Tailored fabrication of a self-rolled-up AlGaN/GaN tubular structure with photoelectrochemical etching.

Group III-nitride semiconductors with tubular structures offer significant potential across various applications, including optics, electronics, and chemical sensors. However, achieving tailored fabrication of these structures remains a challenge. In this study, we present a novel, to the best of our knowledge, method to fabricate micro-sized tubular structures by rolling the layered membrane of group III-nitride alloys utilizing the photoelectrochemical (PEC) etching. To customize the geometry of the tubular structure, we conducted an analytic calculation to predict the strain and deformation for the layered membrane. Based on the calculations, we designed and fabricated an AlGaN/GaN/InGaN/n-GaN/ sapphire structure using metal-organic chemical vapor deposition (MOCVD). Photolithography and PEC etching were employed to selectively etch the sacrificial InGaN layer. We investigated the changes of optical properties of the rolled-up structure by utilizing micro-photoluminescence (µ-PL) and micro-Raman spectroscopy.

Dielectric-Engineered High-Speed, Low-Power, Highly Reliable Charge Trap Flash-Based Synaptic Device for Neuromorphic Computing beyond Inference.

The coming of the big-data era brought a need for power-efficient computing that cannot be realized in the Von Neumann architecture. Neuromorphic computing which is motivated by the human brain can greatly reduce power consumption through matrix multiplication, and a device that mimics a human synapse plays an important role. However, many synaptic devices suffer from limited linearity and symmetry without using incremental step pulse programming (ISPP). In this work, we demonstrated a charge-trap flash (CTF)-based synaptic transistor using trap-level engineered Al2O3/Ta2O5/Al2O3 gate stack for successful neuromorphic computing. This novel gate stack provided precise control of the conductance with more than 6 bits. We chose the appropriate bias for highly linear and symmetric modulation of conductance and realized it with very short (25 ns) identical pulses at low voltage, resulting in low power consumption and high reliability. Finally, we achieved high learning accuracy in the training of 60000 MNIST images.

Electrically Driven Sub-Micrometer Light-Emitting Diode Arrays Using Maskless and Etching-Free Pixelation.

For decades, group-III-nitride-based light-emitting diodes (LEDs) have been regarded as a light emitting source for future displays by virtue of their novel properties such as high efficiency, brightness, and stability. Nevertheless, realization of high pixel density displays is still challenging due to limitations of pixelation methods. Here, a maskless and etching-free micro-LED (µLED) pixelation method is developed via tailored He focused ion beam (FIB) irradiation technique, and electrically driven sub-micrometer-scale µLED pixel arrays are demonstrated. It is confirmed that optical quenching and electrical isolation effects are simultaneously induced at a certain ion dose (≈1014 ions cm-2 ) without surface damage. Furthermore, highly efficient µLED pixel arrays at sub-micrometer scale (square pixel, 0.5 µm side length) are fabricated. Their pixelation and brightness are verified by various optical measurements such as cathodo-, photo-, and electroluminescence. It is expected that the FIB-induced optical quenching and electrical isolation method can pioneer a new defect engineering technology not only for µLED fabrication, but also for sub-micrometer-scale optoelectronic devices.

Spatially isolated neutral excitons via clusters on trilayer MoS2.

In spite of having a large exciton binding energy, two-dimensional (2D) transition metal dichalcogenides (TMDs) are limited as light-emitting materials because the spectral weight of neutral excitons decreases exponentially with increasing the excitation density. That is, neutral excitons easily transfer to trions, and exciton-exciton annihilation (EEA) occurs due to the strengthening of exciton kinetic energy in the layered structure. In here, we come up with an isolated neutral exciton system, maintaining its high spectral weight when the carrier density increased, which is achieved via MoS2 clusters on a MoS2 trilayer directly synthesized by metal-organic chemical vapor deposition (MOCVD). While increasing the excitation density, trions are decomposed by spatial confinement at the saturation level of its full width at half maximum (FWHM), and simultaneously the spectral weight of neutral excitons restarts to increase. Furthermore, we reveal the causality relationship between trions and B excitons, providing a keen insight into organic interactions among radiative recombination processes in 2D TMDs.

