Surface-enhanced Raman scattering from surface and subsurface oxygen species at microscopically well-defined Ag surfaces

Ag(111) and Ag(110) surfaces exposed to oxygen at elevated temperatures (∼800 K) exhibit strongly enhanced Raman bands at 803 and 627 cm−1 which are attributed to O atoms strongly chemisorbed on the surface (Oγ) or held in subsurface sites (Oβ), respectively. In contrast to usual experience, surface-enhanced Raman scattering is occurring here under well-defined conditions up to temperatures of 900 K which is attributed to the joint operation of delocalized electromagnetic enhancement (caused by surface roughness provided by oxygen-induced faceting) and local resonance due to the particular electronic properties of the surface sites

Symmetry superposition studied by surface second-harmonic generation.

The components of a third-rank χ(2) tensor have been split into contributions due to 1-fold, 2-fold, 3-fold, and ∞-fold or isotropic rotation axes for a surface of Cs symmetry. Theoretical analysis of the rotation patterns obtained by the surface second-harmonic (SH) generation indicates that a complete symmetry analysis cannot be performed without knowledge of the relevant distribution functions. Rotation axes of lower symmetry create via ‘‘overtones’’ or ‘‘harmonics’’ contributions apparent in the analysis of the rotation axes of higher symmetry. An experimental example is the observation of structural changes of Au(111) surfaces in an aqueous electrolytic environment. Potential-dependent buildup and removal of a Au(111)-(1×23) surface could be monitored in situ and in real time. Symmetry analysis of the SH rotation patterns reveals both contributions due to a 3-fold axis due to the regular (1×1) structure and simultaneously a 1-fold and a 2-fold axis due to the (1×23) reconstruction

Impact of cyclooxygenase inhibitors in the Women's Health Initiative hormone trials: secondary analysis of a randomized trial.

OBJECTIVES: We evaluated the hypothesis that cyclooxygenase (COX) inhibitor use might have counteracted a beneficial effect of postmenopausal hormone therapy, and account for the absence of cardioprotection in the Women's Health Initiative hormone trials. Estrogen increases COX expression, and inhibitors of COX such as nonsteroidal anti-inflammatory agents appear to increase coronary risk, raising the possibility of a clinically important interaction in the trials. DESIGN: The hormone trials were randomized, double-blind, and placebo-controlled. Use of nonsteroidal anti-inflammatory drugs was assessed at baseline and at years 1, 3, and 6. SETTING: The Women's Health Initiative hormone trials were conducted at 40 clinical sites in the United States. PARTICIPANTS: The trials enrolled 27,347 postmenopausal women, aged 50-79 y. INTERVENTIONS: We randomized 16,608 women with intact uterus to conjugated estrogens 0.625 mg with medroxyprogesterone acetate 2.5 mg daily or to placebo, and 10,739 women with prior hysterectomy to conjugated estrogens 0.625 mg daily or placebo. OUTCOME MEASURES: Myocardial infarction, coronary death, and coronary revascularization were ascertained during 5.6 y of follow-up in the estrogen plus progestin trial and 6.8 y of follow-up in the estrogen alone trial. RESULTS: Hazard ratios with 95% confidence intervals were calculated from Cox proportional hazard models stratified by COX inhibitor use. The hazard ratio for myocardial infarction/coronary death with estrogen plus progestin was 1.13 (95% confidence interval 0.68-1.89) among non-users of COX inhibitors, and 1.35 (95% confidence interval 0.86-2.10) among continuous users. The hazard ratio with estrogen alone was 0.92 (95% confidence interval 0.57-1.48) among non-users of COX inhibitors, and 1.08 (95% confidence interval 0.69-1.70) among continuous users. In a second analytic approach, hazard ratios were calculated from Cox models that included hormone trial assignment as well as a time-dependent covariate for medication use, and an interaction term. No significant interaction was identified. CONCLUSIONS: Use of COX inhibitors did not significantly affect the Women's Health Initiative hormone trial results

