Search

Aim Bacteria naturally produce membrane vesicles (MVs), which have been shown to contribute to the spread of multi-drug resistant bacteria (MDR) by delivering antibiotic-resistant substances to antibiotic-susceptible bacteria. Here, we aim to show that MVs from Gram-positive bacteria are capable of transferring β-lactam antibiotic-resistant substances to antibiotic-sensitive Gram-negative bacteria. Materials and Methods MVs were collected from a methicillin-resistant strain of Staphylococcus aureus (MRSA) and vesicle-mediated fusion with antimicrobial-sensitive Escherichia coli (RC85). It was performed by exposing the bacteria to the MVs to develop antimicrobial-resistant E. coli (RC85-T). Results The RC85-T exhibited a higher resistance to β-lactam antibiotics compared to the parent strain. Although the secretion rates of the MVs from RC85-T and the parent strain were nearly equal, the β-lactamase activity of the MVs from RC85-T was 12-times higher than that of MVs from the parent strain, based on equivalent protein concentrations. Moreover, MVs secreted by RC85-T were able to protect β-lactam-susceptible E. coli from β-lactam antibiotic-induced growth inhibition in a dose-dependent manner. Conclusion MVs play a role in transferring substances from Gram-positive to Gram-negative bacteria, shown by the release of MVs from RC85-T that were able to protect β-lactam-susceptible bacteria from β-lactam antibiotics. Significance and impact of study MVs are involved in the emergence of antibiotic-resistant strains in a mixed bacterial culture, helping us to understand how the spread of multidrug-resistant bacteria could be reduced.

The highly enantioselective aza-Michael reaction of

Highly enantioselective epoxidation of enones has been accomplished with asymmetric phase-transfer catalysis using Cinchona alkaloid-derived meta-dimer catalysts.

Cysteine–cysteine chemokine receptor 5 (CCR5) has been discovered as a co-receptor for cellular entry of human immunodeficiency virus (HIV). Moreover, the role of CCR5 in a variety of cancers and various inflammatory responses was also discovered. Despite the fact that several CCR5 antagonists have been investigated in clinical trials, only Maraviroc has been licensed for use in the treatment of HIV patients. This indicates that there is a need for novel CCR5 antagonists. Keeping this in mind, the present study was designed. The active CCR5 inhibitors with known IC50 value were selected from the literature and utilized to develop a ligand-based common feature pharmacophore model. The validated pharmacophore model was further used for virtual screening of drug-like databases obtained from the Asinex, Specs, InterBioScreen, and Eximed chemical libraries. Utilizing computational methods such as molecular docking studies, molecular dynamics simulations, and binding free energy calculation, the binding mechanism of selected inhibitors was established. The identified Hits not only showed better binding energy when compared to Maraviroc, but also formed stable interactions with the key residues and showed stable behavior throughout the 100 ns MD simulation. Our findings suggest that Hit1 and Hit2 may be potential candidates for CCR5 inhibition, and, therefore, can be considered for further CCR5 inhibition programs.

Many optically active 2-azaspirocyclic structures have frequently been found in biologically active natural products. In particular, Nitraria alkaloids, (+)-nitramine, (+)-isonitramine, (-)-isonitramine, and (-)-sibirine, have stereogenicity on their quaternary carbon of the 2-azaspiro[5,5]undecane-7-ol structure. To synthesize Nitraria alkaloids, we developed a new enantioselective synthetic method for chiral α-quaternary lactams via the α-alkylation of α-tert-butoxycarbonyl lactams. α-Alkylation of α-tert-butoxycarboxylactams in the circumstances of phase-transfer catalytic (PTC) system (solid KOH, toluene, and -40 °C) by virtue of the catalytic action of (S,S)-NAS bromide (5 mol %) furnished the corresponding α-alkyl-α-tert-butoxycarbonyl lactams in very high chemical (

