured the distance between the bilateral dura lateral edge and bilateral V-point on axial cuts of cervical magnetic resonance imaging and 3-dimensional spine computed tomography imaging, respectively, from 80 patients. We then calculate the distance and position between the dura lateral edge and the V-point as surgically critical width (SCW). Transverse interdural distance (TIDW), transverse inter-V-point distance, and anatomical facet joint width were measured. Results The mean TIDW decreased as the levels down in the 40s–60s but increased at the C4–5, C5–6, and C6–7 levels in the 70s. Statistically significant difference was shown at the C6–7 level between the 40s and the 70s. The mean anatomical inter-V-point distance markedly decreased at C5–6 and continued till the C7–Tl level at all age groups. Moreover, a statistically significant difference was shown at the C3–4 and C4–5 level between the 40s and the 70s. The mean negative values of SCW increased from the 40s to 70s at the C5–6 and C6–7 levels (C5–6: -0.60 ± 1.10 mm to -1.63 ± 1.56 mm; C6–7: -0.90 ± 0.74 mm to -2.18 ± 1.25 mm). There were statistically significant differences between the 2 aged groups at the C3–4, C4–5, C5–6, and C6–7 levels. Conclusion A prediction of the correlated position between the lateral dura edge and the V-point is essential for the PECF not to injure the neural structure. In the case of a performing the PECF at the C5–6 and C6–7 level in the old-aged patient, it should be considered the laterally moved dura edge, and more extended bony remove is needed for less neural structure damage.

As a new type of one-dimensional nanomaterial, carbon nanotubes (CNTs) have been used as a chemical sensing material due to their excellent electrical, mechanical and chemical properties. Several recent studies have attempted to obtain an electrochemical sensor based on CNTs, and CNT-based humidity sensors have potential applications in industrial, agricultural and medical fields and in smart wearable electronic devices. Although various CNT-based humidity sensors have been reported, in this work, we investigated the humidity effects in depth and the underlying mechanisms according to CNT type, i.e., semiconducting (s-CNT) and metallic (m-CNT) CNTs, which is determined by the chiral vector during CNT growth. For this purpose, we fabricated CNT-based humidity sensors with highly purified, solution-processed 99% single-walled s-CNT and m-CNT network films bridged by palladium (Pd) electrodes. The fabricated sensors exhibited completely different humidity responses, as denoted by the film resistance as a function of the relative humidity (RH), according to the CNT type. In the s-CNT-based sensor, the resistance tended to decrease as the RH increased, while the m-CNT-based sensor showed the opposite tendency. Based on these results, a humidity sensing mechanism according to the CNT type was proposed in this work. We believe that our findings can serve as design guidelines for CNT-based humidity sensors.

Hardware-oriented neuromorphic computing is gaining great deal of interest for highly parallel data processing and superb energy efficiency, as the candidate for replacement of conventional von Neumann computing. In this work, a novel synaptic transistor constructing the neuromorphic system is proposed, fabricated, and characterized. Amorphous indium-gallium-zinc-oxide ( $\alpha $ -IGZO) and Al2O3 are introduced as the channel and gate dielectric materials, respectively. Along with the high functionality and low-temperature processing viability, geometric peculiarity featuring extended gate structure improves the performances of the proposed transistor as synaptic component in the neuromorphic system. The insight into the substantial effect of optimal device structure design on energy efficiency is highlighted.

Herein, we quantitatively analyze the evolution of the subgap density of states (DOSs) for multilayered molybdenum disulfide (m-MoS2) field effect transistors (FETs) with bilayered SiNx/SiOx gate dielectrics under positive bias stress (PBS) and negative bias stress (NBS) by using optical charge-pumping capacitance-voltage spectroscopy. To decouple external gas ambient effects on device instability, hydrophobic fluoropolymers (cyclized transparent optical polymer; CYTOP) are employed for m-MoS2 FETs followed by the evaluation of subgap-DOSs in the devices for the respective PBS (or NBS). Through extraction of subgap-DOSs and their deconvolution with an analytical model of acceptor (or donor)-like states, it is shown that the device instability is closely correlated with state transitions of DOSs, corresponding to shallow (or midgap) levels for monosulfur vacancy (VS) (or disulfur vacancy ( $\text{V}_{\mathrm {S2}}$ )). Moreover, after PBS, the initial states of VS(0) (or $\text{H}_{\mathrm {S2}}$ (0)) transit toward VS (−1) (or $\text{H}_{\mathrm {S2}}(-1$ )) via electron trapping, whereas the transition toward VS (0) and $\text{H}_{\mathrm {S2}}$ (+1) during NBS is assessed from the initial $\text{V}_{\mathrm {S}}(-1$ ) and $\text{H}_{\mathrm {S2}}$ (0) states. Furthermore, technology computer-aided design (TCAD) simulation based on the extracted DOSs properly replicates the measured I-V characteristics of m-MoS2 FETs with (and without) CYTOP encapsulation. In this study, subgap-DOS characterization via optical charge pumping and validation of the quantitative evolution of subgap-DOSs suggest that this platform can be potentially beneficial for an in-depth understanding of the origins of device instability for transition metal dichalcogenide (MX2)-based FETs, where M is a transition metal and X is a chalcogenide.

