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A promising conducting polymer poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) experiences significant conductivity enhancement when treated with proper ionic liquids (ILs). Based on the hard-soft-acid-base principle, we propose a combination of a hydrophilic hard cation A

Packaging paternal genome into tiny sperm nuclei during spermatogenesis requires 10sup6/sup-fold compaction of DNA, corresponding to a 10-20 times higher compaction than in somatic cells. While such a high level of compaction involves protamine, a small arginine-rich basic protein, the precise mechanism at play is still unclear. Effective pair potential calculations and large-scale molecular dynamics simulations using a simple idealized model incorporating solely electrostatic and steric interactions clearly demonstrate a reversible control on DNA condensates formation by varying the protamine-to-DNA ratio. Microscopic states and condensate structures occurring in semidilute solutions of short DNA fragments are in good agreement with experimental phase diagram and cryoTEM observations. The reversible microscopic mechanisms induced by protamination modulation should provide valuable information to improve a mechanistic understanding of early and intermediate stages of spermatogenesis where an interplay between condensation and liquid-liquid phase separation triggered by protamine expression and post-translational regulation might occur. Moreover, recent vaccines to prevent virus infections and cancers using protamine as a packaging and depackaging agent might be fine-tuned for improved efficiency using a protamination control.

Conductivity enhancement of PEDOT:PSS via the morphological change of PEDOT-rich domains has been achieved by introducing a 1-ethyl-3-methylimidazolium (EMIM)-based ionic liquid (IL) into its aqueous solution, and the degree of such change varies drastically with the anion coupled to the EMIM cation constituting the IL. We carry out a series of molecular dynamics simulations on various simple model systems for the extremely complex mixtures of PEDOT:PSS and EMIM:X IL in water, varying the anion X, the IL concentration, the oligomer model of PEDOT:PSS, and the size of the model systems. The common characteristic found in all simulations is that although planar hydrophobic anions X are the most efficient for ion exchange between PEDOT:PSS and EMIM:X, they tend to bring together planar EMIM cations to PEDOT-rich domains, disrupting PEDOT π-stacks with PEDOT-X-EMIM intercalating layers. Nonplanar hydrophobic anions, which leave most of EMIM cations in water, are efficient for both ion exchange and the formation of extended PEDOT π-stacks, as observed in experiments. Based on such findings, we propose a design principle for new cations replacing EMIM; nonplanar hydrophilic cations combined with hydrophobic anions should improve IL efficiency for PEDOT:PSS treatment.

Water solubility of PEDOT:PSS conducting polymer is achieved by PSS at the expense of disturbing the crystallinity and electron mobility of PEDOT. Recently, PEDOT crystallinity and electron mobility have been improved by treating the PEDOT:PSS aqueous solution with 1-ethyl-3-methylimidazolium- (EMIM-) based ionic liquids (IL) EMIM:X. The amount of such improvement varies drastically with the anion X coupled to EMIM cation in the IL. Herein, using umbrella-sampling molecular dynamics simulations on the aqueous solutions of a minimal model of PEDOT:PSS mixed with various EMIM:X ILs, we show that the solvation of each ion in water plays a major role in the free energies of ion binding and exchange. Anions X efficient for the improvement are weakly stabilized by hydration (i.e., hydrophobic) and prefer binding to hydrophobic PEDOT than to hydrophilic EMIM, favoring the ion exchange. In order to fulfill our design principle, a quantitative criterion based on hydration free energy is proposed to select efficient hydrophobic anions X.

Several analytical calculations and computer simulations propose that cylindrical monodispersive rods having an aspect ratio (ratio of length to diameter) greater than 4 can exhibit liquid crystal (LC) ordering. But, recent experiments demonstrated the signature of LC ordering in systems of 4- to 20-base pair (bp) long nucleic acids (NAs) that do not satisfy the shape anisotropy criterion. Mechanisms of end-to-end adhesion and stacking have been proposed to explain this phenomenon. In this study, using all-atom molecular dynamics (MD) simulation, we explicitly verify the end-to-end stacking of double-stranded RNA (dsRNA) and demonstrate the LC ordering at the microscopic level. Using umbrella sampling (US) calculation, we quantify the potential of mean force (PMF) between two dsRNAs for various reaction coordinates (RCs) and compare our results with previously reported PMFs for double-stranded DNA (dsDNA). The PMF profiles demonstrate the anisotropic nature of inter-NA interaction. We find that, like dsDNA, dsRNA also prefers to stack on top of each other while repelling sideways, leading to the formation of supra-molecular-columns that undergo LC ordering at high NA volume fraction (φ). We also demonstrate and quantify the nematic ordering of the RNAs using several hundred nanosecond-long MD simulations that remain almost invariant for different initial configurations and under different external physiological conditions.

