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It is intriguing that a solid containing ~101 atoms of Ga or IV-A elements (C, Si, Ge, Sn, and Pb) melts at temperatures that are higher than the melting point of the corresponding bulk solid (Tm,b) though the Tm of a solid in the 100–2 nm size range drops universally with the sample size. Consistent insight into the phenomenon of Tm oscillation (suppression followed by elevation as the solid size is reduced from bulk to subnanometre size) over the whole range of sizes remains a scientific challenge. Here we show that the Tm oscillation arises from the joint effect of bond order loss and its consequence on bond strength gain of small clusters in particular for Ga and atoms of the IV-A elements. [ABSTRACT FROM AUTHOR]

Abstract: Incorporating the recent bond-order-length-strength correlation mechanism [Sun CQ, Bai HL, Li S, Tay BK, Jiang EY, Acta Mater 2004;52:501] into the Ising convention and the Brillouin function has enabled the unusual magnetic behavior of a ferromagnetic nanosolid and a surface to be reproduced using Monte Carlo simulations. Examination of the size and temperature dependence of the saturation magnetization (M S) of a solid of various structures reveals that: (i) at low temperatures, the M S increases inversely with solid size due to the contribution from the localized charges that are trapped by the deepened potential well of the lower-coordinated atoms in the surface skins; (ii) at the ambient temperatures, the M S drops with solid size because of the bond-order loss that suppresses the Curie temperature of the specimen; (iii) the quantized features of the surface to volume ratio of the solid is responsible for the observed M S oscillations of smaller clusters at low temperatures. [Copyright &y& Elsevier]

Abstract: The electronic processes of Cu(Ag, V, Rh)(001) surface oxidation are comparatively analyzed based on the recent ‘chemical bond–valence band–potential barrier’ (BBB) correlation mechanism [C.Q. Sun, Prog. Mater. Sci. 48, 521–685 (2003)], which allows reaction formulae for all the observed phases with identification of individual atomic valence and the binding kinetics at the surfaces with the same geometry. It is consistently understood that the forming kinetics of the primary oxide tetrahedron and its derivative on the valence density-of-states (DOS) are intrinsically common for all these analyzed systems, though the patterns of observation in terms of morphology and crystallography vary from situation to situation. However, the lattice size and electronegativity of the host surfaces determine extrinsically the site selectivity of the oxygen, the order of bond formation and the orientation of the oxide tetrahedron. [Copyright &y& Elsevier]

Surface oxidation and porosity variation play significant roles in the dielectric performance of porous silicon (PS) yet discriminating the contribution of these events is a challenge. Here we present an analytical solution that covers contributions from the components of silicon oxide surface, silicon backbone and voids using a serial–parallel capacitance structure. Agreement between modeling predictions and measurement has been realized, which turns out an effective method that enables us to estimate the extent of surface oxidation of a specimen by measuring the porosity dependent dielectric response of the chemically passivated PS, and provides guidelines that could be useful for designing dielectric porous structures with surface oxidation. [Copyright &y& Elsevier]

Size effect on the magnetization and the coercivity of nanocrystalline Ni films has been examined at room temperature. Agreement between modeling predictions and measurements reveals that the size-suppressed magnetization results from the drop of spin–spin exchange energy due to the coordination number (CN) imperfection of atoms near the surface edges, and that the size-enhanced coercivity arises from intergrain interaction that is proportional to the inverse of particle size. Findings herewith and reported previously on the size-induced lattice contraction and Curie temperature suppression evidence the significance of atomic CN imperfection on the unusual behavior of a ferromagnetic nanosolid. [Copyright &y& Elsevier]

We previously reported that injection of the Gram (−) bacteriotoxin, lipopolysaccharide (LPS), into gravid females at embryonic day 10.5 led to the birth of animals with fewer than normal dopamine (DA) neurons when assessed at postnatal days (P) 10 and 21. To determine if these changes continued into adulthood, we have now assessed animals at P120. As part of the previous studies, we also observed that the pro-inflammatory cytokine tumor necrosis factor α (TNFα) was elevated in the striatum, suggesting that these animals would be more susceptible to subsequent DA neurotoxin exposure. In order to test this hypothesis, we injected (at P99) 6-hydroxydopamine (6OHDA) or saline into animals exposed to LPS or saline prenatally. The results showed that animals exposed to prenatal LPS or postnatal 6OHDA alone had 33% and 46%, respectively, fewer DA neurons than controls, while the two toxins combined produced a less than additive 62% loss. Alterations in striatal DA were similar to, and significantly correlated with (r2=0.833) the DA cell losses. Prenatal LPS produced a 31% increase in striatal TNFα, and combined exposure with 6OHDA led to an 82% increase. We conclude that prenatal exposure to LPS produces a long-lived THir cell loss that is accompanied by an inflammatory state that leads to further DA neuron loss following subsequent neurotoxin exposure. The results suggest that individuals exposed to LPS prenatally, as might occur had their mother had bacterial vaginosis, would be at increased risk for Parkinson''s disease. [Copyright &y& Elsevier]

Consistent insight into the size-enhanced E4f-level shift and the size-suppressed melting point of Au nanosolids has been obtained based on the bond order-length-strength (BOLS) correlation mechanism [Sun et al., Acta Mater. 51 (2003) 4631]. Consistency between theory predictions and observations reveals that the atomic-coordination number (CN)-imperfection induced bond contraction and the associated bond energy increase dictate these changes. The increase of binding energy density per unit volume in the relaxed surface region perturbs the Hamiltonian that determines the core-level shift; the decrease of atomic cohesive energy (a product of atomic CN and the single bond energy) determines the thermal energy required for melting. Extending the knowledge to the lower end of the size limit suggests that the metallic bond in the gold monatomic-chain contracts by ∼30% associated with ∼43% magnitude rise of the bond energy. The crystal binding intensity contributing from all the atoms in the solid to the Au-E4f electrons in the bulk is determined to be −2.87 eV. [Copyright &y& Elsevier]

