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The applications of two-dimensional (2D) materials in electronics, optoelectronics, and spintronics are limited by the high contact resistance at the metal/semiconductor interface owing to the strong Fermi-level pinning. In this study, an interlayer insertion strategy is proposed to solve this problem, and first principles calculations are done to study the influences of inserting a SiC layer on the Schottky barrier and electronic properties of MoS2/metals (Mg, Al, In, Cu, Ag, Au, Pd, Ti, and Sc). The average charge value substantially increased (≥0.060 e) at the interface between SiC and MoS2 layers, and then no tunneling barrier appeared except for the MoS2/Au contact by inserting the SiC layer. Moreover, ΦSB,N almost decreases for the MoS2/metal contacts by inserting the SiC layer. When Ti, Cu, Au, and Pd are used as electrodes, the n-type Schottky barrier is formed with the ΦSB,N values of 0.479 eV, −0.073 eV, 0.498 eV, and 0.225 eV, respectively. However, if Al, In, Mg, and Ag are used as electrodes, the systems are transformed into Ohmic contact. These findings provide a practical guideline for depinning the Fermi level at contact interfaces and designing the high performance TMD-based nanoelectronic devices.

Sr0.7Bi0.2TiO3 (SBT) was introduced into Bi0.5Na0.5TiO3 (BNT) via a standard solid-state route to modulate its relaxation behaviour and energy storage performance. With increasing SBT content, the perovskite structure of BNT transforms from a rhombohedral phase to a weakly polarized pseudo-cubic phase, and the relaxation behaviour is enhanced. In particular, the EDBS is improved from 120 kV/cm of BNT to 160 kV/cm of 0.6BNT-0.4SBT, which displays a large recoverable energy storage density (Wrec = 2.20 J/cm3), implying a large potential ability of energy storage for the 0.6BNT-0.4SBT ceramic. Moreover, both dielectric properties (28–326 °C) and energy storage properties (20–140 °C) exhibit a good thermal stability for the same 0.6BNT-0.4SBT composition. These characteristics suggest 0.6BNT-0.4SBT ceramic could be a promising candidate to be applied in a pulse power system over a broad temperature range.

Birefringence, intrinsic to anisotropic phase-structured ceramics, can cause severe light scattering hence low transmittance. In this work, by tuning the addition of Sr(Al0.5Ta0.5)O3 (SAT), we constructed a gradual phase structure evolution in K0.5Na0.5NbO3 (KNN) ceramics at room temperature (RT). Results exhibit that the KNN-0.16SAT ceramic with an isotropic phase structure shows the highest transmittance close to 70% at 2000 nm. The relationship between transparency and phase structure was then systematically investigated, and the contribution of birefringence to transparency was also evaluated in a proposed model. Our work confirms that the absence of birefringence benefits the transparency in the KNN-based transparent ceramics, and fills up the missing link between phase structure and transparency in related fields.

Pure (K0.5Na0.5)NbO3 (KNN) ceramics with high density, fine and uniform-size grains were prepared by mechanochemical activation-assisted process. The time of synthesis is only 100 min, which is 72% – 93% shorter than the 6–24 h of the conventional solid-state method. Compared to samples prepared by conventional solid-state method, both the microstructure evolvement and electric properties were explored in detail. Results show the electric properties was significantly improved. Moreover, the dielectric and ferroelectric properties of obtained KNN ceramics exhibit strong dependence on the crystal size of the initial powders. The optimized ceramics HKNN100 showed a quite high energy storage performance, i.e., large electric energy storage density (Wtol = 1.612 J/cm3) and recoverable energy storage density (Wrec = 0.431 J/cm3), which can be mainly ascribed to the large dielectric breakdown strength (DBS = 110 kV/cm). Our works demonstrated that mechanochemical activation-assisted method possesses advantages for high-efficiency preparation of KNN or KNN-based ceramics.

The applications of two-dimensional (2D) materials in electronics, optoelectronics, and spintronics are limited by the high contact resistance at the metal/semiconductor interface owing to the strong Fermi-level pinning. In this study, an interlayer insertion strategy is proposed to solve this problem, and first principles calculations are done to study the influences of inserting a SiC layer on the Schottky barrier and electronic properties of MoS2/metals (Mg, Al, In, Cu, Ag, Au, Pd, Ti, and Sc). The average charge value substantially increased (≥0.060 e) at the interface between SiC and MoS2 layers, and then no tunneling barrier appeared except for the MoS2/Au contact by inserting the SiC layer. Moreover, ΦSB,N almost decreases for the MoS2/metal contacts by inserting the SiC layer. When Ti, Cu, Au, and Pd are used as electrodes, the n-type Schottky barrier is formed with the ΦSB,N values of 0.479 eV, -0.073 eV, 0.498 eV, and 0.225 eV, respectively. However, if Al, In, Mg, and Ag are used as electrodes, the systems are transformed into Ohmic contact. These findings provide a practical guideline for depinning the Fermi level at contact interfaces and designing the high performance TMD-based nanoelectronic devices.