When the intensity of the incident light increases, the photocurrents of organic photodiodes (OPDs) exhibit relatively early saturation, due to which OPDs cannot easily detect objects against strong backlights, such as sunlight. In this study, this problem is addressed by introducing a light-intensity-dependent transition of the operation mode, such that the operation mode of the OPD autonomously changes to overcome early photocurrent saturation as the incident light intensity passes the threshold intensity. The photoactive layer is doped with a strategically designed and synthesized molecular switch, 1,2-bis-(2-methyl-5-(4-cyanobiphenyl)-3-thienyl)tetrafluorobenzene (DAB). The proposed OPD exhibits a typical OPD performance with an external quantum efficiency (EQE) of100% and a photomultiplication behavior with an EQE of100% under low-intensity and high-intensity light illuminations, respectively, thereby resulting in an extension of the photoresponse linearity to a light intensity of 434 mW cm

We report equilibrium and nonequilibrium molecular dynamics (MD) simulations of two nucleosome core particles (NCPs) stacked with their dyad axes oriented in parallel or antiparallel fashion. From the equilibrium trajectories, we determine the bridging behavior of different histone tails and observe that different sets of histone tails play important roles in the two orientations in stabilizing the NCP stack. While the H4 and H2A tails play important intermediary roles in the parallel stack, the H3 and H2B tails are important in the antiparallel stack. We use steered MD simulations to unstack the two NCPs and find a stark difference in their unstacking pathways. While the average rupture force was found to be higher for the parallel stack, the work done for complete unstacking was similar for both orientations. We use Jarzynski equality to determine the PMF profiles along the unstacking pathway, relate our findings to the behavior of NCP mesophases, and derive insights into the enigmatic nucleosomal organization in the chromatin fiber.

DNA-assisted assembly of ligand-stabilized gold nanoparticles is studied using Monte Carlo simulations with coarse-grained models for DNA and AuNP. Their interaction in a periodic simulation box is described by a combination of electrostatic and pairwise hard core potentials. We first probe the self-assembly of AuNPs resulting in an ordered distribution on a single fixed DNA strand. Subsequently, the effective force calculated between a pair of parallel DNA in the presence of AuNPs shows the attraction between them at short distance associated to a stable equilibrium position. Finally, the osmotic pressure calculated in a compact DNA–AuNP lattice with various amounts of monovalent salt ions shows that an increasing amount of salt prevents aggregate formation.

Herein, we explore the strategy of realizing a red-selective thin-film organic photodiode (OPD) by synthesizing a new copolymer with a highly selective red-absorption feature. PCZ-Th-DPP, with phenanthrocarbazole (PCZ) and diketopyrrolopyrrole (DPP) as donor and acceptor units, respectively, was strategically designed/synthesized based on a time-dependent density functional theory calculation, which predicted the significant suppression of the band II absorption of PCZ-Th-DPP due to the extremely efficient intramolecular charge transfer. We demonstrate that the synthesized PCZ-Th-DPP exhibits not only a high absorption coefficient within the red-selective band I region, as theoretically predicted, but also a preferential face-on intermolecular structure in the thin-film state, which is beneficial for vertical charge extraction as an outcome of a glancing incidence X-ray diffraction study. By employing PCZ-Th-DPP as a photoactive layer of Schottky OPD, to fully match its absorption characteristic to the spectral response of the red-selective OPD, we demonstrate a genuine red-selective specific detectivity in the order of 1012 Jones while maintaining a thin active layer thickness of ∼300 nm. This work demonstrates the possibility of realizing a full color image sensor with a synthetic approach to the constituting active layers without optical manipulation.

