Publications by authors named "Pai W"

Monolayer transition metal dichalcogenide VTe exhibits multiple charge density wave (CDW) phases, mainly (4 × 4) and (4 × 1). Here we report facile dynamic and tens-of-nanometer scale switching between these CDW phases with gentle bias pulses in scanning tunneling microscopy. Bias pulses purposely stimulate a reversible random CDW symmetry change between the isotropic (4 × 4) and anisotropic (4 × 1) CDWs, as well as CDW phase slips and rotation.

View Article and Find Full Text PDF

We identify and manipulate commonly occurring defects in black phosphorus, combining scanning tunneling microscopy experiments with density functional theory calculations. A ubiquitous defect, imaged at negative bias as a bright dumbbell extending over several nanometers, is shown to arise from a substitutional Sn impurity in the second sublayer. Another frequently observed defect type is identified as arising from an interstitial Sn atom; this defect can be switched to a more stable configuration consisting of a Sn substitutional defect + P adatom, by application of an electrical pulse via the STM tip.

View Article and Find Full Text PDF

Understanding the Coulomb interactions between two-dimensional (2D) materials and adjacent ions/impurities is essential to realizing 2D material-based hybrid devices. Electrostatic gating via ionic liquids (ILs) has been employed to study the properties of 2D materials. However, the intrinsic interactions between 2D materials and ILs are rarely addressed.

View Article and Find Full Text PDF
Article Synopsis
  • - The linewidth of the field emission resonance (FER) on MoS surfaces can change significantly, by up to ten times, as the electric field increases.
  • - This variation is explained by a concept called quantum trapping, where an electron becomes temporarily trapped in a potential well because of its wave properties after relaxation from a resonance state.
  • - The Pauli exclusion principle plays a role in lengthening the lifetimes of resonant electrons, allowing them to coexist with relaxed electrons and leading to a notably reduced linewidth of about 12 meV.
View Article and Find Full Text PDF

Single layers of transition metal dichalcogenides (TMDCs) are excellent candidates for electronic applications beyond the graphene platform; many of them exhibit novel properties including charge density waves (CDWs) and magnetic ordering. CDWs in these single layers are generally a planar projection of the corresponding bulk CDWs because of the quasi-two-dimensional nature of TMDCs; a different CDW symmetry is unexpected. We report herein the successful creation of pristine single-layer VSe_{2}, which shows a (sqrt[7]×sqrt[3]) CDW in contrast to the (4×4) CDW for the layers in bulk VSe_{2}.

View Article and Find Full Text PDF

Two-dimensional (2D) topological insulators (TIs) are promising platforms for low-dissipation spintronic devices based on the quantum-spin-Hall (QSH) effect, but experimental realization of such systems with a large band gap suitable for room-temperature applications has proven difficult. Here, we report the successful growth on bilayer graphene of a quasi-freestanding WSe single layer with the 1T' structure that does not exist in the bulk form of WSe. Using angle-resolved photoemission spectroscopy (ARPES) and scanning tunneling microscopy/spectroscopy (STM/STS), we observe a gap of 129 meV in the 1T' layer and an in-gap edge state located near the layer boundary.

View Article and Find Full Text PDF

Increased -linked -acetylglucosamine (-GlcNAc) modification of proteins by -GlcNAc transferase (OGT) is associated with diabetic complications. Furthermore, oxidative stress promotes endothelial inflammation during diabetes. A previous study reported that microRNA-200 (miR-200) family members are sensitive to oxidative stress.

View Article and Find Full Text PDF

The angiotensin-(1-7)/angiotensin-converting enzyme 2/Mas receptor axis counter-regulates the detrimental effects of angiotensin II. Beneficial effects of angiotensin-(1-7), including anti-inflammation, oxidative stress reduction, and anti-thrombosis, have been reported. Previous studies documented that ramipril decreased thrombin generation in human hypertension and that the anti-thrombotic effects of captopril and losartan were angiotensin-(1-7)-dependent, suggesting an interaction between thrombin and angiotensin-(1-7).

View Article and Find Full Text PDF

Direct growth of graphene integrated into electronic devices is highly desirable but difficult due to the nominal ~1000 °C chemical vapor deposition (CVD) temperature, which can seriously deteriorate the substrates. Here we report a great reduction of graphene CVD temperature, down to 50 °C on sapphire and 100 °C on polycarbonate, by using dilute methane as the source and molten gallium (Ga) as catalysts. The very low temperature graphene synthesis is made possible by carbon attachment to the island edges of pre-existing graphene nuclei islands, and causes no damages to the substrates.

View Article and Find Full Text PDF

Two-dimensional materials constitute a promising platform for developing nanoscale devices and systems. Their physical properties can be very different from those of the corresponding three-dimensional materials because of extreme quantum confinement and dimensional reduction. Here we report a study of TiTe from the single-layer to the bulk limit.