Labour supply and skills demands in fashion retailing

If, as Adam Smith once famously suggested, Britain was a nation of shopkeepers then it is now a nation of shopworkers. Retail is now a significant part of the UK economy, accounting for £256 billion in sales and one-third of all consumer spending (Skillsmart, 2007). It is the largest private sector employer in the UK, employing 3m workers, or 1 in 10 of the working population. For future job creation in the UK economy retail is also similarly prominent and the sector is expected to create a further 250,000 jobs to 2014 (Skillsmart, 2007). The centrality of retail to economic success and job creation is apparent in other advanced economies. For example, within the US, retail sales is the occupation with the largest projected job growth in the period 2004-2014 (Gatta et al., 2009) and in Australia retail accounts for 1 in 6 workers (Buchanan et al., 2003). Within the UK these workers are employed in approximately 290,000 businesses, encompassing large and small organizations and also a number of sub-sectors. This variance suggests that retail should not be regarded as homogenous in its labour demands. Hart et al. (2007) note how skill requirements and the types of workers employed may differ across the sector. This chapter further opens up this point, providing an analysis of the labour supply and skills demands for the sub-sectors of clothing, footwear and leather goods, which are described by Skillsmart (2007: 48) as being 'significant categories in UK retailing'

The New ‘Hidden Abode’: Reflections on Value and Labour in the New Economy

In a pivotal section of Capital, volume 1, Marx (1976: 279) notes that, in order to understand the capitalist production of value, we must descend into the ‘hidden abode of production’: the site of the labour process conducted within an employment relationship. In this paper we argue that by remaining wedded to an analysis of labour that is confined to the employment relationship, Labour Process Theory (LPT) has missed a fundamental shift in the location of value production in contemporary capitalism. We examine this shift through the work of Autonomist Marxists like Hardt and Negri, Lazaratto and Arvidsson, who offer theoretical leverage to prize open a new ‘hidden abode’ outside employment, for example in the ‘production of organization’ and in consumption. Although they can open up this new ‘hidden abode’, without LPT's fine-grained analysis of control/resistance, indeterminacy and structured antagonism, these theorists risk succumbing to empirically naive claims about the ‘new economy’. Through developing an expanded conception of a ‘new hidden abode’ of production, the paper demarcates an analytical space in which both LPT and Autonomist Marxism can expand and develop their understanding of labour and value production in today's economy. </jats:p

Nanoscale probing of adsorbed species by tip-enhanced Raman spectroscopy

Tip-enhanced Raman spectroscopy (TERS) is based on the optical excitation of localized surface plasmons in the tip-substrate cavity, which provides a large but local field enhancement near the tip apex. We report on TERS with smooth single crystalline surfaces as substrates. The adsorbates were CN- ions at Au(111) and malachite green isothiocyanate (MGITC) molecules at Au(111) and Pt(110) using either Au or Ir tips. The data analysis yields Raman enhancements of about 4x10(5) for CN- and up to 10(6) for MGITC at Au(111) with a Au tip, probing an area of less than 100 nm radius

An in situ study of reconstructed gold electrode surfaces by second harmonic generation.

Second harmonic generation (SHG) was employed to monitor in situ the potential-induced reconstruction of Au(111) and Au(100) electrodes. Rotating the sample by 360° about the surface normal yields for the unreconstructed Au(111)-(1×1) surface the well-known threefold symmetry pattern in the SHG intensity, while Au(100)-(1×1) shows no rotational anisotropy, as expected for C4v symmetry. For the reconstructed Au(111)-(1×23) surface, however, an additional onefold symmetry pattern is observed, which allows in situ monitoring of the structural transition between (1×1) and (1×23). For the reconstructed Au(100)-(5×20) surface, a threefold symmetry pattern was found

Tip-enhanced Raman spectroscopy (TERS) of malachite green isothiocyanate at Au(111): bleaching behavior under the influence of high electromagnetic fields

Tip-enhanced Raman spectroscopy (TERS) was investigated with malachite green isothiocyanate adsorbed at an Au(111) surface. TERS is based on the excitation of localized surface plasmons in the tip apex, producing strongly enhanced electromagnetic fields. The key conditions for giant TERS are side-illumination of the tip, well-prepared single-crystalline surfaces and sharp, smooth gold tips. A TERS enhancement of about 6 X 106 has been observed for dye molecules adsorbed at the Au(111) substrate in a region of about 50 nm diameter beneath the tip. This corresponds to a 2500-fold increase in the light intensity at the Au(111)/air interface, which in addition causes fast but local bleaching of the dye. This bleaching behavior was analyzed in detail, giving direct insight into the strength and size of the enhanced field. In addition, the bleaching constant was higher for MGITC in an unperturbed environment than for MGITC in an environment that had been substantially bleached. The MGITC spectra were also different for these two cases. Copyright (c) 2005 John Wiley & Sons, Ltd