Vanadium containing 3D MOF, MIL-47 displayed excellent synergistic catalysis with alkyl ammonium halides (TBAX) in the room temperature fixation of CO2. Theoretical intrinsic-reaction-coordinate calculations were performed at the level of M06/LACVP**++ implemented in Jaguar v8.5 software to ascertain the mechanistic pathways of catalysis. A homogeneous complex of vanadium, vanadium acetyl acetonato [VO(acac)2], was used as a model system to investigate the mechanism behind the synergistic activity of the MIL-47/TBAX, which indeed shows that the activation energy of the CO2 fixation is considerably lowered by about 30–35 kcal compared to the uncatalyzed reactions.

Over the past several decades, the six member countries of the Gulf Cooperation Council (GCC) have implemented economic policies for industrial diversification to lessen severe dependence on the oil industry. Such policy efforts have been driven by their awareness of macro-economic and structural risks from heavy volatilities in international oil markets in terms of fiscal and trade sectors. For instance, the drop in international oil prices reduces export performance in the oil and natural gas sectors, which in turn results in a decline in the stability of fiscal revenue. The recent trends of low oil prices since 2014, as well as high unemployment rates, have strengthened the policy regime for industrial diversification and job creation supported by mid- to long-term economic plans of the GCC countries. This report reviews what has been emphasized in the areas of industrial, employment, trade and investment policies. We then derive implications for Korean companies and policymakers for sustainable cooperation between Korea and the Middle East.

Metal oxynitrides have been considered recently as emerging electrode materials for supercapacitors. Herein, we converted titanate nanotubes into a series of titanium oxynitride (TiON) nanorods at nitridation temperatures of 800, 900, and 1000 °C in ammonia gas and tested them as supercapacitor electrodes. TiON-800, TiON-900, and TiON-1000 showed capacities of 60, 140, and 71 F g-1, respectively, at a current density of 1 A g-1. However, because of TiON's low capacity, a heterostructure (TiON-900/MnCo2O4) was designed based on the optimized TiON with MnCo2O4 (MCO). The heterostructure TiON-900-MCO and MCO electrode materials showed specific capacities of 515 and 381 F g-1, respectively, at a current density of 1 A g-1. The cycling stability retention of TiON-900 and MCO were 75 and 68%, respectively; moreover, the heterostructure of TiON-900-MCO reached 78% at a current density of 5 A g-1 over 5000 cycles. The increased capacity and sustained cycling stability retention are attributable to the synergistic effect of TiON-900 and MCO. A coin cell (CC)-type symmetric supercapacitor prototype of TiON-900-MCO was fabricated and tested in the voltage range of 0.0-2.0 V in 1 M LiClO4 in propylene carbonate/dimethyl carbonate electrolyte, and a 79% cycling retention capacity of TiON-900-MCO-CC was achieved over 10 000 cycles at a current density of 250 mA g-1. We demonstrated a prototypical single cell of TiON-900-MCO-CC as a sustained energy output by powering a red-light emitting diode that indicated TiON-900-MCo electrode materials' potential application in commercial supercapacitor devices.

The effect of atomic substitution on the optoelectronic properties of a coplanar donor-acceptor (D-A) semiconducting polymer (SPs), prepared using cyclopentadithiophene (CDT) and 2,1,3-benzothiadiazole (BT) moieties, is investigated. By substituting a carbon atom in the BT unit with CF or C-Cl, two random D-A SPs are prepared, and their optoelectronic properties are thoroughly investigated. Density functional theory calculations demonstrate that the fluorinated polymer has a slightly smaller dihedral angle (ϴ = 0.6°) than the pristine polymer (ϴ = 1.9°) in its lowest-energy conformation, implying efficient charge transport through the coplanar backbone of the fluorinated polymer. However, the chlorinated polymer shows the lowest energy at a relatively larger dihedral angle (ϴ = 139°) due to the steric hindrance induced by bulky chlorine atoms in the backbone, thereby leading to thin-film morphology, which is unfavorable for charge transport. Consequently, the fluorinated polymer yields the highest field-effect mobility (μ) of 0.57 cm2 V-1 s-1 , slightly higher than that of the pristine polymer (μ = 0.33 cm2 V-1 s-1 ), and the extended device lifetime of organic field-effect transistors over 12 d without any encapsulation layers. The results of this study provide design guidelines for air-stable D-A SPs.

