Epsti1 Regulates the Inflammatory Stage of Early Muscle Regeneration through STAT1-VCP Interaction.

During muscle regeneration, interferon-gamma (IFN-γ) coordinates inflammatory responses critical for activation of quiescent muscle stem cells upon injury via the Janus kinase (JAK) - signal transducer and activator of transcription 1 (STAT1) pathway. Dysregulation of JAK-STAT1 signaling results in impaired muscle regeneration, leading to muscle dysfunction or muscle atrophy. Until now, the underlying molecular mechanism of how JAK-STAT1 signaling resolves during muscle regeneration remains largely elusive. Here, we demonstrate that epithelial-stromal interaction 1 (Epsti1), an interferon response gene, has a crucial role in regulating the IFN-γ-JAK-STAT1 signaling at early stage of muscle regeneration. Epsti1-deficient mice exhibit impaired muscle regeneration with elevated inflammation response. In addition, Epsti1-deficient myoblasts display aberrant interferon responses. Epsti1 interacts with valosin-containing protein (VCP) and mediates the proteasomal degradation of IFN-γ-activated STAT1, likely contributing to dampening STAT1-mediated inflammation. In line with the notion, mice lacking Epsti1 exhibit exacerbated muscle atrophy accompanied by increased inflammatory response in cancer cachexia model. Our study suggests a crucial function of Epsti1 in the resolution of IFN-γ-JAK-STAT1 signaling through interaction with VCP which provides insights into the unexplored mechanism of crosstalk between inflammatory response and muscle regeneration.

Presurgical Reduction of the Cleft Palate: Serendipitous Benefit of the Stanford Orthodontic Airway Plate Treatment (SOAP) for Infants with Robin Sequence.

OBJECTIVE: Narrowing of the palatal cleft is often observed in infants with Robin sequence (RS) treated with the Stanford Orthodontic Airway Plate treatment (SOAP) even though SOAP is utilized primarily to establish airway patency. The current study quantified dimensional changes of the cleft palate (CP) in infants with RS treated with SOAP. DESIGN: A retrospective chart review. PATIENTS: Infants with RS and CP who completed SOAP and had maxillary arch models at both pre- and post-treatment time points at a single tertiary referral hospital between September 2019 and July 2023. SETTING AND OUTCOME MEASURE: Maxillary arch models were measured and analyzed using Bivariate statistical analysis. RESULTS: Seventeen infants were included in the study. The median age (min, max) was 6.7 weeks (1.1, 21.9) at pre-treatment and 26.6 weeks (18.7, 37.0) at post-treatment. The median Obstructive Apnea Hypopnea Index was 36.2 events/hour (8.1, 103.1) at pre-treatment and 4.1 events/hour (1.9, 8.6) at post-treatment. The pre-treatment width of CP decreased by an average (± standard diviation) of 6.37 mm (± 3.55, p < 0.001) at post-treatment. The ratio of the posterior cleft width to the total maxillary arch width decreased from 40% (± 9.1) at pre-treatment to 22% (± 11) at post-treatment (p < 0.001). CONCLUSION: The dimensions of CP reduced significantly during SOAP in infants with RS and CP treated for their severe upper airway obstruction. The findings highlight a potential benefit of SOAP that may contribute favorably to the palate repair surgery.

PEMF Potentiates Doxorubicin-induced Late G2 Arrest in MDA-MB-231 Breast Cancer Cells.

