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This is a copy of the slides presented at the meeting but not formally written up for the volume.
We present a high-resolution transmission electron microscopy study, on the unit-cell scale, of the degree of tetragonality and the displacements of cations away from the centrosymmetry positions in an ultra-thin epitaxial PbZr0.2Ti0.8O3 film on a SrRuO3 electrode layer deposited on a SrTiO3 substrate. TEM results show that the lattice is highly tetragonal at the centre of the film with a c/a ratio of about 1.08, while it shows a reduced degree of tetragonality in the regions close to the interfaces. Most strikingly, we find that the maximum off-centre displacements for the central area of the film do not scale with the tetragonality in comparison with the bulk materials. The calculated switched polarization from the measured cationic displacement is 80 ìC/cm2 , and thus only half of the nominal bulk value. It is in very good agreement with electrical measurements of the switched polarization obtained via the PUND method. Furthermore, a systematic reduction of the atomic displacements is measured at the interfaces. This suggests that interface-induced suppression of the ferroelectric polarization plays a critical role in the size effect of nanoscale ferroelectrics. These issues will be discussed further in this presentation. This work was partially supported by the National Science Foundation (NSF) under Grants DMR-0132918, NSF-MRSEC DMR-0080008, and an NSF US-Europe program DMR-0244288. V.N also acknowledges the support of the Alexander von Humboldt Foundation for his stay in Germany and the financial support of an Australian Research Council Discovery Grant 0666231.
Cellulitis is a common infection of the skin and soft tissue. Susceptibility to cellulitis is related to microorganism virulence, the host immunity status and environmental factors. This retrospective study from 2001 to 2013 investigated relationships between the monthly incidence rate of cellulitis and meteorological factors using data from the Taiwanese Health Insurance Dataset and the Taiwanese Central Weather Bureau. Meteorological data included temperature, hours of sunshine, relative humidity, total rainfall and total number of rainy days. In otal, 195 841 patients were diagnosed with cellulitis and the incidence rate was strongly correlated with temperature (γS = 0.84, P < 0.001), total sunshine hours (γS = 0.65, P < 0.001) and total rainfall (γS = 0.53, P < 0.001). The incidence rate of cellulitis increased by 3.47/100 000 cases for every 1° elevation in environmental temperature. Our results may assist clinicians in educating the public of the increased risk of cellulitis during warm seasons and possible predisposing environmental factors for infection.
Vertically aligned nitrogen-doped nanocrystalline diamond nanorods are fabricated from nitrogen-doped nanocrystalline diamond films using reactive ion etching in oxygen plasma. These nanorods show enhanced thermionic electron emission (TEE) characteristics, viz., a high current density of 12.0 mA/cm2 and a work function value of 4.5 eV with an applied voltage of 3 V at 923 K. The enhanced TEE characteristics of these nanorods are ascribed to the induction of nanographitic phases at the grain boundaries and the field penetration effect through the local field enhancement from nanorods owing to a high aspect ratio and an excellent field enhancement factor.
A numerical analysis of flow around a circular cylinder oscillating in-line with a steady flow is carried out over a range of driving frequencies
at relatively low amplitudes
and a constant Reynolds number of 175 (based on the free-stream velocity). The vortex shedding is investigated, especially when the shedding frequency
synchronises with the driving frequency. A series of modes of synchronisation are presented, which are referred to as the
are natural numbers. When a
is detuned to
, representing the shedding of
pairs of vortices over
cycles of cylinder oscillation. The
modes are further characterised by the periodicity of the transverse force over every
cycles of oscillation and a spatial–temporal symmetry possessed by the global wake. The synchronisation modes
with relatively small natural numbers are less sensitive to the change of external control parameters than those with large natural numbers, while the latter is featured with a narrow space of occurrence. Although the mode of synchronisation can be almost any rational ratio (as shown for
smaller than 10), the probability of occurrence of synchronisation modes with
being an even number is much higher than
being an odd number, which is believed to be influenced by the natural even distribution of vortices in the wake of a stationary cylinder.
