Effective Chemical Lift-Off for Air-Tunnel GaN on a Trapezoid-Patterned Sapphire Substrate.

We fabricated an air-tunnel structure between a gallium nitride (GaN) layer and trapezoid-patterned sapphire substrate (TPSS) through the in situ carbonization of a photoresist layer to enable rapid chemical lift-off (CLO). A trapezoid-shaped PSS was used, which is advantageous for epitaxial growth on the upper c-plane when forming an air tunnel between the substrate and GaN layer. The upper c-plane of the TPSS was exposed during carbonization. This was followed by selective GaN epitaxial lateral overgrowth using a homemade metal organic chemical vapor deposition system. The air tunnel maintained its structure under the GaN layer, whereas the photoresist layer between the GaN layer and TPSS disappeared. The crystalline structures of GaN (0002) and (0004) were investigated using X-ray diffraction. The photoluminescence spectra of the GaN templates with and without the air tunnel showed an intense peak at 364 nm. The Raman spectroscopy results for the GaN templates with and without the air tunnel were redshifted relative to the results for free-standing GaN. The CLO process using potassium hydroxide solution neatly separated the GaN template with the air tunnel from the TPSS.

MicroRNA-765 is upregulated in myelodysplastic syndromes and induces apoptosis via PLP2 inhibition in leukemia cells.

Background: Epigenetic studies, particularly research on microRNA (miRNA), have flourished. The abnormal expression of miRNA contributes to the development of hematologic malignancies. miR-765 has been reported to inhibit cell proliferation by downregulating proteolipid protein 2 (PLP2), which causes apoptosis. We investigated miR-765 dysregulation in myelodysplastic syndromes (MDS). Methods: We compared the expression profiles of miR-765 in 65 patients with MDS and 11 controls. Cell proliferation and apoptosis assays were performed to determine the in vitro effects of miR-765 on leukemia cells transfected with the miR-765 mimic. Reverse transcription quantitative PCR (RT-qPCR) and western blotting were performed to examine the targets of miR-765. Results: We found that miR-765 levels were upregulated 10.2-fold in patients with MDS compared to controls. In refractory cytopenia with multilineage dysplasia, the percentage of patients with elevated miR-765 levels was significantly higher than in other forms of MDS. Experiments with leukemia cells revealed that transfection with a miR-765 mimic inhibited cell proliferation and induced apoptosis. RT-qPCR and western blotting demonstrated that the target of miR-765 was PLP2. Conclusion: These findings imply that upregulation of miR-765 induces apoptosis via downregulation of PLP2 and may have a role in MDS pathogenesis.

Selective-Area Growth Mechanism of GaN Microrods on a Plateau Patterned Substrate.

This study provides experimental evidence regarding the mechanism of gallium nitride (GaN) selective-area growth (SAG) on a polished plateau-patterned sapphire substrate (PP-PSS), on which aluminum nitride (AlN) buffer layers are deposited under the same deposition conditions. The SAG of GaN was only observed on the plateau region of the PP-PSS, irrespective of the number of growth cycles. Indirect samples deposited on the bare c-plane substrate were prepared to determine the difference between the AlN buffer layers in the plateau region and silicon oxide (SiO2). The AlN buffer layer in the plateau region exhibited a higher surface energy, and its crystal orientation is indicated by AlN [001]. In contrast, regions other than the plateau region did not exhibit crystallinity and presented lower surface energies. The direct analysis results of PP-PSS using transmission electron microscopy (TEM) and electron backscattered diffraction (EBSD) are similar to the results of the indirect samples. Therefore, under the same conditions, the GaN SAG of the deposited layer is related to crystallinity, crystal orientation, and surface energy.

Establishment of Korean Pediatric Reference Intervals for Estradiol using Ultra-High-Performance Liquid Chromatography-Tandem Mass Spectrometry.