BACKGROUND/AIM: Pulsed electromagnetic field (PEMF) stimulation enhances the efficacy of several anticancer drugs. Doxorubicin is an anticancer drug used to treat various types of cancer, including breast cancer. However, the effect of PEMF stimulation on the efficacy of doxorubicin and the underlying mechanisms remain unclear. Thus, this study aimed to investigate the effect of PEMF stimulation on the anticancer activity of doxorubicin in MDA-MB-231 human breast cancer cells. MATERIALS AND METHODS: MDA-MB-231 cells were seeded and allowed to incubate for 48 h. The cells were treated with doxorubicin, cisplatin, 5-fluorouracil, or paclitaxel for 48 h. Subsequently, the cells were stimulated with a 60-min PEMF session thrice a day (with an interval of 4 h between each session) for 24 or 48 h. Cell viability was assessed by trypan blue dye exclusion assay and cell-cycle analysis was analyzed by flow cytometry. Molecular mechanisms involved in late G2 arrest were confirmed by a western blot assay and confocal microscopy. RESULTS: MDA-MB-231 cells treated with a combination of doxorubicin and PEMF had remarkably lower viability than those treated with doxorubicin alone. PEMF stimulation increased doxorubicin-induced cell-cycle arrest in the late G2 phase by suppressing cyclin-dependent kinase 1 (CDK1) activity through the enhancement of myelin transcription factor 1 (MYT1) expression, cell division cycle 25C (CDC25C) phosphorylation, and stratifin (14-3-3σ) expression. PEMF also increased doxorubicin-induced DNA damage by inhibiting DNA topoisomerase II alpha (TOP2A). CONCLUSION: These findings support the use of PEMF stimulation as an adjuvant to strengthen the antiproliferative effect of doxorubicin on breast cancer cells.

Culture-based susceptibility-guided tailored versus empirical concomitant therapy as first-line Helicobacter pylori treatment: A randomized clinical trial.

BACKGROUND: With the increasing resistance to antimicrobial agents, susceptibility-guided tailored therapy has been emerging as an ideal strategy for Helicobacter pylori treatment. However, susceptibility-guided tailored therapy requires additional cost, time consumption, and invasive procedure (endoscopy) and its superiority over empirical quadruple therapy as the first-line H. pylori treatment remains unclear. AIMS: To compare the efficacy of culture-based susceptibility-guided tailored versus empirical concomitant therapy as the first-line Helicobacter pylori treatment. METHODS: This open-label, randomized trial was performed in four Korean institutions. A total of 312 Patients with H. pylori-positive culture test and naïve to treatment were randomly assigned in a 3:1 ratio to either culture-based susceptibility-guided tailored therapy (clarithromycin-based or metronidazole-based triple therapy for susceptible strains or bismuth quadruple therapy for dual-resistant strains, n = 234) or empirical concomitant therapy (n = 78) for 10 days. Eradication success was evaluated by 13C-urea breath test at least 4 weeks after treatment. RESULTS: Prevalence of dual resistance to both clarithromycin and metronidazole was 8%. H. pylori eradication rates for tailored and concomitant groups were 84.2% and 83.3% by intention-to-treat analysis (p = 0.859), respectively, and 92.9% and 91.5% by per-protocol analysis, respectively (p = 0.702), which were comparable between the two groups. However, eradication rates for dual-resistant strains were significantly higher in the tailored group than in the concomitant group. All adverse events were grade 1 or 2 based on the Common Terminology Criteria for Adverse Events and the incidence was significantly lower in the tailored group. The proportion of patients discontinuing treatment for adverse events was comparable between the two groups (2.1% vs. 2.6%). CONCLUSIONS: The culture-based susceptibility-guided tailored therapy failed to show superiority over the empirical concomitant therapy in terms of eradication rate. Based on these findings, the treatment choice in clinical practice would depend on the background rate of antimicrobial resistance, availability of resources and costs associated with culture and susceptibility testing.

Divine mathematics: Leibniz's combinatorial theory of compossibility.

Leibniz's famous proposition that God has created the best of all possible worlds holds a significant place in his philosophical system. However, the precise manner in which God determines which world is the best remains somewhat ambiguous. Leibniz suggests that a form of "Divine mathematics" is employed to construct and evaluate possible worlds. In this paper, I uncover the underlying mechanics of Divine mathematics by formally reconstructing it. I argue that Divine mathematics is a one-player combinatorial game, in which God's goal is to find the best combination among many possibilities. Drawing on the combinatorial theory, I provide new solutions to some puzzles of compossibility.

Emerging Perspectives of YAP/TAZ in Human Skin Epidermal and Dermal Aging.

