[A study on the first-order interaction of diagnostic performance of coronary CT angiography-derived fractional flow reserve]

Objective: To investigate the effect of image quality, degree of stenosis, calcification, and their first-order interactions on diagnostic performance of coronary computed tomography (CT) angiography-derived fractional flow reserve (CT-FFR). Methods: This is a reanalysis of data from a multi-center retrospective cross-sectional study of CT-FFR in China. A total of 522 patients with suspected or known coronary heart disease [mean age: 61.6 (34.0-83.0) years, 71.8% (354/493) were male] from 11 medical centers including the General Hospital of Eastern Theater Command from May 2015 to October 2019 were enrolled. All patients underwent coronary CT angiography (CCTA), CT-FFR, and invasive FFR examination. Subjective image quality scores of target vessels were recorded on CCTA images, and stenosis was visually assessed at the lesion level. Calcification arc and calcification remodeling index (CRI) were recorded for each lesion. Sensitivity, specificity, accuracy, positive predictive value (PPV), and negative predictive value (NPV) were compared. Two-way analysis of variance was used to analyze the first-order interaction effects of image quality, degree of stenosis, and calcification. Results: A total of 493 patients with 629 lesions with invasive FFR as a reference were included in the study. The overall sensitivity, specificity, and accuracy of CT-FFR were 80.4%, 93.8%, and 88.6%, respectively. The specificity (95.0% vs. 87.3%, χ2=4.11, P=0.043); accuracy (90.1% vs. 81.9%, χ2=6.22, P=0.013); and NPV (89.7% vs. 80.9%, χ2=4.25, P=0.039) of the group with image quality ≥3 was higher than the group with image quality <3. The degree of stenosis affected the sensitivity, PPV, and NPV of CT-FFR and the calcification arc affected the specificity of CT-FFR (all P>0.05). The specificity (95.8% vs. 90.5%, χ2=4.23, P=0.040); accuracy (91.0% vs. 86.1%, χ2=4.01, P=0.045); and NPV (91.1% vs. 83.8%, χ2=5.10, P=0.024) of the group with CRI<1 were higher than that of the group with CRI≥1. In the subgroup of mild and severe stenosis, no calcification, and CRI<1, the accuracy of CT-FFR with image quality ≥3 points were higher than that with image quality <3 points. The accuracy of CT-FFR in the moderate stenosis group was mainly affected by CRI; the accuracy of CT-FFR in the group with CRI<1 was higher than that in the group with CRI≥1 (after Bonferroni correction, P values between groups were statistically significant). Conclusion: Subjective image quality, degree of stenosis, calcification of lesions, and their first-order interactions can all negatively affect the diagnostic performance of CT-FFR.

[Incidence and risk factors of thromboembolism in patients with lung cancer receiving immunotherapy]

Objective: To evaluate the incidence of thromboembolism in a cohort of patients with lung cancer who received immune checkpoint inhibitors (ICIs), and explore relevant clinical risk factors. Methods: We retrospectively collected and analyzed the clinical data of patients with confirmed primary lung cancer and treated with ICIs between March 2018 and June 2021 at three hospitals in China (Tongji Hospital of Tongji Medical College of Huazhong University of Science and Technology, Fudan University Shanghai Cancer Center and Zhongshan Hospital of Fudan University). The cumulative incidence and risk factors of thromboembolism in these patients were analyzed using a competitive risk model. Results: A total of 804 patients were enrolled, there were 623 males and 181 females, with a median age of 59 years (ranged 28-86 years). Of these, 62 patients encountered 65 thromboembolic events, including 51 venous thromboembolism events (VTE) and 14 arterial thromboembolism events. The cumulative incidence of thromboembolism events at 3, 6, 12 and 24 months were 4.3%, 6.1%, 10.1% and 16.8%, respectively. And the cumulative incidence of venous thromboembolism events at 3, 6, 12 and 24 months were 3.4%, 4.7%, 9.0% and 13.3%, respectively. Multivariate analysis showed that history of thromboembolism (HR=6.345, 95%CI: 2.917-13.802,P<0.001),liver metastasis (HR=2.249, 95%CI: 1.123-4.502,P=0.022) and peripherally inserted central venous catheter (HR=3.674, 95%CI: 1.751-7.712, P<0.001) were independent risk factors for venous thromboembolism during ICIs therapy in patients with lung cancer. Conclusions: Patients with lung cancer under ICIs therapy are at high risk of thromboembolism. And history of thromboembolism, liver metastasis and peripherally inserted central venous catheter are risk factors of venous thromboembolism.