Effective Photoluminescence Imaging of Bubbles in hBN-Encapsulated WSe2 Monolayer.

Interfacial bubbles are unintentionally created during the transfer of atomically thin 2D layers, a required process in the fabrication of van der Waals heterostructures. By encapsulating a WSe2 monolayer in hBN, we study the differing photoluminescence (PL) properties of the structure resulting from bubble formation. Based on the differentiated absorption probabilities at the bubbles compared to the pristine areas, we demonstrate that the visibility of the bubbles in PL mapping is enhanced when the photoexcitation wavelength lies between the n = 1 and n = 2 resonances of the A-exciton. An appropriate choice of detection window, which includes localized exciton emission but excludes free exciton emission, further improves bubble imaging capability. The interfacial position dependence of the bubbles, whether they are located above or below the WSe2 monolayer, gives rise to measurable consequences in the PL shape.

Mechanical Stimulation of the HT7 Acupuncture Point to Reduce Ethanol Self-Administration in Rats.

BACKGROUND: Alcoholism, which is a disabling addiction disorder, is a major public health problem worldwide. The present study was designed to determine whether the application of acupuncture at the Shenmen (HT7) point suppresses voluntary alcohol consumption in addicted rats and whether this suppressive effect is potentiated by the administration of naltrexone. METHODS: Rats were initially trained to self-administer a sucrose solution by operating a lever. A mechanical acupuncture instrument (MAI) for objective mechanical stimulation was used on rats whose baseline response had been determined. In addition, the effect of HT7 acupuncture on beta-endorphin concentration and ethanol intake via naltrexone were investigated in different groups. RESULTS: We found that ethanol intake and beta-endorphin level in rats being treated with the MAI at the HT7 point reduced significantly. The treatment of naltrexone at high doses reduced the ethanol intake and low-dose injection of naltrexone in conjunction with the MAI also suppressed ethanol intake. CONCLUSIONS: The results of the current study indicate that using the MAI at the HT7 point effectively reduces ethanol consumption in rats. Furthermore, the coadministration of the MAI and a low dose of naltrexone can produce some more potent reducing effect of ethanol intake than can acupuncture alone.

Inoculation of Lewis lung carcinoma cells enhances formalin-induced pain behavior and spinal Fos expression in mice.

The incidence of lung cancer has rapidly increased and cancer patients at a later cancer stage frequently suffer from unbearable cancer-associated pain. However, the pathophysiology of lung cancer pain has not been fully described due to a lack of appropriate animal models. This study was designed to determine the effect of Lewis lung carcinoma (LLC) cell inoculation on formalin-induced pain behavior and spinal Fos expression in C57BL/6 mice. LLC cells (1.5 × 105, 2.5 × 105, 3.0 × 105 or 5.0 × 105) were inoculated into back or peri-sciatic nerve areas. Back area inoculation was adopted to determine the effect of cancer cell circulating factors and the peri-sciatic nerve area was used to evaluate the possible effects of cancer cell contacting and circulating factors on formalin-induced pain. At postinoculation day 7, LLC cell (5.0 × 105) inoculations in both back and peri-sciatic nerve area significantly increased formalin-induced paw-licking time and spinal Fos expression over those in cell-media-inoculated (control) mice. Enhanced pain behavior and spinal Fos expression were significantly suppressed by ibuprofen pretreatment (250 mg/kg). The results of this study suggest that LLC cell circulating factors and inflammatory responses may be critical in enhancing pain sensation in the early stage of lung cancer cell inoculation.

Safety recommendations for moxa use based on the concentration of noxious substances produced during commercial indirect moxibustion.