In this study, we demonstrate both of digital and analog memory operations in InGaZnO (IGZO) memristor devices by controlling the electrode materials for neuromorphic application. The switching properties of the devices are determined by the initial energy barrier characteristics between the metal electrodes and the IGZO switching layer. Digital switching characteristics are obtained after the forming process when Schottky junction occurs at both of top and bottom electrodes. On the other hands, analog resistive switching is achieved when Schottky and Ohmic junctions exist at each side because the applied voltage modulates the Schottky barrier height through the Ohmic contact. In addition, the weight-update properties of the devices are verified depending on identical and incremental pulse schemes. The incremental pulse trains improve the linearity and variation of weight modulation, leading to the stable learning characteristics of neuromorphic system in terms of pattern recognition with MNIST hand-written digit images.

In this work, two types of InGaZnO (IGZO) memristors were fabricated to confirm the conduction mechanism and degradation characteristics of memristors with different electrode materials. The IGZO memristor exhibits abrupt switching characteristics with the Pd electrode owing to the formation and destruction of conductive filaments but shows gradual switching characteristics with the p-type Si electrode according to the amount of generated oxygen vacancy. The electrical characteristics and conduction mechanisms of the device are analyzed using an energy band diagram and experimentally verified with random telegraph noise characteristics confirming the trap effects on the device conduction.

In this article, we study the post-annealing effect on the synaptic characteristics in Pd/IGZO/SiO2/p+-Si memristor devices. The O-H bond in IGZO films affects the switching characteristics that can be controlled by the annealing process. We propose a switching model based on using a native oxide as the Schottky barrier. The barrier height is extracted by the conduction mechanism of thermionic emission in samples with different annealing temperatures. Additionally, the change in conductance is explained by an energy band diagram including trap models. The activation energy is obtained by the depression curve of the samples with different annealing temperatures to better understand the switching mechanism. Moreover, our results reveal that the annealing temperature and retention can affect the linearity of potentiation and depression. Finally, we investigate the effect of the annealing temperature on the recognition rate of MNIST in the proposed neural network.

This paper introduces a compact SPICE model of a two-terminal memory with a Pd/Ti/IGZO/p+-Si structure. In this paper, short- and long-term components are systematically separated and applied in each model. Such separations are conducted by the applied bias and oxygen flow rate (OFR) during indium gallium zinc oxide (IGZO) deposition. The short- and long-term components in the potentiation and depression curves are modeled by considering the process (OFR of IGZO) and bias conditions. The compact SPICE model with the physical mechanism of SiO2 modulation is introduced, which can be useful for optimizing the specification of memristor devices.

In this work, the resistive switching behavior of bilayer ZnO/Al2O3-based resistive-switching random access memory (RRAM) devices is demonstrated. The polycrystalline nature of the ZnO layer confirms the grain boundary, which helps easy oxygen ion diffusion. Multilevel resistance states were modulated under DC bias by varying the current compliance from 0.1 mA to 0.8 mA, the SET operations where the low resistance state of the memristor device was reduced from 25 kΩ to 2.4 kΩ. The presence of Al2O3 acts as a redox layer and facilitates oxygen vacancy exchange that demonstrates stable gradual conductance change. Stepwise disruption of conductive filaments was monitored depending on the slow DC voltage sweep rate. This is attributed to the atomic scale modulation of oxygen vacancies with four distinct reproducible quantized conductance states, which shows multilevel data storage capability. Moreover, several crucial synaptic properties such as potentiation/depression under identical presynaptic pulses and the spike-rate-dependent plasticity were implemented on ITO/ZnO/Al2O3/TaN memristor. The postsynaptic current change was monitored defining the long-term potentiation by increasing the presynaptic stimulus frequency from 5 Hz to 100 Hz. Moreover, the repetitive pulse voltage stimulation transformed the short-term plasticity to long-term plasticity during spike-number-dependent plasticity.