Crystal binding energy of a core electron at the 3d[sub 5/2] level of a Pd atom has been estimated to be -4.0±0.02 eV by decoding the X-ray photoelectron spectra obtained from both the Pd surfaces and the Pd nanoparticles. Findings indicate that the increase in the binding energy originates from the effect of coordination number (CN) imperfection of atoms at a flat surface or at the curved surface of a nanosolid. The CN imperfection shortens the remaining bonds of the lower-coordinated atoms spontaneously associated with bond energy increase, which perturbs the Hamiltonian of an extended solid and hence shifts the core level to higher binding energy. Therefore, the significance of atomic CN imperfection cannot be overlooked in dealing with a low-dimensional system, and the recent bond-order–length–strength (BOLS) correlation mechanism is essentially adequate, for the significance of atomic CN imperfection. [ABSTRACT FROM AUTHOR]

This report features the recent progress in understanding the behaviour of atoms and valence electrons involved in the process of oxidation, and some technological development driven by the new knowledge. It is initiated and verified that a chemical bond contracts spontaneously at a surface associated with magnitude rise of the bond energy due to the coordination imperfection and that an oxygen atom hybridizes its sp orbitals upon reacting with a solid surface. The former leads to the bond order–length–strength (BOLS) correlation for the physical aspect of a surface and a nano-solid and the latter to a bond–band–barrier (BBB) correlation for chemical reaction. In the process of oxidation, non-bonding lone pairs, anti-bonding dipoles and hydrogen-like bonds are involved, which add corresponding density-of-states (DOS) features to the valence band of the host. Bond forming also alters the sizes and valencies of the involved atoms and causes a collective dislocation of these atoms, which corrugate the morphology or the potential barrier of the surface. Based on the above premises, the oxidation of the low-index surfaces of transition metals Cu, Co, Ag and V, noble metals Rh, Ru, and Pd and non-metallic diamond has been consistently analyzed. Identities probed with various techniques, such as STM, LEED, XRD, STS, PES, TDS, EELS and Raman, have been systematically defined in terms of atomic valencies, bond geometry, valence DOS, bond strength and bond forming kinetics. It is understood that formation of the basic oxide tetrahedron, and consequently, the four discrete stages of bond forming kinetics and the oxygen-derived DOS features, are intrinsically common for all the analyzed systems though the patterns of observations may vary from situation to situation. What differs one oxide surface from another in observations are: (i) the site selectivity of the oxygen adsorbate, (ii) the order of the ionic bond formation and, (iii) the orientation of the tetrahedron at the host surfaces. The valencies of oxygen, the scale and geometrical orientation of the host lattice and the electronegativity of the host elements determine these specific differences extrinsically. Extending the premise of sp-orbital hybridization to the reactions of (C, N)–Ni(001) surfaces has led to a novel approach neutralizing the diamond–metal interfacial stress and hence strengthening the diamond–metal adhesion substantially. The BOLS correlation has provided consistent insight into the shape-and-size dependence of a number of properties for nano-solids. The BBB correlation has led to new findings in designing and fabricating materials for photoluminescence, electron emission and ultrahigh elasticity, etc. [Copyright &y& Elsevier]

Effects of surface passivation and particle-substrate interfacial reaction on the size dependent 2p3/2-level shift of nanosolid Cu have been numerically analyzed, leading to information about the reactivity of Cu nanosolid with different substrates, such as graphite, polymer and alumina. It has been found that Ar+ bombardment promotes the Cu-polymer reaction and N+ passivation strengthens the surface bond due to nitride formation. Cu atom interacts with alumina slightly stronger at room temperature than at 80 K. Matching predictions to the measured size-dependent Cu-2p level shift reveals that the intra-atomic trapping energy of a core electron at the Cu 2p3/2-level is −931.0 eV and the bulk crystal bonding intensity to the 2p3/2 electron is −1.70 eV, which is beyond the scope of conventional approaches. [Copyright &y& Elsevier]

Investigates the effect of protein kinase C isoforms on tumor necrosis factor-alpha-mediated cellular damage using a human intestinal cell line. Role in decreasing the extent of intestinal cellular viability; Factors that causes changes in cellular integrity; Impact on cellular apoptosis.

In the application of thin ferroelectric films to IR sensors, problems may arise to affect the sensitivities of the devices. The effects to influence the pyroelectric properties can be mainly categorized into two groups. One is the intrinsic effect due to the reduction in grain size. The other is the effect caused by residual stress. In this paper the stress effect on the pyroelectric properties of PbTiO 3 thin films will be studied by using the Landau-Ginsburg-Devonshire (LGD) phenomenological theory. It is found that a compressive stress increases the figure of merit while a tensile stress increases the pyroelectric coefficient for the films with the polarization vectors normal to the surface. [ABSTRACT FROM AUTHOR]

Adding the effect of surface bond contraction to the Hamiltonian of an extended solid leads to a new mechanism indicating that the blue-shift in the photoluminescence (PL) of CdS and CdSe nanosolids arises from the surface-relaxation-enhanced binding energy and the PL shift depends on the portion of surface atoms of the solid. Consistency between predictions and observations evidences that a surface bond contracts more than it does on a flat surface when the surface curvature increases and that the Cd–Se bond contracts faster than the Cd–S bond when the solid approaches to the lower end of size limit. [ABSTRACT FROM AUTHOR]

Deals with a study which determined the impact of ectopic expression of Betaig-h3 gene in asbestos-induced tumorigenic human bronchial epithelial cells on tumorigenecity. Method used to ascertain the tumor suppressive effect of Betaig-h3 gene; Tumorigenecity of asbestos-induced tumorigenic cells after Betaig-h3 gene transfection; Role of cytokines in asbestos-induced proliferation.

Microwave plasma enhanced chemical vapor deposition (MW-PECVD) is considered as one of the most successful growth techniques in recent diamond and crystalline carbon nitride investigations. In this study, we tried to synthesize crystalline carbon nitride film using MW-PECVD by gradually increasing the content of nitrogen into H2/CH4 gas mixture. Well-faceted crystalline diamond films could be synthesized with a H2/CH4 gas ratio of 198:2. With the gradual increase of nitrogen content up to 3% in the gas mixture diamond film quality deteriorates seriously, and the morphological crystal size and growth rate of diamond coatings decreased significantly. With the nitrogen gas content increased to approximately 6–22%, a lot of separated round diamond or diamond-like carbon particles formed on the surface rather than a continuous film. Only with the nitrogen content increased above 72%, could some tiny crystals with a type of hexagonal facet form on the silicon surface, together with many large, round diamond particles. With the further increase of nitrogen gas content above 90%, many large, well-faceted hexagonal crystals formed on Si surface. However, XRD, energy dispersive X-ray spectrometry, X-ray photoelectron spectroscopy and nano-indentation analysis indicated that these crystals were actually silicon carbonitride (Si–C–N) with a crystalline structure of Si3N4 modified with the introduction of carbon atoms, rather than carbonitride as expected and regarded. [Copyright &y& Elsevier]