Yes-associated protein (YAP) and transcriptional coactivator with PDZ-binding motif (TAZ) are key downstream effectors of the Hippo signaling pathway, which plays a central role in tissue homeostasis, organ development, and regeneration. While the dysregulation of YAP/TAZ has been linked to various human diseases, their involvement in the aging of human skin has only recently begun to manifest. In the skin, the YAP/TAZ effectors emerge as central regulators in maintaining homeostasis of epidermal stem cells and dermal extracellular matrix, and thus intimately linked to skin aging processes. This review underscores recent molecular breakthroughs highlighting how age-related decline of YAP/TAZ activity impacts human epidermal and dermal aging. Gaining insight into the evolving roles of YAP/TAZ in human skin aging presents a promising avenue for the development of innovative therapeutic approaches aimed at enhancing skin health and addressing age-related skin conditions.

Survey of patient satisfaction with genetic counseling services in Korea.

Since the 1990s, genetic clinics have been established in South Korea, enabling the provision of clinical genetics services. However, genetic counseling services are not widely used in the medical system. In contrast, recently, the demand for genetic counseling has increased due to the rapid development of genomic medicine. Therefore, it is important for medical geneticists and genetic counselors to collaboratively provide genetic counseling services. This study aimed to evaluate the perception and satisfaction of patients with rare genetic diseases and their families regarding genetic counseling services provided by a genetics team at the medical genetics center of a tertiary general hospital for rare genetic diseases. From April to November 2021, a survey was conducted with 203 individuals, including 111 and 92 individuals in the patient and family groups, respectively. Overall, 164 individuals (80.8%) responded that they were aware of genetic counseling services, and 135 individuals (66.5%) responded that they were aware of the role of genetic counselors. Patients and their families wanted to receive information about the following from genetic counseling: clinical manifestation and prognosis of the diagnosed disease (78.8%), treatment and management of the disease (60.6%), risk of recurrence within the family (55.7%), treatment options and alternatives for family and prenatal testing, and various support services. The score of satisfaction with genetic counseling services provided by the genetics team was 8.19 ± 1.68 out of 10. Patients with rare genetic diseases and their families were satisfied with genetic counseling services regarding their diseases, test results, and treatment options. Moreover, the patients could receive psychosocial support and referrals to other medical service providers and support services. As a genetic team approach, collaboration between medical geneticists and certified genetic counselors would be useful in providing information and in diagnosing, treating, and managing patients.

Maxillary Bone Necrosis in Post-COVID-19 Patients: Possibility of Medication-Related Osteonecrosis of Jaws (MRONJ) Induced by Tocilizumab.

Medication-related osteonecrosis of the jaws (MRONJ) is a serious condition often linked with antiresorptive, immune modulating, and antiangiogenic drugs, initially associated with bisphosphonates but now including a broader range of medications. Tocilizumab, an interleukin-6 (IL-6) receptor-inhibiting monoclonal antibody used for conditions like rheumatoid arthritis and recently for COVID-19 to reduce IL-6 activity and alleviate symptoms, has raised concerns over its potential to induce MRONJ, particularly in post-COVID-19 patients. A case involving a 36-year-old male who developed tooth mobility and pain in the right maxillary posterior region after COVID-19 treatment with tocilizumab and dexamethasone is highlighted. Despite treatments like antibiotics, the necrosis persisted until more extensive surgery was performed, leading to improvement without recurrence over 2 years. This case emphasizes the need for awareness and research into the risk of MRONJ in patients treated with tocilizumab after COVID-19, underlining the importance for healthcare professionals to recognize and manage this complication.

Pulsed Electromagnetic Field Enhances Caffeic Acid Phenethyl Ester-induced Death of MCF-7 Breast Cancer Cells.