The Yellow Sea region is of high global importance for waterbird populations, but recent systematic bird count data enabling identification of the most important sites are relatively sparse for some areas. Surveys of waterbirds at three sites on the coast of southern Jiangsu Province, China, in 2014 and 2015 produced peak counts of international importance for 24 species, including seven globally threatened and six Near Threatened species. The area is of particular global importance for the ‘Critically Endangered’ Spoon-billed Sandpiper Calidris pygmaea (peak count across all three study sites: 62 in spring  and 225 in autumn  and ‘Endangered’ Spotted Greenshank Tringa guttifer (peak count across all three study sites: 210 in spring  and 1,110 in autumn ). The southern Jiangsu coast is therefore currently the most important migratory stopover area in the world, in both spring and autumn, for both species. Several serious and acute threats to waterbirds were recorded at these study sites. Paramount is the threat of large-scale land claim which would completely destroy intertidal mudflats of critical importance to waterbirds. Degradation of intertidal mudflat habitats through the spread of invasive Spartina, and mortality of waterbirds by entrapment in nets or deliberate poisoning are also real and present serious threats here. Collisions with, and displacement by, wind turbines and other structures, and industrial chemical pollution may represent additional potential threats. We recommend the rapid establishment of effective protected areas for waterbirds in the study area, maintaining large areas of open intertidal mudflat, and the urgent removal of all serious threats currently faced by waterbirds here.
Patients with early cognitive impairment (ECI) face the prospect of progressive cognitive decline that impairs their ability to make decisions on financial and personal matters. Advance care planning (ACP) is a process that facilitates decision making on future care and often includes identifying a proxy decision maker. This prospective study explores factors related to completion or non-completion of ACP in patients with ECI.
Patients with ECI (n = 158, Mage = 76.2 ± 7.25 years) at a memory clinic received psycho-education and counseling on the importance of ACP and followed-up longitudinally for up to 12 months to ascertain if ACP had been completed. Univariate and logistic regression were used to analyze factors related to completion and non-completion of ACP.
Seventy-seven patients (48.7%) were initially willing to consider ACP after the counseling and psycho-educational session but only 17 (11.0%) eventually completed ACP. On logistic regression, patients who were single were 8.9 times more likely to complete ACP than those who were married (p = 0.007). Among those initially willing to consider ACP, factors impeding completion of ACP included patient (48.0%), process (31.0%), and family factors (21.0%).
As unmarried patients may not have immediate family members to depend on to make decisions, they may perceive ACP to be more important and relevant. Understanding the barriers to ACP completion can facilitate targeted interventions to improve the uptake of ACP.
This study aimed to comprehensively evaluate factors that influence the likelihood of syphilis infection from risk-taking behaviours and medical conditions. A retrospective case-control study was conducted by enrolling 664 syphilis inpatients (excluding 11 congenital syphilis patients) and 800 sex- and age-matched controls. Medical histories, clinical data and patient interview data were collected and subjected to logistic regression analyses. The prevalence of syphilis in the study population was 3·9% (675/17 304). By univariate analysis, syphilis infection was associated with migration between cities, marital status, smoking, reproductive history, hypertension, elevated blood urea nitrogen (BUN) and infection with hepatitis B virus (HBV) (P < 0·05). A high rate of syphilis-HBV co-infection was observed in HIV-negative patients and further research revealed an association between syphilis and specific HBV serological reactivity. Syphilis was also associated with the frequency, duration and status of tobacco use. Multivariate analysis indicated that syphilis infection was independently associated with migration between cities [adjusted odds ratio (aOR) 1·368, 95% confidence interval (CI) 1·048–1·785], current smoking (aOR 1·607, 95% CI 1·177–2·195), elevated BUN (aOR 1·782, 95% CI 1·188–2·673) and some serological patterns of HBV infection. To prevent the spread of infectious diseases, inpatients and blood donors should be tested for HIV, syphilis, HBV and HCV simultaneously.
We determined the prevalence and seasonality of infections by Fasciola of goats and bovine species (cattle and water buffalo) in Hubei and Anhui provinces of China. Faecal samples were collected at 2- to 3-month intervals from 200 goats in Hubei province and from 152 bovine species in Anhui province. All faecal samples were examined for the presence of parasites. We determined the nucleotide sequences of the first and second internal transcribed spacers (ITS-1 and ITS-2) of the nuclear ribosomal DNA (rDNA) of 39 Fasciola worms from Anhui province. The prevalence of Fasciola infection in goats ranged between 3.5 and 37.0%, with mean eggs per gram (EPG) ranging between 29.0 and 166.0. Prevalence and EPG exhibited downward trends over time with significant differences. The prevalence of Fasciola infection in cattle ranged between 13.3 and 46.2% (mean EPG, 36.4–100.0), and that of water buffalo ranged between 10.3 and 35.4% (mean EPG, 25.0–89.6), with a higher prevalence of infection and EPG from June to October compared with December to March. Analysis of ITS-1 and ITS-2 sequences revealed that F. hepatica and F. gigantica were present in all bovine species of Anhui province and that F. gigantica mainly infected water buffalo. This is the first demonstration of Fasciola infection in Hubei province and detection of F. hepatica and F. gigantica in Anhui province. The present study of Hubei province shows that mass treatment of livestock with closantel sodium injections in April and August/September controlled Fasciola infection effectively.