Mixed Transcriptome Analysis Revealed the Possible Interaction Mechanisms between Zizania latifolia and Ustilago esculenta Inducing Jiaobai Stem-Gall Formation

The smut fungus Ustilago esculenta infects Zizania latifolia and induces stem expansion to form a unique vegetable named Jiaobai. Although previous studies have demonstrated that hormonal control is essential for triggering stem swelling, the role of hormones synthesized by Z. latifolia and U. esculenta and the underlying molecular mechanism are not yet clear. To study the mechanism that triggers swollen stem formation, we analyzed the gene expression pattern of both interacting organisms during the initial trigger of culm gall formation, at which time the infective hyphae also propagated extensively and penetrated host stem cells. Transcriptional analysis indicated that abundant genes involving fungal pathogenicity and plant resistance were reprogrammed to maintain the subtle balance between the parasite and host. In addition, the expression of genes involved in auxin biosynthesis of U. esculenta obviously decreased during stem swelling, while a large number of genes related to the synthesis, metabolism and signal transduction of hormones of the host plant were stimulated and showed specific expression patterns, particularly, the expression of ZlYUCCA9 (a flavin monooxygenase, the key enzyme in indole-3-acetic acid (IAA) biosynthesis pathway) increased significantly. Simultaneously, the content of IAA increased significantly, while the contents of cytokinin and gibberellin showed the opposite trend. We speculated that auxin produced by the host plant, rather than the fungus, triggers stem swelling. Furthermore, from the differently expressed genes, two candidate Cys2-His2 (C2H2) zinc finger proteins, GME3058_g and GME5963_g, were identified from U. esculenta, which may conduct fungus growth and infection at the initial stage of stem-gall formation.

High-transmission polarization-dependent active plasmonic color filters

Plasmonic color filters, exhibiting great promise as an alternative for existing colorant-based filters, often only output one fixed color. Developing active color filters with controllable color output will lead to more compact color filter-based devices. In this paper, we present an approach to achieve active color filtering with a polarization-dependent plasmonic structural color filter, which comprises arrays of asymmetric cross-shaped nanoapertures in an ultrathin film of silver. A systematical study for aperture size, array period, and the thickness of silver film dependences of color filter properties is carried out, and strategies for polarization-dependent color filter designing are generated. A polarization-dependent and high tunability of color can be achieved by selecting the appropriate nanostructure parameters, which imply many potential applications.

Structure and dynamical properties of liquid Ni64Zr36 and Ni65Hf35 alloys: an ab initio molecular dynamics study

Ab initio molecular dynamics simulations are performed to investigate the atomic structures and dynamics of Ni₆₄Zr₃₆ and Ni₆₅Hf₃₅ metallic liquids in a temperature range of 1400-2500 K. Calculated results are in good agreement with recently reported high temperature experimental data. Local atomic structures are analyzed and compared for Ni₆₄Zr₃₆ and Ni₆₅Hf₃₅ metallic liquids in terms of average bond length, coordination number, Honey-Andersen index, Bond-orientation order, spatial correlation and Voronoi tessellation methods. It is found that Zr-Zr bonds have larger average length of 3.32 Å than 3.22 Å for Hf-Hf bonds, causing sluggish diffusion in Ni₆₅Hf₃₅ liquids. Zr and Hf atom-centered clusters with higher coordination numbers are inclined to aggregate with high-coordinated clusters, while Ni atom-centered clusters with lower coordination numbers prefer to avoiding to be the nearest neighbor with each other. Temperature dependent diffusion coefficients reveal the decoupled diffusion in both liquids, which are related with different spatial correlations for Ni- and Zr- (or Hf-) centered clusters.

Structural Signature of β-Relaxation in La-Based Metallic Glasses

The secondary β-relaxation is an intrinsic feature in glassy materials. However, its structural origin is still not well understood. Here we report that the β-relaxations in La₅₀Al₁₅Ni₃₅ and La₅₀Al₁₅Cu₃₅ metallic glasses (MGs) mainly depend on the vibration of small Ni and Cu atoms in local cages. By using advanced synchrotron X-ray techniques and theoretical calculations, we elucidate that the tricapped-trigonal-prism-like polyhedra with more large La atoms in shells favor the local vibration of center Ni atoms, leading to the pronounced β-relaxation event. In contrast, the in-cage vibration of Cu atoms is somehow suppressed by the appearance of more shell Cu atoms. Nevertheless, they could easily diffuse out of the cages compared with Ni, thus triggering the onset of α-relaxation. This work provides a pathway to understand the different structural relaxation behaviors in MGs and other disordered materials from their local atomic packing and dynamics points of view.

Temperature dependent structural evolution in liquid Ag50Ga50 alloy

The temperature dependence of atomic structural evolution in liquid Ag₅₀Ga₅₀ alloy has been studied using an in situ high energy x-ray diffraction (XRD) experiment combined with first-principles molecular dynamics (FPMD) simulations. The experimental data show a reversible structural crossover at the temperature of about 1050 K. Changes in both electrical resistivity and absolute thermoelectric power at about 1100 K strongly support the XRD results. Additionally, FPMD simulations reveal the abnormal temperature dependent behavior of partial coordination number and atomic diffusivity at about 1200 K, elucidating that the partition experimentally observed changes in structure and properties could be linked with the repartition between Ag and Ga atoms in the liquid at around 1050-1200 K. This finding will trigger more studies on the structural evolution of noble-polyvalent metals in particular and metallic liquids in general.

