Micro-Current Stimulation Suppresses Inflammatory Responses in Peptidoglycan-Treated Raw 264.7 Macrophages and Propionibacterium acnes-Induced Skin Inflammation via TLR2/NF-κB Signaling Pathway.

Acne is a common inflammatory disorder of the human skin and a multifactorial disease caused by the sebaceous gland and Propionibacterium acnes (P. acnes). This study aimed to evaluate the anti-inflammatory effect of micro-current stimulation (MC) on peptidoglycan (PGN)-treated raw 264.7 macrophages and P. acnes-induced skin inflammation. To specify the intensity with anti-inflammatory effects, nitric oxide (NO) production was compared according to various levels of MC. As the lowest NO production was shown at an intensity of 50 µA, subsequent experiments used this intensity. The changes of expression of the proteins related to TLR2/NF-κB signaling were examined by immunoblotting. Also, immunofluorescence analysis was performed for observing NF-κB p65 localization. All of the expression levels of proteins regarding TLR2/NF-κB signaling were decreased by the application of MC. Moreover, the application of MC to PGN-treated raw 264.7 cells showed a significant decrease in the amount of nuclear p65-protein. In the case of animal models with P. acnes-induced skin inflammation, various pro-inflammatory cytokines and mediators significantly decreased in MC-applied mice. In particular, the concentration of IL-1ß in serum decreased, and the area of acne lesions, decreased from the histological analysis. We suggest for the first time that MC can be a novel treatment for acne.

Micro-Current Stimulation Has Potential Effects of Hair Growth-Promotion on Human Hair Follicle-Derived Papilla Cells and Animal Model.

Recently, a variety of safe and effective non-pharmacological methods have been introduced as new treatments of alopecia. Micro-current electrical stimulation (MCS) is one of them. It is generally known to facilitate cell proliferation and differentiation and promote cell migration and ATP synthesis. This study aimed to investigate the hair growth-promoting effect of MCS on human hair follicle-derived papilla cells (HFDPC) and a telogenic mice model. We examined changes in cell proliferation, migration, and cell cycle progression with MCS-applied HFDPC. The changes of expression of the cell cycle regulatory proteins, molecules related to the PI3K/AKT/mTOR/Fox01 pathway and Wnt/ß-catenin pathway were also examined by immunoblotting. Subsequently, we evaluated the various growth factors in developing hair follicles by RT-PCR in MCS-applied (MCS) mice model. From the results, the MCS-applied groups with specific levels showed effects on HFDPC proliferation and migration and promoted cell cycle progression and the expression of cell cycle-related proteins. Moreover, these levels significantly activated the Wnt/ß-catenin pathway and PI3K/AKT/mTOR/Fox01 pathway. Various growth factors in developing hair follicles, including Wnts, FGFs, IGF-1, and VEGF-B except for VEGF-A, significantly increased in MCS-applied mice. Our results may confirm that MCS has hair growth-promoting effect on HFDPC as well as telogenic mice model, suggesting a potential treatment strategy for alopecia.

Bright Mid-Infrared Photoluminescence from Thin-Film Black Phosphorus.

Recently rediscovered layered black phosphorus (BP) provides rich opportunities for investigations of device physics and applications. The band gap of BP is widely tunable by its layer number and a vertical electric field, covering a wide electromagnetic spectral range from visible to mid-infrared. Despite much progress in BP optoelectronics, the fundamental photoluminescence (PL) properties of thin-film BP in mid-infrared have rarely been investigated. Here, we report bright PL emission from thin-film BP (with thickness of 4.5 to 46 nm) from 80 to 300 K. The PL measurements indicate a band gap of 0.308 ± 0.003 eV in 46 nm thick BP at 80 K, and it increases monotonically to 0.334 ± 0.003 eV at 300 K. Such an anomalous blueshift agrees with the previous theoretical and photoconductivity spectroscopy results. However, the observed blueshift of 26 meV from 80 to 300 K is about 60% of the previously reported value. Most importantly, we show that the PL emission intensity from thin-film BP is only a few times weaker than that of an indium arsenide (InAs) multiple quantum well (MQW) structure grown by molecular beam epitaxy. Finally, we report the thickness-dependent PL spectra in thin-film BP in mid-infrared regime. Our work reveals the mid-infrared light emission properties of thin-film BP, suggesting its promising future in tunable mid-infrared light emitting and lasing applications.