BACKGROUND: Moxibustion therapy has been used historically for thousands of years and there are many clinical trials supporting its efficacy and effectiveness for various conditions. Moxa smoke has been a major reason for avoiding moxibustion due to its smell and potential risks to the human body. METHODS: 10 units of commercial indirect moxa (CIM) from six manufacturers (A-F) were burnt in a 2.5×2.5×2.5 m chamber without ventilation, and concentrations of carbon oxides (CO and CO2), nitrogen oxides (NOx), and volatile organic compounds (VOCs) from the indoor air samples were measured. RESULTS: For brands A, B, C, D, E, and F, respectively, relative to baseline values, we observed an increase in CO (from 0.002 to 0.007, 0.006, 0.005, 0.006, 0.005, and 0.006 parts per billion (ppb)), NOx (from 0.009 to 0.051, 0.025, 0.015, 0.050, 0.019, and 0.020 ppb), and total VOCs (TVOC; from 48.06 to 288.83, 227.93, 140.82, 223.22, 260.15, and 161.35 µg/m3), while the concentration of CO2 was not elevated. Each CIM brand demonstrated different VOC emission characteristics, which could be divided into three groups. On average, we estimated that 20 units of CIM or 2.41 g moxa floss would need to be combusted in order to exceed the safe levels set by Korean environmental law. This limit is likely to be greater in the case of a larger room or use of ventilation. CONCLUSIONS: Despite increased CO/NOx/VOC concentrations, overall levels remained within safe limits. These findings may help clinicians to maintain safe moxibustion treatment conditions to help keep both patients and clinicians safe from the pollutants generated by moxa combustion.

Effects of intermittent traction therapy in an experimental spinal column model.

Traction therapy, which is known to be a treatment method for scoliosis, one of many muscles disease, has been used since Hippocrates introduced it. However, the effects of traction therapy are still not clear. In addition, the meridian sinew theory, which is related to muscle treatment and is mentioned in the book on meridian sinews in the Miraculous Pivot of Huangdi's Internal Classic, has not been the subject of much study. For these reasons, experimental spinal models were made for this study to observe and analyze the lengths of vertebral interspaces after intermittent traction therapy, which is known to be excellent among muscle treatment methods, with various tensile forces. The results showed that the effects of intermittent traction therapy were unclear and that it might be harmful, especially when the pain was induced by muscle weakness. Because the results of this study on intermittent traction therapy were different from those expected from osteopathy or craniosacral theory, better studies of the subject are necessary.

Single Dose Toxicity of Chukyu (spine-healing) Pharmacopuncture Injection in the Muscle of Rats.

OBJECTIVES: This study was performed to analyze the single dose toxicity of Chukyu (spine-healing) pharmacopuncture. METHODS: All experiments were conducted at the Biotoxtech, an institution authorized to perform non-clinical studies under the regulations of Good Laboratory Practice (GLP) regulations. Sprague-Dawley rats were chosen for the pilot study. Doses of Chukyu (spine-healing) pharmacopuncture, 0.1, 0.5 and 1.0 mL, were administered to the experimental groups, and a dose of normal saline solution, 1.0 mL, was administered to the control group. This study was conducted under the approval of the Institutional Animal Ethic Committee. RESULTS: No deaths or abnormalities occurred in any of the four groups. No significant changes in weight, hematological parameters or clinical chemistry between the control group and the experimental groups were observed. To check for abnormalities in organs and tissues, we used microscopy to examine representative histological sections of each specified organ; the results showed no significant differences in any of the organs or tissues except in one case, where interstitial infiltrating macrophages were found in one female rat in the 0.5-mL/animal experimental group. CONCLUSION: The above findings suggest that treatment with Chukyu (spine-healing) pharmacopuncture is relatively safe. Further studies on this subject are needed to yield more concrete evidence.

Single Intramuscular-dose Toxicity of Samgihwalryeok-Pharmacopuncture in Sprague-Dawley Rats.