Access to protein-inspired polyisocyanates with high molecular weights (MWs) from anionic polymerization of isocyanates is challenging as it requires exceptional livingness. For this purpose, a dimerically self-associated sodium diphenylamide (NaDPA) was introduced as a robust chain-end-protective initiator in the anionic polymerization of n-hexyl isocyanate (HIC) in the absence or presence of sodium tetraphenylborate (NaBPh4) additive. At [NaDPA]0/[NaBPh4]0 = 5, unusual one-half initiation efficiency and one-half order of reaction kinetics were observed. Accordingly, initiator-transfer anionic polymerization (ITAP), a mechanism driven by the dimer of NaDPA ((NaDPA)2) in a dual role is proposed, in which one unimer initiates the polymerization and the other reversibly deactivates the propagating chain end through its repetitive cycles of 1:1 cross-association/dissociation. Living ITAP by NaDPA with NaBPh4 was proven by X-ray crystallography, density functional theory calculation, and quantitative yield of...

Understanding charge transfer processes between graphene and functional materials is crucial from the perspectives of fundamental sciences and potential applications, including electronic devices, photonic devices, and sensors. In this study, we present the charge transfer behavior of graphene and amine-rich polyethyleneimine (PEI) upon CO2 exposure, which was significantly improved after introduction of hygroscopic polyethylene glycol (PEG) in humid air. By blending PEI and PEG, the number of protonated amine groups in PEI was remarkably increased in the presence of water molecules, leading to a strong electron doping effect on graphene. The presence of CO2 gas resulted in a large change in the resistance of PEI/PEG-co-functionalized graphene because of the dramatic reduction of said doping effect, reaching a maximum sensitivity of 32% at 5,000 ppm CO2 and an applied bias of 0.1 V in air with 60% relative humidity at room temperature. This charge transfer correlation will facilitate the development of portable graphene-based sensors for real-time gas detection and the extension of the applications of graphene-based electronic and photonic devices.

The epitaxial synthesis of molybdenum carbide (Mo2C, a 2D MXene material) via chemical conversion of molybdenum disulfide (MoS2) with thermal annealing under CH4 and H2 is reported. The experimental results show that adjusting the thermal annealing period provides a fully converted metallic Mo2C from MoS2 and an atomically sharp metallic/semiconducting hybrid structure via partial conversion of the semiconducting 2D material. Mo2C/MoS2 hybrid junctions display a low contact resistance (1.2 kΩ·μm) and low Schottky barrier height (26 meV), indicating the material’s potential utility as a critical hybrid structural building block in future device applications. Density functional theory calculations are used to model the mechanisms by which Mo2C grows and forms a Mo2C/MoS2 hybrid structure. The results show that Mo2C conversion is initiated at the MoS2 edge and undergoes sequential hydrodesulfurization and carbide conversion steps, and an atomically sharp interface with MoS2 forms through epitaxial growth of ...

A polymeric network of 1-(4-tritylphenyl)urea (TPU) built via layer-by-layer cross-linking polymerization has been proposed to be an excellent mesh equipped with single-molecule-thick pores (i.e., cyclic poly-TPU rings), which can sieve glucose (∼0.7 nm) out of its mixture with urea for hemodialysis applications. Monte Carlo search for the lowest-energy conformation of various sizes of poly-TPU rings unravels the origin of narrow pore size distribution, which is around the sizes of dimer and trimer rings (0.3-0.8 nm). Flexible rings larger than the dimer and trimer rings, in particular tetramer rings, prefer a twisted conformation in the shape of the infinity symbol (∞, which looks like two dimer rings joined together) locked by a hydrogen bond between diphenylurea linker groups facing each other. Translocation energy profiles across these TPU rings reveal their urea-versus-glucose sieving mechanism: glucose is either too large (to enter dimers and twisted tetramers) or too perfectly fit (to exit trimers), leaving only a dimer-sized free space in the ring, whereas smaller-sized urea and water pass through these effective dimer-sized rings (bare dimers, twisted tetramers, and glucose-filled trimers) without encountering a substantial energy barrier or trap.