The orphan nuclear receptor 4A1 (NR4A1) is highly expressed in human pancreatic cancer cells and exerts pro-oncogenic activity. In a previous study, we demonstrated that fangchinoline (FCN), a natural inhibitor of nuclear NR4A1, induces NR4A1-dependent apoptosis in human pancreatic cancer cells. In this study, we evaluated FCN and its structural analogs (berbamine, isotetrandrine, tetrandrine, and tubocurarine) for their inhibitory effects on NR4A1 transactivity, and confirmed that tetrandrine (TTD) showed the highest inhibitory effect in pancreatic cancer cells. Moreover, in a tryptophan fluorescence quenching assay, TTD directly bound to the ligand binding domain (LBD) of NR4A1 with a KD value of 10.60 μM. Treatment with TTD decreased proliferation and induced apoptosis in Panc-1 human pancreatic cancer cells in part through the reduced expression of the Sp1-dependent anti-apoptotic gene survivin and induction of ROS-mediated endoplasmic reticulum stress, which are the well-known NR4A1-dependent proapoptotic pathways. Furthermore, at a dose of 25 mg/kg/day, TTD reduced tumor growth in an athymic nude mouse xenograft model bearing Panc-1 cells. These data show that TTD is an NR4A1 antagonist and that modulation of the NR4A1-mediated pro-survival pathways is involved in the antitumor effects of TTD.

Introduction: There is paucity of literature on application of endoscopic spine surgery in thoracic spine for ossified ligamentum flavum. We aim to evaluate the clinical and radiological outcomes Uniportal Thoracic Endoscopic Laminotomy With Bilateral Decompression Using One Block Resection Technique (TE-ULBD) for Thoracic Ossified Ligamentum Flavum in our cohort of patients. Methods: Retrospective evaluation performed for all patients who underwent TE-ULBD for thoracic ossified ligamentum flavum. Pre and postoperative parameters of axial cut spinal canal area in upper, middle and lower disc, VAS, ODI and JOA at preoperative, postoperative 1 week, 6 months and final follow up were compared. Results: 35 levels of TE-ULBD performed in 28 patients. The complication rate of TE-ULBD was 2.8%. In our TE-ULBD cohort there was significant clinical improvement in VAS, ODI and JOA score in postoperative 1 week, 6 months and final score. The mean difference as compared to preoperative VAS in postoperative final follow up 4.80, p

Designing multi-value logic transistors with stable and reliable intermediate states remains a challenge. Here, the authors report the mobility edge quantization phenomenon via resonant hybridization of ZnO QDs embedded in amorphous ZnO domains to enable adjustable multi-value intermediate states.

In this work, the correlation between SiO2 deposition thickness and hydrogen content is discussed and the effect of the SiO2 layer on the properties of synaptic InGaZnO (IGZO) TFTs is analyzed. Three types of IGZO synaptic thin-film transistors (TFTs) were fabricated with different gate insulators, and the effect of SiO2 as a gate insulator was investigated. XPS analysis confirmed that the hydrogen content in the Al2O3 and SiO2 layers increased during SiO2 deposition step for all depth regions. Hydrogen injected by the SiO2 layer deposition step was confirmed to improve the memory window through more threshold voltage shift under positive bias stress (PBS) and negative bias stress (NBS) conditions. In addition, the retention characteristics were improved due to the low hydrogen movement velocity in the SiO2 layer. These results contribute to the optimization of the amount of hydrogen, and the proposed device has potential as a synaptic device capable of neuromorphic computing.

Excessive oxidative stress plays a role in hepatotoxicity and the pathogenesis of hepatic diseases. In our previous study, the phenolic extract of beluga lentil (BLE) showed the most potent in vitro antioxidant activity among extracts of four common varieties of lentils; thus, we hypothesized that BLE might protect liver cells against oxidative stress-induced cytotoxicity. BLE was evaluated for its protective effects against oxidative stress-induced hepatotoxicity in AML12 mouse hepatocytes and BALB/c mice. H2O2 treatment caused a marked decrease in cell viability; however, pretreatment with BLE (25–100 μg/mL) for 24 h significantly preserved the viability of H2O2-treated cells up to about 50% at 100 μg/mL. As expected, BLE dramatically reduced intracellular reactive oxygen species (ROS) levels in a dose-dependent manner in H2O2-treated cells. Further mechanistic studies demonstrated that BLE reduced cellular ROS levels, partly by increasing expression of antioxidant genes. Furthermore, pretreatment with BLE (400 mg/kg) for 2 weeks significantly reduced serum levels of alanine transaminase and triglyceride by about 49% and 40%, respectively, and increased the expression and activity of glutathione peroxidase in CCl4-treated BALB/c mice. These results suggest that BLE protects liver cells against oxidative stress, partly by inducing cellular antioxidant system; thus, it represents a potential source of nutraceuticals with hepatoprotective effects.