It has been elegantly accepted that oxygen adsorption onto the Cu(110) surface induces an expansion of the first layer-spacing and a contraction of the second in addition to the alternative Cu[001] row that is either missing or forming the O-Cu-O row of high protrusions. However, it needs yet to clarify the vertical position of the oxygen and the hard-sphere models of added-, missing- and buckled-row. Here we justify that all the structures determined and all the models developed so far are correct in the sense of numerical solutions and phenomenological descriptions. A tetrahedral bond configuration of sp-orbital hybridization developed recently, however, may serve as a criterion to identify the physical solution that could account consistently for the observations using scanning tunneling microscopy/spectroscopy (STM/S), X-ray diffraction (XRD), and ultraviolet photoelectron spectroscopy (UPS). [ABSTRACT FROM AUTHOR]

Further to the previous part [Surf. Rev. Lett. S(3/4), 367 (2001)], this part deals with VLEED numerical quantification of the Cu[sub 3]O[sub 2] bond-forming kinetics on the Cu(001) surface. Besides the solution-number certainty that has been ensured, the modeling exercises have enabled the full capacity of VLEED to be explored, revealing that the bond geometry and the elastic potential define the shapes of the VLEED fine-structure features while the inelastic potential contributes to the absolute intensity. VLEED, covering the valence band in energy, is found to be able to collect nondestructive information from the top atomic layer, as the inelastic damping dominates in this region. Except for the bond geometry, dislocation of a single atom in the unit cell produces no feature that can match the VLEED spectral change, indicating the essentiality of the parametrization techniques developed. It is the right premise that it has enabled the four-stage O-Cu(001) reaction kinetics, revealed by VLEED, to be quantified as the evolution of the CuO[sub 2] to the Cu[sub 3]O[sub 2]. In addition, it is revealed that annealing provides disturbance rather than driving force strengthening the bond energy. Therefore, formulation in terms of bond making and its consequence on the behavior of atoms and valence electrons, and the corresponding parametrization, are demonstrated to be able to correctly reflect the real process of reaction and the correlation of the parameters as well as their natural link to the observations using LEED, STM and PES, or equivalent approaches. [ABSTRACT FROM AUTHOR]

Although asbestos is carcinogenic to humans, the mechanism(s) by which it induces cancer is unknown. Using tumor cell lines generated previously by asbestos treatment of immortalized human bronchial epithelial (BEP2D) cells, we examined alterations in p16 and p21Cip1 genes together with their protein levels. Results were compared with untreated BEP2D cells, normal human bronchial epithelial cells (NHBE), as well as non-tumorigenic fusion cell lines generated by fusing tumor cells with BEP2D cells. No deletion in the p16 gene was found in any of the tumor cell lines examined. Although p16 protein was expressed at a similar level in tumor and BEP2D cells, there was a fourfold decrease in its expression among NHBE cells. In contrast, both the protein and mRNA expression levels of p21Cip1 were decreased by about threefold in tumor cell lines when compared with either BEP2D or NHBE cells, which had a similar expression level. Expression of p21Cip1 mRNA was restored to the control level in all the fusion cell lines examined. The results suggested that down regulation of p21Cip1 expression is linked to the tumorigenic conversion of BEP2D cells by asbestos. Oncogene (2001) 20, 7301–7306. [ABSTRACT FROM AUTHOR]

This work consists of two sequential parts, which review the advances in uncovering the capacity of VLEED, STM and PES in revealing the nature and kinetics of oxidation bonding and its consequences for the behavior of atoms and valence electrons at a surface; and in quantifying the O-Cu(001) bonding kinetics. The first part describes the model in terms of bond making and its effect on the valence DOS and on the surface potential barrier (SPB) for surfaces with chemisorbed oxygen. One can replace the hydrogen in a H[sub 2]O molecule with an arbitrary less electronegative element and extend the M[sub 2]O to a solid surface with Goldschmidt contraction of the bond length, which formulates a specific oxidation surface with identification of atomic valences and their correspondence to the STM and PES signatures. As consequences of bond making, oxygen derives four additional DOS features in the valence band and above, i.e. O-M bonding (∼ -5 eV), oxygen nonbonding lone pairs (∼ -2 eV), holes (≤ E[sub F]), and antibonding metal dipoles (≥ E[sub F]), in addition to the hydrogen-bond-like formation. The evolution of O[sup -1] to O[sup -2] transforms the CuO[sub 2] pairing off-centered pyramid in the c(2 × 2)-2O[sup -1] into the Cu[sub 3]O[sub 2] pairing tetrahedron in the (2 √2 × √2)R45°-2O[sup -2] phase on the Cu(001) surface. The new decoding technique has enabled the model to be justified and hence the capacity of VLEED, PES and STM to be fully uncovered in determining simultaneously the bond geometry, the SPB, the valence DOS, and their interdependence. [ABSTRACT FROM AUTHOR]

Examines the role of protein kinase C (PKC) isozymes in tumor necrosis factor-alpha-induced cytotoxicity in rat intestinal epithelial cell (IEC) line. Susceptibility of cells to apoptosis in the presence of PKC; Translocation of PKC isoforms from cytosol to membrane fractions; Presence of nuclear fragments; Reduction of apoptosis by the inhibition of caspase-3.

Presents information on a study which investigated the role of protein kinase C isoforms in tumor necrosis factor-mediated cytotoxicity and apoptosis in intestinal cells. Materials and method; Results of the study; Discussion.