Size effect on atomic structure in low-dimensional Cu-Zr amorphous systems

The size effect on atomic structure of a Cu₆₄Zr₃₆ amorphous system, including zero-dimensional small-size amorphous particles (SSAPs) and two-dimensional small-size amorphous films (SSAFs) together with bulk sample was investigated by molecular dynamics simulations. We revealed that sample size strongly affects local atomic structure in both Cu₆₄Zr₃₆ SSAPs and SSAFs, which are composed of core and shell (surface) components. Compared with core component, the shell component of SSAPs has lower average coordination number and average bond length, higher degree of ordering, and lower packing density due to the segregation of Cu atoms on the shell of Cu₆₄Zr₃₆ SSAPs. These atomic structure differences in SSAPs with various sizes result in different glass transition temperatures, in which the glass transition temperature for the shell component is found to be 577 K, which is much lower than 910 K for the core component. We further extended the size effect on the structure and glasses transition temperature to Cu₆₄Zr₃₆ SSAFs, and revealed that the T_g decreases when SSAFs becomes thinner due to the following factors: different dynamic motion (mean square displacement), different density of core and surface and Cu segregation on the surface of SSAFs. The obtained results here are different from the results for the size effect on atomic structure of nanometer-sized crystalline metallic alloys.

Comparative study of crystallization process in metallic melts using ab initio molecular dynamics simulations

The crystallization process of liquid metals is studied using ab initio molecular dynamics simulations. The evolution of short-range order during quenching in Pb and Zn liquids is compared with body-centered cubic (bcc) Nb and V, and hexagonal closed-packed (hcp) Mg. We found that the fraction and type of the short-range order depends on the system under consideration, in which the icosahedral symmetry seems to dominate in the body-centered cubic metals. Although the local atomic structures in stable liquids are similar, liquid hcp-like Zn, bcc-like Nb and V can be deeply supercooled far below its melting point before crystallization while the supercooled temperature range in liquid Pb is limited. Further investigations into the nucleation process reveal the process of polymorph selection. In the body-centered cubic systems, the polymorph selection occurs in the supercooled state before the nucleation is initiated, while in the closed-packed systems it starts at the time of onset of crystallization. Atoms with bcc-like lattices in all studied supercooled liquids are always detected before the polymorph selection. It is also found that the bond orientational ordering is strongly correlated with the crystallization process in supercooled Zn and Pb liquids.

Plasmonic reflection color filters with metallic random nanostructures

We develop reflective color filters with randomly distributed nanodisks and nanoholes fabricated with hydrogen silsesquioxane and Ag films on silicon substrate. They exhibit high resolution, angle-independence and easily up-scalable fabrication, which are the most important factors for color filters for industrial applications. We uncover the underlying mechanism after systematically analyzing the localized surface plasmon polariton coupling in the electric-field distribution. The agreement of the experimental results with those from the simulation indicates that tunable colors across the visible spectrum can be obtained by simply varying the diameter of the nanodisks, promoting their applications.

Composition- and temperature-dependent liquid structures in Al-Cu alloys: an ab initio molecular dynamics and x-ray diffraction study

The composition- and temperature-dependent liquid structures in eight Al_rich-Cu binary alloys (from hypoeutectic Al₉₃Cu₇ to hypereutectic Al₇₀Cu₃₀) have been experimentally and computationally studied by x-ray diffraction (XRD) experiments and ab initio molecular dynamics (AIMD) simulations. The remarkable agreements of structure factors for all liquid Al_rich-Cu alloys obtained from high-temperature high-energy XRD measurements and AIMD simulations have been achieved, which consolidates the analyses of structural evolutions in Al_rich-Cu liquids during the cooling processing by AIMD simulations. The heat capacity of liquid Al_rich-Cu alloys continuously increases and presents no abnormal peak when reducing the temperature, which differs from the reported prediction for 55-atom Al_rich-Cu nanoliquids. The diffusivities of Al and Cu undergo an increasing deviation from Arrhenius behavior by tuning Cu concentration from 7 to 30 atomic percentages, correlated to the local ordering in these liquids by means of coordination number, bond-angle distribution, Honeycutt-Andersen index, bond-orientational order and Voronoi tessellation analyses. Upon cooling, the microstructure of the liquid Al_rich-Cu alloys inclines to form Al₂Cu crystal-like local atomic ordering, especially in the hypereutectic liquids. The favorable short-range ordering between Cu and Al atoms could cause the non-Arrhenius diffusion behavior.

Abnormal correlation between phase transformation and cooling rate for pure metals

This work aims to achieve deep insight into the phenomenon of phase transformation upon rapid cooling in metal systems and reveal the physical meaning of scatter in the time taken to reach crystallization. The total number of pure metals considered in this work accounts for 14. Taking pure copper as an example, the correlation between phase selection of crystal or glass and cooling rate was investigated using molecular dynamic simulations. The obtained results demonstrate that there exists a cooling rate region of 6.3 × 10¹¹–16.6 × 10¹¹ K/s, in which crystalline fractions largely fluctuate along with cooling rates. Glass transformation in this cooling rate region is determined by atomic structure fluctuation, which is controlled by thermodynamic factors. According to the feature of bond-orientation order at different cooling rates, we propose two mechanisms of glass formation: (i) kinetic retardation of atom rearrangement or structural relaxation at a high cooling rate; and (ii) competition of icosahedral order against crystal order near the critical cooling rate.

Polarization-independent plasmonic subtractive color filtering in ultrathin Ag nanodisks with high transmission

We demonstrate a TE/TM polarization-independent plasmonic subtractive color filtering scheme employing ultrathin two-dimensional Ag nanodisks. These TE/TM polarization-independent subtractive color filters exhibit small feature sizes (below 200 nm) and high transmission up to 70% in the visible spectral region, superior to previously reported plasmonic color filters. Simulated optical transmission spectra and colors are in good agreement with experimental results. The color-filtering behaviors strongly depend on thickness and period of nanodisks. Underlying mechanisms are also discussed in detail.