Low spatial coherence electrically pumped semiconductor laser for speckle-free full-field imaging.

The spatial coherence of laser sources has limited their application to parallel imaging and projection due to coherent artifacts, such as speckle. In contrast, traditional incoherent light sources, such as thermal sources or light emitting diodes (LEDs), provide relatively low power per independent spatial mode. Here, we present a chip-scale, electrically pumped semiconductor laser based on a novel design, demonstrating high power per mode with much lower spatial coherence than conventional laser sources. The laser resonator was fabricated with a chaotic, D-shaped cavity optimized to achieve highly multimode lasing. Lasing occurs simultaneously and independently in ∼1,000 modes, and hence the total emission exhibits very low spatial coherence. Speckle-free full-field imaging is demonstrated using the chaotic cavity laser as the illumination source. The power per mode of the sample illumination is several orders of magnitude higher than that of a LED or thermal light source. Such a compact, low-cost source, which combines the low spatial coherence of a LED with the high spectral radiance of a laser, could enable a wide range of high-speed, full-field imaging and projection applications.

Electrically pumped continuous-wave 1.3 µm quantum-dot lasers epitaxially grown on on-axis (001) GaP/Si.

We demonstrate the first electrically pumped continuous-wave (CW) III-V semiconductor lasers epitaxially grown on on-axis (001) silicon substrates without offcut or germanium layers, using InAs/GaAs quantum dots as the active region and an intermediate GaP buffer between the silicon and device layers. Broad-area lasers with uncoated facets achieve room-temperature lasing with threshold current densities around 860 A/cm2 and 110 mW of single-facet output power for the same device. Ridge lasers designed for low threshold operations show maximum lasing temperatures up to 90°C and thresholds down to 30 mA.

Large-Area Dry Transfer of Single-Crystalline Epitaxial Bismuth Thin Films.

We report the first direct dry transfer of a single-crystalline thin film grown by molecular beam epitaxy. A double cantilever beam fracture technique was used to transfer epitaxial bismuth thin films grown on silicon (111) to silicon strips coated with epoxy. The transferred bismuth films retained electrical, optical, and structural properties comparable to the as-grown epitaxial films. Additionally, we isolated the bismuth thin films on freestanding flexible cured-epoxy post-transfer. The adhesion energy at the bismuth/silicon interface was measured to be ∼1 J/m2, comparable to that of exfoliated and wet transferred graphene. This low adhesion energy and ease of transfer is unexpected for an epitaxially grown film and may enable the study of bismuth's unique electronic and spintronic properties on arbitrary substrates. Moreover, this method suggests a route to integrate other group-V epitaxial films (i.e., phosphorus) with arbitrary substrates, as well as potentially to isolate bismuthene, the atomic thin-film limit of bismuth.

Bulk AlInAs on InP(111) as a novel material system for pure single photon emission.

In this letter, we report on quantum light emission from bulk AlInAs grown on InP(111) substrates. We observe indium rich clusters in the bulk Al0.48In0.52As (AlInAs), resulting in quantum dot-like energetic traps for charge carriers, which are confirmed via cross-sectional scanning tunnelling microscopy (XSTM) measurements and 6-band k·p simulations. We observe quantum dot (QD)-like emission signals, which appear as sharp lines in our photoluminescence spectra at near infrared wavelengths around 860 nm, and with linewidths as narrow as 50 µeV. We demonstrate the capability of this new material system to act as an emitter of pure single photons as we extract g(2)-values as low as gcw(2)(0)=0.05-0.05+0.17 for continuous wave (cw) excitation and gpulsed, corr.(2)=0.24±0.02 for pulsed excitation.

Evaluation of Antibacterial Activity of Titanium Surface Modified by PVD/PACVD Process.

The aim of this study was to evaluate the response of Streptococcus mutans (S. mutans) via crystal violet staining assay on titanium surface modified by physical vapor deposition/plasma assisted chemical vapor deposition process. Specimens were divided into the following three groups: polished titanium (control group), titanium modified by DC magnetron sputtering (group TiN-Ti), and titanium modified by plasma nitriding (group N-Ti). Surface characteristics of specimens were observed by using nanosurface 3D optical profiler and field emission scanning electron microscope. Group TiN-Ti showed TiN layer of 1.2 microm in thickness. Group N-Ti was identified as plasma nitriding with X-ray photoelectron spectroscopy. Roughness average (Ra) of all specimens had values < or = 0.2 microm (the threshold Ra), which had no effect on bacterial adhesion. No significant difference of S. mutans adhesion was found between the surfaces of control, TiN-Ti, and N-Ti (P > 0.05). Within the process condition of this study, modified titanium surfaces by DC magnetron sputtering and plasma nitriding did not influence the adhesion of S. mutans.