Magnesium batteries have received attention as a type of post-lithium-ion battery because of their potential advantages in cost and capacity. Among the host candidates for magnesium batteries, orthorhombic α-V2O5 is one of the most studied materials, and it shows a reversible magnesium intercalation with a high capacity especially in a wet organic electrolyte. Studies by several groups during the last two decades have demonstrated that water plays some important roles in getting higher capacity. Very recently, proton intercalation was evidenced mainly using nuclear resonance spectroscopy. Nonetheless, the chemical species inserted into the host structure during the reduction reaction are still unclear (i.e., Mg(H2O)n2+, Mg(solvent, H2O)n2+, H+, H3O+, H2O, or any combination of these). To characterize the intercalated phase, the crystal structure of the magnesium-inserted phase of α-V2O5, electrochemically reduced in 0.5 M Mg(ClO4)2 + 2.0 M H2O in acetonitrile, was solved for the first time by the ab initi...

The RNA recognition motif of Arabidopsis splicing factor SF1 affects the alternative splicing of FLOWERING LOCUS M pre-mRNA and a heat shock transcription factor HsfA2 pre-mRNA. Splicing factor 1 (SF1) plays a crucial role in 3′ splice site recognition by binding directly to the intron branch point. Although plant SF1 proteins possess an RNA recognition motif (RRM) domain that is absent in its fungal and metazoan counterparts, the role of the RRM domain in SF1 function has not been characterized. Here, we show that the RRM domain differentially affects the full function of the Arabidopsis thaliana AtSF1 protein under different experimental conditions. For example, the deletion of RRM domain influences AtSF1-mediated control of flowering time, but not the abscisic acid sensitivity response during seed germination. The alternative splicing of FLOWERING LOCUS M (FLM) pre-mRNA is involved in flowering time control. We found that the RRM domain of AtSF1 protein alters the production of alternatively spliced FLM-β transcripts. We also found that the RRM domain affects the alternative splicing of a heat shock transcription factor HsfA2 pre-mRNA, thereby mediating the heat stress response. Taken together, our results suggest the importance of RRM domain for AtSF1-mediated alternative splicing of a subset of genes involved in the regulation of flowering and adaptation to heat stress.

Anodic water splitting is driven by hydroxide (OH–) adsorption on the catalyst surface and consequent O2 desorption. In this work, various heteroatoms (S/N/B/P) with different electronegativities and oxophilicities are introduced to alter the catalytic activity of reduced graphene oxide (RGO) as a catalyst for the oxygen evolution reaction (OER). It is found that, surprisingly, S-doped RGO outperforms the other RGOs doped with more electropositive or electronegative and more oxophilic heteroatoms, and this effect becomes more prominent after Fe treatment of the respective catalysts. Herein, we evaluate the OER activity of a series of Fe-treated mono-heteroatom (S/N/B/P)-doped RGO (Fe-X-G) catalysts, among which interestingly S-doped RGO catalyst treated with Fe (Fe-S-G) is found to show better OER activity than the well-known active Fe-N-C catalyst, demonstrating the best activity among all of the prepared catalysts, close to that of the state of the art IrO2/C catalyst, along with pronounced long-term st...

The correlation between dimensionality and active sites on deciding the catalytic performance of an MOF catalyst in CO2–epoxide cycloaddition reactions has been studied. Seven In(III) based MOFs built from carboxylic and N-donor ligands possessing different dimensionalities and distinct coordination environments were chosen as solid acid catalysts for this study. The origin of the catalytic activity of an In3+/TBAB bifunctional system in a CO2–PO reaction was studied in detail by performing density functional theory (DFT) calculations at the M06/LACVP**++ level. The energy barrier of the propylene oxide ring opening in the presence of In3+/Br− is 11.5 kcal mol−1, which is significantly lower than those of un-catalyzed (55–63 kcal mol−1) and Br−-catalyzed (19.5 kcal mol−1) reactions, which confirms the importance of the In3+/Br− binary catalytic system in the CO2–epoxide cycloaddition reactions. The one-dimensional (1D) MOF with unsaturated metal centers exhibited higher catalytic activity (PO conversion: 91%, temperature: 50 °C, and time: 12 h) than the two- and three-dimensional MOFs. The roles of dimensionality and unsaturated metal centers in cycloaddition reactions were explained on the basis of the results of activity testing and structural investigations. In addition, a plausible reaction mechanism for the catalytic activity of the 1D MOF was proposed with reference to our structure-density functional theory correlations.