From the perspective of sp orbital hybrid bonding and its consequence on the behavior of valence electrons, new insight is presented into the nature of oxygen-derived features in the valence band and above of metals. It is suggested that the crystal geometry and the surface morphology may vary from surface to surface and from material to material but the oxygen-derived features in energy space are substantially the same in nature. The derived features can be consistently specified as oxygen-metal bonding (-5 to -8 eV), a nonbond lone pair of oxygen (-1 to -2 eV), holes of metal ions (∼ E[sub F]) and antibondng metal dipole states (> E[sub F]), other than the addition of the 2s or 2p states of the isolated oxygen additives. From the perspective of sp orbital hybrid bonding and its consequence on the behavior of valence electrons, new insight is presented into the nature of oxygen-derived features in the valence band and above of metals. It is suggested that the crystal geometry and the surface morphology may vary from surface to surface and from material to material but the oxygen-derived features in energy space are substantially the same in nature. The derived features can be consistently specified as oxygen-metal bonding (-5 to -8 eV), a nonbond lone pair of oxygen (-1 to -2 eV), holes of metal ions (∼ E[sub F]) and antibondng metal dipole states (> E[sub F]), other than the addition of the 2s or 2p states of the isolated oxygen additives. [ABSTRACT FROM AUTHOR]

This brief review focuses on the nature, kinetics, dynamics and consequences of the sp-orbital hybrid bonding of C, N and O to the Ni/Rh(001) surfaces which give rise to the same kind of "radial and then the p4g clock" reconstruction. It is identified that the "radial" and the subsequent "clock" reconstruction result from the adsorbate-substrate bond formation with sp-orbital hybridization, and that the driving force behind the reconstruction originates from the electrostatic interaction along the 〈11〉 direction. At the initial stage, A[sup -1] (A = C, N or O adsorbate) sinks into the fourfold hollow site and forms one bond with a B (B = Ni or Rh host atom) underneath, giving rise to an AB[sub 5] cluster with four dipoles at the surface. As A[sup -1] evolves into the hybridized-A[sup -n] (n = 4, 3, 2), the AB[sub 5] cluster evolves into an AB[sub 4] tetrahedron. Meanwhile, the AB[sub 4] tetrahedron redefines three of the four surface dipoles as B[sup +], B[sup 2+], B[sup +/dipole] or B[sup dipole], depending on the valence value of the adsorbate. The electrostatic force arises upon repopulating the valence electrons, which creates rhombus strings along the 〈11〉 direction. With the presence of nonbonding lone pairs, the clock rotation on Ni(001)-(2 × 2)p4g-2N[sup -3] and Rh(001)(2 × 2)p4g-20[sup -2] surfaces is initiated by the alternate attraction and repulsion in the 〈11〉 direction and the rotation is stabilized by bond tension; whereas the clock rotation on the Ni(001)-(2 × 2)p4g-2C[sup -4] surface is driven by the nonequivalent electrostatic repulsion in the 〈11〉 direction and the rotation is balanced by strong bond compression. The findings so far have led to technical innovation for the adhesion between diamond and metals by designing a gradient TiCN transition layer to neutralize the bond stress. [ABSTRACT FROM AUTHOR]

A new description of bonding and band-forming is presented for the nature and dynamics of O-Rh(111) and O-Ru(0001) surface bonding and its consequences on the behavior of atoms and electrons at the surfaces. The sp-orbital hybridization and electron transportation define that oxygen retains inside the hcp hollow site throughout the course of reaction in which O[sup -1] forms and then O[sup -2]-hybrid follows with production of nonbonding lone pairs and the lone-pair induced antibonding dipoles. Consequently, the valence band and surface morphology are modified with the corresponding features, and the radial and pairing-row reconstruction arises in the corresponding phases. [ABSTRACT FROM AUTHOR]

Abstract: A very important factor that influences the properties of a composite is related to the interfacial reaction. In present study, the hydroxyapatite (HA) materials reinforced by Ti–Fe particles were fabricated, and then the interfacial reactions between the HA and Ti–Fe were investigated. The results showed that the desirable Ti phase remained in the matrix after sintering since the introduction of Fe suppressed both the decomposition of HA and interaction between HA and Ti. Furthermore, it was found that a certain amount of small pores near/in interface was beneficial for obtaining an appropriate interfacial bonding between reinforcing Ti–Fe particles and HA matrix. [Copyright &y& Elsevier]

Atomic undercoordination entitles the inert gold even more noble at sites pertained to adatoms, defects, kinks, and skins of bulk and sized crystals with unclear mechanism. Systematic analysis of the electron emission spectra of XPS and STM/S of the undercoordinated gold atoms revealed that the 4 f and 5 d bands undergo quantum entrapment while the 6 s level is subject to localization and polarization because of the undercoordination-induced local bond contraction and bond strength gain – named bond order-length-strength correlation and nonbonding electron polarization (BOLS-NEP). Such a bonding and electronic relaxation result in the undercoordination derivacy of properties such as its extraordinary catalytic ability that the bulk gold does never demonstrate. The BOLS-NEP in the skin-electrical-double-layer shell dictates the nanostructure size dependency of the known bulk properties such as the chemical potential, inner potential constant, elasticity, and thermal stability. The exercise not only establishes a powerful means monitoring the Hamiltonian perturbation by atomic undercoordination but also offers information on the atomic-site-resolved local bond length, bond energy, chemical potentials, energy density, and atomic cohesive energy and the associated properties. Image 1 • Atomic undercoordination shortens the local bond and polarizes nonbonding electrons. • Polarization derives the intriguing properties of catalytic ability and chemical reactivity. • Bond relaxation in the skin EDL results in the size dependency of sized crystals. • Electron spectrometrics offers information of local bonding and electronic dynamics. [ABSTRACT FROM AUTHOR]

A new model is presented to describe the quantum confinement and surface passivation effects of nanoclusters. The quantum well depth (φ) and the band gap width (E[sub g]) of nanoclusters are independent concepts, because the $\phi$ depends on the surface electron density while the E[sub g] is a function of the crystal field of the solid. The φ and E[sub g] can be correlated with the joint physical and chemical effects, which are quite simple but have rarely been noticed. It is suggested that the bond contraction at the surface and the rise in the surface-to-volume ratio (γ), as well as the cluster interaction, enhance intrinsically the crystal field and hence the band gap E[sub g]. Reaction with electronegative elements, such as oxygen and nitrogen, widens extrinsically the E[sub g] by producing holes below the Fermi level [Appl. Phys. Lett.72, 1706 (1998)]. The formulation agrees well with experimental observations on the band gap enlargement by reducing particle size. [ABSTRACT FROM AUTHOR]