Design of ultrafast laser-driven microactuator based on photoacoustic mechanism

In this work, an ultrafast laser-driven microactuator based on the photoacoustic mechanism was proposed with large amplitude and high response frequency. The microactuator was fabricated by LIGA technology. The displacement of the microactuator could be up to 11 μm at resonance state when the repeat frequency was around 14 kHz using a nanosecond pulse laser. Theoretical model was set up and the calculated results agree reasonably well with the experimental data. The microactuator based on the photoacoustic mechanism provides a more efficient actuation method.

Effect of relative nanohole position on colour purity of ultrathin plasmonic subtractive colour filters

Plasmonic subtractive color filters through patterning periodic nanostructures on ultrathin Ag films deposited on a glass substrate, exhibiting good durability, simple fabrication, and flexible color tunability, have attracted considerable attention due to their tremendous potential applications. While previous studies have mainly focused on their extraordinary physical mechanisms, color purity, which is another key parameter for high quality imaging applications, has been much less investigated. In this work, we demonstrate that the relative position of nanoholes patterned on ultrathin Ag films can largely affect the color purity of plasmonic subtractive color filters. The calculated results agree reasonably well with the experimental data, revealing that the purity of subtractive colors can be improved by changing the nanohole arrays from square lattice to triangular lattice without reducing transmission at visible frequencies. In addition, underlying mechanisms are clarified by systematically analyzing the dominant valley in transmission spectra.

Dynamic properties of a metal photo-thermal micro-actuator

This work presents the design, modeling, simulation, and characterization of a metal bent-beam photo-thermal micro-actuator. The mechanism of actuation is based on the thermal expansion of the micro-actuator which is irradiated by a laser, achieving noncontact control of the power supply. Models for micro-actuators were established and finite-element simulations were carried out to investigate the effects of various parameters on actuation properties. It is found that the thermal expansion coefficient, thermal conductivity, and the geometry size largely affected actuation behavior whereas heat capacity, density, and Young's modulus did not. Experiments demonstrated the dynamic properties of a Ni micro-actuator fabricated via LIGA technology with 1100/30/100 μm (long/wide/thick) arms. The tip displacement of the micro-actuator could achieve up to 42 μm driven by a laser beam (1064 nm wavelength, 1.2 W power, and a driving frequency of 1 HZ). It is found that the tip displacement decreases with increasing laser driving frequency. For 8 Hz driving frequency, 17 μm (peak-valley value) can be still reached, which is large enough for the application as micro-electro-mechanical systems. Metal photo-thermal micro actuators have advantages such as large displacement, simple structure, and large temperature tolerance, and therefore they will be promising in the fields of micro/nanotechnology.

Evolution of atomic structure in Al75Cu25 liquid from experimental and ab initio molecular dynamics simulation studies

X-ray diffraction and electrostatic levitation measurements, together with the ab initio molecular dynamics simulation of liquid Al(75)Cu(25) alloy have been performed from 800 to 1600 K. Experimental and ab initio molecular dynamics simulation results match well with each other. No abnormal changes were experimentally detected in the specific heat capacity over total hemispheric emissivity and density curves in the studied temperature range for a bulk liquid Al(75)Cu(25) alloy measured by the electrostatic levitation technique. The structure factors gained by the ab initio molecular dynamics simulation precisely coincide with the experimental data. The atomic structure analyzed by the Honeycutt-Andersen index and Voronoi tessellation methods shows that icosahedral-like atomic clusters prevail in the liquid Al(75)Cu(25) alloy and the atomic clusters evolve continuously. All results obtained here suggest that no liquid-liquid transition appears in the bulk liquid Al(75)Cu(25) alloy in the studied temperature range.

Effects of JNJ-40929837, a leukotriene A4 hydrolase inhibitor, in a bronchial allergen challenge model of asthma

Leukotriene B4 (LTB4) is a chemotactic mediator implicated in the pathogenesis of asthma. JNJ-40929837 is an oral inhibitor of LTA4 hydrolase, which catalyzes LTB4 production. We evaluated the effects of JNJ-40929837 in a human bronchial allergen challenge (BAC) model. In this double-blind, 3-period crossover study, 22 patients with mild, atopic asthma were randomized to one of three treatments per period: 100 mg/day JNJ-40929837 for 6 days followed by 50 mg/day on day 7; 10 mg/day montelukast for 6 days; and matched placebo. The BAC was performed on day 6 of each treatment period. Primary outcome was BAC-induced late asthmatic response (LAR) measured by maximal percent reduction in forced expiratory volume (FEV1) in one second. Secondary outcomes included early asthmatic response (EAR) by maximal percent reduction in FEV1, EAR and LAR evaluated by area under the FEV1/time curve (AUC0-2, AUC3-10, respectively), change in baseline FEV1 after 5-day treatment, safety, and correlation of JNJ-40929837 to the divalent cation ionophore A23187-stimulated whole blood LTB4 levels and sputum basal LTB4 levels. No significant differences were observed in the primary or secondary FEV1 endpoints with JNJ-40929837 versus placebo. Compared with placebo (n = 17, LS mean = 27.7), there was no significant attenuation of the maximal percent reduction in the LAR FEV1 with JNJ-40929837 (n = 16, LS mean = 28.6, P = 0.63) but montelukast (n = 17, LS mean = 22.6, P = 0.01) significantly attenuated the LAR. JNJ-40929837 substantially inhibited LTB4 production in whole blood, decreased sputum LTB4 levels and was well-tolerated. The number of adverse events leading to study withdrawal was the same in JNJ-40929837 and placebo groups. In conclusion, JNJ-40929837 demonstrated target engagement in blood and sputum. No significant impact in response to allergen inhalation was observed with JNJ-40929837 versus placebo.