Waveguide-integrated single-crystalline GaP resonators on diamond.

Large-scale entanglement of nitrogen-vacancy (NV) centers in diamond will require integration of NV centers with optical networks. Toward this goal, we present the fabrication of single-crystalline gallium phosphide (GaP) resonator-waveguide coupled structures on diamond. We demonstrate coupling between 1 µm diameter GaP disk resonators and waveguides with a loaded Q factor of 3,800, and evaluate their potential for efficient photon collection if integrated with single photon emitters. This work opens a path toward scalable NV entanglement in the hybrid GaP/diamond platform, with the potential to integrate on-chip photon collection, switching, and detection for applications in quantum information processing.

PM10-bound microplastics and trace metals: A public health insight from the Korean subway and indoor environments.

Inhalable airborne microplastics (MPs) presented in indoor and outdoor environments, can deeply penetrate the lungs, potentially triggering inflammation and respiratory illnesses. The present study aims to evaluate human health risks from respirable particulate matter (PM)-bound trace metals and MPs in indoor (SW- subway and IRH- indoor residential houses) and outdoor (OD) environments. This research provides an initial approach to human respiratory tract (HRT) mass depositions of PM10-bound total MPs and nine specific MP types to predict potential human health threats from inhalation exposure. Results indicate that PM-bound trace metals and MPs were around 4 times higher in SW microenvironments compared to OD locations. In IRH, cancer risk (CR) levels were estimated 9 and 4 times higher for PM10 and PM2.5, respectively. Additionally, MP particle depositions per gram of lung cell weight were highest in IRH (23.77), followed by OD and SW. Whereas, lifetime alveoli depositions of MPs were estimated at 13.73 MP/g, which exceeds previously reported respiratory disease fatality cases by 10 to 5 times. Prolonged exposure duration at IRH emerged as a key factor contributing to increased CR and MP lung deposition levels. This research highlights severe lung risks from inhaling PM-bound MPs and metals, offering valuable health insights.

Micro-current stimulation could inhibit IL-1ß-induced inflammatory responses in chondrocytes and protect knee bone cartilage from osteoarthritis.

This study aimed to evaluate the inhibitory effects of micro-current stimulation (MCS) on inflammatory responses in chondrocytes and degradation of extracellular matrix (ECM) in osteoarthritis (OA). To determine the efficacy of MCS, IL-1ß-treated chondrocytes and monosodium iodoacetate (MIA)-induced OA rat model were used. To evaluate the cytotoxicity and nitric oxide (NO) production in SW1353 cells, the presence or absence of IL-1ß treatment or various levels of MCS were applied. Immunoblot analysis was conducted to evaluate whether MCS can modulate IL-1R1/MyD88/NF-κB signaling pathway and various indicators involved in ECM degradation. Additionally, to determine whether MCS alleviates subchondral bone structure destruction caused by OA, micro-CT analysis, immunoblot analysis, and ELISA were conducted using OA rat model. 25 and 50 µA levels of MCS showed effects in cell proliferation and NO production. The MCS group with IL-1ß treatment lead to significant inhibition of protein expression levels regarding IL-1R1/MyD88/NF-κB signaling and reduction of the nucleus translocation of NF-κB. In addition, the protein expression levels of MMP-1, MMP-3, MMP-13, and IL-1ß decreased, whereas collagen II and aggrecan increased. In animal results, morphological analysis of subchondral bone using micro-CT showed that MCS induced subchondral bone regeneration and improvement, as evidenced by increased thickness and bone mineral density of the subchondral bone. Furthermore, MCS-applied groups showed decreases in the protein expression of MMP-1 and MMP-3, while increases in collagen-II and aggrecan expressions. These findings suggest that MCS has the potential to be used as a non-pharmaceutical method to alleviate OA.

Interaction between the electrical stimulation of a face-selective area and the perception of face stimuli.