The use of SiO2/4H–SiC metal-oxide-semiconductor field-effect transistors (MOSFETs) can be problematic due to high interface state density (Dit) and low field-effect mobility (μfe). Here, we present a tetra-ethyl-ortho-silicate (TEOS)-based low-pressure chemical vapor deposition (LPCVD) method for fabricating the gate oxide of 4H–SiC MOSFETs using nitric oxide post-deposition annealing. SiO2/4H–SiC MOS capacitors and MOSFETs were fabricated using conventional wet and TEOS oxides. The measured effective oxide charge density (Qeff) and Dit of the TEOS-based LPCVD SiO2/4H–SiC MOS capacitor with nitridation were 4.27 × 1011 cm−2 and 2.99 × 1011 cm−2eV−1, respectively. We propose that the oxide breakdown field and barrier height were dependent on the effective Qeff. The measured μfe values of the SiO2/4H–SiC MOSFETs with wet and TEOS oxides after nitridation were, respectively, 11.0 and 17.8 cm2/V due to the stable nitrided interface between SiO2 and 4H–SiC. The proposed gate stack is suitable for 4H–SiC power MOSFETs.

In this study, degradation phenomena due to gate bias stress at elevated temperature for the reliability test of punch-through IGBTs, which are widely used in DC circuit systems for automotive applications, were investigated. For the reliability tests of various temperatures, 4000 times temperature cycle stress was applied in IGBTs between −40°C and 200°C to accelerate the degradation process using the wide range temperature. And the delamination of the passivation layer and the metal layer in IGBTs was observed using the scan acoustic microscopy. In addition, the positive bias stress with 48 V at elevated temperature of 150°C for 60 min was applied to the gate, the threshold voltage increased up to 6.07 V due to charge trapping at gate oxide. We also compared the recovery of the devices, but the IGBTs that stressed with high DC field and elevated temperature slowed down the recovery process after 24 hours without reverse voltage. This work was focused to find the device recovery considering real conditions. Therefore, the various temperature stress and high electric field stress are important in the reliability test for IGBTs, it was reported the IGBT degradation process and failure symptoms using the accelerated and various reliability tests.

Spleen tyrosine kinase (SYK) is an essential mediator of immune cell signaling and has been anticipated as a therapeutic target for autoimmune diseases, notably rheumatoid arthritis, allergic rhinitis, asthma, and cancers. Significant attempts have been undertaken in recent years to develop SYK inhibitors; however, limited success has been achieved due to poor pharmacokinetics and adverse effects of inhibitors. The primary goal of this research was to identify potential inhibitors having high affinity, selectivity based on key molecular interactions, and good drug-like properties than the available inhibitor, fostamatinib. In this study, a 3D-QSAR model was built for SYK based on known inhibitor IC50 values. The best pharmacophore model was then used as a 3D query to screen a drug-like database to retrieve hits with novel chemical scaffolds. The obtained compounds were subjected to binding affinity prediction using the molecular docking approach, and the results were subsequently validated using molecular dynamics (MD) simulations. The simulated compounds were ranked according to binding free energy (ΔG), and the binding affinity was compared with fostamatinib. The binding mode analysis of selected compounds revealed that the hit compounds form hydrogen bond interactions with hinge region residue Ala451, glycine-rich loop residue Lys375, Ser379, and DFG motif Asp512. Identified hits were also observed to form a desirable interaction with Pro455 and Asn457, the rare feature observed in SYK inhibitors. Therefore, we argue that identified hit compounds ZINC98363745, ZINC98365358, ZINC98364133, and ZINC08789982 may help in drug design against SYK.

Diarrheal diseases due to foodborne

Hybrid supercapacitors show high energy densities with good long-term cycling stability when used as energy sources. However, their poor rate performance as a consequence of their low ionic diffusion capability at high currents during cycling should be improved. Here, we propose using a spray-drying process to fabricate a novel structure comprising open-porous spherical lithium manganese oxide as an electrode material for hybrid supercapacitors. The resultant hybrid supercapacitor comprising full-cell systems shows a high specific capacitance (33.8 F cm−3 at a current of 1 A) and remarkable high-rate performance (25.6 F cm−3 at a current of 16 A). Moreover, outstanding cycling stability of 83% was attained at a current of 2 A after 5400 cycles. Our new strategy provides a useful methodology to increase the abundance of electrochemically active sites by fabricating a spherical structure using nanosized primary particles, which also leads to shorter diffusion pathways and to improved ionic electron transport because of the open-porous structure of the electrode materials.