Electrical contacts are crucial to the high performances of electronic devices, and they become more prominent for the popular two-dimensional (2D) semiconductors because they commonly have high contact resistances and are sensitive to the interfacial states. In this paper, taking monolayer MoS2 as an example, first-principles calculations are done to study and predict the influences of the contact mode on the interfacial electronic states of monolayer MoS2/metal (metal = Mg, Al, In, Cu, Ag, Au, Pd, Sc, and Ti). It is found that the interfacial properties are determined by the matching degree between the electronic states of the monolayer MoS2 and metal electrodes. The top contact configuration is preferred for the monolayer MoS2/Sc system as a result of an extremely low Schottky barrier (0.086 eV) as compared to that (0.439 eV) in the edge contact configuration, however, the edge contact configuration is preferred for Ag, Cu, Au, and Pd electrodes. Furthermore, metal electrodes in the top contact configuration might usually result in n-type doping of monolayer MoS2, but lead to p-type doping in the edge contact configuration. The pinning factor S (0.257, −0.009, −0.132, and −0.172) of monolayer MoS2 in both contact modes is close to zero, suggesting a strong electronic pinning effect. The findings provide theoretical guidance for the selection of electrodes for high-performance 2D material based devices.

It is difficult to generate p–n junctions in atomically thin transition metal dichalcogenides (TMDs) because of the great challenge of selective doping. First-principles calculations demonstrate that the electronic states in monolayer MoS2 could be substantially tuned through contact with hydrogenated SiC sheets, as a result of interface-induced electronic doping. Specifically, monolayer MoS2 exhibits metallic characteristics when put in contact with the Si termination of SiC–H (MoS2/SiC–H), but exhibits ambipolar type polarization when in contact with the C termination of CSi–H (MoS2/CSi–H). Furthermore, monolayer MoS2 can be switched from p-type on H–Si terminations (MoS2/H–SiC and MoS2/H–SiC–H) to n-type on H–C terminations (MoS2/H–CSi and MoS2/H–CSi–H). Accordingly, p–n junctions can be generated in bilayer MoS2 if a fully hydrogenated monolayer SiC is inserted between the layers. In addition, the staggered band alignment of the top and bottom monolayers of MoS2 leads to considerable rectification of current. The results are helpful for the design of TMD based nanoelectronic devices.

Ferromagnetic (FM) two-dimensional (2D) transition metal dichalcogenides (TMDs) have potential applications in modern electronics and spintronics and doping of TMDs with transition metals can enhance the magnetic characteristics. In this work, the structural stability, electronic states, and magnetic properties of Mn-doped monolayer/bilayer MoS2 are studied systematically by first-principles calculations. Substitutional Mn dopants at the Mo sites are energetically favorable in both monolayer and bilayer MoS2 under the S-rich condition which is common in the synthesis of MoS2 nanosheets. Two Mn dopants participate in the FM interaction in monolayer MoS2 and magnetic coupling of two Mn dopants via the double-exchange mechanism can be mediated by the nearest neighboring S. Magnetic coupling can be ascribed to the competition between the double-exchange, direct-exchange, and super-exchange interactions, which take place between two Mn dopants in bilayer MoS2 with the MniMnMo, MniMnS and MnMo–MnMo configurations. Our results reveal the geometrical dependence of magnetic-exchange coupling suggesting that Mn-doped monolayer/bilayer MoS2 has large potential in spintronic devices.

Understanding the interfacial properties between two-dimensional (2D) semiconductors and metal electrodes is vital for designing and realization of electronic devices. In this paper, first-principle calculations are done to study the influences of the defects on the interfacial electronic states of mMoS2/metal (metal= Mg, Al, In, Cu, Ag, Au, and Pd). It is found that the electron states at the interface are substantially increased if defects are induced in mMoS2 contacted with metals. As a result, the tunneling barrier is reduced. The Schottky barrier height (SBH) is increased in mMoS2 contacted with Mg, Al, In, and Au, but is reduced in defective mMoS2 contacted with Cu, Ag, and Pd. Furthermore, the pinning factor S are 0.227, 0.238, and 0.238 for the VS, VMo, and SMo in mMoS2, but the S value is only 0.030 for substitution of S by Mo (MoS) in mMoS2. Our findings are in good agreement with the experimental results. The results give insight into the contact physics of 2D semiconductors with metals and it is suggested that defects play a key role on the future generation electronic applications.