We report a means by which atomic and molecular secondary ions, including cholesterol and fatty acids, can be sputtered through single-layer graphene to enable secondary ion mass spectrometry (SIMS) imaging of untreated wet cell membranes in solution at subcellular spatial resolution. We can observe the intrinsic molecular distribution of lipids, such as cholesterol, phosphoethanolamine and various fatty acids, in untreated wet cell membranes without any labeling. We show that graphene-covered cells prepared on a wet substrate with a cell culture medium reservoir are alive and that their cellular membranes do not disintegrate during SIMS imaging in an ultra-high-vacuum environment. Ab initio molecular dynamics calculations and ion dose-dependence studies suggest that sputtering through single-layer graphene occurs through a transient hole generated in the graphene layer. Cholesterol imaging shows that methyl-β-cyclodextrin preferentially extracts cholesterol molecules from the cholesterol-enriched regions in cell membranes.

Nitrogen (N)-doped carbon is widely used as an anode material for Li-ion battery (LIB). However, the identification of a specific type of N-configuration responsible for Li-ion storage in N-doped carbon is an elusive topic for LIB. Herein, the N-doped porous carbon nanofibers (N-pCNFs) with various atomic percentages of N and different types of N-configurations are prepared by carbonization of polyacrylonitrile-Zeolitic imidazolate framework-8 fibres at 800, 900, and 1000 °C in N2 atmosphere. The N content of pCNFs-800, N-pCNFs-900, and N-pCNFs-1000 samples are found to be 12.9, 9.4, and 4.8% atomic percentage, respectively. The free-standing/binder-free N-pCNFs-800, N-pCNFs-900, and N-pCNFs-1000 anode electrodes deliver the reversible Li storage capacity of 650, 805, and 520 mAh g−1, respectively at 0.1 C-rate. The ex-situ X-ray diffraction, scanning electron, and transmission electron microscopic results of N-pCNFs-900 indicate the formation of the solid electrolyte interface (SEI) layer. Further, the ex-situ X-ray photoelectron spectroscopy (XPS) analysis of N-pCNFs-900 identifies the presence of LiF, LixPF5-x, LixPOF5-x, Li-O-C, and R-COOLi constituents of the SEI layer and the deconvoluted XPS N1s spectra confirms that the pyridinic-N is responsible for Li-ion storage sites in N-pCNFs.

The porin pores of biological cell membranes enable molecules to be sieved out selectively while water molecules traverse the channel in a single file. Imitating this streaming mechanism is a promising way to create artificial liquid-sieving membranes, but ultrathin molecular pores need to be produced in a large membrane format to be functional under high transmembrane pressures. Here we show that a membrane composed of a covalent molecular mesh can filter mixtures of small molecules in a liquid by the porin-like mechanism. Tetrahedral network formers are polymerized layer-by-layer on a nanoporous substrate to yield a thin layer of a covalent molecular network containing an array of molecular meshes grown by a pore-limited mechanism. Each of the meshes exhibits high water permeability, estimated to be greater than 2500 Lm–2 h–1. Glucose or larger molecules are selectively sieved out while the solvent and solutes smaller than glucose traverse the mesh.

We report the CVD synthesis of a monolayer of MoS2 nanoparticles such that the nanoparticle size was controlled over the range 5–100 nm and the chemical potential of sulfur was modified, both by controlling the hydrogen flow rate during the CVD process. As the hydrogen flow rate was increased, the reaction process of sulfur changed from a “sulfiding” process to a “sulfo-reductive” process, resulting in the growth of smaller MoS2 nanoparticles on the substrates. The size control, crystalline quality, chemical configuration, and distribution uniformity of the CVD-grown monolayer MoS2 nanoparticles were confirmed. The growth of the MoS2 nanoparticles at different edge states was studied using density functional theory calculations to clarify the size-tunable mechanism. A non-volatile memory device fabricated using the CVD-grown size-controlled 5 nm monolayer MoS2 nanoparticles as a floating gate showed a good memory window of 5–8 V and an excellent retention period of a decade.