A great effort to discover new therapeutic ingredients is often initiated through the discovery of the existence of novel marine natural products. Since substances produced by the marine environment might be structurally more complex and unique than terrestrial natural products, there have been cases of misassignments of their structures despite the availability of modern spectroscopic and computational chemistry techniques. When it comes to refutation to erroneously or tentatively proposed structures empirical preparations through organic chemical synthesis has the greatest contribution along with close and sophiscated inspection of spectroscopic data. Herein, we analyzed the total synthetic studies that have decisively achieved in revelation of errors, ambiguities, or incompleteness of the isolated structures of marine natural products covering the period from 2018 to 2021.

In this study, the effect of applying the tilted ion implantation process of a 1.2 kV SiC trench metal–oxide–semiconductor field-effect transistor on the electrical characteristics of the devices was investigated. P-shielding with tilted ion implantation protects both the sidewall and bottom of the trench from an electric field, enabling stable high-voltage operation, and the cell pitch can be reduced by using only one channel. Moreover, the tilted ion implantation process has the advantage of not requiring additional masks. For a comparative analysis, the tilt angle for ion implantation into the trench was changed in a TCAD simulation. A high breakdown voltage of 1617 V was achieved under an optimized tilt angle of 18.2°, and a low on-resistance of 2.9 mΩ cm2 was obtained via structural optimization.

The performance of Li-ion hybrid supercapacitors (asymmetric-type) depends on many factors such as the capacity ratio, material properties, cell designs and operating conditions. Among these, in consideration of balanced electrochemical reactions, the capacity ratio of the negative (anode) to positive (cathode) electrode is one of the most important factors to design the Li-ion hybrid supercapacitors for high energy storing performance. We assemble Li-ion hybrid supercapacitors using activated carbon (AC) as anode material, lithium manganese oxide as cathode material, and organic electrolyte (1 mol L−1 LiPF6 in acetonitrile). At this point, the thickness of the anode electrode is controlled at 160, 200, and 240 μm. Also, thickness of cathode electrode is fixed at 60 μm. Then, the effect of negative and positive electrode ratio on the electrochemical performance of AC/LiMn2O4 Li-ion hybrid supercapacitors is investigated, especially in the terms of capacity and cyclability at high current density. In this study, we demonstrate the relationship of capacity ratio between anode and cathode electrode, and the excellent electrochemical performance of AC/LiMn2O4 Li-ion hybrid supercapacitors. The remarkable capability of these materials proves that manipulation of the capacity ratio is a promising technology for high-performance Li-ion hybrid supercapacitors.

Many optically active 2-azaspirocyclic structures have frequently been found in biologically active natural products. In particular

Extracellular vesicles (EVs) containing specific cargo molecules from the cell of origin are naturally secreted from bacteria. EVs play significant roles in protecting the bacterium, which can contribute to their survival in the presence of antibiotics. Herein, we isolated EVs from methicillin-resistant Staphylococcus aureus (MRSA) in an environment with or without stressor by adding ampicillin at a lower concentration than the minimum inhibitory concentration (MIC). We investigated whether EVs from MRSA under stress condition or normal condition could defend susceptible bacteria in the presence of several β-lactam antibiotics, and directly degrade the antibiotics. A comparative proteomic approach was carried out in both types of EVs to investigate β-lactam resistant determinants. The secretion of EVs from MRSA under antibiotic stressed conditions was increased by 22.4-fold compared with that of EVs without stress. Proteins related to the degradation of β-lactam antibiotics were abundant in EVs released from the stressed condition. Taken together, the present data reveal that EVs from MRSA play a crucial role in the survival of β-lactam susceptible bacteria by acting as the first line of defense against β-lactam antibiotics, and antibiotic stress leads to release EVs with high defense activity.

A 7-step enantioselective synthetic method for preparing (S)(+)-coerulescine is reported through the use of diphenylmethyl tert-butyl α-(2-nitrophenyl)malonate (16% overall yield, >99% ee). Allylation is the key step under phase-transfer catalytic conditions (86% ee). This synthetic method can be used as a practical route for the synthesis of various derivatives of (S)(+)-coerulescine for analyzing its structure–activity relationships against its biological activities.

