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The risk of malaria outbreak surfaced in Vanuatu after Tropical Cyclone (TC) Pam in March 2015. In June and July 2015 we conducted malariometric surveys on the islands of Tanna, Aneityum, and Erromango in Tafea Province, where malaria elimination had been targeted, to determine if malaria incidence had increased after TC Pam. No Plasmodium infection was detected by microscopy and PCR in 3009 survey participants. Only 6·3% (190/3007) of participants had fever. Spleen rates in children aged ⩽12 years from Aneityum and Tanna were low, at 3·6% (14/387) and 5·3% (27/510), respectively. Overall bed net use was high at 72·8% (2175/2986); however, a significantly higher (P < 0·001) proportion of participants from Aneityum (85·9%, 796/927) reported net use than those from Tanna (67·1%, 751/1119) and Erromango (66·8%, 628/940). A recent decrease in malaria incidence in Tafea Province through comprehensive intervention measures had reduced the indigenous parasite reservoir and limited the latter's potential to spur an outbreak after TC Pam. The path towards malaria elimination in Tafea Province was not adversely affected by TC Pam.
We have been monitoring the flux density of Sagittarius A* (Sgr A*) at 22 GHz since DOY=42 (11 Feb. 2013) with a sub-array of the Japanese VLBI Network in order to search the increase of 22-GHz emission from Sgr A* induced by the interaction of the G2 cloud with the accretion disk. The flux densities observed until DOY=322 (18 Nov. 2013) are consistent with the previously observed values before the approaching of the cloud. We have detected no large flare during this period.
We show that the dispersion in the Schmidt-Kennicutt (SK) law in galaxies is affected significantly by the evolutionary stage of star forming molecular gas, using narrow band Paα imaging of Taffy I, an interacting pair of galaxies. Star forming regions in the system show very uniform ages except for the bridge region, and the SK law of regions at the same age show a exceptionally tight SK law.
We review the progress in the electron tomography of dislocation microstructures in the transmission electron microscope (TEM). Dislocation contrast is visible both in conventional TEM and scanning TEM (STEM) modes and, despite the complicated intensity variations, dislocation contrast can be isolated using computational filtering techniques prior to reconstruction. We find that STEM annular dark-field (STEM-ADF) imaging offers significant advantages in terms of dislocation contrast and background artifacts. We present several examples, both in semiconducting and metallic systems, illustrating the properties of 3D dislocations. We present the high-angle triple-axis (HATA) specimen holder where the diffraction condition can be chosen at will and dislocation tomograms of multiple reflections can be combined. 3D dislocations are analyzed in terms of dislocation density and dislocation nodal structures. Several avenues of study are suggested that may exploit the 3D dislocation data.
We have synthesized nickel by means of pulsed laser ablation. A nickel disc was used for ablation with the focused output of fundamental harmonic from Nd:YAG laser. X-ray diffraction result shows that the synthesized nanoparticles are of pure metallic nickel with a face-centred cubic structure and the average particle size is 35 nm. The extended X-ray absorption fine structure (EXAFS) studies of pure nickel foil and the synthesized nanoparticles show similar structures. The position of the main peak is same in these nanoparticles with reference to the nickel foil. The only difference was observed in the reduction of the amplitude. The nearest-neighbour distance is similar as for pure nickel foil. The Debye–Waller factor is also similar. There is no trace of oxide and hydroxide in the EXAFS data, suggesting that the synthesized nanoparticles contain only nickel metal.
We have conducted all disk imaging of M33 in 12CO(1-0) using the 45-m telescope at Nobeyama Radio Observatory. We present preliminary results of this project. The spatial resolution of ~ 80 pc is comparable to the size of GMCs. The identified GMCs show wide variety in star forming activity. The variety can be regarded as the difference of their evolutionary stage. We found that Kennicutt-Schmidt law breaks in GMC scale (~ 80 pc), although it is still valid in 1 kpc scale. The correlation between molecular gas fraction, fmol = Σ(H2)/Σ(HI+H2) and gas surface density shows two distinct sequences and shows that fmol tends to be higher near the center. We also made partial mapping 12CO(3-2) with ASTE telescope. These data show that the variation of physical properties of molecular gas are correlated with the GMC evolution and mass. That is, GMCs with more active star formation and more mass tend to have higher fraction of dense gas.