ING2 (inhibitor of growth protein-2) is a member of the ING-gene family and participates in diverse cellular processes involving tumor suppression, DNA repair, cell cycle regulation, and cellular senescence. As a subunit of the Sin3 histone deacetylase complex co-repressor complex, ING2 binds to H3K4me3 to regulate chromatin modification and gene expression. Additionally, ING2 recruits histone methyltransferase (HMT) activity for gene repression, which is independent of the HDAC class I or II pathway. However, the physiological function of ING2 in mouse preimplantation embryo development has not yet been characterized previously. The expression, localization and function of ING2 during preimplantation development were investigated in this study. We showed increasing expression of ING2 within the nucleus from the 4-cell embryo stage onwards; and that down-regulation of ING2 expression by endoribonuclease-prepared small interfering RNA (esiRNA) microinjection results in developmental arrest during the morula to blastocyst transition. Embryonic cells microinjected with ING2-specific esiRNA exhibited decreased blastulation rate compared to the negative control. Further investigation of the underlying mechanism indicated that down-regulation of ING2 significantly increased expression of p21, whilst decreasing expression of HDAC1. These results suggest that ING2 may play a crucial role in the process of preimplantation embryo development through chromatin regulation.
Concentrated electric field is crucial in generation of needleless electrospinning; the electric field profile together with electric field intensity of the spinneret directly affect the needleless electrospinning performance. Understanding the electric field of different spinnerets would definitely benefit the design and optimization of needleless electrospinning. Three-dimensional (3D) finite element analysis has been used to analyze the electric field profile and electric field intensity of different spinnerets for needleless electrospinning by using the simulation software COMSOL Multiphysics 3.5a. It has been found that evolution of the spinneret of needleless electrospinning from cylinder to multiple disks and then to multiple rings results in stronger and more concentrated electric field. The analysis based on 3D simulation of the electric field could benefit further development of needleless electrospinning in which the production rate and quality of as-spun nanofibers are of great importance.
This paper is concerned with the asymptotic spreading of competition diffusion systems, with the purpose of formulating the propagation modes of a co-invasion–coexistence process of two competitors. Using the comparison principle for competitive systems, some results on asymptotic spreading are obtained. Our conclusions imply that the interspecific competitions slow the invasion of one species and decrease the population densities in the coexistence domain. Therefore, the interspecific competitions play a negative role in the evolution of competitive communities.
The system of accretion disk and black hole is usually considered as the central engine of Gamma-ray Bursts (GRBs). It is usually thought that the disk in the central engine of GRBs is the advection-dominated accretion disk, which is developed from a massive (mass Mdisk) torus at radius rdisk. We find a positive correlation between the isotropic gamma-ray energy Eiso and duration (so-called T90) for GRBs. We interpret this correlation within the advection-dominated accretion disk model, associating Eiso and T90 with Mdisk and viscous timescale respectively.
An effective strategy to produce thermo-responsive islands-in-the-sea hydrogel nanofibres was developed using a single needle electrospinning setup. The produced hydrogel nanofibre mats not only showed excellent temperature response and high response speed, but also showed nanostructured surfaces.
Nanofiber yarns with controlled twist levels were prepared by twisting a narrow fibrous strip cut directly from electrospun nanofiber mats. The effects of fiber morphology, diameter and orientation, as well as the yarn twist level on the yarn tensile properties were examined. For the yarns made from randomly oriented fine uniform nanofibers (e.g., diameter 359 nm) and beaded nanofibers, the tensile strength increased with increasing the yarn twist level. Higher fiber diameter (e.g., 634 nm) led to the tensile strength having an initial increase and then decrease trend. The modulus increased with the twist level for all the yarns studied. However, the elongation at break increased initially with the twist level and subsequently decreased. The orientation of aligned fibers within the fiber strip greatly influenced the yarn tensile properties. When the fibers were oriented along the fiber length direction, both tensile strength and modulus were the largest.