Considering the potential bioactivities of natural product and natural product-like compounds with highly complex and diverse structures, the screening of collections and small-molecule libraries for high-throughput screening (HTS) and high-content screening (HCS) has emerged as a powerful tool in the development of novel therapeutic agents. Herein, we review the recent advances in divergent synthetic approaches such as complexity-to-diversity (Ctd) and biomimetic strategies for the generation of structurally complex and diverse indole-based natural product and natural product-like small-molecule libraries.

The widespread and uncontrollable emergence of antibiotic-resistant bacteria, especially methicillin-resistant Staphylococcus aureus, has promoted a wave of efforts to discover a new generation of antibiotics that prevent or treat bacterial infections neither as bactericides nor bacteriostats. Due to its crucial role in virulence and its nonessentiality in bacterial survival, sortase A has been considered as a great target for new antibiotics. Sortase A inhibitors have emerged as promising alternative antivirulence agents against bacteria. Herein, the structural and preparative aspects of some small synthetic organic compounds that block the pathogenic action of sortase A have been described.

A 7-step enantioselective synthetic method for preparing (S)(+)-coerulescine is reported through the use of diphenylmethyl tert-butyl α-(2-nitrophenyl)malonate (16% overall yield, >99% ee). Allylation is the key step under phase-transfer catalytic conditions (86% ee). This synthetic method can be used as a practical route for the synthesis of various derivatives of (S)(+)-coerulescine for analyzing its structure–activity relationships against its biological activities.

Gram-negative bacteria have an outer membrane inhibiting the entry of antibiotics. Porins, found within the outer membrane, are involved in regulating the permeability of &beta, lactam antibiotics. &beta, lactamases are enzymes that are able to inactivate the antibacterial properties of &beta, lactam antibiotics. Interestingly, porins and &beta, lactamase are found in outer membrane vesicles (OMVs) of &beta, lactam-resistant Escherichia coli and may be involved in the survival of susceptible strains of E. coli in the presence of antibiotics, through the hydrolysis of the &beta, lactam antibiotic. In this study, OMVs isolated from &beta, lactam-resistant E. coli and from mutants, lacking porin or &beta, lactamase, were evaluated to establish if the porins or &beta, lactamase in OMVs were involved in the degradation of &beta, lactam antibiotics. OMVs isolated from E. coli deficient in &beta, lactamase did not show any degradation ability against &beta, lactam antibiotics, while OMVs lacking OmpC or OmpF showed significantly lower levels of hydrolyzing activity than OMVs from parent E. coli. These data reveal an important role of OMVs in bacterial defense mechanisms demonstrating that the OmpC and OmpF proteins allow permeation of &beta, lactam antibiotics into the lumen of OMVs, and antibiotics that enter the OMVs can be degraded by &beta, lactamase.

In this study, high electron mobility transistor (HEMT) device was used as an immuno biosensor to measure concentration of a stress hormone, cortisol, by using selective binding on cortisol monoclonal antibody (c-Mab). Also, the HEMT sensor was enhanced in its sensitivity through light illumination to generate photocurrent. The optical pumping could assist the biosensor to discriminate more detailed change, which could result in an increment of limit of detection (LOD) to 1.0 pM cortisol level. It was the lowest level of detection with semiconductor device-based cortisol biosensors and the enhancement of surface potential sensitivity was induced by laser light (532 nm). Output current amplificated by photocurrent was higher than dark original current at about 3.39% when gate voltage is applied with −3 V. Since the device could be applied to not only standard cortisol solution but also real human salivary sample, it is expected to apply for in vitro direct diagnosis of point-of-care test (POCT).

High-power switching applications, such as thyristor valves in a high-voltage direct current converter, can use 4H-SiC. The numerical simulation of the 4H-SiC devices requires specialized models and parameters. Here, we present a numerical simulation of the 4H-SiC thyristor on an N+ substrate gate current during the turn-on process. The base-emitter current of the PNP bipolar junction transistor (BJT) flow by adjusting the gate potential. This current eventually activated a regenerative action of the thyristor. The increase of the gate current from P+ anode to N+ gate also decreased the snapback voltage and forward voltage drop (Vf). When the doping concentration of the P-drift region increased, Vf decreased due to the reduced resistance of a low P-drift doping. An increase in the P buffer doping concentration increased Vf owing to enhanced recombination at the base of the NPN BJT. There is a tradeoff between the breakdown voltage and forward characteristics. The breakdown voltage is increased with a decrease in concentration, and an increase in drift layer thickness occurs due to the extended depletion region and reduced peak electric field.