We evaluated the synergistic effects of pentosan polysulfate sodium (PPS) and mesenchymal stem cells (MSCs) in an interstitial cystitis (IC) rat model. After generation of the IC rat model, the rats were divided into 4 groups according to the treatment they received: phosphate-buffered saline injection into bladder submucosa, daily oral PPS feeding, MSC injection into bladder submucosa, or MSC injection into bladder submucosa with daily oral PPS feeding. After treatment, conscious cystometry and pain scale measurement were performed and their bladders were obtained for histological and proinflammatory-related gene expression analysis. On cystometric analysis, all treatment groups showed significantly increased intercontraction intervals and lower pain scores compared to those of the control group. Histological analysis revealed regenerated urothelium, less fibrosis, and decreased mast cell infiltration in all treatment groups compared to the control group. Significantly lower expression of TNF-α, IFN-γ, MCP, IL-6, TLR2, and TLR11 was observed in the PPS with MSC group compared to the other groups. Combination therapy with PPS and MSCs showed histological and functional effects in an IC rat model, including synergistic effects leading to increased intercontraction interval and decreased inflammatory reactions.

Solution-processed carbon nanotubes (CNTs) have recently attracted significant attention as p-type thin-film transistor (TFT) channels due to their high carrier mobility, high uniformity, and low process temperature. However, implementing sophisticated macroelectronics with a combination of single CNT-TFTs has been challenging because it is difficult to fabricate n-type CNT-TFTs. Therefore, in combination with indium-gallium-zinc-oxide (IGZO), which has excellent electrical performance and has been commercialized as an n-type oxide TFT, we demonstrated various hybrid complementary metal-oxide semiconductor integrated circuits, such as inverters and nor and nand gates. This hybrid integration approach allows us to combine the strength of p-type CNT- and n-type IGZO-TFTs, thus offering a significant improvement for macroelectronic applications.

ObjectivesWe investigated the incidence and characteristics of pseudo-spontaneous nystagmus (PSN) in benign paroxysmal positional vertigo involving the lateral semicircular canal (LC-BPPV) and evaluated the correlation between PSN and the bow and lean test.MethodsWe examined nystagmus in the sitting position using video-oculography goggles in 131 LC-BPPV patients. The positioning test and bow and lean test were also performed. Patients were divided into canalolithiasis and cupulolithiasis groups according to the character of nystagmus. In each group, the incidence and direction of PSN, correlation with the bow and lean test, and treatment outcome were analyzed.ResultsPSN was observed in 25 cases (19.1%) in LC-BPPV patients, 7 of which were canalolithiasis and 18 of which were cupulolithiasis (p = 0.098). Of the 25 patients with PSN, 21 (84%) exhibited nystagmus consistent with the lean test whereas 4 (16%) exhibited nystagmus consistent with the bow test. In patients with PSN, nystagmus was observed in the bow and lean test in all cases (23/23), but in patients without PSN, no nystagmus was observed in 13 cases (13/87) in the bow and lean test (p = 0.048). The number of barbecue maneuvers performed until the end of treatment was 1.4 ± 0.7 in patients with PSN and 1.4 ± 0.9 in those without PSN (p = 0.976).ConclusionWe identified PSN in patients with LC-BPPV irrelevant of subtype. Moreover, all patients with PSN showed nystagmus in the bow and lean test. The direction of PSN was mostly consistent with that of the lean test (21/25, 84%). The presence of PSN was not related to the treatment outcome in this study.