BACKGROUND: Ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) is a reliable and accurate method for measuring steroid hormone levels. There is an increasing need for sensitive and precise methods to measure estradiol in pediatric patients. Here, we established reference intervals for estradiol in healthy children using a UHPLC-MS/MS-based method for the first time in South Korea. METHODS: Serum estradiol was measured using a Sciex Triple QuadTM 6500 + UHPLC-MS/MS (Sciex, Framingham, MA, USA). Reference intervals for estradiol were established according to the CLSI document EP28-A3c:2008. The reference intervals were validated using serum samples from 634 pediatric patients, including neonates, children, and adolescents. Among them, 389 specimens were used in analysis of the specimen acceptance time. Statistical analysis was performed using MedCalc (MedCalc, Ostend, Belgium) and Analyse-it (Analyse-it Software Ltd., Leeds, United Kingdom) software. RESULTS: Reference intervals for boys (n = 297) were <16.6, <7.3, <19.0, <30.5, 7.6-96.5, and 10.6-134.4 pmol/L among those aged <1, 1-5, 6-9, 10-11, 12-14, and 15-17 years, respectively. Reference intervals for girls (n = 337) were <114.7, <24.2, <34.8, 8.0-177.0, 10.4-480.5, and 9.1-486.7 pmol/L among those aged <1, 1-5, 6-9, 10-11, 12-14, and 15-17 years, respectively. Overall, there was no effect of specimen acceptance time on estradiol measurements in boys or girls, except for that in the group aged 10-11 years. CONCLUSIONS: The reference intervals for healthy children were validated using a UHPLC-MS/MS-based method. The highly analytical sensitive UHPLC-MS/MS method may be useful for estradiol determination in pediatric patients.

Upregulation of microRNA-597 in myelodysplastic syndromes induces apoptosis through FOSL2 inhibition.

INTRODUCTION: Dysregulation of microRNAs (miRNAs) has been associated with the pathophysiology of myelodysplastic syndrome (MDS). Trisomy 8 is the most frequent chromosomal abnormalities in Korean patients with MDS. We investigated the dysregulation of miR-597-5p, located on chromosome 8, which is reported to induce cell death in numerous cancers. MATERIALS AND METHODS: We compared the expression profiles of miR-597-5p among 65 MDS patients and 11 controls, and analyzed the in vitro effects of miR-597 on leukemic cells using an acute myeloid leukemia cell line transfected with miR-597. RESULTS: We found that miR-597-5p levels were upregulated 4.05-fold in MDS patients compared to those in controls. In vitro study results demonstrated that transfection with a miR-597 mimic induced apoptosis through downregulation of FOS like 2 (FOSL2). CONCLUSION: These findings suggest that upregulation of miR-597 induces apoptosis and that miR-597 has a possible role in the pathophysiology of MDS.

Accuracy of ASTA MicroIDSys, a new matrix-assisted laser desorption/ionization time-of-flight mass spectrometry system, for the identification of Korean reference and clinical bacterial and yeast strains.

This study compared the accuracy of a new MALDI-TOF mass spectrometry system, ASTA MicroIDSys system, with that of MALDI Biotyper system for the identification of reference and clinical bacterial and yeast strains. The identification accuracy of the 2 systems was compared using a total of 406 strains comprising 142 aerobic and 180 anaerobic bacterial strains and 84 yeast strains. The genus and species identification rates were 98.0% and 89.4% using MicroIDSys and 96.1% and 89.4% using Biotyper, respectively. The species identification rates of MicroIDSys and Biotyper for aerobic bacteria were 93.0% and 97.2%, respectively, and those for anaerobic bacteria were 85.6% and 81.7%, respectively. The accuracy of yeast identification at the species level was 91.7% using MicroIDSys and 92.9% using Biotyper. These findings indicate that MicroIDSys could be useful for the accurate identification of bacteria and yeast in clinical microbiology laboratories.