Organic light emitting diodes (OLEDs) with Tthermally activated delayed fluorescence (TADF) emitting dopantsemitter has been developed with highly twisted donor–acceptor configurations and efficient color-pure blue emitters. In this study, Synthesized 4-(4-(4,6-diphenylpyrimidin-2-yl)phenyl)-10H-spiro[acridine-9,9'-fluorene] (4,6–PhPMAF) doped device two types of substance nitrogenous position in dipyridylpyrimidine are synthesized for color-pure and high-efficiency TADF OLEDs. Synthesized emitters with spiroacridine as a donor unit and diphenylpyrimidine as acceptor exhibit different the device characteristics that such as the luminescence, external quantum efficiencies, current efficiencies, and power efficiencies display corresponding to 213 cd/m2, 2.95%, 3.27 cd/A, and 2.94 lm/W with Commission International de l’Eclairage (CIE) CIE coordinates of (0.15, 0.11) in 4,6–-PhPMAF-doped DPEPO emitter, while. T thehe reported 10-(4-(2,6-diphenylpyrimidin-4-yl)phenyl)-10H-spiro[acridine-9,9'-fluorene] (2,6–PhPMAF) 2,4-PhPMAF-doped DPEPO emitterdevice exhibit high device performance with 1445 cd/m2, 12.38%, 19.6 cd/A, and 15.4 lm/W, which might be originated from increased internal quantum efficiency by up-converted triplet excitons to the singlet state with relatively smaller ΔEST of 0.17 eV and higher reverse intersystem crossing rate (kRISC) of 1.0×108/s in 2,6–PhPMAF than 0.27 eV and 3.9×107/s in 4,6–PhPMAF. with CIE coordinates of (0.16, 0.19). Although Despite low performance of 4,6–-PhPMAF doped device, synthesized 4,6–PhPMAF has better color-purity as a deep-blue emission with y-axis (0.11) than reported 2,6–PhPMAF with y-axis (0.19) in CIE coordinate. with CIE coordinates of (0.16, 0.19).The synthesized 4,6–PhPMAF has higher good thermal stability of any transition up to 300 oC and decomposition temperature with only 5% weight loss in 400 oC than reported 2,6-PhPMAF, it has lower device properties than the 2,4-PhPMAF-doped device. These results could be originated from improved internal quantum efficiency by up-converted triplet excitons to the singlet state with relatively smaller charge-transfer gap of ΔEST = 0.1023 eV in 2,4-PhPMAF than ΔEST = 0.282eV in 4,6-PhPMAF. The synthesized acridine and dipyridylpyrimidine-based emitters can be used for high-performance deep-blue emitters in a TADF-OLEDs.The maximum PL emission of 4,6–PhPMAF in various solvents appeared at 438 nm, which has blue-shift about 20 nm than that of 2,6–PhPMAF, which contributes deep-blue emission in synthesized 4,6–PhPMAF.

Employing iPrMgCl as an advanced base instead of lithium hexamethyldisilazane (LHMDS) resulted in dramatic improvements in aza-Claisen rearrangement. This advance is considered responsible for the increased bulkiness of the alkoxide moiety (including magnesium cation and ligands), followed by a resultant conformational change of the transition state. To support this hypothesis, various substrates of aza-Claisen rearrangement were prepared and screened. In addition, a molecular dynamic simulation study was performed to investigate and compare the structural stability of reaction intermediates.