As the Nobeyama Radio Observatory Legacy Project: Survey of Giant Molecular Clouds in M33, we have been mapping M33 in CO(1-0) with the multi-beam receiver BEARS equipped on the 45-m telescope using the OTF mapping technique since 2007. The purpose of this project is to investigate the physical properties of GMCs and understand the evolutionary process from GMC formation to star formation in GMCs by comparing with various data such as CO(3-2), 1.1 mm continuum obtained with ASTE10m telescope at Atacama and the optical data obtained with SUBARU. We identified 87 GMCs using the first year data of CO(1-0) and observed 28 GMCs among them in CO(3-2) with ASTE (Onodera 2009, PhD thesis, University of Tokyo). From the comparison of these lines, it was shown that the CO(3-2)/CO(1-0) ratio increases with star forming activity in the GMCs. Furthermore, we found that more massive GMCs tend to have higher CO(3-2)/CO(1-0) ratio. Since the ratio is thought to be an indicator of the fraction of warm and dense molecular gas, our results imply that the fraction of warm and dense gas increases with GMC mass. Especially, since the ratio in the GMCs with low star forming activity is in the range where the ratio depends mainly on the density, we speculate that dense gas fraction increases with GMC mass.
Successful offspring production after intracytoplasmic injection of freeze-dried sperm has been reported in laboratory animals but not in domesticated livestock, including pigs. The integrity of the DNA in the freeze-dried sperm is reported to affect embryogenesis. Release of endonucleases from the sperm is one of the causes of induction of sperm DNA fragmentation. We examined the effects of chelating agents, which inhibit the activation of such enzymes, on DNA fragmentation in freeze-dried sperm and on the in vitro and in vivo developmental ability of porcine oocytes following boar sperm head injection. Boar ejaculated sperm were sonicated, suspended in buffer supplemented with (1) 50 mM EGTA, (2) 50 mM EDTA, (3) 10 mM EDTA, or (4) no chelating agent and freeze-dried. A fertilization medium (Pig-FM) was used as a control. The rehydrated spermatozoa in each group were then incubated in Pig-FM at room temperature. The rate of DNA fragmentation in the control group, as assessed by the TUNEL method, increased gradually as time after rehydration elapsed (2.8% at 0 min to 12.2% at 180 min). However, the rates in all experimental groups (1–4) did not increase, even at 180 min (0.7–4.1%), which were all significantly lower (p < 0.05) than that of the control group. The rate of blastocyst formation after the injection in the control group (6.0%) was significantly lower (p < 0.05) than those in the 50 mM EGTA (23.1%) and 10 mM EDTA (22.6%) groups incubated for 120–180 min. The average number of blastocyst cells in the 50 mM EGTA group (33.1 cells) was significantly higher (p < 0.05) than that in the 10 mM EDTA group (17.8 cells). Finally, we transferred oocytes from 50 mM EGTA or control groups incubated for 0–60 min into estrous-synchronized recipients. The two recipients of the control oocytes became pregnant and one miscarried two fetuses on day 39.
The results suggested that fragmentation of DNA in freeze-dried boar sperm is one of the causes of decreased in vitro developmental ability of injected oocytes to the blastocyst stage. Supplementation with EGTA in a freeze-drying buffer improves this ability.