We electrically stimulated the face-selective area in epileptic patients while they were performing a face-categorization task. Face categorization was interfered by electrical stimulation but was restored by increasing the visual signal. More importantly, face-categorization interference by electrical stimulation was confined to face-selective electrodes, and the amount of interference was positively correlated with the sensitivity of the face-selective electrodes. These results strongly support the hypothesis that the face-selective area has a direct causal link to face perception.

Adverse impacts of Asian dust events on human health and the environment-A probabilistic risk assessment study on particulate matter-bound metals and bacteria in Seoul, South Korea.

This study aimed to assess the impact of Asian dust (AD) on the human health and the environment. Particulate matter (PM) and PM-bound trace elements and bacteria were examined to determine the chemical and biological hazards associated with AD days and compared with non-AD days in Seoul. On AD days, the mean PM10 concentration was ∼3.5 times higher than that on non-AD days. Elements generated from the Earth's crust (Al, Fe, and Ca) and anthropogenic sources (Pb, Ni, and Cd) were identified as major contributors to coarse and fine particles, respectively. During AD days, the study area was recognized as "severe" for pollution index and pollution load index levels, and "moderately to heavily polluted" for geoaccumulation index levels. The potential cancer risk (CR) and non-CR were estimated for the dust generated during AD events. On AD days, total CR levels were significant (in 1.08 × 10-5-2.22 × 10-5), which were associated with PM-bound As, Cd, and Ni. In addition, inhalation CR was found to be similar to the incremental lifetime CR levels estimated using the human respiratory tract mass deposition model. In a short exposure duration (14 days), high PM and bacterial mass deposition, significant non-CR levels, and a high presence of potential respiratory infection-causing pathogens (Rothia mucilaginosa) were observed during AD days. Significant non-CR levels were observed for bacterial exposure, despite insignificant levels of PM10-bound elements. Therefore, the substantial ecological risk, CR, and non-CR levels for inhalation exposure to PM-bound bacteria, and the presence of potential respiratory pathogens, indicate that AD events pose a significant risk to both human lung health and the environment. This study provides the first comprehensive examination of significant non-CR levels for bacteria and carcinogenicity of PM-bound metals during AD events.

Micro-Current Stimulation Can Modulate the Adipogenesis Process by Regulating the Insulin Signaling Pathway in 3T3-L1 Cells and ob/ob Mice.

Obesity is a disease in which fat is abnormally or excessively accumulated in the body, and many studies have been conducted to overcome it with various techniques. In this study, we evaluated whether micro-current stimulation (MCS) can be applied to prevent obesity by regulating the adipogenesis through 3T3-L1 cells and ob/ob mice. To specify the intensity of MCS, Oil Red O staining was conducted with various intensities of MCS. Based on these, subsequent experiments used 200 and 400 µA for the intensity of MCS. The expressions of insulin signaling pathway-related proteins, including phosphorylation of IGF-1 and IR, were decreased in all MCS groups, and in turn, downstream signals such as Akt and ERK were decreased. In addition, MCS reduced the nucleus translocation of PPAR-γ and decreased the protein expression of C/EBP-α. In the ob/ob mouse model, MCS reduced body weight gain and abdominal adipose tissue volume. In particular, the concentration of triglycerides in serum was also decreased. Taken together, our findings showed that MCS inhibited lipid accumulation by regulating insulin signaling in 3T3-L1, and it was effective at reducing body weight and adipose tissue volume in ob/ob mice. These suggest that MCS may be a useful treatment approach for obesity.

Metatranscriptional characterization of metabolic dynamics in anaerobic membrane bioreactor producing methane from low-strength wastewater.

An anaerobic membrane bioreactor (AnMBR) with media is an emerging carbon-neutral biotechnology for low-strength wastewater (LSWW) treatment and methane recovery. Understanding metabolic dynamics among methanogens and syntrophic bacteria is important in optimizing the design and operation of AnMBR. However, little is known about it, especially in media-attached microbial communities. This study explored metabolic dynamics to compare media-attached and suspended conditions. Accordingly, metagenomes and metatranscriptomes from AnMBRs with polymeric media and fed with different influent concentrations (350 and 700 mg-COD/L) were analyzed. Metabolic dynamics were profoundly influenced by the different growth habitats and influent conditions, although the applied influent concentrations are within the range of typical LSWW. Metabolic dynamics prediction results suggest that media-attached-growth habitats may have provided a more favorable microenvironment for methanogens to grow and produce methane, especially under low influent conditions. These findings provide significant implications for optimizing floating media design and operation of AnMBR-producing methane from LSWW.