The variable lymphocyte receptor (VLR) mediates the humoral immune response in jawless vertebrates, including lamprey (Petromyzon marinus) and hagfish (Eptatretus burgeri). Hagfish VLRBs are composed of leucine-rich repeat (LRR) modules, conjugated with a superhydrophobic C-terminal tail, which contributes to low levels of expression in recombinant protein technology. In this study, we screened Ag-specific VLRBs from hagfish immunized with nervous necrosis virus (NNV). The artificially multimerized form of VLRB was constructed using a mammalian expression system. To enhance the level of expression of the Ag-specific VLRB, mutagenesis of the VLRB was achieved in vitro through domain swapping of the LRR C-terminal cap and variable LRR module. The mutant VLRB obtained, with high expression and secretion levels, was able to specifically recognize purified and progeny NNV, and the Ag binding ability of this mutant was increased by at least 250-fold to that of the nonmutant VLRB. Furthermore, preincubation of the Ag-specific VLRB with NNV reduced the infectivity of NNV in E11 cells in vitro, and in vivo experiment. Our results suggest that the newly developed Ag-specific VLRB has the potential to be used as diagnostic and therapeutic reagents for NNV infections in fish.

In this letter, we report gallium nitride-based metal-insulator-semiconductor high-electron-mobility transistors (GaN MIS-HEMTs) with a 16-nm-thick silicon nitride (SiN x ) gate insulator and surface passivation layer grown using low-temperature (300 °C) hollow cathode plasma-enhanced atomic layer deposition. Tris(dimethylamino) silane and a remote N2 plasma were used as the silicon precursor and the nitrogen co-reactant, respectively. Though the growth temperature was as low as 300 °C, we obtained excellent film properties such as a high refractive index (2.00), a high film density (2.9 g/cm3), and a low wet etch rate (0.8 nm/min) in 100:1 hydrofluoric acid. High-resolution transmission electron microscopy images of the gate stacks showed ~1.5 nm $\beta $ -phase Si3N4 crystalline interfacial layer on the GaN surface. The devices showed a negligible hysteresis of ~50 mV, a steep subthreshold slope of 76 mV/dec, and a high ON/OFF drain current ratio of ~109. In addition, the devices showed a small positive/negative bias temperature threshold voltage ( ${V}_{\text {th}}$ ) instability ( $\Delta {V}_{\text {th}}\le 0.2$ V at 25 °C and 150 °C) as well as a mitigated current collapse under an off-state quiescent ${V}_{\text {DS}}$ of 20 V.

Post-deposition annealing (PDA) was used to improve gate oxide physical and electrical properties. Deposition was accomplished by plasma-enhanced atomic layer deposition (PEALD). We investigated the densification silicon dioxide (SiO2) formed by PEALD on 4H-silicon carbide (SiC) using PDA without oxidation and nitridation. PDA was conducted at 400–1200 °C in argon (Ar) ambient. The thickness of the SiO2 was reduced by up to 13.5% after Ar PDA at 1000 °C. As the temperature of the Ar PDA increased, the etching rate of SiO2 decreased. At temperatures greater than 1000 °C, the SiO2 etching rate was low compared with that of thermal SiO2. After PDA, the SiO2/4H-SiC interface was smoother than that of thermal SiO2/4H-SiC. The current density versus oxide field and capacitance versus voltage of the SiO2/4H-SiC metal oxide semiconductor (MOS) capacitors were measured. Sufficient densification of SiO2 formed by PEALD on 4H-SiC was obtained using Ar PDA at 1200 °C.

Reactive sputtering followed by N2, NH3, O2, and NO post-deposition annealing (PDA) of SiO2 on 4H-SiC was investigated in this study. The results of ellipsometry, an etching test, and X-ray photoemission spectroscopy showed that N2 and NH3 PDA nitrified the SiO2. Devices using N2 and NH3 PDA exhibited a high gate leakage current and low breakdown field due to oxygen vacancies and incomplete oxynitride. SiO2/4H-SiC MOS capacitors were also fabricated and their electrical characteristics measured. The average breakdown fields of the devices using N2, NH3, O2, and NO PDA were 0.12, 0.17, 4.71 and 2.63 MV/cm, respectively. The shifts in the flat-band voltage after O2 and NO PDA were 0.95 and −2.56 V, respectively, compared with the theoretical value. The extracted effective oxide charge was −4.11 × 1011 cm−2 for O2 PDA and 1.11 × 1012 cm−2 for NO PDA. NO PDA for 2 h at 1200 °C shifted the capacitance–voltage curve in the negative direction. The oxygen containing PDA showed better electrical properties than non-oxygen PDA. The sputtering method described can be applied to 4H-SiC MOS fabrication.