The batch-foaming behavior of multiphase polymer blends and block copolymers was systematically investigated using carbon dioxide as a blowing agent. Three different polymer systems were evaluated: (i) nanostructured triblock terpolymers, (ii) microstructured polymer blends, and (iii) nanostructured polymer blends. In order to obtain nanostructured blends, immis-cible blends of poly(2,6-dimethyl-1,4-phenylene ether)/poly(styrene-co-acrylonitrile) (PPE/SAN) were melt-compatibilised via polystyrene-b-polybutadiene-b-poly(methyl methacry-late) triblock terpolymers. Due to the specific interaction between the respective components, a nanostructured interphase between PPE and SAN was observed. With regard to neat block co-polymers, the self-assembly of solvent-cast SBM triblock terpolymers was exploited in order to produce nanostructured morphologies. In each case, the resulting foam morphology was charac-terized by evaluating the foam density as well as the cell size. Combined with the multiphase structure of the non-foamed material and its thermal as well as physical behavior, relationships between the foaming characteristics and the cellular morphology were established. As an exam-ple for the foaming results, submicro-cellular structures were observed by foaming nanostruc-tured polymer blends, while the cell walls still revealed the nanostructured morphology. In con-trast, batch-foaming of neat triblock terpolymers led to the formation of microcellular foams; however, as highlighted by scanning electron microscopy, the cell walls did undergo some fur-ther expansion and formed additional nano-sized cells. In the light of these results, new routes for preparing cellular polymers are derived by systematically exploiting the multiphase charac-teristics of polymer blends and block copolymers.
A new method of fabricating nanocomposite films made up of multiwall carbon nanotube and nanocrystalline copper was developed by using an electrochemical deposition. The electroplated CNT/Cu nanocomposites have the microstructure that CNTs are well dispersed in both the planar and depth directions without any voids in the matrix. The conditions were successfully achieved by using some amphiphilic polymers, organic additives and a pulse electrodeposition method. The microstructure and CNT composition of nanocomposite films were strongly affected by the concentration of CNT in the electrolyte. The mechanical and electrical properties of CNT/Cu nanocomposite films were investigated with the variation of CNT content in the nanocomposite films.
Industrially viable blends having microstructures that can be converted into a nanostructured material by post chemical treatments, potentially should have a commercially viable solution to the development of nanostructured materials for practical applications. In this regard a polypropylene-boron oxide (PPBO) blend provides a model study here. In this paper we wish to report the synthesis of PPBO blends with different concentrations of boron oxide by melt grafting and through reactive extrusion. The tensile strengths of the ideal blend has been found to be 62% higher than polypropylene (PP). By chemically treating the blends for a period of 24 hours to 72 hours the tensile strength of the blends increased by 152%. The blends have been characterized by fourier transform infra red spectroscopy (FTIR) and scanning electron microscopy (SEM). An interesting characteristic of the PPBO blend has been the development of surface potential that changes upon visible light excitation. The increased tensile strength has been attributed to the conversion of micro structured blends to nanostructured blends. The improvement in thermal stability can be attributed to a good PP matrix-oxide interaction and also due to the thermal conductivity of the boron oxide. The good dispersion of the nanotubes in the polymer matrix allows the spreading of heat uniformly along the fiber.
Solutions or mixtures of aluminum halides AlX3 (X = Cl, Br, I) or aluminum halide alkoxide (ROAlX2; R= i-Pr, X = Cl, Br) are prepared in toluene, or pentamethyldiethylenetriamine (PMDETA) and treated with a slight excess of 50:50 (wt.) sodium potassium alloy (Na/K). Upon agitation, the reaction takes place slowly. The reaction appears to be limited by the deposition of insoluble products on the surface of the Na/K since sonication in an ordinary ultrasonic cleaner is necessary to bring the reaction to completion in several hours. Aluminum nanoparticles (NPs) and Na and K halides are formed, and soluble Al compounds, are also formed in some cases. Lithium powder is used instead of Na/K to reduce Al(N(SiMe3)2)3 to Al NPs. In an effort to passivate the surface of the Al particles to oxidation or hydrolysis, various agents are added either during the reaction or afterward. The products are characterized by SEM, XRD, NMR, and TEM, and the stability to water and air is evaluated.