The fabrication of large-area, free-standing GaN by a novel nanoetching process.

A simple yet versatile nanoetching process in porosifying and 'machining' GaN is reported in this work. By combining different porosifying conditions through potentiostatic modulation or embedding doping design, we are able to separate and lift off GaN layers over a macroscopic area (≥cm(2)). Strain relaxation and single crystallinity are confirmed by Raman and transmission electron microscopy, respectively. This method is expected to open up a new dimension in epitaxy, design and manufacture of GaN heterostructures and devices.

Exploring Socio-Demographic Factors Affecting Psychological Symptoms in Humidifier Disinfectant Survivors.

This study aimed to compare the psychological symptoms of humidifier disinfectant survivors to the general population and explore socio-demographic factors influencing survivors' psychological symptoms. A one-way Multivariate Analysis of Covariance (MANCOVA) and a series of two-way MANCOVA were conducted with a sample of 228 humidifier disinfectant survivors and 228 controls. The results demonstrated that the survivor group displayed higher anxious/depressed symptoms, withdrawn symptoms, somatic complaints, thought problems, attention problems, aggressive behavior and rule-breaking behavior than the general group. Moreover, among the socio-demographic factors, the two-way interaction effects of group × family economic status and group × number of friends were found to be statistically significant. The limitations and implications of this study are discussed.

Local delivery of cardiac stem cells overexpressing HIF-1α promotes angiogenesis and muscular tissue repair in a hind limb ischemia model.

Critical limb ischemia (CLI) is the most advanced stage of peripheral artery disease, associated with significant risk of limb loss, morbidity and mortality; however, there remains unmet therapeutic needs for arterial revascularization and ischemic tissue repair. Stem cell therapies have emerged as compelling candidates due to beneficial proangiogenic and immunosuppressive function. Nevertheless, in vivo efficacy was insufficient in proliferation, differentiation and survival/engraftment rate. Cardiac stem cells (CSCs) was firstly attempted for CLI as a novel therapeutic modality to provide superior angiogenic potency to bone marrow-derived stem cells (BMSCs). It was noted that CSCs demonstrated 3.2-fold in HGF, 2.9-fold in VEGF and 8.7-fold in PDGF-B higher gene expressions compared to BMSCs. To enhance the hypoxia-induced proangiogenic effect, CSCs were transfected with hypoxia-inducible factor-1 alpha (HIF-1α) by using electroporation method, specifically optimized for CSCs yielding 45.77% of transfection efficiency and 89.75% of viability. HIF-1α overexpression significantly increased CSC survival in hypoxia, proangiogenic factors production and endothelial differentiation. In mouse hind limb ischemia model, local intramuscular delivery of CSC overexpressing HIF-1α (HIF-CSC) significantly improved the blood flow recovery. Histological analysis revealed that muscle degeneration and fibrosis in the ischemic limb were attenuated. Local delivery of HIF-CSC might be a promising option for ischemic tissue restoration.

Enhanced selective enrichment of partial nitritation and anammox bacteria in a novel two-stage continuous flow system using flat-type poly (vinylalcohol) cryogel films.

To improve stability of nitrogen removal in partial nitritation (PN)-anammox process, flat-type cryogel films using poly (vinylalcohol) named as FT-CPVAF were applied in continuous reactors. Stable PN operation was maintained with short acclimation of 8 days and ammonium oxidation rate of 1.68 ± 0.12 kg N m-3 d-1 comparatively higher than previous studies. The nitrogen removal, initially inhibited by an oxygen shock, was immediately reactivated with short lag-period by immobilization of anammox bacteria in FT-CPVAF. A novel two-stage PN-anammox process was operated in a continuous flow using FT-CPVAF for treatment of ammonium-rich synthetic wastewater (influent 315 mg NH4+-N L-1) showing 89.6 ± 0.76% of nitrogen removal at short hydraulic retention time (7.7 h). The use of FT-CPVAF enhanced selective enrichment of AOB and anammox bacter ia confirmed by high-throughput sequencing of i.e., relative abundances of Nitrosomonas europaea C-31 (37.14% in PN reactor) and 'Candidatus Jettenia caeni' (34.36% in anammox reactor).