Herein, we review the recent progress in the synthesis of representative nonsteroidal anti-inflammatory drugs (NSAIDs), ibuprofen and naproxen. Although these drugs were discovered over 50 years ago, novel practical and asymmetric approaches are still being developed for their synthesis. In addition, this endeavor has enabled access to more potent and selective derivatives from the key frameworks of ibuprofen and naproxen. The development of a synthetic route to ibuprofen and naproxen over the last 10 years is summarized, including developing methodologies, finding novel synthetic routes, and applying continuous-flow chemistry.

Novel phosphorescent emitters, FIr4mpic and FIr4tpic were designed and prepared synthetically to improve the chromaticity and emission efficiency of FIrpic, one of the main blue phosphor. Apparently, methyl and tert-butyl on 4-position of picolinic acid of FIrpic were installed attaining FIr4mpic and FIr4tpic, respectively. With these new ancillary ligand-tuned cyclometalated iridium(III) complexes, phosphorescent organic light-emitting diodes (PHOLEDs) devices were constructed. The ultraviolet–visible (UV–vis) and photoluminescence (PL) spectra of FIr4mpic and FIr4tpic were similar to those of FIrpic; however, in terms of their electroluminescent properties, higher luminance was observed with FIr4mpic device. FIr4mpic and FIr4tpic exhibited deeper blue light emission than that of FIrpic. Once optimized, a maximum external quantum efficiency (EQE) of 18.77% and a maximum current efficiency (CE) of 36.17 cd/A were achieved with the FIr4mpic-based PHOLED. Along with the experimental information we also investigated the electronic properties by means of density functional theory (DFT) calculations being keen to explain the improved quantum yield of FIr4mpic over the other emitters.

A new efficient synthetic method for chiral α-azido-α-alkylmalonates and α-aryloxy-α-alkylmalonates was developed. The enantioselective α-alkylation of diphenylmethyl tert-butyl α-bromomalonate under phase-transfer catalytic conditions [(S,S)-3,4,5-trifluorophenyl-NAS bromide, 50% KOH, toluene, and −40 °C) provided the corresponding α-bromo-α-alkylmalonates in high chemical yields (≤98%) and high optical yields (≤99% ee). The resulting α-alkylated products were converted to α-azido-α-alkylmalonates (≤96%, ≤97% ee) and α-aryloxy-α-alkylmalonates (≤79%, ≤93% ee) by SN2 substitution with sodium azide and aryloxides, respectively.

The occurrence of CD4 helper T cells has already been established for a number of teleost species, though, it has not been possible to analyze these responses at a cellular level due to a large lack of appropriate monoclonal antibodies (mAbs). In the present study, we produced a mAb against olive flounder (Paralichthys olivaceus) CD4-1 lymphocyte to investigate the functional activity of the cells to improve our understanding of the T cell response in this species. This mAb is specifically able to detect CD4-1 lymphocytes in olive flounder proved by immunofluorescence staining and RT-PCR analysis. In flow cytometry analysis, the number of CD4-1-positive lymphocytes was observed to gradually increase from 3 days post infection (dpi) and then reach peak at 7 dpi against two viruses challenge. As a conclusion, both the basic properties of CD4-1 T cells and its response to viral infections in olive flounder are very similar to the helper T cells in terrestrial animals.

In this paper, the chemical conjugation of marine natural products with other bioactive molecules for developing an advanced anti-cancer agent is described. Structural complexity and the extraordinary biological features of marine natural products have led to tremendous research in isolation, structural elucidation, synthesis, and pharmacological evaluation. In addition, this basic scientific achievement has made it possible to hybridize two or more biologically important skeletons into a single compound. The hybridization strategy has been used to identify further opportunities to overcome certain limitations, such as structural complexity, scarcity problems, poor solubility, severe toxicity, and weak potency of marine natural products for advanced development in drug discovery. Further, well-designed marine chimera molecules can function as a platform for target discovery or degradation. In this review, the design, synthesis, and biological evaluation of recent marine chimera molecules are presented.

