Organometallic cluster analogues of tamoxifen: Synthesis and biochemical assay

Simple organometallic cluster analogues of tamoxifen containing triosmium or dicobalt carbonyl fragments have been prepared. Attempts at elaboration of these towards the tamoxifen skeleton were hampered by sensitivity of the cluster–ligand linkage towards the McMurry coupling conditions. Preliminary biological tests on various substrates indicate that the transition metal carbonyl fragment increases lipophilicity dramatically and reduces affinity for the estrogen receptor.     

The glow curve structure for the LiF:Mg,Cu,Na,Si TL detector with dopants concentrations and sintering temperatures

The glow curve structures for LiF:Mg,Cu,Na,Si TL detectors with various dopant concentrations and sintering temperatures were investigated for the improvement of the glow curve structure and sensitivity of the TL detector. The dopant concentrations were varied over the following ranges: Mg (0–0.25 mol%), Cu (0–0.07 mol%), Na and Si (0–1.5 mol%). With increasing Cu concentration, the intensity of the main peak was intensified and reached a maximum at a concentration of 0.05 mol%. The high-temperature peak was reduced. The dependency of the main peak intensity on the Mg concentration exhibits a sharp maximum at 0.2 mol%. The intensity of the high-temperature peak tends to rise slightly with increasing Mg concentration. It was found that the optimum concentrations of the dopants in the LiF:Mg,Cu,Na,Si TL material are Mg: 0.2 mol%, Cu: 0.05 mol%, Na and Si: 0.9 mol%. The dependency of the main peak intensity on sintering temperature exhibits a very sharp maximum at 830°C. The high-temperature peak was rapidly reduced after 825°C.     

Fabrication and Characteristics of Sol-Gel Derived Fluorinated Hybrid Material Films

Fluorinated inorganic-organic hybrid materials (HYBRIMER) were successfully prepared from fluoroalkylsilanes (FASs) containing fluoro-alkyl functions and methacryloxypropyltrimethoxysilane (MPTMS) through a sol-gel process. The influence of concentration and fluoro-alkyl chain lengths of FASs on the physical characteristics of the fluorinated HYBRIMER films was examined. Larger fluorine contents lowered the refractive index within a range, which was closely dependent on the fluoro-alkyl chain lengths of FASs. Thermo-optic coefficients (TOC) were negative values, and the values grew with increasing fluorine contents and fluoro-alkyl chain lengths. Also, the thermal stability is enhanced by addition of fluorine in the HYBRIMER.     

Generation of 0.2-TW 5.5-fs optical pulses at 1 kHz using a differentially pumped hollow-fiber chirped-mirror compressor

Optical pulses with 1.1-mJ energy and 5.5-fs duration have been generated at 1-kHz repetition rate from a chirped pulse amplification Ti:Sapphire laser incorporating a differentially pumped hollow-fiber chirped-mirror compressor. The effects of self-focusing and multi-photon ionization during the beam propagation were minimized by differentially pumping the hollow fiber filled with neon. The spectral broadening at the hollow-fiber compressor was optimized by adjusting gas pressure, laser intensity, and laser chirp, covering from 540 nm to 950 nm. PACS 42.65.Jx; 42.65.Re     

Validation of the catalytic properties of Cu-Os/13X using single fixed bed reactor in selective catalytic reduction of NO

Catalytic decomposition of NO over Cu-Os/13X has been carried out in a tubular fixed bed reactor at atmospheric pressure and the results were compared with literature data performed by high-throughput screening (HTS). The activity and durability of Cu-Os/13X prepared by conventional ion-exchange method have been investigated in the presence of H₂O and SO₂. It was found that Cu-Os/13X prepared by ion-exchange shows a high activity in a wide temperature range in selective catalytic reduction (SCR) of NO with C₃H₆ compared to Cu/13X, proving the existence of more NO adsorption site on Cu-Os/13X. However, Cu-Os/13X exhibited low activity in the presence of water, and was quite different from the result reported in literature. SO₂ resistance is also low and does not recover its original activity when the SO₂ was blocked in the feed gas stream. This result suggested that catalytic activity between combinatorial screening and conventional testing should be compared to confirm the validity of high-throughput screening.     