Performance assessment of ASTA MicroIDSys, a new matrix assisted laser desorption ionization-time of flight mass spectrometry system, for identification of viridans group streptococci.

The performance of the ASTA MicroIDSys system (ASTA), a new matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) system, was evaluated for the identification of viridans group streptococci (VGS) and compared with the results obtained with the Bruker Biotyper system (Bruker Daltonics). A total of 106 Streptococcus reference strains belonging to 24 species from the bacterial strain bank was analyzed using the two MALDI-TOF MS systems. Of the 106 reference strains tested, ASTA MicroIDSys and Bruker Biotyper correctly identified 84.9% and 81.1% at the species level, 100% and 97.2% at the group level and 100% and 98.1% at the genus level, respectively. The difference between the two systems was not statistically significant (P = 0.289). Out of 24 species, 13 species were accurately identified to the species level with 100% accurate identification rates with both systems. The accurate identification rates at the species level of ASTA MicroIDSys and Bruker Biotyper were 100% and 87.5% for the S. anginosus group; 78.4% and 73.5% for the S. mitis group; 91.7% and 91.7% for the S. mutans group; and 100% and 100% for the S. salivarius group, respectively. The ASTA MicroIDSys showed an identification performance equivalent to that of the Bruker Biotyper for VGS. Therefore, it would be useful for the identification of VGS strains in clinical microbiology laboratories.

Mistreatment from Multiple Sources: Interaction Effects of Abusive Supervision, Coworker Incivility, and Customer Incivility on Work Outcomes.

Despite the large body of research on workplace mistreatment, surprisingly few studies have examined the interaction effect of multiple interpersonal stressors on employee outcomes. To fill this gap, our research aimed to test the moderating effects of coworker incivility and customer incivility on the relationship between abusive supervision, emotional exhaustion, and job performance. Analyses conducted on 651 South Korean frontline service employees revealed that abusive supervision exerted a significant indirect effect on job performance through emotional exhaustion. Customer incivility strengthened the positive relationship between abusive supervision and emotional exhaustion, as well as the indirect effect of abusive supervision on job performance through emotional exhaustion. Our post hoc analysis demonstrated a three-way interaction between abusive supervision, coworker incivility, and customer incivility; the relationship between abusive supervision and emotional exhaustion was significantly positive only when coworker incivility was high and customer incivility was low. We discuss the implications of our findings for theory and practice.

Genome wide CRISPR screening reveals a role for sialylation in the tumorigenesis and chemoresistance of acute myeloid leukemia cells.

Aberrant activation of cytokine and growth factor signal transduction pathways confers enhanced survival and proliferation properties to acute myeloid leukemia (AML) cells. However, the mechanisms underlying the deregulation of signaling pathways in leukemia cells are unclear. To identify genes capable of independently supporting cytokine-independent growth, we employed a genome-wide CRISPR/Cas9-mediated loss-of-function screen in GM-CSF-dependent human AML TF-1 cells. More than 182 genes (p < 0.01) were found to suppress the cytokine-independent growth of TF-1 cells. Among the top hits, genes encoding key factors involved in sialylation biosynthesis were identified; these included CMAS, SLC35A1, NANS, and GNE. Knockout of either CMAS or SLC35A1 enabled cytokine-independent proliferation and survival of AML cells. Furthermore, NSG (NOD/SCID/IL2Rγ-/-) mice injected with CMAS or SLC35A1-knockout TF-1 cells exhibited a shorter survival than mice injected with wild-type cells. Mechanistically, abrogation of sialylation biosynthesis in TF-1 cells induced a strong activation of ERK signaling, which sensitized cells to MEK inhibitors but conferred resistance to JAK inhibitors. Further, the surface level of α2,3-linked sialic acids was negatively correlated with the sensitivity of AML cell lines to MEK/ERK inhibitors. We also found that sialylation modulated the expression and stability of the CSF2 receptor. Together, these results demonstrate a novel role of sialylation in regulating oncogenic transformation and drug resistance development in leukemia. We propose that altered sialylation could serve as a biomarker for targeted anti-leukemic therapy.