BACKGROUND/AIM: Caffeic acid phenethyl ester (CAPE) exerts anticancer effects against several cancer types, including breast cancer. Pulsed electromagnetic field (PEMF) improves the efficiency of some chemotherapeutic drugs. In this study, we examined the effects of PEMF stimulation on the anticancer activity of CAPE in MCF-7 breast cancer cells and the underlying signal transduction pathways. MATERIALS AND METHODS: MCF-7 cells were seeded and incubated for 24 h. Each of the drugs (5-fluorouracil, paclitaxel, gefitinib, or CAPE) was added to the cells on day 0. Then, cells were immediately stimulated with a 60-min PEMF session thrice a day (with 4-h interval between sessions) for 1-3 days. Cell death and viability were assessed by flow cytometry and trypan blue dye exclusion assay. Molecular mechanisms involved in cell death were confirmed by western blot assay. RESULTS: Compared with treatment with CAPE alone, co-treatment with CAPE and PEMF more strongly reduced the viability of MCF-7 cells, further increased the percentage of the sub-G1 population, poly (ADP-ribose) polymerase (PARP) cleavage, activation of apoptotic caspases, up-regulation of pro-apoptotic proteins, such as Fas cell surface death receptor (FAS) and BCL2 associated X, apoptosis regulator (BAX), and reduced the expression of anti-apoptotic proteins, such as BCL-2 apoptosis regulator (BCL-2), MCL-1 apoptosis regulator, BCL-2 family member (MCL-1), and survivin. PEMF stimulation also increased CAPE-induced phosphorylation of p53, and inhibition of p53 partially restored the PEMF-reduced viability of CAPE-treated MCF-7 cells. CONCLUSION: PEMF stimulation enhanced CAPE-induced cell death by activating p53, which regulates the expression of apoptosis-related molecules, subsequently activating the caspase-dependent apoptotic pathway in MCF-7 cells, suggesting that PEMF can be utilized as an adjuvant to enhance the effect of CAPE on breast cancer cells.

Microwave-transparent metallic metamaterials for autonomous driving safety.

Maintaining the surface transparency of protective covers using transparent heaters in extreme weather is imperative for enhancing safety in autonomous driving. However, achieving both high transmittance and low sheet resistance, two key performance indicators for transparent heaters, is inherently challenging. Here, inspired by metamaterial design, we report microwave-transparent, low-sheet-resistance heaters for automotive radars. Ultrathin (approximately one ten-thousandth of the wavelength), electrically connected metamaterials on a millimetre-thick dielectric cover provide near-unity transmission at specific frequencies within the W band (75-110 GHz), despite their metal filling ratio exceeding 70 %. These metamaterials yield the desired phase delay to adjust Fabry-Perot resonance at each target frequency. Fabricated microwave-transparent heaters exhibit exceptionally low sheet resistance (0.41 ohm/sq), thereby heating the dielectric cover above 180 °C at a nominal bias of 3 V. Defrosting tests demonstrate their thermal capability to swiftly remove thin ice layers in sub-zero temperatures.

Incidence and survival rates of primary cutaneous malignancies in Korea, 1999-2019: A nationwide population-based study.

Primary cutaneous malignancies are among the most commonly diagnosed types of cancer worldwide. We aimed to examine the incidence and 5-year survival rates of all types of primary cutaneous malignancies in the Korean population. Data from the Korean Nationwide Cancer Registry from 1999 to 2019 were analyzed. The crude incidence rates, age-standardized incidence rates, and 5-year relative survival rates of each type of skin cancer were calculated. A total of 89 965 patients were diagnosed with primary cutaneous malignancies, which was a 7-fold increase from 1999 to 2019. The age-standardized incidence rates increased 3.4-fold in basal cell carcinoma (3.7/100 000 person-years), 2.0-fold in squamous cell carcinoma (1.6/100 000 person-years), 12.0-fold in Bowen disease (1.2/100 000 person-years), and 1.8-fold in malignant melanoma (0.7/10 000 person-years) in 2019. Average annual percentage changes in age-standardized incidence rates were statistically significant in basal cell carcinoma (15.8%), Bowen disease (5.8%), squamous cell carcinoma (5.1%), malignant melanoma (1.2%), melanoma in situ (1.1%), dermatofibrosarcoma protuberans (1.2%), mycosis fungoides (0.5%), primary cutaneous CD30+ T-cell proliferations (0.5%), adnexal and skin appendage carcinoma (0.4%), extramammary Paget's disease (0.2%), and Merkel cell carcinoma (0.2%). The 5-year relative survival rates were the highest in basal cell carcinoma (103.3%), followed by dermatofibrosarcoma protuberans (99.7%) and mycosis fungoides (96.6%), and lowest in angiosarcoma (24.7%). The 5-year relative survival rates steadily increased in extramammary Paget's disease (23.6%), cutaneous B-cell lymphoma (21.3%), mycosis fungoides (20.2%), extranodal NK/T-cell lymphoma, nasal type (18.1%), and malignant melanoma (16.1%) from 1996-2000 to 2015-2019. Most primary cutaneous malignancies have increased in incidence and survival rates in the Korean population, but to varying extents depending on the type of skin cancer.