OBJECTIVES: This study was performed to examine the single-dose toxicity of Samgihwalryeok pharmacopuncture. METHODS: Forty six-week-old Sprague-Dawley (SD) rats were divided into four groups of 10 rats each; each group was then sub-divided into two smaller groups, one of five males and the other of five females. Group 1 (G1, control) received 1.0 mL of normal saline solution, while group 2 (G2, low-dose group), group 3 (G3, mid-does group, and group 4 (G4, high-dose group) received 0.1, 0.5, and 1.0 mL of Samgihwalryeok pharmacopuncture, respectively. RESULTS: No mortalities or clinical signs were observed in the four groups. Also, no significant changes in body weights were observed among the group, and no significant differences in hematology/biochemistry, necropsy, or histopathology results were noted. CONCLUSION: The above findings suggest that treatment with Samgihwalryeok pharmacopuncture is relatively safe. Further studies on this subject are needed.

A Pilot Study on Single-dose Toxicity Testing of Scolopendrid Pharmacopuncture in Sprague-Dawley Rats.

OBJECTIVES: This study was performed to analyze single dose toxicity and the lethal dose of Scolopendrid Pharmacopuncture in rats. METHODS: All experiments were conducted at the Korea Testing & Research Institute (KTR), an institution authorized to perform non-clinical studies, under the regulations of Good Laboratory Practice (GLP). Sprague-Dawley rats were chosen for the pilot study. Doses of Scolopendrid pharmacopuncture, 0.1, 0.5, and 1.0 mL, were administered to the experimental group, and 1.0 mL doses of normal saline solution were administered to the control group. This study was conducted under the approval of the Institutional Animal Ethic Committee. RESULTS: No deaths or abnormalities occurred in any of the groups. No significant changes in the weight, hematological parameters or clinical chemistry were noted between the control group and the experimental group. To check for abnormalities in organs and tissues, we used microscopy to examine representative histological sections of each specified organ; the results showed no significant differences in any of the organs or tissues. CONCLUSION: The above findings suggest Scolopendrid Pharmacopuncture is a relatively safe to use for treatment. Further studies on the subject should be conducted to yield more concrete evidence.

Study on a Single-Dose Toxicity Test of D-Amino Acid Oxidase (DAAO) Extracts Injected into the Tail Vein of Rats.

OBJECTIVE: This study was performed to analyze the single-dose toxicity of D-amino acid oxidase (DAAO) extracts. METHODS: All experiments were conducted at the Korea Testing & Research Institute (KTR), an institution authorized to perform non-clinical studies, under the regulations of Good Laboratory Practice (GLP). Sprague-Dawley rats were chosen for the pilot study. Doses of DAAO extracts, 0.1 to 0.3 cc, were administered to the experimental group, and the same doses of normal saline solution were administered to the control group. This study was conducted under the approval of the Institutional Animal Ethics Committee. RESULTS: In all 4 groups, no deaths occurred, and the LD50 of DAAO extracts administered by IV was over 0.3 ml/kg. No significant changes in the weight between the control group and the experimental group were observed. To check for abnormalities in organs and tissues, we used microscopy to examine representative histological sections of each specified organ, the results showed no significant differences in any organs or tissues. CONCLUSION: The above findings suggest that treatment with D-amino acid oxidase extracts is relatively safe. Further studies on this subject should be conducted to yield more concrete evidence.

Analytical Research to Determine the effects of the Components of ONGABO on the Viability of HepG2 Cancer Cells by Using the Sovereign, Minister, Assistant and Courier Principle ().