Relationships between Relative Expression of RND Efflux Pump Genes, H33342 Efflux Activity, Biofilm-Forming Activity, and Antimicrobial Resistance in Acinetobacter baumannii Clinical Isolates.

Various mechanisms underlying antimicrobial resistance in Acinetobacter baumannii have been reported. However, the relationships between efflux pump activity, biofilm formation, and antimicrobial resistance in A. baumannii is controversial. In this study, we investigated the relative expression of RND efflux pump genes, H33342 efflux activity, and biofilm-forming activity in 120 A. baumannii clinical isolates, examined their potential relationships with each other, and statistically analyzed their effects on antibiotic resistance. High adeB expression and high H33342 efflux activity were correlated with low biofilm-forming activity. High adeB expression was significantly correlated with resistance to tigecycline and cefotaxime, but not with the multidrug resistance (MDR) phenotype. Importantly, only high adeJ expression was significantly correlated with the MDR phenotype and was correlated with resistance to various antibiotics. However, we found no significant correlation between adeJ expression and biofilm-forming activity. Furthermore, adeG expression was not correlated with antibiotic resistance and biofilm-forming activity. The results of multivariate analysis showed that adeB overexpression and high H33342 efflux activity were related to biofilm-forming activity, and only adeJ overexpression was significantly associated with the MDR phenotype, highlighting the importance of adeJ overexpression.

Acute myelomonocytic leukemia during pembrolizumab treatment for non-small cell lung cancer: A case report.

BACKGROUND: Pembrolizumab is a highly selective IgG4 kappa isotype monoclonal antibody against the programmed cell death-1 (PD-1) molecule. In the treatment of non-small cell lung cancer (NSCLC), pembrolizumab has demonstrated significant efficacy, significant survival outcomes, long-lasting responses, and a good safety profile compared with cytotoxic chemotherapy. CASE SUMMARY: A 79-year-old Korean male presented with a left side palpable neck mass. An ultrasound-guided core-needle biopsy of the largest neck mass was performed, and squamous cell carcinoma was confirmed based on the histological and immunohistochemical findings. He was diagnosed with squamous cell carcinoma of the lung with multiple lymph nodes and rib metastases (T1N3M1b, Stage IVA) using enhanced chest computed tomography and 18F-fluorodeoxyglucose positron emission/computed tomography. After 4 cycles of gemcitabine and carboplatin, we clinically judged the disease as progressive. Owing to the high PD-1 expression demonstrated by the patient, pembrolizumab was initiated (200 mg every 3 wk). After 3 cycles of pembrolizumab, a complete response was achieved. At the 4th cycle of pembrolizumab, the white blood cell count was markedly elevated. Peripheral blood smear analysis and bone marrow biopsy were performed. The patient was diagnosed with acute myelomonocytic leukemia. CONCLUSION: We present the first report of acute myelomonocytic leukemia during pembrolizumab treatment in an NSCLC patient; the mechanism remains unknown.

CD226hiCD8+ T Cells Are a Prerequisite for Anti-TIGIT Immunotherapy.

Clinical trials are evaluating the efficacy of anti-TIGIT for use as single-agent therapy or in combination with programmed death 1 (PD-1)/programmed death-ligand 1 blockade. How and whether a TIGIT blockade will synergize with immunotherapies is not clear. Here, we show that CD226loCD8+ T cells accumulate at the tumor site and have an exhausted phenotype with impaired functionality. In contrast, CD226hiCD8+ tumor-infiltrating T cells possess greater self-renewal capacity and responsiveness. Anti-TIGIT treatment selectively affects CD226hiCD8+ T cells by promoting CD226 phosphorylation at tyrosine 322. CD226 agonist antibody-mediated activation of CD226 augments the effect of TIGIT blockade on CD8+ T-cell responses. Finally, mFOLFIRINOX treatment, which increases CD226hiCD8+ T cells in patients with pancreatic ductal adenocarcinoma, potentiates the effects of TIGIT or PD-1 blockade. Our results implicate CD226 as a predictive biomarker for cancer immunotherapy and suggest that increasing numbers of CD226hiCD8+ T cells may improve responses to anti-TIGIT therapy.