Optimal fabrication of a thin-film thermocouple (TFTC) using Alumel/chromel junctions.

Thin-film thermocouple (TFTC) technology is a novel measurement method that produces a thermocouple sensor during the deposition process, even though it is a complex surface, to obtain the surface temperature. TFTC is a thin film sensor for measuring temperature by contact methods, consisting of two different metals which can generate thermoelectric forces named "Seebeck effects". In the past decade there have been many attempts to measure the cutting temperature during machining processes using TFTF sensors. However, research has not yet progressed to optimize the sensor performance or fabrication process. This paper studies a preliminary technique for the fabrication of a TFTC sensor on a cutting tool surface and optimizes the deposition conditions, TFTC design, and sensor performance. Chromel and Alumel, which are materials commonly used in K-type thermocouples, were used for the thermal evaporation process. When the Chromel has a nickel to chrome ratio of 9:1, low resistivity and minimal variation with increasing temperature were observed. When the contact area of the deposited electrode (+) and (-) poles increased, the resistivity decreased and the TFTC sensitivity improved. Data acquisition tests using a DAQ system connected to the TFTC sensor show the lowest resistivity in TFTC B and C types are able to measure temperature data. It is expected that the heat generated during the cutting process can be detected using the TFTC sensor with B-type shape and Chromel with a 9:1 nickel to chrome ratio.

Can medication-related osteonecrosis of the jaw be attributed to specific microorganisms through oral microbiota analyses? A preliminary study.

BACKGROUND: Medication-related osteonecrosis of the jaw (MRONJ) can cause significant pain and loss of aesthetics and function if not treated properly. However, diagnosis still relies on detailed intraoral examinations and imaging. Prognosis varies even among patients with similar stages or conditions of MRONJ, emphasizing the need for a deeper understanding of its complex mechanisms. Thus, this study aimed to identify the oral microbiota of patients with MRONJ. METHODS: This single-center prospective cohort study included patients with confirmed MRONJ who visited the Department of Oral and Maxillofacial Surgery at Yonsei University Dental Hospital between 2021 and 2022. Oral swab samples were collected from the affected and unaffected sides of each patient. The composition and enumeration of the microbial communities were analyzed, and the diversity was compared to verify ecological changes in the groups using a next-generation sequencing-based 16S metagenomic analysis. A statistical analysis was performed using Wilcoxon signed-rank test with SPSS version 22, and values of P less than 0.05 were considered statistically significant. RESULTS: The final study sample included 12 patients. The mean age was 82.67 ± 5.73 (range, 72-90) years. Changes in microbial composition were observed at different taxonomic levels (phylum, genus, and species). The identified microorganisms were commonly associated with periodontitis, gingival disease, and endodontic infection, suggesting a multifactorial etiology of MRONJ. CONCLUSIONS: Although this study is based on a small number of cases, it shows that MRONJ is not caused by a specific microorganism but can rather be caused by a variety of factors. By addressing these findings in large-scale studies, the significance of oral microbiome in pathogenesis can be further elucidated and can facilitate the development of effective therapeutic interventions for patients with MRONJ.

Innate Immune-Enhancing Effect of Pinus densiflora Pollen Extract via NF-κB Pathway Activation.

Considering the emergence of various infectious diseases, including the coronavirus disease 2019 (COVID-19), people's attention has shifted towards immune health. Consequently, immune-enhancing functional foods have been increasingly consumed. Hence, developing new immune-enhancing functional food products is needed. Pinus densiflora pollen can be collected from the male red pine tree, which is commonly found in Korea. P. densiflora pollen extract (PDE), obtained by water extraction, contained polyphenols (216.29 ± 0.22 mg GAE/100 g) and flavonoids (35.14 ± 0.04 mg CE/100 g). PDE significantly increased the production of nitric oxide (NO) and reactive oxygen species (ROS) but, did not exhibit cytotoxicity in RAW 264.7 cells. Western blot results indicated that PDE induced the expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase (COX)-2. PDE also significantly increased the mRNA and protein levels of cytokines and the phosphorylation of IKKα/ß and p65, as well as the activation and degradation of IκBα. Additionally, western blot analysis of cytosolic and nuclear fractions and immunofluorescence assay confirmed that the translocation of p65 to the nucleus after PDE treatment. These results confirmed that PDE increases the production of cytokines, NO, and ROS by activating NF-κB. Therefore, PDE is a promising nutraceutical candidate for immune-enhancing functional foods.