Abstract Background Polycyclic aromatic hydrocarbons (PAHs) produced by incomplete combustion have negative effects on human health due to their carcinogenicity and teratogenicity. Indoor sources of PAHs include tobacco smoke, heating sources, and cooking. This study evaluated the relationship between human PAH exposure and residence characteristics. Method This study was based on the second Korean National Environmental Health Survey (2012–2014). Non-smoking housewives were included in the analyses (n = 1269). The concentrations of urinary PAH metabolites (2-naphthol, 2-hydroxyfluorene, 1-hydroxyphenanthrene, and 1-hydroxypyrene) were adjusted by urine creatinine level. The geometric mean concentrations of urinary PAH metabolites by residential factors were examined. Logistic regression models were used to evaluate associations between residential variables and PAH exposures. Results The adjusted geometric mean concentrations of urinary 2-hydroxyfluorene and 1-hydroxyphenanthrene were significantly higher in the group residing within 100 m of a major road (p 100 m from a major road. In logistic regression analyses, the odds ratio (OR) for exceeding the third quartile of urinary 1-hydroxypyrene concentration was significantly higher in the group using coal or wood fuel for residential heating than in the group using gas (OR = 2.745, 95% confidence interval [CI] = 1.295–5.819). The detached house group had a significantly higher OR for 1-hydroxyphenanthrene compared with the apartment group (OR = 1.515, 95% CI = 1.023–2.243). Conclusion Our study shows the evidence of associations between some urinary PAH metabolite levels (1-hydroxyphenanthrene and 1-hydroxypyrene) and residence characteristics. Additional studies are needed to clarify these associations.

Heterotopic pancreas in the stomach is usually asymptomatic and benign. Here, we presented a rare case of an early gastric cancer overlying a heterotopic pancreas. A 48-year-old woman underwent esophagogastroduodenoscopy, which revealed a subepithelial mass measuring 2.0×1.5 cm on the gastric antrum with a 1-cm erosive erythematous discoloration on the surface. A biopsy specimen showed moderately differentiated tubular adenocarcinoma. Endosonography showed a heterogeneous hypoechoic mass measuring 1.3×0.6 cm, with indistinct margins in the second and third layers of the gastric wall; anechoic tubular structures within the mass were suggestive of heterotopic pancreas. Distal gastrectomy was performed, which confirmed an early gastric cancer confined to the mucosa, and a separate underlying heterotopic pancreas. Although heterotopic pancreas is most likely benign, careful endoscopic observation of the mucosal surface is necessary to avoid overlooking a coincident early gastric cancer.

It has been elucidated that the responses to light by the human eye influence not only color and brightness recognition but also physiological aspects such as hormones. Melatonin, which affects human circadian rhythms, is sensitive to the blue wavelength region of light. We have investigated the spectroscopic effects of light from virtual reality (VR) and augmented reality (AR) display devices on nonvisual characteristics by means of an analysis of the spectral power distribution (SPD). The circadian illuminance and melatonin suppression value were introduced as representative figures of merits for spectroscopically evaluating nonvisual characteristics. A VR/AR-like custom-made instrument was used to study how the SPD of the display light source affects nonvisual characteristics. Moreover, using multilayer thin-film filters, optimal conditions for minimizing the change of the visual color characteristics of the display while reducing the influence on the non-visual characteristics are also discussed. For the AR device, we found that its spectrum was mostly affected by external light rather than by the spectrum of the AR display itself.

Abstract Background The objective of this study is to suggest revised recognition standards for occupational disease due to chromium (VI) by reflecting recent domestic and international research works and considering domestic exposure status with respect to target organs, exposure period, and cumulative exposure dose in relation to the chromium (VI)-induced occupational disease compensation. Methods In this study, the reports published by major international institutions such as World Health Organization (WHO) International Agency for Research on Cancer (IARC) (2012), Occupational Safety and Health Administration (OSHA) (2006), National Institute for Occupational Safety and Health (NIOSH) (2013), American Conference of Governmental Industrial Hygienists (ACGIH) (2004), National Toxicology Program (NTP) (2014), and Agency for Toxic Substances and Disease Registry (ASTDR) (2012) were reviewed and the recent research works searched by PubMed were summarized. Results Considering the recent research works and the domestic situation, only lung cancer is conserved in the legislative bill in relation to chromium (VI), and the exposure period is not included in the bill. Nasal and paranasal sinus cancer was excluded from the list of cancers that are compensated as the chromium (VI)- induced occupational disease, while lung cancer remains in the list. In the view of legislative unity, considering the fact that only the cancers having sufficient evidence are included in the conventional list of cancers compensated as occupational disease, nasal and paranasal sinus cancer having limited evidence were excluded from the list. The exposure period was also removed from the legislative bill due to the insufficient evidence. Recent advices in connection with cumulative exposure dose were proposed, and other considerable points were provided with respect to individual occupational relevance. Conclusions It is suggested that the current recognition standard which is “Lung cancer or nasal and paranasal sinus cancer caused by exposure to chromium (VI) or compounds thereof (exposure for two years or longer), or nickel compounds” should be changed to “Lung cancer caused by exposure to chromium (VI) or compounds thereof, and lung cancer or nasal and paranasal sinus cancer caused by exposure to nickel compounds”.