It is shown that the atomic states, bonding dynamics, driving force and bond strain for the C–Ni(100) surface reaction can be consistently understood by considering the sp orbital hybridization of carbon. It is proposed that, at the initial stage, C sinks into the hollow site and bonds to one Ni atom underneath. The C[sup -1] polarizes and pushes its surface neighbors radially away from the site center, and hence a Ni[sub 5]C cluster forms. Then, sp hybridization of the C happens, leading to a Ni[sub 4]C tetrahedron. Besides the Ni[sup +] underneath the C adsorbate, three of the four surface Ni neighbors donate electrons to the adsorbate. The half-monolayer coverage of C defines therefore half of the surface Ni atoms to be Ni[sup +] ions and the other half to be Ni[sup 2+] ions. As a result, one-dimensional nonuniform “- (+) - (2+) – (2+) - (+) – (+) -” chains form along the < 11> direction. It is suggested that the forces arising from charge redistribution drive the reconstruction. Calculation reveals that an increase of ∼ 90 dyne electrostatic repulsion along the < 11> direction and a responding ∼ 130 dyne bond compression stabilize the network of (2× 2)p4g clock rotation. [ABSTRACT FROM AUTHOR]

Counterflow centrifugal elutriation (CCE) is capable of separating cells on the basis of size. CCE has been used successfully to deplete allogeneic bone marrow (BM) grafts of T lymphocytes to decrease the risk of acute graft-versus-host disease. Previous studies have shown that more immature CD34+ cells in human BM tend to be smaller than more mature CD34+ cells. Human BM was subjected to CCE with the 4 ml standard chamber at constant rotor speed (2300 r.p.m.) and increasing flow-rate (14–23 ml/min, rotor-off). The eleven fractions collected were assayed for CD34+ and CD3+ cells, and for CFU-GM, HPP-CFC and long-term culture initiating cells (LTC-IC). The CD3+ T cells were enriched in the early (small-cell) fractions 14–17 ml/min. CD34+ cells were enriched in fractions 17–21 ml/min, and CFU-GM were concentrated in the same fractions. HPP-CFC and LTC-IC showed nearly identical CCE profiles, with enrichment in fractions 16–18 ml/min. When fraction 17 ml/min was chosen as cut-off, the small-cell fraction contained 94.0% of all CD3+ cells, 44.4% of total cells, 33.2% of CD34+ cells and 34.7% of CFU-GM; however, 67.6% of HPP-CFC and 72.4% of LTC-IC were recovered in this small-cell fraction. These data suggest that T cell depletion through CCE as used by us, while losing only minor proportions of CD34+ cells and CFU-GM, carries the risk of losing the majority of more immature progenitor cells. This may lead to an increased risk of graft failure, in particular in HLA-mismatched transplants. [ABSTRACT FROM AUTHOR]

The paper describes a hydrothermal synthesis of one new-style inorganic modified graphene nanomaterial called magnesium silicate hydroxide/graphene (MSH/graphene) in a MgO-SiO 2 -graphite-H 2 O system, and reveals its tribological behaviors as additives in poly-alpha-olefin (PAO). These MSH/graphene nanocomposites consist of MSH and various forms of graphene evolved from natural microcrystalline graphite. Four-ball experiments indicate that MSH/graphene nanocomposites as additives in PAO display outstanding tribological performances and nearly eliminate wear despite a severe contact pressure of 3.91 GPa. This can be attributed to the attachment of graphene to MSH, enabling it to successfully enter the asperity clearances so as to bring into full play to graphene's extreme mechanical strength and/or forming a tribofilm consisting of nanocrystalline graphite and amorphous carbon (a-C) on the sliding surfaces. MSH/graphene nanocomposites were hydrothermally synthetized using graphite as one of the raw materials. This type of nanocomposites consist of MSH and various forms of graphene. Image 1 • MSH/graphene nanocomposites were hydrothermally synthesized using graphite as a raw material. • MSH/graphene consists of MSH and various types of graphene. • The slid surfaces lubricated with MSH/graphene-containing oil have infinitesimal wear under a pressure of 3.91 GPa. • Tribological tests confirm graphene competitively penetrate into the contact area and form a tribofilm. [ABSTRACT FROM AUTHOR]

Deep engineering of liquid water by charge and impurity injection, charged support, current flow, hydrophobic confinement, or applying a directional field has becoming increasingly important to the mankind toward overcoming energy and environment crisis. One can mediate the processes or temperatures of molecular evaporation for clean water harvesting, H O bond dissociation for H 2 fuel generation, solidification for living-organism cryopreservation, structure stiffening for bioengineering, etc., with mechanisms being still puzzling. We show that the framework of "hydrogen bonding and electronic dynamics" has substantiated the progress in the fundamental issues and the aimed engineering. The segmental disparity of the coupled hydrogen bond (O:H O or HB with ":" being lone pair of oxygen) resolves their specific-heat curves and turns out a quasisolid phase (QS, bound at −15 and 4 °C). Electrification shows dual functionality that not only aligns, orders, polarizes water molecules but also stretches the O:H O bond. The O:H O segmental cooperative relaxation and polarization shift the QS boundary through Einstein's relation, ΔΘ Dx ∝ Δω x , resulting in a gel-like, viscoelastic, and stable supersolid phase with raised melting point T m and lowered temperatures for vaporization T V and ice nucleation T N. The supersolidity and electro structure ordering provide additional forces to reinforce Armstrong's water bridge. QS dispersion and the secondary effect of electrification such as compression define the T N for Dufour's electro-freezing. The T V depression, surface stress disruption, and electrostatic attraction raise Asakawa's molecular evaporability. Composition of opposite, compatible fields eases the H O dissociation and soil wetting. Progress evidences not only the essentiality of the coupled O:H O bond theory but also the feasibility of engineering water and solutions by programmed electrification. Unlabelled Image • Electrification shows dual functionality on anisotropic structure ordering and phase stability • Electrification raises the T m and lowers the T N and T V through O:H O bond relaxation • Surface stress disruption, T V depression, and electrostatic attraction ensure Asakawa's evaporation • Supersolid viscoelasticity, raised T m and depressed T N entitle Armstrong's floating bridge • Water skin electric-double-layer stabilize fogs and clouds from being separating or agglomerating [ABSTRACT FROM AUTHOR]

To determine the frequency of co-infections with Plasmodium species in southern Myanmar, we investigated the prevalence of P. knowlesi. More than 20% of patients with malaria had P. knowlesi infection, which occurred predominantly as a co-infection with either P. falciparum or P. vivax. [ABSTRACT FROM AUTHOR]