Considering the environment and human health, highly transparent lead-free (1 − x)K0.5Na0.5NbO3–xCa(Zn1/3Nb2/3)O3 (abbreviated as KNN–xCZN) piezoceramics were synthesized by a solid state reaction method. The effects of Ca(Zn1/3Nb2/3)O3 on the microstructures, phase structures, characteristic frequency and electrical properties were investigated. Fine grain and relaxor-like behaviors were obtained, and the Ca(Zn1/3Nb2/3)O3 also increased the crystal structure of the ceramics transformation from orthorhombic to pseudo-cubic. It was found that the highest transmittance of 70.42% (with a thickness of 0.5 mm in the visible spectrum) was obtained for the KNN–xCZN ceramics at x = 0.07, which was due to the high relative density, low apparent porosity, uniform and fine-grained microstructures, high symmetry of the pseudo-cubic structure, NbO6 octahedron reduced distortion and more relaxor-like behavior. In addition, the transparent piezoelectric ceramics KNN–xCZN with x = 0.07 possessed high transmittance (∼84% at near-infrared wavelengths) and excellent electrical properties (er = 1162, d33 = 102 pC N−1). All of the above demonstrated that the KNN–xCZN ceramics could be promising lead-free transparent piezoceramics.

High transparency was obtained in (1− x )(K 0.5 Na 0.5 )NbO 3 – x Sr(Mg 1/3 Nb 2/3 )O 3 ( x =0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08) lead-free ceramics by pressure-less sintering procedure. The effects of Sr(Mg 1/3 Nb 2/3 )O 3 content on the microstructure, phase transition, optical properties and electrical properties were studied in detail. The X-ray diffraction results showed that the crystal structure of ceramics gradually transformed from orthorhombic phase into pseudo-cubic phase with doping of Sr(Mg 1/3 Nb 2/3 )O 3 . The fine grain microstructure with clear grain boundary was observed in all compositions, while the grain size exhibited significant composition dependence. It was found that a more uniform distribution with smaller grain size was favorable to high optical transmittance, owing to the decreased scattering by grains and grain boundaries. In addition, a strong diffuse phase transformation in KNN-based ceramics induced by Sr(Mg 1/3 Nb 2/3 )O 3 doping, causing the ceramics become more relaxor-like and transparent. The transmittance and electric properties results indicated that the 0.95(K 0.5 Na 0.5 )NbO 3 –0.05 Sr(Mg 1/3 Nb 2/3 )O 3 ceramics exhibited higher transmittance (60% in the near-IR region) accompanied with better electrical properties ( e m =2104, P r =5.0 μC/cm 2 , d 33 =92 pC/N).

Seeking for high energy storage materials has become an urgent task in the circumstance of energy crisis. In this work, a series of relaxor ferroelectrics (1 − x)Bi0.5Na0.5TiO3-xSr0.7La0.2TiO3 ((1 − x)BNT-xSLT) with excellent energy storage performance were successfully fabricated. The SLT as a second component was doped into BNT and served three main functions: (1) efficiently decreased the grain size and increased the band gap and thus enhanced the breakdown electric field, (2) drove the ferroelectric phase gradually to a relaxor character, (3) reduced the tolerance factor (t) to defer the electric field of polarization saturation. Eventually, we achieved an impressive recoverable energy storage density (Wrec) of 4.14 J/cm3 and an ultrahigh energy storage efficiency (ƞ) of 92.2% simultaneously at 315 kV/cm in the ceramic of x = 0.45. Furthermore, the sample also exhibited an excellent stability against testing temperature, frequency and cycle, a high power density (182 MW/cm3) and a fast discharge speed (123 ns), all of which are ideal characteristics for high power energy storage devices.

Ferromagnetic (FM) two-dimensional (2D) transition metal dichalcogenides (TMDs) have potential applications in modern electronics and spintronics and doping of TMDs with transition metals can enhance the magnetic characteristics. In this work, the structural stability, electronic states, and magnetic properties of Mn-doped monolayer/bilayer MoS

The magnetic properties and electronic structure of Mn2NiSi and Ni2MnSi Heusler alloys have been studied by using the first-principles. The possible non-modulated martensitic transformations in Mn2NiSi and Ni2MnSi alloys have been investigated. In both austenitic and martensitic phases, Mn2NiSi is a ferrimagnet. The antiparallel alignment of Mn (A) and Mn (B) moments is found. In martensitic Mn2NiSi, the global energy minimum occurs at c/a=1.37 with 1% decrease of the martensitic cell volume. The energy difference ΔE between the austenitic and martensitic phases is 400 meV/cell, so it is more likely to realize martensitic transformation for Mn2NiSi alloy. Unlike Mn2NiSi alloy, the global energy minimum occurs at c/a=1.02 without cell volume change in martensitic Ni2MnSi. But the energy difference ΔE between the austenitic and martensitic phases is only 0.3 meV/cell. Meanwhile, around c/a=1 an anomaly is observed in the Etot–c/a curve which is related to a very slightly martensitic distortion trend in Ni2MnSi.