Given that light is known to function as a zeitgeber, having the greatest influence on the human circadian rhythm, it is necessary to assess the effects of light on humans with the goal of maintaining the circadian rhythm. Herein, we fabricated a simple circadian light meter that directly measures the non-visual effects of light using optical filters that mimic the non-visual action spectrum. The fabricated light meter was calibrated and verified through the values obtained from a conventional illuminance spectrophotometer. Furthermore, during 24 h of everyday life, 11 participants wore hats equipped with the developed light meter so that we could investigate the effects of the light environment to which they were exposed to, both indoors and outdoors. For comparison, natural outdoor illumination was also measured with the same light meter. Based on the considerable difference between the light exposure levels during the daytime and nighttime, it is possible that the participant’s melatonin levels would be impacted by the light exposure measured by the light meter. Consequently, based on the light exposure measurements made in this study, the proposed circadian light meter would be a valuable tool for real world circadian lighting studies that require actual light dose to the eyes of the test subjects.

Abstract Background The prognosis of a gastrointestinal stromal tumor (GIST) is influenced by its anatomic site; however, few studies on the prognosis of gastric GISTs have been reported. The aims of this study were to evaluate long-term prognoses of patients who underwent surgical resection for gastric GISTs and to compare the clinical efficacy of two staging systems: the National Institutes of Health (NIH) consensus criteria and the 7th Union for International Cancer Control/American Joint Committee on Cancer (UICC/AJCC) tumor-node-metastasis (TNM) staging system. Methods We conducted a retrospective observational study of 145 patients who underwent surgical resection for gastric GISTs between February 2001 and June 2012 at Pusan National University Hospital (Busan, Korea). Recurrence and 5-year recurrence-free survival (RFS) rates were analyzed. Results During a median follow-up period of 44 months (range, 6–144 months), 11 recurrent lesions were detected in 9 patients (6.4%). On multivariate analysis, tumor size (>5 cm), mitotic count (>5/50 high-power fields), and epithelioid and mixed pathological type were significantly associated with recurrence. The overall 5-year RFS rate was 93.4%. Although no statistically significant differences were detected (C-statistic difference P = 0.886), all metrics showed lower values for the UICC/AJCC TNM staging system than for the NIH consensus criteria, suggesting that the UICC/AJCC TNM staging system may be a better model. Conclusions The 5-year RFS rate in patients who underwent curative resection for gastric GISTs was excellent. The UICC/AJCC TNM staging system may be more useful than the NIH consensus criteria for risk categorization of patients with gastric GISTs.

Lymphocytes cross vascular boundaries via either disrupted tight junctions (TJs) or caveolae to induce tissue inflammation. In the CNS, Th17 lymphocytes cross the blood-brain barrier (BBB) before Th1 cells; yet this differential crossing is poorly understood. We have used intravital two-photon imaging of the spinal cord in wild-type and caveolae-deficient mice with fluorescently labeled endothelial tight junctions to determine how tight junction remodeling and caveolae regulate CNS entry of lymphocytes during the experimental autoimmune encephalomyelitis (EAE) model for multiple sclerosis. We find that dynamic tight junction remodeling occurs early in EAE but does not depend upon caveolar transport. Moreover, Th1, but not Th17, lymphocytes are significantly reduced in the inflamed CNS of mice lacking caveolae. Therefore, tight junction remodeling facilitates Th17 migration across the BBB, whereas caveolae promote Th1 entry into the CNS. Moreover, therapies that target both tight junction degradation and caveolar transcytosis may limit lymphocyte infiltration during inflammation.

Purpose We evaluated 5 different rat models using different agents in order to establish a standard animal model for interstitial cystitis (IC) in terms of the functional and pathologic characteristics of the bladder. Methods Five IC models were generated in 8-week-old female Sprague-Dawley rats via transurethral instillation of 0.1M hydrogen chloride (HCl) or 3% acetic acid (AA), intraperitoneal injection of cyclophosphamide (CYP) or lipopolysaccharide (LPS), or subcutaneous injection of uroplakin II (UPK2). After generating the IC models, conscious cystometry was performed on days 3, 7, and 14. All rats were euthanized on day 14 and their bladders were obtained for histological and pro-inflammatory-related gene expression analysis. Results In the cystometric analysis, all experimental groups showed significantly decreased intercontraction intervals compared with the control group on day 3, but only the LPS and UPK groups maintained significantly shorter intercontraction intervals than the control group on day 14. The histological analysis revealed that areas with severe urothelial erosion (HCl, AA, and UPK) and hyperplasia (CYP and LPS), particularly in the UPK-treated bladders, showed a markedly increased infiltration of toluidine blue-stained mast cells and increased tissue fibrosis. In addition, significantly elevated expression of interleukin-1b, interleukin-6, myeloperoxidase, monocyte chemotactic protein 1, and Toll-like receptors 2 and 4 was observed in the UPK group compared to the other groups. Conclusions Among the 5 different agents, the injection of UPK generated the most effective IC animal model, showing consequent urothelial barrier loss, inflammatory reaction, tissue fibrosis stimulation, and persistent hyperactive bladder.