REGISTRATION

This study is registered at ClinicalTrials.gov: NCT01241422.

The crystallization process of liquid vanadium studied by ab initio molecular dynamics

We present a study of the crystallization process in liquid vanadium over a temperature range from 3000 K down to 1500 K using ab initio molecular dynamics simulations. Short-range order evolution during solidification is studied using various structural analysis methods. We show that the icosahedral-like short-range order is detected in the stable liquid phase and grows upon supercooling. The system undergoes a first-order phase transition (from a liquid to a solid state) at a temperature of about 1600 K. The crystal nucleation process is further studied using the time-temperature transformation mechanism by annealing the system at 1650 K. The nucleation is examined using bond-orientational order and density fluctuation analysis. Our finding is that various precursors appear in the region of high bond-orientational order with the majority having body-centered cubic (bcc)-like symmetry. This bcc-like region grows on annealing via thermal fluctuations. Our results reveal that the bond-orientational order precedes the density fluctuation, and is the main driving factor for nucleation.

Atomic structure evolution during solidification of liquid niobium from ab initio molecular dynamics simulations

Atomic structure transitions of liquid niobium during solidification, at different temperatures from 3200 to 1500 K, were studied by using ab initio molecular dynamics simulations. The local atomic structure variations with temperature are investigated by using the pair-correlation function, the structure factor, the bond-angle distribution function, the Honeycutt-Anderson index, Voronoi tessellation and the cluster alignment methods. Our results clearly show that, upon quenching, the icosahedral short-range order dominates in the stable liquid and supercooled liquid states before the system transforms to crystalline body-center cubic phase at a temperature of about 1830 K.

Facile and rapid synthesis of RGO-In2S3 composites with enhanced cyclability and high capacity for lithium storage

A sheet-on-sheet reduced graphene oxide-β-In(2)S(3) (RGO-In(2)S(3)) composite, was successfully synthesized via a one-step mild method. This fresh composite used as an anode material exhibits enhanced cyclability and specific capacity for lithium storage. These results are linked with the intrinsic layered structure of β-In(2)S(3) sheets and the effective combination of β-In(2)S(3) and RGO sheets. This results in a high specific surface area and good conductivity of RGO-In(2)S(3) composites, with higher transport rates of electrolyte ions and electrons, and a more effective electrochemical reaction of the active material. This facile and rapid synthesis method is a promising route for a large-scale production of graphene-based metal sulfides, which could be used as electrode materials for Li-ion batteries.

Atomic-scale mechanisms of the glass-forming ability in metallic glasses

The issue, composition dependence of glass-forming ability (GFA) in metallic glasses (MG), has been investigated by systematic experimental measurements coupled with theoretical calculations in Cu-Zr and Ni-Nb alloy systems. It is found that the atomic-level packing efficiency strongly relates to their GFA. The best GFA is located at the largest difference in the packing efficiency of the solute-centered clusters between the glassy and crystal alloys in both MG systems. This work provides an understanding of GFA from atomic level and will shed light on the development of new MGs with larger critical sizes.

Magnetic stability of SnO₂ nanosheets

Room temperature ferromagnetism has been observed in freshly synthesized and post-annealed SnO₂ nanosheets. The results of x-ray diffraction and x-ray photoelectron spectroscopy reveal that the newly synthesized samples and those annealed at 400 °C under either an O₂ or Ar atmosphere possess rutile structure and no other impurity phases are observed. The fitting results of the O 1s and Sn 3d spectra from SnO₂ samples annealed at 400 °C under an O₂ or Ar atmosphere both indicate that oxygen vacancies inevitably exist in these samples. It is found that the saturation magnetization of all the annealed samples does not feature mono-dependence on oxygen vacancies, whereas an Sn vacancy related origin seems more plausible to account for variations in the magnetization of samples studied. This finding corresponds to first-principle calculation results from our previous work. Furthermore, the Curie temperature of SnO₂ nanosheets was estimated to be around 300 °C, rendering it a very good option for the next generation of spintronics.

Color tuning by local sputtering metal nanolayer on microstructured porous alumina

This article reports a novel color tuning method by local sputtering nanolayers on microstructured porous alumina (PA) templates with different pore depths. With the aid of scanning electron microscopy observation, physical models of the original and sputtered PA templates are set up, and the details of the color tuning method are further proposed. Two series of colors covering the whole visible range are first obtained by respectively sputtering Cr and Ag nanolayers on two groups of PA templates with pore-depths ranging from 230 to 490 nm. A vivid colorful pattern of "Butterfly wings" is then prepared by local sputtering such Cr and Ag nanolayers on the surface of a PA with 310 nm pore-depth. The scanning electron microscopy images of Cr and Ag sputtered PA surfaces show different microstructures, which is in agreement with different color exhibiting. This method is expected to have a potential of being widely applied in the fields of micro-optics, microstructures, advanced materials, and micro/nanotechnology.