BOK promotes erythropoiesis in a mouse model of myelodysplastic syndrome.

Myelodysplastic syndromes are clonal hematopoietic stem cell disorders characterized by cytopenia and intramedullary apoptosis. BCL-2 Ovarian Killer (BOK) is a pro-apoptotic member of the BCL-2 family of proteins which, when stabilized from endoplasmic reticulum-associated degradation (ERAD), induces apoptosis in response to ER stress. Although ER stress appropriately activates the unfolded protein response (UPR) in BOK-disrupted cells, the downstream effector signaling that includes ATF4 is defective. We used Nup98-HoxD13 (NHD13) transgenic mice to evaluate the consequences of BOK loss on hematopoiesis and leukemogenesis. Acute myeloid leukemia developed in 36.7% of NHD13 mice with a Bok gene knockout between the age of 8 and 13 months and presented a similar overall survival to the NHD13 mice. The loss of BOK exacerbated anemia in NHD13 mice, and NHD13/BOK-deficient mice exhibited significantly lower hemoglobin, lower mean cell hemoglobin concentration, and higher mean cell volume than NHD13 mice. Hematopoietic progenitor cell assays revealed a decreased amount of erythroid progenitor stem cells (BFU-E) in the bone marrow of NHD13-transgenic/BOK-deficient mice. RT-qPCR analysis demonstrated decreased mean value of ATF4 in the erythroid progenitors of NHD13 and NHD13/BOK-deficient mice. Our results suggest that in addition to induction of apoptosis in response to ER stress, BOK may regulate erythropoiesis when certain erythroid progenitors experience cell stress.

Three-dimensional measurement and registration accuracy of a third-generation optical tracking system for navigational maxillary orthognathic surgery.

OBJECTIVE: The purpose of this study was to evaluate the accuracy of an optical tracking system during reference point localization, measurement, and registration of skull models for navigational maxillary orthognathic surgery. STUDY DESIGN: Accuracy was first evaluated on the basis of the position recording discrepancy at a static point and at 2 points of fixed lengths. Ten reference points were measured on a skull model at 7 different locations, and their measurements were compared with predicted positions by using 4 registration methods. Finally, positional tracking of reference points for simulated maxillary surgery was performed and compared with laser scan data. RESULTS: The average linear measurement discrepancy was 0.28 mm, and the mean measurement discrepancy with the 5 registered cranial points was 1.53 mm. The average measurement discrepancy after maxillary surgery was 1.91 mm (for impaction) and 1.56 mm (for advancement). The registration discrepancy in jitter and point registration on the y-axis was significantly greater than on the other axes. CONCLUSIONS: The optical tracking system seems clinically acceptable for precise tracking of the maxillary position during navigational orthognathic surgery, notwithstanding the chance of greater measurement error on the y-axis.

MicroRNA-661 upregulation in myelodysplastic syndromes induces apoptosis through p53 activation and associates with decreased overall survival.

MicroRNA (miRNA) dysregulation contributes to myelodysplastic syndromes (MDS), and apoptosis is one of the pathogenic features of MDS. We investigated the dysregulation of miRNA expression and its biological significance in MDS. We compared the expression profiles of miRNAs encoded by chromosome 8 in 65 patients with MDS and 11 controls, and analyzed the in vitro effect of the upregulated miRNA expression. We found that compared to the controls, miR-661 was upregulated by 5.28-fold in patients with MDS. Patients with high miR-661 expression showed significantly decreased overall survival. In vitro study results demonstrated that transfection with a miR-661 mimic induced apoptosis through the activation of p53. These findings suggest that high miR-661 expression can be associated with decreased overall survival and recapitulates apoptosis, the characteristic feature of MDS.