Energy density and structure stability are of key concerns in devising energy materials such as CNHO molecular crystals and the emerging cyclo-N 5 − complexes for desired explosive functionalities with a mechanism being open for exploration. An extension of the recent progress in solvation suggests that a combination of the intermolecular hydrogen bond (X:H–Y or HB with ':' being electron lone pair of X, Y = O or N) tension and the super-HB (X:⇔:Y) or anti-HB (H↔H) compression not only stabilizes the structure but also stores excessive energy by shortening the intramolecular bonds. The presence of the X:H constrains and the presence of the X:⇔:Y and/or H↔H fosters the explosion. Observations suggest that the absence of X:H–Y tension results in the spontaneous aquatic explosion of alkali metals and molten alkali halides. The lack of X:⇔:Y repulsion fosters no explosion of the molten NaCl in liquid NH 3 , nor the molten Na 2 CO 3 salt or H 3 BO 3 acid in water. The findings shall offer guidelines for devising efficient energy materials and reconciling the nature origin of water ice, aqueous solutions, and explosive energy materials – significance of electron lone pairs and protons. The combination of the hydrogen-bond (X:H–Y) tension and the super-HB (X:⇔:Y) or the anti-HB (H↔H) repulsion not only stabilizes the structure but also stores energy by shortening the intramolecular covalent bonds. The X:H tension constrains and the X:⇔:Y repulsion fosters explosion. Unlabelled Image • Segmental cooperativity of the X:H-Y oscillator pair dictates the behavior of aqueous solutions. • Excessive H+ or lone pairs ":" derive H↔H or X:⇔:Y repulsion in molecular crystals/liquids. • X:⇔:Y or/and H↔H repulsion and X:H-Y tension governs the stability and energy of crystals. • The absence/presence of the X:H-Y tension fosters the spontaneous/constrained explosion. [ABSTRACT FROM AUTHOR]

The wetting and interfacial reaction between the liquid Ag-Cu-Ti and SiO 2f /SiO 2 composites were studied at 860 °C for various holding durations. Typical interfacial microstructure of the AgCuTi-SiO 2f /SiO 2 system was firstly investigated. The formation sequence of the reaction layers was discussed. Then the relationship between contact angles and the types of reaction products were revealed. Results show that the formation of the Cu x Ti 6-x O (x = 2, 3) phase plays a key role on the wettability of the AgCuTi-SiO 2f /SiO 2 system. The microstructural evolution of the reaction products at the AgCuTi-SiO 2f /SiO 2 interface versus various holding durations was studied. Finally, the wetting mechanism of the AgCuTi-SiO 2f /SiO 2 system was proposed. This study can offer new insights into the reaction and joining nature of the AgCuTi-SiO 2f /SiO 2 system. • Ti 5 Si 3 + TiO 2 /Cu x Ti 6-x O (x = 2, 3) reaction layer formed for the AgCuTi-SiO 2f /SiO 2 wetting system. • Ti 5 Si 3 + TiO 2 proved to form first and Cu x Ti 6-x O(x = 2, 3) layer formed subsequently. • Cu x Ti 6-x O(x = 2, 3) layer became unstable with the extension of the holding duration. • Cu x Ti 6-x O(x = 2, 3) layer was the key that promoted the wetting of the SiO 2f /SiO 2 by AgCuTi. • 4 stages were divided for the wetting process of the AgCuTi-SiO 2f /SiO 2 system. [ABSTRACT FROM AUTHOR]

The Nb and Nb/Ni interlayers were designed for the diffusion bonding of the hydrogenated TC4 alloy and GH3128 superalloy joint. Typical microstructure of the TC4-0.3 H/Nb(Ni/Nb)/GH3128 joints were investigated. The effects of holding temperatures and durations on the microstructure evolution of the hydrogenated TC4/GH3128 joints were investigated. The addition of a Nb interlayer can successfully suppress the brittle Ti-Ni phase formation and the maximum joint strength reached 245 MPa bonded at 860 ℃/60 min under 10 MPa. The design of the Nb/Ni interlayer successfully eliminated the unbonded voids and the Ni-Cr layer formed when bonding with a single Nb interlayer. The maximum shear strength of ˜270 MPa was achieved when bonding at 860 ℃ for 80 min under 10 MPa. Fracture mechanism of the hydrogenated TC4/GH3128 joints bonded with two interlayers were analyzed finally. [ABSTRACT FROM AUTHOR]

Abstract: The tumorigenic effects of galactic cosmic rays (GCR) have become a major concern to the members of the international space station program. Normal human small airway epithelial cells were immortalized by ectopic expression of hTERT. The hTERT-expressing cells were exposed to 56Fe ions which simulate GCR irradiation. The irradiated cells underwent a stepwise transformation process. They showed phenotypic alterations and loss of some chromosomes compared with control hTERT-expressing cells. [Copyright &y& Elsevier]

A single band of photoluminescence (PL) has been detected at room temperature from the Pb(Zr[sub x]Ti[sub 1-x])O[sub 3] (x=0–1.0) surface. The intense and stable PL band covers 475±50 nm (or 2.67±0.25 eV) wavelengths and the corresponding photoexcitation (PE) band is in the range of 305±45 nm. It is found that changing the x value causes a negligible shift of the PL and PE peaks, and the light emission is subject to the Pb presence. The minimal lifetime of the excited photons was found to be 0.03 ms at x=0.5 and the maximum lifetime of 0.60 ms can be achieved by either decreasing or increasing the x values. © 2001 American Institute of Physics. [ABSTRACT FROM AUTHOR]

The dielectric behavior of nanostructured diamond films has been investigated by using an impedance analyzer up to 500 °C. Impedance data are presented in the form of the Cole-Cole plot. It is found that: (i) the resistivity contributed both from bulk grain interior and grain boundary decreases with increasing temperature; (ii) above 250 °C, the impurities at grain boundaries are thermally activated, and thus contribute to the dielectric relaxation; and (iii) the electrical conductivity of diamond films follows an Arrhenius law with an activation energy transition from 0.13 to 0.67 eV at 250 °C. Similar activation energy is found for the Arrhenius plot of relaxation frequencies from 0.14 to 0.73 eV. The dielectric transition is explained as the change of crystal field caused by the thermal expansion or by surface bond contraction of nanosized particles. © 2001 American Institute of Physics. [ABSTRACT FROM AUTHOR]