Tuning color by pore depth of metal-coated porous alumina

A simple and effective color tuning method has been developed by controlling the pore depth of the metal-coated porous alumina (PA) template. The mechanism for color tuning in this method was uncovered, which can be used to design a colorful complex pattern. A colorful 'world map' was produced and exhibited on a PA template by this method. Such vivid color tuning is predominantly due to the interference enhancement of the nanostructure. This method has the potential for tuning colors and being widely applied in the fields of nanotechnology, physics and photonics.

Synthesis of erbium oxide nanosheets and up-conversion properties

A novel erbium-based compound as well as Er(2)O(3) nanosheets have been synthesized through a simple hydrothermal route. The nanosheets are of 200 nm width and 10-15 nm thickness. It is suggested that this erbium-based compound has a possible formula of Er(2)O(5)H(4) with a primitive tetragonal structure (cell parameters: a = 8.465(1) and c = 15.117(2) Å). Face-centered cubic and body-centered cubic structured Er(2)O(3) nanosheets were obtained after calcination of this compound at 623 and 973 K, respectively, both having a paramagnetic behavior. Er(2)O(5)H(4) and Er(2)O(3) nanosheets have similar up-conversion properties with strong blue emission, which is rarely reported in the literature. The existence of absorbed surface contaminations in nanosheets might be the origin for the blue emission enhancement.

Stability and Properties of Two-Dimensional Graphene Hydroxide

Systematic study of interaction between graphene and hydroxyls is carried out by first-principles calculations. Although single hydroxyl adsorbed on graphene presents magnetic properties, hydroxyls prefer to adsorb on graphene in pairs without magnetic properties. The formation energy of hydroxyl pairs with graphene is coverage-dependent, and the most stable structure is half-covered by hydroxyl pairs along zigzag chains with alternative sp2 and sp3 hybridization between carbon atoms. The bandgap of this structure is 0.97 eV in GW approximation, close to the bandgap of Si, and this structure is stable at room temperature. It is possible to build graphene-based electronic circuits from graphene hydroxide without the need for cutting or etching.

Synthesis and characterization of gold cubic nanoshells using water-soluble GeO₂templates

Size-tunable GeO₂ nanocubes were initially prepared by a modified sono-assisted reverse micelle method and then functionalized with an amino-terminated silanizing agent. Subsequently, gold decorated GeO₂ nanocomposites were prepared at pH ≈ 7 and 80 °C. It was found that well-dispersed gold nanoparticles on GeO₂ nanocubes could be obtained only if gold salt is abundant to favor simultaneous, homogeneous nucleation of gold particles. Additional gold ions were reduced onto these attached 'seed' particles accompanied by synchronous dissolution of water-soluble GeO₂ cores, resulting in gold hollow cubic shells. The GeO₂ nanocubes and Au/GeO₂ nanocomposites as well as gold hollow cubic shells were characterized by transmission electron microscopy, scanning electron microscopy, x-ray diffraction and UV-visible spectroscopy. In particular, gold hollow cubic shells feature a plasmon resonance peak at above 900 nm, which renders it quite promising in biochemical applications.

Heterogeneities in CuZr-based bulk metallic glasses studied by x-ray scattering

Inhomogeneities in two CuZr-based bulk metallic glasses (BMGs) were studied by using synchrotron radiation x-ray scattering techniques. (Cu(4.5/5.5)Ag(1/5.5))(46)Zr(46)Al(8) BMG was found to be more inhomogeneous than Cu(46)Zr(46)Al(8) BMG on the small length scale, where Cu and Ag atoms form enriched zones. Such heterogeneities are locally favorable for forming close-packed icosahedron-like clusters in three-dimensional space, greatly promoting the glass forming ability of this alloy. Upon annealing near the T(g) temperature, the heterogeneities were reduced initially at low temperature and short time annealing, then regenerated again for temperature increase and time extension. The average environment around Zr atoms almost does not change. However, the heterogeneity increases for Cu, Zr and Ag atoms once nanocrystallization happens.

Light non-metallic atom (B, N, O and F)-doped graphene: a first-principles study

First-principles calculations are performed to study the geometry, electronic structure and magnetic properties of light non-metallic atom-doped graphene (B, N, O and F). The planar structure and the quasi-linear energy dispersion near the Dirac point remain through doping with B and N atoms, by which p-type doping and n-type doping graphene are respectively induced. A bandgap of about 0.5 eV is generated through O doping, and geometrically the O atom is also in the graphene plane. No magnetic moment is detected in B- , N- and O-doped graphene. For F doping, the F atom bonds with one of the carbon atoms close to the vacancy, with the other two carbon atoms undergoing a Jahn-Teller distortion. A weak polarized magnetic moment of 0.71 µ(B) is detected through F doping.