The thermal stress behavior of silicon/quartz bonded wafer pairs is examined. Sliding, debonding, and cracking are the observed mechanisms of relaxation. When the elastic energy due to the different thermal expansion coefficients of silicon and quartz exceeds the bonding energy, sliding will start and lead to a serrated curve on the curvature-versus-temperature graph. Finally, debonding will occur once the peeling stress exceeds the interface bonding strength. The debonded parts crack due to the overhang structure, and debonding-cracking processes continue during a further temperature increase. The stress behavior of the hydrogen-implantation induced layer splitting process (the so-called “Smart-Cut process”) of silicon/quartz pairs is also monitored in a stress measurement setup. It is observed that Smart-Cut process is a sudden process in agreement with the observations reported in the literature.
For embedded DRAM (E-DRAM) devices with feature sizes of 0.25 µm and beyond, contact processes with low contact resistance and low junction leakage current are required. The contact etch process needs to etch through multi-layer structures with SiO2, SiON/SiN layers and stop on Ti-polycide gate and Ti-salicide active regions at the same time. The key issues include high selectivity to TiSix, vertical profile, complete removal of SiON/SiN cap layer and no polymer residues. In this paper, multi-layer contact etching without attacking TiSix is reported. Using new process chemistry, the new contact etch process has been demonstrated for the manufacturing of 0.25 µm E-DRAM and beyond.
One of the parameters that limit the efficiency of a thin film solar cell, especially the a-Si and the nc-Si solar cell is the cell thickness. Although thicker film can absorb most of the sun light, the optical generated carriers will recombination through the numerous gap states in the film that obtained lower short circuit current and fill factor. In the controversy, thinner film could not absorb enough sun light that also limit the short circuit current. In this works, we utilize nanowire structure to solve the conflict between the light absorption and the carrier transport. The designed structure has ZnO:Al nanowire array on the substrate. The p-i-n a-Si solar cell structure is grown along the surface of each ZnO: Al nanowire sequentially. Under sunlight illumination, the light is absorbed in the axis direction of the nanowire. However, the carrier transport is along the radial direction of the solar cell. Therefore, the long nanowire could absorb most of the solar light. In the mean time, the thickness of the solar cell still is thin enough for photo-generated carrier transport. The dependence of short circuit current, open circuit voltage and fill factor to the length, diameter and density of ZnO:Al nanowires were simulated.
A novel design electroplating spring frame structure specimen is demonstrated here. The specimen can be fit into a specially designed microtensile apparatus which is capable of carrying out a series of tests on submicron scale freestanding thin films.
Certain thin films applicable in CMOS interconnect and low K materials were tested including sputtered Copper, Tantalum Nitride thin films. Metal specimens were fabricated by sputtering. For Tantalum Nitride film samples, Nitrogen gas was introduced into the chamber during sputtering Tantalum films on the silicon wafer.
We found the modulus of Copper and Tantalum Nitride thin films thin films with thickness of 200 to 800nm at room temperature.
Biomaterials such as DNA are currently being explored as potential application in nanotechnology. DNA templates were immobilized on crystal-violet-treated mica by spin coating as a grid-like network. The DNA templates were then activated with PdCl2, followed by reduction with dimethylamine borane (DMAB) to form seeding nanoclusters on the DNA chain. Afterward the DNA chain with deposition of zero-valence Pd nanoclusters was grew in a Co electroless plating bath. SEM/EDS analysis revealed that Co nanoparticles could be assembled on the DNA template to form magnetic nanowires with a diameter of 25nm to 250nm by a conventional electroless plating. Vibrating Sample Magnetometer analysis indicated that Co-DNA nanowires showed a paramagnetic characteristic. Grid-like networks of DNA template were effectively preserved after Co electroless plating. These characteristics indicated that DNA is an ideal template for the production of magnetic nanowires, which could be useful in the development of high-density memory storage or magnetic field sensors.
Particle-containing silica sol was synthesized by co-hydrolysis and co-condensation of two silane precursors, tetraethylorthosilicate (TEOS) and an organic silane composed of a non-hydrolyzable functional group (e.g., alkyl, fluorinated alkyl, and phenyl), and used to produce superhydrophobic coatings on fabrics. It has been revealed that the non-hydrolyzable functional groups in the organic silanes have a considerable influence on the fabric surface wettability. When the functional group was long chain alkyl (C16), phenyl, or fluorinated alkyl (C8), the treated surfaces were highly superhydrophobic with a water contact angle (CA) greater than 170°, and the CA value was little affected by the fabric type. The washing durability of the superhydrophobic coating was improved by introducing the third silane containing epoxide group, 3-glycidoxypropyltrimethoxysilane (GPTMS), for synthesis. Although the presence of epoxide groups in the coating slightly reduced the fabrics' superhydrophobicity, the washing durability was considerably improved when polyester and cotton fabrics were used as substrates.