The effect of surface bond-order loss on the electronic thermal conductivity of metallic polycrystalline films is examined using Boltzmann transport theory. A modification of the grain boundary potential barrier has been made by adding depressed potential wells of intra-atomic trapping [C. Q. Sun, Phys. Rev. B 69, 045105 (2004)] to both sides of the grain boundaries. Electron scattering by film surfaces is also considered to follow the line of Fuchs’ convention. Results show that the thermal conductivity of the films is sensitive to the film thickness, mean grain size, and Fermi energy. In particular, thermal conductivity increases significantly with the depth of the atomic trapping due to the bond-order loss induced surface bond contraction and associated bond strength gain. [ABSTRACT FROM AUTHOR]

Deep level transient spectroscopy and optical absorption spectroscopy measurement revealed three outstanding features of density-of-states (DOS) appeared above the valence band edge (Ev) of Al oxide thin films. The broad peak located at 0.39 eV above Ev disappears while the other two located at 1.0 and 1.3 eV shift in position and attenuate in intensity upon annealing at 200 °C. The latter two peaks are removed by annealing at temperature up to 400 °C. The observed midgap DOS feature dynamics is in accordance with the oxygen lone pair features as confirmed earlier with Raman spectroscopy in the low-frequency ranges [C. Q. Sun et al., J. Appl. Phys. 90, 2615 (2001)] and thermal desorption measurements of other oxide surfaces. © 2004 American Institute of Physics. [ABSTRACT FROM AUTHOR]

Dielectric impedance measurements of porous silicon within the frequency range of 50 Hz-1.0 MHz and temperature range of 298-798 K revealed three semicircles in a Cole-Cole plot when the temperature is raised to 773 K; they are thought to correspond to contributions from the grain interior, grain boundary, and electrode/film interface, respectively. The enhancement in conductivity by heating follows an Arrhenius law with an activation energy transition from 0.07 to 0.79 eV at ∼565 K, which originates from band tail hopping that occurs around the Fermi edge. At a critical temperature, a high degree of dispersion in the real and imaginary parts of the permittivity also occurs at low frequencies. This dispersion behavior is interpreted as a combination of electron-lattice polarization associated to the band tail hopping and the crystal field weakening due to thermal expansion. [ABSTRACT FROM AUTHOR]

The formation of the Ontong Java Nui super oceanic plateau (OJN), which is based on the model that the submarine Ontong Java Plateau (OJP), Manihiki Plateau (MP), and Hikurangi Plateau (HP) were once its contiguous fragments, could have been the largest globally consequential volcanic event in Earth's history. This OJN hypothesis has been debated given the paucity of evidence, for example, the differences in crustal thickness, the compositional gap between MP and OJP basalts and the apparent older age of both plateaus relative to HP remain unresolved. Here we investigate the geochemical and 40Ar-39Ar ages of dredged rocks recovered from the OJP's eastern margin. Volcanic rocks having compositions that match the low-Ti MP basalts are reported for the first time on the OJP and new ~ 96–116 Ma and 67–68 Ma 40Ar-39Ar age data bridge the temporal gap between OJP and HP. These results provide new evidence for the Ontong Java Nui hypothesis and a framework for an integrated tectonomagmatic evolution of the OJP, MP, and HP. The isotopic data imply four mantle components in the source of OJN that are also expressed in present-day Pacific hotspots sources, indicating origin from (and longevity of) the Pacific Large Low Shear-wave Velocity Province. [ABSTRACT FROM AUTHOR]

The energy-saving operation of manufacturing systems is becoming increasingly significant due to the pressures of social sustainability and cost reduction. One method of saving energy in manufacturing systems is reducing the idle times of machines, which are non-value-added activities but consume non-negligible energy. Based on real-time data of manufacturing systems, this paper proposes a fuzzy control method to switch a machine into sleep/off mode when the idle state is about to arise and turn the machine on when production has to be resumed. A basic control module of a manufacturing system is described, considering stochastic failure of machines. The fuzzy rules for energy-saving operation are presented by analysing the buffer levels of machines based on production knowledge. Simulation studies are carried out to validate and illustrate the effectiveness of the method both for serial and parallel manufacturing systems. The proposed fuzzy control method is a simple and preferable way to achieve the energy-saving operation of unreliable manufacturing systems. [ABSTRACT FROM AUTHOR]

Abstract To address the thermal stress issue in the brazed SiO 2f /SiO 2 -Invar joints, a novel nano-TiO 2p (p: particle) modified braze filler was developed. Wetting of the SiO 2f /SiO 2 composite by AgCuTi-based composite braze filler with different TiO 2p contents were conducted first and a TiO 2p content lower than 5 wt% was fixed. Then the microstructure evolution and mechanical performance of the SiO 2f /SiO 2 -Invar joints brazed with different TiO 2p additions and different brazing parameters were discussed. The highest shear strength of 30 ± 8 MPa was obtained at 910 °C/10 min. After using the TiO 2p modified braze filler, the fracture probability of the SiO 2f /SiO 2 -Invar joints dropped down by 75% (Taking 22 MPa as an example). Finally, a FEM was employed to get an in-depth understanding of the stress relief effects when using a TiO 2p modified braze filler. Results show that the compressive stress on the SiO 2f /SiO 2 side dropped down by 30% after using a 2 wt% TiO 2p modified braze filler. The in-situ formed Cu x Ti 6-x O (x = 2, 3) phases played a key role in relieving the residual stress of the brazed joints. The development of the novel TiO 2p modified braze filler was particularly suitable for the joining of the oxide ceramics and oxides-based composites. [ABSTRACT FROM AUTHOR]