Monodispersed NiO nanoflowers with anomalous magnetic behavior

Nickel oxide (NiO) nanoflowers, prepared by thermal decomposition, exhibit anomalous magnetic properties far below the blocking temperature, i.e., a cusp in both the zero-field-cooled and field-cooled curves at about 21 K. Detailed characterization discloses that the individual NiO nanoflower consists of porous crystals with holes (1.0-1.5 nm in size) inside. We believe that the low temperature magnetic feature observed here could be a new kind of spin transition for the uncompensated spins around the holes and will trigger more studies in other nanostructured antiferromagnetic materials.

Low-density to high-density transition in Ce75Al23Si2 metallic glass

Using in situ high-pressure x-ray diffraction (XRD), we observed a pressure-induced polyamorphic transition from the low-density amorphous (LDA) state to the high-density amorphous (HDA) state in Ce(75)Al(23)Si(2) metallic glass at about 2 GPa and 300 K. The thermal stabilities of both LDA and HDA metallic glasses were further investigated using in situ high-temperature and high-pressure XRD, which revealed different pressure dependences of the onset crystallization temperature (T(x)) between them with a turning point at about 2 GPa. Compared with Ce(75)Al(25) metallic glass, minor Si doping shifts the onset polyamorphic transition pressure from 1.5 to 2 GPa and obviously stabilizes both LDA and HDA metallic glasses with higher T(x) and changes their slopes dT(x)/dP. The results obtained in this work reveal another polyamorphous metallic glass system by minor alloying (e.g. Si), which could modify the transition pressure and also properties of LDA and HDA metallic glasses. The minor alloying effect reported here is valuable for the development of more polyamorphous metallic glasses, even multicomponent bulk metallic glasses with modified properties, which will trigger more investigations in this field and improve our understanding of polyamorphism and metallic glasses.

PbTiO3 nanofibers with edge-shared TiO6 octahedra

A new tetragonal phase of PbTiO(3) was discovered, in which each TiO(6) octahedron pair shares an edge and stacks over following pairs in an interlaced manner to form a one-dimensional (1D) columned structure along the c-axis. This new tetragonal phase of PbTiO(3) transforms into a normal perovskite phase in air at elevated temperature.

Origin of pressure-induced polyamorphism in Ce75Al25 metallic glass

Using high-pressure synchrotron x-ray absorption spectroscopy, we observed the Ce 4f electron in Ce(75)Al(25) metallic glass transform from its ambient localized state to an itinerant state above 5 GPa. A parallel x-ray diffraction study revealed a volume collapse of about 8.6%, coinciding with 4f delocalization. The transition started from a low-density state below 1.5 GPa, went through continuous densification ending with a high-density state above 5 GPa. This new type of electronic polyamorphism in densely packed metallic glass is dictated by the Ce constituent, and is fundamentally distinct from the well-established structural polyamorphism in which densification is caused by coordination change and atomic rearrangement.

Stability, elastic and electronic properties of palladium nitride

The crystal structure, stability, elastic constants and electronic properties of PdN(2) for four polymorph structures: pyrite, marcasite, CoSb(2) and ST(AA), have been investigated using first-principles calculations. At zero pressure all four polymorphs are metallic and thermodynamically unstable but mechanically stable. Pyrite PdN(2) is found to be the lowest energy phase. It is metallic at ambient pressure but becomes a semiconductor at pressures higher than 18 GPa. The calculated phonon band structures of pyrite PdN(2) show the structure is dynamically stable up to 60 GPa. Good agreement between calculated and observed Raman frequencies was found, indicating that the recently synthesized palladium nitride at high pressure is likely to have a pyrite structure.

Surface magnetism in amine-capped ZnO nanoparticles

Magnetic behaviors of pure ZnO nanoparticles have been investigated both experimentally and theoretically. It is found that monodisperse ZnO nanoparticles wrapped with oleylamine with an average particle size of about 9.6 nm prepared by thermal decomposition do show ferromagnetic behavior with a saturation magnetization of about 34 memu g(-1) and coercive force of about 22 Oe, whereas ZnO nanoparticles with an average particle size of 5.2 nm prepared by ultrasonic irradiation without solvents show a weak ferromagnetic property with a saturation magnetization of about 0.12 memu g(-1) and coercive force of about 150 Oe at ambient temperature. First-principles calculations reveal that the 2p holes on the atoms at the surface (dangling bond of O atoms at ZnO(0001) or 2p electrons of N atom in NH(3) adsorbed on Zn(0001)) could be the source for the magnetic behavior of oxide nanoparticles.

New class of plastic bulk metallic glass

An intrinsic plastic Cu(45)Zr(46)Al(7)Ti(2) bulk metallic glass (BMG) with high strength and superior compressive plastic strain of up to 32.5% was successfully fabricated by copper mold casting. The superior compressive plastic strain was attributed to a large amount of randomly distributed free volume induced by Ti minor alloying, which results in extensive shear band formation, branching, interaction and self-healing of minor cracks. The mechanism of plasticity presented here suggests that the creation of a large amount of free volume in BMGs by minor alloying or other methods might be a promising new way to enhance the plasticity of BMGs.

Second amorphous-to-crystalline phase transformation in Cu(60)Ti(20)Zr(20) bulk metallic glass

The second amorphous-to-crystalline phase transformation in Cu(60)Ti(20)Zr(20) bulk metallic glass was investigated by differential scanning calorimetry and x-ray diffractometry. The difference of the Gibbs free energies between the amorphous phase and the crystalline products during the transformation is estimated to be about 2.46 kJ mol(-1) at 753 K, much smaller than the 61 kJ mol(-1) obtained assuming that it is a polymorphic transformation. It was revealed that the phase transformation occurs through a eutectic crystallization of Cu(51)Zr(14) and Cu(2)TiZr, having an effective activation energy of the order of 400 kJ mol(-1). The average Avrami exponent n is about 2.0, indicating that the crystallization is diffusion controlled.