Parkin is associated with various inflammatory diseases, including Parkinson's disease (PD) and rheumatoid arthritis (RA). However, the precise role of Parkin in RA is unclear. The present study addressed this issue by comparing the development of RA between non-transgenic (non-Tg) mice and PARK2 knockout (KO) mice. We found that cyclooxygenase-2 and inducible nitric oxide synthase expression and nuclear factor-κB activity were reduced but p53 activation was increased in PARK2 KO as compared to non-Tg mice. These effects were associated with reduced p53 degradation. Parkin was found to interact with p53; however, this was abolished in Parkin KO mice, which prevented p53 degradation. Treatment of PARK2 KO mice with p53 inhibitor increased Parkin expression as well as inflammation and RA development while decreasing nuclear p53 translocation, demonstrating that PARK2 deficiency inhibits inflammation in RA via suppression of p53 degradation. These results suggest that RA development may be reduced in PD patients. Keywords: Parkin, Arthritis, p53, Ubiquitination

Abstract Background Benzene, toluene, ethylbenzene, and xylene (BTEX) are emitted in the combustion or volatilization of hazardous wastes and fossil fuels. Paint, varnishing agents, and cigarette smoke are also sources of BTEX in living environments. Few studies have examined indoor exposure to BTEX using biomarkers, especially in residential settings. In this study, we evaluated the relationship between residence factors and BTEX exposure using biomarkers among Korean homemakers. Method We obtained data on 893 non-smoking homemakers older than 19 years from the Korean National Environmental Health Survey (2009–2011). The concentrations of urinary BTEX metabolites (t,t-muconic acid, hippuric acid, mandelic acid, phenylglyoxylic acid, and total methylhippuric acid) were adjusted using the urinary creatinine. Analysis of covariance (ANCOVA) and logistic regression analysis were used to evaluate the associations between residence parameters and urinary BTEX metabolites. Results The geometric mean concentrations of t,t-muconic acid and methylhippuric acid were significantly higher in the group that had remodeled within the previous 6 months (p

Accurate circuit simulation reflecting physical and electrical stress is of importance in indium gallium zinc oxide (IGZO)-based flexible electronics. In particular, appropriate modeling of threshold voltage (VT) changes in different bias and bending conditions is required for reliability-aware simulation in both device and circuit levels. Here, we present SPICE compatible compact modeling of IGZO transistors and inverters having an atomic layer deposition (ALD) Al2O3 gate insulator on a polyethylene terephthalate (PET) substrate. Specifically, the modeling was performed to predict the behavior of the circuit using stretched exponential function (SEF) in a bending radius of 10 mm and operating voltages ranging between 4 and 8 V. The simulation results of the IGZO circuits matched well with the measured values in various operating conditions. It is expected that the proposed method can be applied to process improvement or circuit design by predicting the direct current (DC) and alternating current (AC) responses of flexible IGZO circuits.

In this study, we analyzed the threshold voltage shift characteristics of bottom-gate amorphous indium-gallium-zinc-oxide (IGZO) thin-film transistors (TFTs) under a wide range of positive stress voltages. We investigated four mechanisms: electron trapping at the gate insulator layer by a vertical electric field, electron trapping at the drain-side GI layer by hot-carrier injection, hole trapping at the source-side etch-stop layer by impact ionization, and donor-like state creation in the drain-side IGZO layer by a lateral electric field. To accurately analyze each mechanism, the local threshold voltages of the source and drain sides were measured by forward and reverse read-out. By using contour maps of the threshold voltage shift, we investigated which mechanism was dominant in various gate and drain stress voltage pairs. In addition, we investigated the effect of the oxygen content of the IGZO layer on the positive stress-induced threshold voltage shift. For oxygen-rich devices and oxygen-poor devices, the threshold voltage shift as well as the change in the density of states were analyzed.