To realize ceramic/polymer nanocomposites for polymer waveguides, PMMA-coated Ta2O5 nanoparticles are synthesized as core/shell particles. Therefor a gas-phase process is used: the Karlsruhe Microwave Plasma Process. The organic coating is supposed to reduce the agglomeration of the ceramic cores and should facilitate the incorporation into the polymer resin. TEM investigations of the nanoparticles exhibit crystalline and amorphous Ta2O5 with sizes around 3 to 6 nm, confirmed by electron diffraction. Although the polymer coating is not visible in TEM imaging, electron energy loss spectroscopy (EELS) exhibits a significant C-edge, proofing the organic coating. The Ta2O5/PMMA nanoparticles are incorporated with different weight fractions to a maximum of 1 wt% by a dissolver stirrer into PMMA resin. The optical properties (refractive index, transmission) are determined as a function of the nanoparticle content. Compared to the pure polymer, the refractive index of the modified composite, measured at 633 nm, is increased by 0.001 and 0.004 at 0.1 wt% and 0.7 wt%, respectively. A similar tendency is observed at 1550 nm. The transmission in the near infrared (NIR) is similar to that of PMMA up to a content of 0.3 wt%. At higher nanoparticle contents transmission is reduced. The reduction in transmission is due to the presence of agglomerates larger then 1/10 of the applied wavelength, confirmed by TEM. The concept of incorporating inorganic/organic hybrid nanoparticles with intrinsic high refractive index in polymer matrices is very promising. A suitable effect in refractive index for application of ceramic nanoparticle/polymer nanocomposites as polymer waveguides could be observed even with low particle concentration.
Morphology control is a key challenge in the straightforward hydrothermal production of technologically relevant anisotropic oxide materials. The use of readily available ionic additives as growth modifiers is discussed and compared for molybdenum- and tungsten oxide-based systems, and it is extended upon the formation of ternary W/Mo-oxides. Generally, the one-step hydrothermal synthesis of ternary and higher oxides is an important goal, because their properties often outperform those of the binary oxides. This holds especially for the Bi2O3-MoO3-VOx (BIMOVOx) system as a rich source of new materials. We present a new solution-based approach to α-Bi2O3 nanobelts starting from commercial Bi2O3 and K2SO4 as a key step on the way to anisotropic BIMOVOx-oxides. This hydrothermal process is an illustrative example of highly selective and efficient morphology control through an inorganic additive. As mechanistic and kinetic studies are crucial for the design of complex oxide nanomaterials, the Bi2O3-K2SO4 system is compared to our previous studies on Mo-, W- and V-oxides with respect to its hydrothermal parameter window and robustness.
Nanoparticles that fluoresce or absorb light in the visible and near-IR wavelengths are desirable for a variety of applications including biological tagging for medical imaging purposes and for solar control glazing in the automobile industry. Semiconductor quantum dots are commercially available and dyed polymer nanoparticles as well as organic dye/silica core shell nanoparticles have also been demonstrated. We report the synthesis, characterization, and optical properties of another luminescent nanoparticle: doped zirconia. The zirconia nanoparticles reported in this study are doped with up to 10% of the lanthanide dopants Er, Gd, Nd and Eu. These materials emit in the visible and near-IR wavelengths depending on the dopant and are refractory, making them useful for high temperature applications. These cations were found to stabilize the cubic phase over the monoclinic phase of zirconia, at approximately 10% dopant, as characterized by X-ray diffraction. We report the luminescence spectra of these nanoparticles at various wavelengths which reveal emissions from the matrix as well as from the dopants.
We describe the dynamics of the synthesis of gold nanoparticles by glow discharge in aqueous solutions. Initial [AuCl4]− concentration and the voltage applied between the electrodes were varied. Reduction rates were calculated from changes in concentration of [AuCl4]− vs. discharge time. A pulsed power supply was used to generate discharges in the aqueous solutions. The morphology of the nanoparticles obtained was observed by transmission electron microscopy (TEM). [AuCl4]− was reduced by H radicals or electrons generated by the discharge. Dendrite-shaped nanoparticles ∼150 nm in size were formed after discharge for 1 min. The pH of the solution decreased gradually with increasing discharge time. The decrease in pH led to dissolution of gold nanoparticles. The reduction and dissolution rates increased proportionately with the applied voltage. The size of gold nanoparticles decreased during discharge and was 20 nm after discharge for 45 min. When the reduction rate lowered as a result of dissolution, anisotropic nanoparticles were formed and continued to grow in the solution.