Using the first-principles projector augmented wave potential within the generalized gradient approximation, we investigate the magnetic and electronic properties in the bulk and (001) surface of the Heusler alloy Ti2MnAl with Hg2CuTi-type. For the bulk, our calculations indicate that the Heusler alloy Ti2MnAl exhibits antiferromagnetic half-metallicity at the equilibrium lattice constant. Owing to the surface effects, the half-metallicity which can be observed in bulk is destroyed in five terminations. The high spin polarization only maintains in TiMn-termination. Through further studies on the atomic magnetic moments, we find that the moment of surface Ti1 is enhanced obviously, as well as the absolute value of surface Mn atomic moment.

Cerium oxide films have been fabricated using dual plasma deposition. X-ray diffraction. (XRD) reveals a crystalline phase and X-ray photoelectron spectroscopy (XPS) shows that La exists predominantly in the +4 oxidation state. The activated partial thromboplastin time is longer than that of blood plasma and stainless steel. Furthermore, the numbers of adhered, aggregated and morphologically changed platelets are reduced compared to low-temperature isotropic carbon (LTIC). HUVEC cells exhibit good adhesion and proliferation behavior on cerium oxide films. This study suggests rare earth oxide films are potential blood-contacting biomedical materials.

Lanthanide ions such as lanthanum (La) and neodymium (Nd) were implanted into 316 stainless steel samples using metal vapor vacuum arc to improve the surface corrosion resistance and antithrombogenic properties. X-ray photoelectron spectroscopy shows that lanthanum and neodymium exist in the +3 oxidation state in the surface layer. The corrosion properties of the implanted and untreated control samples were investigated utilizing electrochemical tests and our results show that La and Nd implantations enhance the surface corrosion resistance. In vitro activated partial thromboplastin time (APTT) tests were used to evaluate the antithrombogenic properties. The APTT time of the implanted samples was observed to be prolonged compared to that of the unimplanted stainless steel control. La and Nd ion implantations can be used to improve the surface corrosion resistance and biomedical properties of 316 stainless steels.

The Pap test has effectively reduced the incidence and mortality of cervical cancer. However, because of the morphological basis of this test, sensitivity and specificity are less than ideal, a situation that complicates the clinical management of women diagnosed with low-grade cervical abnormalities. In an attempt to understand the molecular basis of cervical tumorigenesis and to discover molecular markers for accurate cervical cancer screening, we used cDNA microarrays containing30,000 Unigene clones to examine the gene expression patterns of 34 cervical tissues from different clinically defined stages. It was found that global gene expression patterns separated normal cervical tissues and low-grade squamous intraepithelial lesions from cervical cancers and most of the high-grade squamous intraepithelial lesions (HSILs). Among the top 62 genes/(expressed sequence tags) that were overexpressed in tumors and HSIL tissues, 35 were confirmed using in situ hybridization on cervical tissue micorarrays. Many of these genes were overexpressed in high-grade dysplastic and malignant cervical epithelium or in stroma adjacent to the diseased tissues, with cellular proliferation and extracellular matrix-associated genes being the most common. In general, the extent of gene overexpression increased as the lesions progressed from low-grade squamous intraepithelial lesions to HSILs and finally to cancer. It is hoped that with additional development, some of these markers will improve the interpretation of cervical screening tests and provide useful information for patient management decisions.

2528^ Background: LEE011, an orally bioavailable, highly specific CDK4/6 inhibitor, causes cell cycle arrest and tumor growth inhibition in multiple preclinical models with intact retinoblastoma pr...