View Article and Find Full Text PDF

We demonstrate that a C(60) overlayer enhances the perpendicular magnetic anisotropy of a Co thin film, inducing an inverse spin reorientation transition from in plane to out of plane. The driving force is the (60)/Co interfacial magnetic anisotropy that we have measured quantitatively in situ as a function of the (60) coverage. Comparison with state-of-the-art ab initio calculations show that this interfacial anisotropy mainly arises from the local hybridization between (60) p(z) and Co d(z(2)) orbitals.

View Article and Find Full Text PDF

This study reports the isolation and characterization of a new type of transparent zebrafish Danio rerio mutant called pinky (pk), which has been visually isolated from a spontaneous mutation in a D. rerio colony. The pk larvae possess complex mutations affecting pigmentation because of missing pigment cells or a dramatic reduction in the chromatophore number.

View Article and Find Full Text PDF

The ubiquitous transcription factor Yin Yang 1 (YY1) is known to have diverse and complex cellular functions. Although relevant literature has reported that YY1 expression can induce the down-regulation of C/EBP homologous protein 10 (CHOP-10) and then allow the transactivation of certain transcription factors required for lipogenesis, similar properties of YY1 are poorly understood in animal model systems. In this study, we demonstrate hepatic lipid accumulation in YY1 transgenic zebrafish (GY).

View Article and Find Full Text PDF

The activated cannabinoid receptor 1 (CB1R) is exclusively responsible for food intake and weight gain and regulates several pathological features associated with obesity in mammals. However, the precise role of CB1R in non-mammalian model systems is poorly understood. To investigate the functions of CB1R in zebrafish liver, we conditionally expressed CB1R proteins using a liver-specific Tet(off) transgenic system.

View Article and Find Full Text PDF

Food products, such as milk and meat products including cheese, milk powder, fermented milk, sausage, etc. are susceptible to the contamination by pathogenic and deteriorative bacteria. These bacteria include Listeria monocytogens, Staphylococcus aureus, Enterobacter sakazakii, Escherichia coli O157:H7, Salmonella spp.

View Article and Find Full Text PDF

Gankyrin is a small ankyrin-repeat protein that previous research has confirmed to be overexpressed in hepatocellular carcinoma (HCC). Although relevant literature has reported on gankyrin functions in cellular proliferation and tumorigenesis, the exact role of gankyrin is poorly understood in animal model systems. This study analyzed hepatic lipid accumulation in gankyrin transgenic (GK) zebrafish.

View Article and Find Full Text PDF

Objective: To determine the range and elemental composition of alloys used for PFM and crown-and-bridge restorations by New Zealand dental laboratories, and to understand the reasons for their selection.

Materials And Methods: Two waves of data collection were carried out via post and telephone interview. The source population was dental laboratories advertised with the Yellow Pages Group in 2007/2008.

View Article and Find Full Text PDF

We demonstrate the charge state of C60 on a Cu(111) surface can be made optimal, i.e., forming C60(3-) as required for superconductivity in bulk alkali-doped C60, purely through interface reconstruction rather than with foreign dopants.

View Article and Find Full Text PDF

Background: One of the most common complications in infants under parenteral nutrition treatment is parenteral nutrition-associated cholestasis (PNAC). The etiology of PNAC is thought to be multifactorial. The aims of this study were to evaluate the risk factors for PNAC in our neonatal intensive care unit and determine useful predictors.

View Article and Find Full Text PDF

Fluorescent nanodiamond (FND) contains nitrogen-vacancy defect centers as fluorophores. The intensity of its fluorescence can be significantly enhanced after deposition of the particle (35 or 140 nm in size) on a nanocrystalline Ag film without a buffer layer. The excellent photostability (i.

View Article and Find Full Text PDF

In the rich phase diagram of NaxCoO2, x=0.71 enjoys special stability and is called the Curie-Weiss metal due to its anomalous properties. Similarly, x=0.

View Article and Find Full Text PDF

Streptococcus agalactiae, Streptococcus uberis, and Streptococcus bovis are three of the major pathogens which cause mastitis in dairy herds. Since conventional methods for the detection of these mastitis pathogens are laborious and time-consuming, rapid methods are needed. With an attempt to know if heat shock protein (HSP) genes other than HSP60 gene, could be used for PCR primer designing, in this study, we tried to design PCR primers based on the heat shock protein genes hsp70, hsp40, and hsp10 for the specific detection of S.

View Article and Find Full Text PDF

Sodium ion ordering on an in situ cleaved NaxCoO2 (x=0.84) surface has been studied by ultrahigh vacuum scanning tunneling microscopy at room temperature. Three main phases, with p(3 x 3), ( radical7 x radical7), and (2 radical3 x 2 radical3) hexagonal unit cells and a surface Na concentration of 1/3, 3/7, 1/2, respectively, were identified.

View Article and Find Full Text PDF

The migration behavior of C60 on Ni(111) has been inferred from its growth morphology at various substrate temperatures, as observed with scanning tunneling microscopy. The number density of islands increased and their average sizes decreased anomalously in the temperature range of approximately 573 K to approximately 973 K. This trend contradicts the prediction in conventional nucleation theory.

View Article and Find Full Text PDF