Abstract Carbon nanotubes (CNTs) used as semiconducting channels induce high mobility, thermal conductivity, mechanical flexibility, and chemical stability in field-effect, thin-film transistors (TFTs). However, the contact interfaces in CNT-TFTs have contact resistances that are difficult to reduce; this contact resistance can eventually limit the overall performance of CNT-TFTs. The contact interface between the source/drain electrodes and CNTs, especially for those CNT-TFTs in which the channel comprises randomly networked CNTs, plays a particularly dominant role in determining the performance and degree of variability in CNT-TFTs. However, no studies have reported a determination method that individually extracts each contact resistance at the source/drain electrodes. The present work presents an efficient method for directly determining the contact interfaces in CNT-TFTs by extracting each contact resistance produced at the source (R S ) and drain (R D ) electrodes. Moreover, we comprehensively simulated the randomly networked CNTs using an in-depth Monte-Carlo method, which provides an efficient method for visualizing the uniformity of a CNT network with various controllable CNT parameters. The proposed method provides guidance and a means for optimizing the design of the CNT network channel in CNT-TFTs and additional insights into improving the performance of CNT-TFTs.

Abstract Background Occupational physicians (OPs) have complex relationships with employees, employers, and the general public. OPs may have simultaneous obligations towards third parties, which can lead to variable conflicts of interests. Among the various studies of ethical issues related to OPs, few have focused on the Korean OPs. The aim of the present survey was to investigate the ethical contexts, the practical resolutions, and the ethical principles for the Korean OPs. Methods An email with a self-administered questionnaire was sent to members of the Korean Society of Occupational and Environmental Medicine, comprising 150 specialists and 130 residents. The questionnaire was also distributed to 52 specialists and 46 residents who attended the annual meeting of the Korean Association of Occupational and Environmental Clinics in October 2015, and to 240 specialists by uploading the questionnaire to the online community ‘oem-doctors’ in February 2016. The responses to each question (perception of general ethical conflicts, recognition of various ethical codes for OPs, core professional values in ethics of occupational medicine, and a mock case study) were compared between specialists and residents by the chi-squared test and Fisher’s exact test. Results Responses were received from 80 specialists and 71 residents. Most participants had experienced ethical conflicts at work and felt the need for systematic education and training. OPs suffered the most ethical conflicts in decisions regarding occupational health examination and evaluation for work relatedness. Over 60% of total participants were unaware of the ethical codes of other countries. Participants thought ‘consideration of worker’s health and safety’ (26.0%) and ‘neutrality’ (24.7%) as the prominent ethical values in professionality ofoccupational medicine. In mock cases, participants chose beneficence and justice for fitness for work and confidential information acquired while on duty, and beneficence and respect for autonomy in pre-placement examinations. Conclusions This study evaluated the current perception of and attitude toward ethical issues among the Korean OPs. These findings will facilitate the development of a code of ethics and the ethical decision-making program forthe Korean OPs.

Background: Severe collapsed disc secondary to degenerative spinal conditions leads to significant foraminal stenosis. We hypothesized that uniportal posterolateral transforaminal lumbar interbody fusion with endoscopic disc drilling technique could be safely applied to the collapsed disc space to improve patients’ pain score, restore disc height, and correct the segmental angular parameters. Methods: We included patients who met the indication criteria for lumbar fusion and underwent uniportal full endoscopic posterolateral transforaminal lumbar interbody fusion with pre-operative Computer Tomography mid disc height of less than or equal to 5 mm and MRI of Grade 3 Foraminal Stenosis. Visual analogue scale and computer tomography pre-operative and post-operative sagittal disc height in the anterior, middle and posterior part of the disc; sagittal focal segmental angle; mid coronal disc height and coronal wedge angles were evaluated. Results: 30 levels of Endo-TLIF were included, with a mean follow up of 12 months. The mean improvement in decreasing pain score was 2.5 ± 1.1, 3.2 ± 0.9 and 4.3 ± 1.0 at 1 week post operation, 3 months post operation and at final follow up, respectively, p < 0.05. There was significant increase in mid sagittal computer tomographic anterior, middle and posterior disc height of 6.99 ± 2.30, 6.28 ± 1.44, 5.12 ± 1.79 mm respectively, p < 0.05. CT mid coronal disc height showed an increase of 7.13 ± 1.90 mm, p < 0.05. There was a significant improvement in the CT coronal wedge angle of 2.35 ± 4.73 and the CT segmental focal sagittal angle of 1.98 ± 4.69, p < 0.05. Conclusion: Application of Uniportal Endoscopic Posterolateral Lumbar Interbody Fusion in patients with severe foraminal stenosis secondary to severe collapsed disc space significantly relieved patients’ pain and restored disc height without early subsidence or exiting nerve root dysesthesia in our cohort of patients.