We have developed a xylose-dependent expression system for tight and modulated expression of cloned genes in Bacillus subtilis . The expression system is contained on plasmid pSWEET for integration at the amyE locus of B. subtilis and incorporates components of the well-characterized, divergently transcribed xylose utilization operon. The system contains the xylose repressor encoded by xylR , the promoter and 5′ portion of xylA containing an optimized catabolite-responsive element, and intergenic xyl operator sequences. We have rigorously compared this expression system to the isopropyl-β- d -thiogalactopyranoside-induced spac system using a thermostable β-galactosidase reporter (BgaB) and found the xyl promoter-operator to have a greater capacity for modulated expression, a higher induction/repression ratio (279-fold for the xyl system versus 24-fold with the spac promoter), and lower levels of expression in the absence of an inducer. We have used this system to probe an essential function in wall teichoic acid biosynthesis in B. subtilis . Expression of the teichoic acid biosynthesis gene tagD , encoding glycerol-3-phosphate cytidylyltransferase, from the xylose-based expression system integrated at amyE exhibited xylose-dependent complementation of the temperature-sensitive mutant tag-12 when grown at the nonpermissive temperature. Plasmid pSWEET thus provides a robust new expression system for conditional complementation in B. subtilis .

Background: LEE011 is an oral small molecule inhibitor with highly specific nanomolar inhibitory activity against CDK4/cyclinD1 and CDK6/cylinD3 complexes. Preclinical studies with LEE011 have demonstrated robust anti-tumor activity in several tumor models with functional retinoblastoma protein (pRb). Methods: The primary objective this phase 1 dose escalation study was to determine the maximum tolerated dose (MTD) based on cycle 1 dose-limiting toxicities (DLTs) and establish the recommended dose for expansion (RDE) of LEE011 in patients (pts) with pRb-positive advanced solid tumors or lymphomas. Using a Bayesian logistic regression model with overdose control principle, escalating doses of LEE011 were administered daily for 21 days of 28-day cycles. Following MTD determination, a continuous dosing schedule was also evaluated. Evaluation of safety and pharmacokinetics (PK) from all pts contributed to defining the RDE. Results: As of June 28, 2013, a total of 70 pts were treated in the escalation phase at doses from 50-1200 mg. DLTs are described in the table. MTD was defined at 900 mg on a 21 of 28-day dosing schedule. Additional patients were treated at 750 mg and 600 mg on the current schedule and at 600 mg on a continuous schedule to define the RDE and sustain optimal long-term dosing. Following review of PK and safety data, including AEs observed beyond cycle 1, the planned RDE is 600 mg for 21 days of a 28-day treatment cycle. Common adverse events (AEs) were gastrointestinal (nausea 40%, diarrhea 30%) and hematologic (anemia 43%, neutropenia 40%); the majority of AEs were grades 1/2 and reversible. Asymptomatic QTc prolongation was observed at the higher doses. LEE011 is absorbed orally with Tmax ≈ 4 hours and effective t1/2 ≈24 hours. Dose-dependent increases in exposure were observed. Preliminary evidence of activity was observed including stable disease for ≥ 6 cycles in 10/70 pts (14%) and 1 confirmed partial response in a pt with ER-positive breast cancer. Preliminary tumor pharmacodynamic data shows evidence of modulation at doses of 600 mg and above. Conclusions: LEE011, a highly selective inhibitor of CDK4/6, exhibited an acceptable safety profile, dose dependent PK, and preliminary clinical activity. Enrollment will continue in the expansion phase. Citation Information: Mol Cancer Ther 2013;12(11 Suppl):A276. Citation Format: Jeffrey R. Infante, Geoffrey I. Shapiro, Petronella O. Witteveen, John F. Gerecitano, Vincent Ribrag, Rashmi Chugh, Abhijit Chakraborty, Alessandro Matano, Xumei Zhao, Sudha Parasuraman, Philippe A. Cassier. Phase 1 multicenter, open label, dose-escalation study of LEE011, an oral inhibitor of cyclin-dependent kinase 4/6, in patients with advanced solid tumors or lymphomas. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2013 Oct 19-23; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2013;12(11 Suppl):Abstract nr A276.

Natural genetic transformation in Haemophilus influenzae involves DNA binding, uptake, translocation, and recombination. In this study, we cloned and sequenced a 3.8-kbp H. influenzae DNA segment capable of complementing in trans the transformation defect of an H. influenzae strain carrying the tfo-37 mutation. We used subcloning, deletion analysis, and in vivo protein labeling experiments to more precisely define the gene required for efficient DNA transformation on the cloned DNA. A novel gene, which we called dprA+, was shown to encode a 41.6-kDa polypeptide that was required for efficient chromosomal but not plasmid DNA transformation. Analysis of the deduced amino acid sequence of DprA suggested that it may be an inner membrane protein, which is consistent with its apparent role in DNA processing during transformation. Four other open reading frames (ORFs) on the cloned DNA segment were identified. Two ORFs were homologous to the phosphofructokinase A (pfkA) and alpha-isopropyl malate synthase (leuA) genes of Escherichia coli and Salmonella typhimurium, respectively. Homologs for the two other ORFs could not be identified.