The forward current–voltage characteristics of p-type diamond pseudo-vertical Schottky barrier diodes are investigated via numerical simulation. Impact ionization decrease the hole concentration of the p− drift layer from 1015 to 1014 cm–3 at 300 K, thereby increasing the forward voltage drop and on-resistance. When we consider an incomplete ionization with increasing temperature, the increase in the hole concentration is more dominant than the enhanced phonon scattering, thereby resulting in an increasing forward current. We modified the Ohmic contact for both metallic conduction at the p+ layer and incomplete ionization at the p– drift layer. The Baliga figure-of-merit of the device with and without incomplete ionization is 25 and 192 MW cm−2, respectively. Incomplete ionization should be considered in the numerical study of diamond power devices.

Disruptor of telomeric silencing-1 like (DOT1L) is a histone H3 methyltransferase which specifically catalyzes the methylation of histone H3 lysine-79 residue. Recent findings demonstrate that DOT1L is abnormally overexpressed and the upregulated DOT1L evokes the proliferation and metastasis in human breast cancer cells. Therefore, the DOT1L inhibitor is considered a promising strategy to treat breast cancers. Non-nucleoside DOT1L inhibitors, selenopsammaplin A and its analogues, were firstly reported in the present study. Selenopsammaplin A was newly designed and synthesized with 25% overall yield in 8 steps from 3-bromo-4-hydroxybenzaldahyde, and thirteen analogues of selenopsammaplin A were prepared for structure-activity relationship studies of their cytotoxicity against cancer cells and inhibitory activity toward DOT1L for antitumor potential. All synthetic selenopsammaplin A analogues exhibited the higher cytotoxicity compared to psammaplin A with up to 6 - 60 times depending on cancer cells, and most analogues showed significant inhibitory activities against DOT1L. Among the prepared analogues, the phenyl analogue (10) possessed the most potent activity with both cytotoxicity and inhibition of DOT1L. Compound 10 also exhibited the antitumor and antimetastatic activity in an orthotopic mouse metastasis model implanted with MDA-MB-231 human breast cancer cells. These biological findings suggest that analogue 10 is a promising candidate for development as a cancer chemotherapeutic agent in breast cancers.

We propose a new multi-floating-zone junction-termination-extension (MFZ-JTE) using an exponentially modulated space and width for 4.5 kV SiC power devices to effectively spread out the electric field in reverse blocking mode and improve the tolerance against imprecise process control. A modified MFZ-JTE design with an exponential model was also proposed considering a stable patterning process. The blocking characteristics of the proposed MFZ-JTE using various exponential coefficients (α) in the model were evaluated for undesirable variations in the fabrication processes through TCAD simulations. The modified design for a 4.5 kV MFZ-JTE with α = 0.046 exhibited a low breakdown voltage deviation of 0.13% when the space variation ranged from –0.2 to +0.2 μm and 0.14% when the variation in the surface charge density at the SiO2/SiC interface was within the range of 0 to –1 × 1012 cm–3.

The design and synthesis of a novel homoleptic triply cyclometalated iridium(III) complex containing the 6-(pyridin-2-yl)isoquinoline moiety [Ir(pyiq)3] was demonstrated for the first time. The performance of a phosphorescent organic light emitting diode (PHOLED) based on Ir(pyiq)3 is described with adoption of tris(4-carbazoyl-9-ylphenyl)amine (TCTA) and 2,2′,2"-(1,3,5-benzinetriyl)-tris(1-phenyl-1-H-benzimidazole) (TPBi) which are co-host materials showing excellent compatibilities as well as CBP host with the prepared phosphorescent dopants. The photoluminescence (PL) of Ir(pyiq)3 produced orange emission with maximum emission peak at 583 nm. The highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital energy (LUMO) levels of Ir(pyiq)3 were −5.41 eV and −3.20 eV. An optimized solution-processed device doped with Ir(pyiq)3 had a maximum external quantum efficiency (EQE) of 8.71% and a maximum current efficiency (CE) of 22.51 cd/A. This correspond to 17% higher efficiency than that with bis(2-phenylbenzothiozolato-N,C2′)iridium(acetylacetonate) (bt)2Ir(acac), which is commonly used in orange PHOLEDs. This study rationalizes the promising application of new trimeric organometallic complex that possesses isoquinoline and pyridine in solution-processed PHOLEDs with good quantum and power efficiency.