International audience; A new series of D–A–D-type small-molecule photovoltaic donors are designed and virtually screened before synthesis using time-dependent density functional theory calculations carefully validated against various polymeric and molecular donors. In this series of new design, benzodithiophene is kept as D to achieve the optimum highest-occupied molecular orbital energy level, while thienopyrroledione is initially chosen as A but later replaced by difluorinated benzodiathiazole or its selenide derivative to achieve the optimum band gap. The D–A–D core is end-capped by pyridone units which could not only enhance their self-assembly via hydrogen bonds but also play a role as an acceptor (A′) to form an extended A′–D–A–D–A′ small-molecule donor.

Purpose: For improving result of estimated remaining useful life in Prognostics and Health Management (PHM), a system which is able to consider a lot of environment and load data is required.Method: A load profile monitoring system was presented based on cloud computing for gathering and process-ing raw data which is included environment and load data. Result: Users can access results of load profile information on the In ternet. The developed system provides information which consists of distribution of load data, basic statistics, etc.Conclusion: We developed the load profile monitoring system for considering much environment and load data. This system has advantages such as improving accessibility through smart device, reducing cost, and covering various conditions.Key Words: Prognostics and Health Management. Load Profile Monitoring. Cloud Computing. Big Data. Automotive ● Received 19 November 2015, 1st revised 3 December 2015, accepted 14 December 2015Corresponding Author(chongman@mju.ac.kr)ⓒ 2015, The Korean Society for Quality ManagementThis is an Open Access article distributed under the terms of t he Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0) which permits u nrestricted non-Commercial use, distribution, and re-production in any medium, provided the original work is properl y cited.※ 이 논문은 2014년도 정부(미래창조과학부)의 재원으로 한국연구재단의 지원을 받아 수행된 기초연구사업임 (NO. 2012R1A1A1015120)

Purpose: The purpose of this retrospective study was to identify the diagnostic performance of positron emission tomography/computed tomography (PET/CT) compared to conventional modalities, such as ultrasonography (US) and contrast-enhanced computed tomography (CT) in detecting axillary lymph node metastasis (ALNM) in patients with breast cancer. Methods: Two hundred thirty-three consecutive patients diagnosed with primary breast cancer who had not been treated with neoadjuvant chemotherapy and had been examined by US, CT, and PET/CT before surgery were included. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of each imaging modality and combinations of modality according to tumor size were obtained, and were compared with the histopathological results of sentinel lymph node biopsy or axillary lymph node dissection. Results: ALNM was confirmed in 32.6% (76/233) of patients. The sensitivity, specificity, PPV, NPV, and accuracy of US for detecting ALNM were 65.8%, 86.6%, 70.4%, 84.0%, and 79.8%, respectively. The sensitivity, specificity, PPV, NPV, and accuracy of CT were 72.4%, 72.6%, 56.1%, 84.4%, and 72.5%, respectively. The sensitivity, specificity, PPV, NPV, and accuracy of PET/CT were 69.7%, 86.0%, 70.7%, 85.4%, and 80.7%, respectively. The combination of US and PET/CT showed the most accurate results with specificity, PPV and accuracy values of 93.6%, 81.5%, and 82.0%, respectively. Conclusion: The diagnostic performance of PET/CT was comparable to that of US and CT. Combination of US and PET/CT could be a reliable strategy for determining preoperative ALNM in patients with operable breast cancer.

Molecular conformation, intermolecular interaction, and electrode–molecule contacts greatly affect charge transport in molecular junctions and interfacial properties of organic devices by controlling the molecular orbital alignment. Here, we statistically investigated the charge transport in molecular junctions containing self-assembled oligophenylene molecules sandwiched between an Au probe tip and graphene according to various tip-loading forces (FL) that can control the molecular-tilt configuration and the van der Waals (vdW) interactions. In particular, the molecular junctions exhibited two distinct transport regimes according to the FL dependence (i.e., FL-dependent and FL-independent tunneling regimes). In addition, the charge-injection tunneling barriers at the junction interfaces are differently changed when the FL ≤ 20 nN. These features are associated to the correlation effects between the asymmetry-coupling factor (η), the molecular-tilt angle (θ), and the repulsive intermolecular vdW force (Fv...