Volumetric changes in temporomandibular joint space following trans-oral vertical ramus osteotomy in patients with mandibular prognathism: a one-year follow-up study.

This study measured and analyzed chronological changes in temporomandibular joint space volume by compartment following transoral vertical ramus osteotomy (TOVRO) using reconstructed 3-dimensional (3D) images of patients with mandibular prognathism. It included 70 joints of 35 patients who underwent TOVRO between January 2018 and December 2021. Computed tomography (CT) or cone-beam CT (CBCT) was performed before surgery (T0) and at 3 days (T1), 6 months (T2), and 12 months postoperatively (T3). These scans were then analyzed using 3D software. The volumes of the overall (Vjs), anterior (Vajs), posterior (Vpjs), medial (Vmjs), and lateral (Vljs) joint spaces were calculated at each time point. A linear mixed model and repeated-measures covariance pattern with unstructured covariance were used to evaluate significant changes in joint space volume over time. Vjs significantly increased to 134.54 ± 34.28 mm3 at T3 compared to T0 (p < 0.001). Vpjas and Vljs increased by 130.72 ± 10.07 mm3 and 109.98 ± 7.52 mm3 at T3 compared to T0, respectively (p < 0.001). However, no significant difference was observed between T0 and T2 in Vajs and Vmjs (p = 0.9999). The observed volume increases in Vpjs and Vljs appeared to contribute to the overall Vjs increase.

Which Skeletal Factors Can Affect Lip Canting in Facial Asymmetry?: Statistical Analysis.

Lip canting, which is a noticeable factor in patients with facial asymmetry, can be influenced by the dentofacial skeleton. During orthognathic surgery, postoperative changes in facial soft tissue occur along the newly positioned hard tissue. Therefore, the evaluation of soft tissue before surgery is important. The purpose of this study was to investigate the skeletal factors that can affect lip canting by statistically comparing 2 facial horizontal planes using a three-dimensional reconstruction model. The findings of the present study showed a statistical correlation between lip canting and 3 skeletal factors: menton deviation, maxillary canting, and ramal length differences. Furthermore, a statistical correlation was identified between the Frankfort Horizontal plane and the intercanthal plane compared with the lip canting line. This result suggests that the intercanthal plane could be a standard horizontal plane in three-dimensional reconstruction model analysis.

Distribution of sika deer (Cervus nippon) and the bioclimatic impact on their habitats in South Korea.

Invasive species and climate change are primary factors influencing biodiversity, and examining the behavior of invasive species is essential for effective conservation management. Here, we report the global distribution of the sika deer (Cervus nippon) based on locations reported in published literature (Google Scholar), the Global Biodiversity Information Facility (GBIF) database, and the International Union for Conservation of Nature report. We used the maximum entropy (Maxent) model to examine the impact of climate change on sika deer habitats in South Korea based on GBIF occurrence data and WorldClim bioclimatic variables. Habitat suitability analysis was performed using the Maxent model under Representative Concentration Pathways (RCPs) 4.5 and 8.5 (for predicted climatic conditions in both 2050 and 2070) to project the effects of different climate change scenarios on South Korean sika deer habitats. We identified that the sika deer is distributed in 39 countries worldwide. Due to climate change effects, South Korean sika deer habitats will decline by approximately 24.98% and 20.63% (under RCP 4.5) and by 50.51% and 57.35% (under RCP 8.5) by 2050 and 2070, respectively. Our findings shed light on sika deer ecology and provide reference data for future conservation management strategies and policy design.

Enhanced Performance of Inverted Perovskite Quantum Dot Light-Emitting Diode Using Electron Suppression Layer and Surface Morphology Control.