OBJECTIVES: This study used the basic principle of Oriental medicine, the sovereign, minister, assistant and courier principle () to investigate the effects of the component of ONGABO, which is composed of Ginseng Radix (Red Ginseng), Angelica Gigantis Radix, Schisandrae Fructus, Cuscuta Semen and Curcumae tuber on the viability of HepG2 cells. METHODS: Single and mixed extracts of the component of ONGABO were prepared by lypohilizing powder of Red Ginseng (6-year root from Kanghwa), Angelica Gigantis Radix, Schisandrae Fructus, Cuscuta Semen, Curcumae Tuber (from Omniherb Co., Ltd., Korea) at the laboratory of herbal medicine in Woosuk University and were eluted after being macerated with 100% ethanol for three days. The cell viability of HepG2 was determined by using an absorptiometric analysis with PrestoBlue (Invitrogen) reagent after the plate had been incubated for 48 hours. All of the experiments were repeated three times to obtain the average value and standard deviation. The statistical analysis was done and the correlation factor was obtained by using Microsoft Office Excel 2007 and Origin 6.0 software. RESULTS: Although Ginseng Radix (Red Ginseng) and Schisandrae Fructus did not enhance the viability of HepG2 cells, they were shown to provide protection of those cells. On the other hand, Angelica Gigantis Radix decreased the viability of HepG2 cells significantly, Cuscuta Semen and Curcumae Tuber had a small or no effect on the viability of HepG2 cells. CONCLUSIONS: In the sovereign, minister, assistant and courier principle (), Ginseng Radix (Red Ginseng) corresponds to the sovereign component because it provides cell protection effects, Angelica Gigantis Radix corresponds to minister medicinal because it kills cells, Schisandrae Fructus corresponds to the assistant medicinal to help red ginseng having cell protect effects. Cuscuta Semen and Curcumae Tuber correspond to the courier medicinal having no effect in cell viability in HepG2. We hope this study provides motivation for advanced research on the sovereign, minister, assistant and courier principle.

Anatomical discrimination of the differences between torn mesentery tissue and internal organ-surface primo-vessels.

The most difficult step in the morphological study of the internal organ-surface primo-vessel (Bong-Han duct) system is the correct identification of samples, due to similarities between torn mesentery and primo-vessel tissue. Without proper sample discernment, the subsequent parts of morphological studies cannot be trusted. Here, we present differences between torn mesentery and primo-vessel tissues as determined by minimal operation, using stereoscopic and microscopic observation. Stereoscopic observation revealed that torn mesentery is tightly connected to the organ surface and does not branch; the detached margin has a fan-shaped membrane without any swollen portions. Primo-vessels are slightly connected to the organ surface and branched, while detached margins lack a membrane and possess a swelling termed the primo-node (Bong-Han corpuscle). Microscopic observation shows bundle patterns in primo-vessel tissue, but irregular arrangement in torn mesentery tissue. These characteristics can be used to distinguish torn mesentery from primo-vessels.

Selaginella tamariscina induces apoptosis via a caspase-3-mediated mechanism in human promyelocytic leukemia cells.

Cell apoptosis is now known to play an important role in the maintenance of cellular homeostasis and anticarcinogenesis. Selaginella tamariscina (ST) is a traditional medicinal plant for treatment of advanced cancer in the Orient. In the present study, the anticancer effect of ST was investigated by analyzing its potential to induce apoptosis in human leukemia HL-60 cells. ST-induced cytotoxicity of HL-60 cells was monitored by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. The apoptosis was determined by microscopic examination of apoptotic morphology, determination of DNA fragmentation by electrophoresis, activation of caspase-3, and protein expression of procaspase-3, poly(ADP-ribose) polymerase (PARP) cleavage, Bcl-2, and Bax. ST was cytotoxic to HL-60 cells in a dose-dependent manner. However, ST-induced cytotoxicity was suppressed by reactive oxygen species scavengers, including superoxide dismutase (SOD) and catalase. ST caused DNA fragmentation and nuclear condensation, all characteristics of apoptosis. ST-induced apoptosis is accompanied by the activation of caspase-3 and the specific proteolytic cleavage of PARP. Concomitantly, ST treatments led to an increase in the proapoptotic Bax levels, while Bcl-2 expression was decreased. Moreover, this effect was attenuated by SOD and catalase. These results suggest that oxidative stress may be involved in the cytotoxicity of ST, and that ST-induced apoptosis of HL-60 cells is primarily mediated by the caspase activation pathway.