Inhibition of MEK with trametinib enhances the efficacy of anti-PD-L1 inhibitor by regulating anti-tumor immunity in head and neck squamous cell carcinoma.

Major histocompatibility complex (MHC) class I downregulation is the primary immune evasion mechanism associated with failure in anti-PD-1/PD-L1 blockade therapies for cancer. Here, we examined the role of MEK signaling pathway inhibition in head and neck squamous cell carcinoma (HNSCC) both in vitro and in vivo. We found that trametinib, a small molecule inhibitor of MEK, significantly enhanced MHC class I and PD-L1 expression in human HNSCC cell lines, and this occurred via STAT3 activation. Trametinib also further upregulated the increase in CXCL9 and CXCL10 expression caused by IFN-γ in HNSCC cells, which is associated with T cell infiltration in tumor tissues. Finally, we evaluated the therapeutic efficacy of trametinib combined with an anti-PD-L1 monoclonal antibody in vivo, using SCCVII mouse syngeneic tumor model for HNSCC. While neither PD-L1 blockade nor trametinib treatment alone affected tumor growth, the combined therapy significantly delayed tumor growth. Our results indicate that in the combined therapy trametinib increases CD8+ T cell infiltration in the tumor site and upregulates antigen presentation, and this may be associated with enhanced PD-L1 blockade efficacy. Furthermore, our results suggest that this combination would therapeutically benefit patients with HNSCC.

How and When Are Job Crafters Engaged at Work?

The importance of work engagement and the lack of engaged employees have led researchers to focus on how to enhance employees' levels of engagement in the workplace. Although job crafting as a principal driver of work engagement has recently received much attention from academics, little is known about the processes and conditions in which employees who craft their tasks become engaged. In order to address these research gaps, we hypothesize that psychological capital (PsyCap) is likely to mediate the association between job crafting and work engagement, and that coworker support, rather than supervisor support, is likely to moderate the relationship between job crafting and PsyCap. Further, we integrated these hypotheses and tested the moderated mediation effect. Using survey data from 175 flight attendants in South Korea, we found the results to be in line with our expectations. The findings of this empirical research contribute to the understanding of how and when job crafters become engaged at work.

Mean platelet volume: a potential biomarker of the risk and prognosis of heart disease.

Platelets are essential for progression of atherosclerotic lesions, plaque destabilization, and thrombosis. They secrete and express many substances that are crucial mediators of coagulation, inflammation, and atherosclerosis. Mean platelet volume (MPV) is a precise measure of platelet size, and is routinely reported during complete blood count analysis. Emerging evidence supports the use of MPV as a biomarker predicting the risk of ischemic stroke in patients with atrial fibrillation, and as a guide for prescription of anticoagulation and rhythm-control therapy. In addition, MPV may predict the clinical outcome of percutaneous coronary intervention (PCI) in patients with coronary artery disease and indicate whether additional adjunctive therapy is needed to improve clinical outcomes. This review focuses on the current evidence that MPV may be a biomarker of the risk and prognosis of common heart diseases, particularly atrial fibrillation and coronary artery disease treated via PCI.

A Novel FLCN c.1489_1490delTG Mutation that Escapes the Nonsense-Mediated Decay System.

A novel FLCN c.1489_1490delTG (p.Val497Glyfs*22) mutation at the genomic DNA and mRNA levels was identified in a 43-year-old woman with complaining of recurrent primary spontaneous pneumothorax. The aberrant FLCN mRNA escaped the nonsense-mediated decay system (NMD) because of a premature termination code located in an NMD-incompetent region. To the best of our knowledge, this is the first case report of an FLCN mutation escaping the NMD.