The energy level offset at inorganic layer-organic layer interfaces and the mismatch of hole/electron mobilities of the individual layers greatly limit the establishment of balanced charge carrier injection inside the emissive layer of halide perovskite light-emitting diodes (PeQLEDs). In contrast with other types of light-emitting devices, namely OLEDs and QLEDs, various techniques such as inserting an electron suppression layer between the emissive and electron transport layer have been employed as a means of establishing charge carrier injection into their respective emissive layers. Hence, in this study, we report the use of a thin layer of Poly(4-vinylpyridine) (PVPy) (an electron suppression material) placed between the emissive and electron transport layer of a halide PeQLEDs fabricated with an inverted configuration. With ZnO as the electron transport material, devices fabricated with a thin PVPy interlayer between the ZnO ETL and CsPbBr3 -based green QDs emissive layer yielded a 4.5-fold increase in the maximum observed luminance and about a 10-fold increase in external quantum efficiency (EQE) when compared to ones fabricated without PVPy. Furthermore, the concentration and coating process conditions of CsPbBr3 QDs were altered to produce various thicknesses and film properties which resulted in improved EQE values for devices fabricated with QDs thin films of lower surface root-mean-square (RMS) values. These results show that inhibiting the excessive injection of electrons and adjusting QDs layer thickness in perovskite-inverted QLEDs is an effective way to improve device luminescence and efficiency, thereby improving the carrier injection balance.

Measurement of inkjet droplet size based on Fraunhofer diffraction.

Inkjet printers have started to manufacture OLED/QLED pixel arrays for the display industry, and the precise measurement and control of ink droplet volume during the printing process has become important. We investigated the feasibility of Fraunhofer diffraction analysis as a volume measurement tool for fast-moving inkjet droplets. To confirm the basic idea, two Fraunhofer diffraction-based methods were used to calculate the wire diameters of well-known sized and steady-positioned metal wires. The first method was to curve-fit the whole measured diffraction intensity curve with the extensive Fraunhofer diffraction equation. The second one was to use the simple approximate diameter calculation equation with the measured position data of minimum diffraction intensity. The metal wire diameters calculated by the two methods showed less than 1.17% error. For the size measurement of fast-moving inkjet droplets, the first method showed 24.5 µm diameter and 7.7 pL volume, while the second method showed 25.4 µm diameter and 8.58 pL volume. We found that the second method was more suitable for real-time inkjet monitoring because its average computer calculation time was 33 ms, and the first method took an average of 34 ms, about 1000 times more CPU time. Hence, Fraunhofer diffraction analysis as an inkjet droplet volume measurement tool was feasible with a good balance of measurement time and measurement accuracy.

Sublimation-based wafer-scale monolayer WS2 formation via self-limited thinning of few-layer WS2.

Atomically-thin monolayer WS2 is a promising channel material for next-generation Moore's nanoelectronics owing to its high theoretical room temperature electron mobility and immunity to short channel effect. The high photoluminescence (PL) quantum yield of the monolayer WS2 also makes it highly promising for future high-performance optoelectronics. However, the difficulty in strictly growing monolayer WS2, due to its non-self-limiting growth mechanism, may hinder its industrial development because of the uncontrollable growth kinetics in attaining the high uniformity in thickness and property on the wafer-scale. In this study, we report a scalable process to achieve a 4 inch wafer-scale fully-covered strictly monolayer WS2 by applying the in situ self-limited thinning of multilayer WS2 formed by sulfurization of WOx films. Through a pulsed supply of sulfur precursor vapor under a continuous H2 flow, the self-limited thinning process can effectively trim down the overgrown multilayer WS2 to the monolayer limit without damaging the remaining bottom WS2 monolayer. Density functional theory (DFT) calculations reveal that the self-limited thinning arises from the thermodynamic instability of the WS2 top layers as opposed to a stable bottom monolayer WS2 on sapphire above a vacuum sublimation temperature of WS2. The self-limited thinning approach overcomes the intrinsic limitation of conventional vapor-based growth methods in preventing the 2nd layer WS2 domain nucleation/growth. It also offers additional advantages, such as scalability, simplicity, and possibility for batch processing, thus opening up a new avenue to develop a manufacturing-viable growth technology for the preparation of a strictly-monolayer WS2 on the wafer-scale.