Complementary DNA microarray analysis of chemokines and their receptors in allergic rhinitis

OBJECTIVE

To analyze the roles of chemokines and their receptors in the pathogenesis of allergic rhinitis by observing the complementary DNA (cDNA) expression of the chemokines and their receptors in the nasal mucosa of patients with and without allergic rhinitis, using gene chips.

METHODS

The total RNAs were isolated from the nasal mucosa of 20 allergic rhinitis patients and purified to messenger RNAs, and then reversely transcribed to cDNAs and incorporated with samples of fluorescence-labeled with Cy5-dUPT (rhinitis patient samples) or Cy3-dUTP (control samples of nonallergic nasal mucosa). Thirty-nine cDNAs of chemokines and their receptors were latticed into expression profile chips, which were hybridized with probes and then scanned with the computer to study gene expression according to the different fluorescence intensities.

RESULTS

The cDNAs of the following chemokines were upregulated: CCL1, CCL2, CCL5, CCL7, CCL8, CCL11, CCL13, CCL14, CCL17, CCL18, CCL19, CCL24, and CX3CL1 in most of the allergic rhinitis sample chips. CCR2, CCR3, CCR4, CCR5, CCR8 and CX3CR1 were the highly expressed receptor genes. Low expression of CXCL4 was found in these tissues.

CONCLUSION

The T helper cell (T(H)) immune system is not well regulated in allergic rhinitis. Most of the upregulated genes we identified are of chemokines and their receptors that play important roles in T(H)2 response, and some are involved in the induction of allergic reaction, accumulation of inflammatory cells, and degranulation of sensitized cells. These findings can point to new strategies for allergic rhinitis immunotherapy.

Wurtzite-to-Rocksalt Structural Transformation in Nanocrystalline CoO

Hexagonal CoO nanocrystals are coarsened under hydrothermal conditions to investigate the effect of particle size on phase transformation and stability property. Structural stability and phase transformation of the hexagonal CoO phase have been investigated by X-ray powder diffraction with Rietveld refinement, transmission electron microscopy, X-ray absorption fine structure, and differential scanning calorimeter. It is found that the hexagonal CoO phase is a metastable phase, which increases its grain size from 50 to 250 nm for refluxing times from 1 to 6 h at 200 degrees C. After 12 h, cubic-structured CoO grains with an average grain size of 20 nm are observed, which spread around big hexagonal CoO grains. After about 24 h, only the cubic CoO phase with an average grain size of 25 nm is detected. The onset temperature of hexagonal-to-cubic phase transformation in CoO is estimated to be 378 degrees C by DSC, using a heating rate of 20 deg/min. The results obtained indicate that the hexagonal-to-cubic phase transformation in nanocrystalline CoO is by nucleation and growth mechanism, starting from the surface to the center of the hexagonal grains.

Atomic structure of Al(89)La(6)Ni(5) metallic glass

Atomic structures of amorphous Al(89)La(6)Ni(5), prepared by single-roller melt spinning, and pre-annealed at 493 and 588 K for 1 h, were characterized by differential scanning calorimetry, x-ray diffraction with a large wavevector transfer value, La L(3)-edge and Ni K-edge x-ray absorption fine structure and the reverse Monte Carlo technique. In the as-prepared amorphous alloy, our study reveals that the Ni-Al distance is 2.38 ± 0.02 Å coupled with a coordination number as low as 6.2. The Al-Al distance was found to be ∼4.5% shorter than the nominal atomic diameter of aluminium and the coordination number to be ∼39% less than expected from the dense random packing model. Crystallization of the Al(89)La(6)Ni(5) glassy alloy at high temperatures can be described as follows: [amorphous alloy] [Formula: see text] [fcc-Al] + [bcc-(AlLa)] + residual amorphous [Formula: see text] [fcc-Al] + [o-Al(3)Ni ] + [o-La(3)Al(11) ].

Amorphouslike diffraction pattern in solid metallic titanium

Amorphouslike diffraction patterns of solid elemental titanium have been detected under high pressure and high temperature using in situ energy-dispersive x-ray diffraction and a multianvil press. The onset pressure and the temperature of formation of amorphous titanium is found to be close to the alpha-beta-omega triple point in the P-T phase diagram. Amorphous Ti has been found to be thermally stable up to 1250 degrees C for at least 3 min at some pressures. By analyzing the conditions for producing amorphous elemental Zr and Ti, we observed a multi-phase-point amorphization phenomenon for preparing single-element bulk amorphous metals. The results reported may open a new way to preparing single-element bulk amorphous metals with a high thermal stability.

Preparation of ZnO nanocrystals via ultrasonic irradiation

A simple and rapid process has been developed for the preparation of nanometer-sized ZnO crystals via ultrasonic irradiation, by which pure ZnO nanocrystals with an average size of 6 nm and narrow size distribution can be synthesized in a short time and without using any solvents for the precipitation of ZnO.