Sr isotope analysis of plutonic rocks is an important method for deriving the provenance and age of ancient magmatic episodes, and the petrogenetic processes operating during intrusive activity. We determined the 87 Sr/ 86 Sr isotopic compositions of fresh and variably altered feldspars from the 1.14 Ga gabbroic Great Abitibi Dyke, Ontario, Canada, through the use of Laser Ablation Inductively-Coupled Plasma Mass Spectrometry (LA-ICPMS). The data show an alteration trend between fresh, low-Rb plagioclase with 87 Sr/ 86 Sr ratios of 0.7045 and high-Rb alkali feldspar with 87 Sr/ 86 Sr ratios of 0.7059, which may be used to constrain the 87 Sr/ 86 Sr ratio of the mantle source. This trend is incompatible with simple mixing and instead has age significance. As post-intrusive alteration through hydrothermal circulation starts immediately following emplacement, LA-ICPMS analysis allows rapid estimation of initial 87 Sr/ 86 Sr ratios and intrusive age, suitable for sample screening and selection for more precise dating. For the Great Abitibi Dyke, the Rb-Sr age estimate of emplacement of 1.10 ± 0.23 Ga (2σ) is concordant with the precise U-Pb emplacement age of the dyke (1140.6 ± 2.0 Ma). The most altered high-Rb alkali feldspars return younger ages, suggesting that post-intrusive alteration lasted several hundred million years. This study highlights the need for microanalysis to differentiate between alteration and magmatic processes on basis of Sr isotopic signatures, and outlines a rapid method to determine initial 87 Sr/ 86 Sr ratios and to estimate Rb-Sr ages of plutonic rocks in terranes with long histories of multiple intrusive magmatic episodes. [ABSTRACT FROM AUTHOR]

In order to improve the ZrC-SiC and TC4 brazed joint property, functionally graded material (FGM) layers (two SiC particles reinforced TC4-based composite layers) were designed to relieve the residual stress in the ZrC-SiC and TC4 brazed joint. The FGM layers were fabricated on the TC4 surface using laser additive manufacturing technology before the brazing. Then the TC4 coated with the FGM layers and ZrC-SiC ceramic were brazed using Ti-15Cu-15Ni (wt%) filler. According to the SEM and TEM results, the volume fractions of SiC particles in the FGM layers could reach 20% and 39% respectively. Ti from the braze filler and TC4 reacted with the ZrC-SiC ceramic to form TiC and Ti 5 Si 3 adjacent to the ZrC-SiC ceramic. The shear test results indicate that the adoption of the FGM layers and the brazing temperature both affected the joint property significantly. The FGM layers could benefit the mitigation of coefficient of thermal expansion (CTE) mismatch between the ZrC-SiC and TC4, so that the residual stress caused by the CTE mismatch in the joint was relieved and the joint strength increased. The brazing temperature would affect the microstructure of the brazing seam and then control the joint strength. When the ZrC-SiC ceramic and TC4 coated with the FGM layers were brazed at 970 °C for 10 min, the maximum shear strength could reach 91 MPa, and cracks propagated in the ZrC-SiC ceramic substrate during the shear test. [ABSTRACT FROM AUTHOR]

To design a catalyst for the dissociation of H 2 with better CO-tolerance performance is very important for proton exchange membrane fuel cells (PEMFCs) towards high efficiency. With slab model, the catalytic properties of overlayer Pt on Cu substrate (Pt/Cu) are analyzed by first-principle calculations. The CO saturation coverage (40%) on Pt 2 /Cu is found to be lower than that of pure Pt (about 75%). The dissociation barrier from H 2 to H is less than 0.4 eV under the saturation coverage of CO. On the basis of kinetics of proton formation, the CO-tolerance ability on double-layer Pt with Cu is found to be greatly improved compared with that on pure Pt. It is expected that Pt overlayer on Cu(1 1 1) is a potential anode material with lower cost for PEMFCs. [ABSTRACT FROM AUTHOR]

An AgCu-4.5 wt.%Ti/W/AgCu-1 wt.%Ti composite interlayer was designed to braze the Invar-SiO 2f /SiO 2 joints. Ti contents in the interlayer between the tungsten foil and the Invar alloy was optimized. The effects of the tungsten-foil thickness on the microstructure, elemental distribution and mechanical properties of the brazed joints were investigated. Compared with a single AgCu-4.5 wt.%Ti interlayer, a sufficient metallurgical reaction happened on the SiO 2f /SiO 2 composite side and the formation of Fe 2 Ti, Ni 3 Ti compounds which are detrimental to the joint properties, was greatly inhibited by using a low-expansion composite interlayer (LECI). The tungsten interlayer can reduce the CTE (coefficient of thermal expansion) mismatch in the Invar-SiO 2f /SiO 2 joint. The highest shear strength of joints brazed with an LECI was 33 MPa, which was 1.75 times higher than the joints brazed with a single AgCu-4.5 wt.%Ti interlayer. [ABSTRACT FROM AUTHOR]

Detailed density functional theory (DFT) calculations of the adsorption energies (Ead) for oxygen on monolayer Pd on top of the Pd–Cu face-centered cubic (FCC) alloy and intermetallic B2 structure revealed a linear correspondence between the adsorption energies and the d-band center position. The calculated barrier (Ebarrier) for oxygen dissociation depends linearly on the reaction energy difference (ΔE). The O2 has a stronger adsorption strength and smaller barrier on the intermetallic Pd–Cu surface than on its FCC alloy surface. The room-temperature free energy (ΔG) analysis suggests the oxygen reduction reaction (ORR) pathways proceed by a direct dissociation mechanism instead of hydrogenation into OOH. These results might be of use in designing intermetallic Pd–Cu as ORR electrocatalysts. [ABSTRACT FROM AUTHOR]

An incorporation of the hydrogen bond (O:H O or HB) cooperativity notion, contact angle detection, and the differential phonon spectrometrics (DPS) has enabled us to gain refined information on the HCl, KCl and KOH solvation resolved solute-solvent molecular interactions and the solution surface stresses. Results show that ionic polarization stiffens the solvent H O bond phonon from 3200 to 3480 cm −1 in the hydration shells. The HO − in alkaline solution, however, shares not only the same H O phonon redshift of compressed water from 3200 to < 3100 cm −1 but also the dangling bonds of H 2 O surface featured at 3610 cm −1 . Salt and alkaline solvation enhances the solution surface stress by K + and Cl − ionic polarization. The excessive H + proton in acid solution forms a H↔H anti-HB that depresses the solution surface stress, instead. The solute capability of transforming the fraction of the O:H O bonds of the solvent matrix is featured by: f H = 0 and f x ∝ 1-exp(-C/C 0 ) (x = HO − , K + and Cl − ) towards saturation. Exercises not only confirm the presence of the H↔H anti-HB point fragilization, the O:⇔:O super-HB point compression, and ionic polarization dominating the performance of the respective HCl, KOH, and KCl solutions, but also demonstrate the power of the DPS that enables high resolution of solute-solute-solvent interactions and correlation between HB relaxation and solution surface stress. [ABSTRACT FROM AUTHOR]