Optimization of in-vacuo template-stripped Pt surfaces via UHV STM

A recently demonstrated [1] in-vacuo template-stripping process is applied to the study of platinum films stripped from ultra-flat silicon-oxide surfaces. Template-stripped (TS) Pt surfaces, prepared with a range of post-deposition annealing times prior to being stripped from the templating surface in an ultra-high vacuum (UHV) environment, are examined by UHV scanning tunneling microscopy (STM). These studies reveal that without post-deposition annealing, TS Pt surfaces are largely made up of poorly-ordered, granular nanostructures undesirable for many applications. The post-deposition annealing treatments explored in the study result in the emergence and continuous growth of large smooth crystallites. Issues with crystallite orientation relative to the TS surface and artefacts arising as a result of the epoxy used in the template-stripping process are presented and discussed in relation to optimizing the template-stripping procedure for specific applications such as self-assembled monolayer (SAM) formation for molecular electronics. PACS 68.37.Ef; 68.47.De; 68.55.Jk; 81.05.Bx; 81.15.Ef     

Lattice parameter and luminescence properties of europium activated yttrium oxide

Samples of yttrium oxide doped with trivalent europium have been prepared by ceramic techniques, under different synthesis conditions; barium chloride (BaCl₂) and sodium tetraborate (Na₂B₄O₇) were tested as flux. The improvement of luminescence properties in dependence on substitution of Eu³⁺ for Y³⁺ in the host lattice, under electron and UV excitations is demonstrated. The lattice parameter as a quantitative assessment of activator incorporation degree is proposed. The obtained results are discussed with respect to the employed processing method.     

Hydrophobic recovery of UV/ozone treated poly(dimethylsiloxane): adhesion studies by contact mechanics and mechanism of surface modification

Silicone elastomers (Sylgard 184 and 170), based on poly(dimethylsiloxane) (PDMS), were surface treated by a combined exposure to UV and ozone. The effects of the treatments were analyzed as a function of time elapsed after stopping the treatments using different standard surface characterization techniques, such as water contact angle measurements, XPS and atomic force microscopy (AFM). However, the primary focus of this study was to apply the Johnson–Kendall–Roberts (JKR) contact mechanics approach to investigate PDMS samples prior to and following UV/ozone surface treatment. A gradual formation of a hydrophilic, silica-like surface layer with increasing modulus was observed with increasing UV/ozone exposure. A subsequent hydrophobic recovery after UV/ozone exposure was observed, as indicated by increasing contact angles. This supports the hypothesis that the hydrophobic recovery is mainly caused by the gradual coverage of a permanent silica-like structure with free siloxanes and/or reorientation of polar groups. PDMS containing a homogenously dispersed filler (Sylgard 184), exhibited a decreasing surface roughness (by AFM) when the oxidized surface region “collapsed” into a smooth SiO_x layer (final surface roughness <2 nm). PDMS containing heterogeneously distributed, aggregated filler particles (Sylgard 170), exhibited an increasing surface roughness with treatment dose, which was attributed to the “collapse” of the oxidized surface region thus exposing the contours of the underlying filler aggregates (final surface roughness ∼140 nm). A dedicated device was designed and built to study the contact mechanics behavior of PDMS prior to, and following surface treatment. The value of the combined elastic modulus obtained for PDMS lens and semi-infinite flat surface system showed an increase in full agreement with the formation of a silica-like layer exhibiting a high elastic modulus (compared with untreated PDMS). The work of adhesion observed in JKR experiments exhibited an increasing trend as a function of treatment done in agreement with contact angle data. JKR experiments showed hydrophobic recovery behavior as anticipated from contact angle measurements. Single pull-off force measurements by JKR and numerical analysis of full-approach JKR curves were in quantitative agreement regarding practical work of adhesion values.     

Broadband Light Source for Wavelength-Division Multiple Access Passive Optical Network

We demonstrated a unified two-band broadband light source based on erbium-doped fiber. The proposed scheme generates high output power at both bands and saves doped-fiber and pump lasers.     

Photoemission studies of oxygen adsorbed on a LiAl(1 1 0) alloy surface: Role of Li segregation

We investigated that the effect of the number of segregated Li atoms on the rate of oxidation on a LiAl alloy surface. Oxygen molecules adsorbed on the LiAl alloy react with the surface atoms to form stable oxides. The segregated Li atoms at reconstructed surfaces (c(2×2) and (2×1)) enhance the oxidation rate and form stable LiAlO_x and Li₂O. The degree of enhancement of oxidation by segregated Li atoms varies as a function of O₂ exposure and annealing temperature, where the latter is directly related to the mode of surface reconstruction by Li segregation.