Metal-Free Dihydrogen Oxidation by a Borenium Cation:A Combined Electrochemical/Frustrated Lewis Pair Approach

In order to use H2 as a clean source of electricity, prohibitively rare and expensive precious metal electrocatalysts, such as Pt, are often used to overcome the large oxidative voltage required to convert H2 into 2 H+ and 2 e−. Herein, we report a metal-free approach to catalyze the oxidation of H2 by combining the ability of frustrated Lewis pairs (FLPs) to heterolytically cleave H2 with the in situ electrochemical oxidation of the resulting borohydride. The use of the NHC-stabilized borenium cation [(IiPr2)(BC8H14)]+ (IiPr2=C3H2(NiPr)2, NHC=N-heterocyclic carbene) as the Lewis acidic component of the FLP is shown to decrease the voltage required for H2 oxidation by 910 mV at inexpensive carbon electrodes, a significant energy saving equivalent to 175.6 kJ mol−1. The NHC–borenium Lewis acid also offers improved catalyst recyclability and chemical stability compared to B(C6F5)3, the paradigm Lewis acid originally used to pioneer our combined electrochemical/frustrated Lewis pair approach

Labor Force Participation: Timing and Persistence

This paper examines the relative importance of timing and persistence elements in explaining cyclical fluctuations in labor supply. Data from the natural experiment provided by World War I1 and cross-sectional data on American local labor markets, as well as aggregate time-series data are used in the empirical work. We find little evidence that timing effects play an important role in labor market dynamics. The evidence suggests that views emphasizing persistence are more accurate, and that previous employment tends to raise the probability of subsequent employment.

Labor Market Dynamics and Unemployemnt: A Reconsideration

macroeconomics, unemployment

The Dynamics of Youth Unemployment

This paper analyzes the dynamics of youth unemployment. Three broad conclusions emerge. First, the problem of youth joblessness extends beyond the unemployed. We find that over one-half of youth unemployment spells end in labor force withdrawal. Much of youth non-employment is not picked up in the official unemployment statistics, because many young people give up the search for work and leave the labor force. Second, a large part of youth unemployment is accounted for by a relatively small, hard core group of young people who experience long spells of unemployment. While most unemployment spells are short, this is due to the high rates of labor force withdrawal, rather than to job finding. Among male teenagers out of school, for example, we find that over half of unemployment was due to those with more than six months of unemployment in the year. Third, a shortage of attractive jobs is the principle source of long term non-employment. While instability and frequent turnover are major factors in determining the overall pattern of teenage unemployment, we find that the lack of desirable employment opportunities is the crux of the problem for those most seriously affected by youth unemployment.

Demographic Differences in Cyclical Employment Variation

Demographic differences in patterns of employment variation over the business cycle are examined in this paper. Three primary conclusions emerge. First, both participation and unemployment must be considered in any analysis of cyclical changes in the labor market. Second, young people bear a disproportionate share of cyclical employment variation. Third, failure to consider participation has led to undue pessimism about the effect of aggregate demand policy on high unemployment groups. If participation did not surge, reduction in overall unemployment to its 1969 level would reduce the unemployment of almost all demographic groups to very low levels.

Studies on the mechanism of sodium transport at the tonoplast of Beta vulgaris.

The aim of the work described in this thesis was to characterise the mechanism of Na+ transport at the vacuole membrane (tonoplast) of red beet using isolated tonoplast vesicles. It was confirmed that pure tonoplast vesicles could be prepared from red beet storage root. However, it was found that the KI treatment used in published tonoplast vesicle preparation protocols was deleterious to tonoplast, so this was subsequently modified. Attempts to characterise a Na+/H+ antiport reported by Blumwald and Poole (1985a; Plant Physiol. 78, 163-167) by studying the effect of Na+ on pH gradients imposed by a pH jump were not successful. Under the conditions used by these workers the fluorescent pH gradient probe acridine orange misreported the pH gradient and apparently good evidence for a Na+/H+ antiport was shown to be artefactual. With modifications to the media used for these experiments, acridine orange could be used to monitor the pH gradient and these results were confirmed using another pH gradient probe, [14C] methyl amine. However, no evidence was found for a Na+/H+ antiport as it was not possible to distinguish between changes in the pH gradient due to an Na+/H+ antiport and changes caused by electrically-coupled Na+ and H+ fluxes. In an attempt to avoid these problems, +Na uptake by tonoplast vesicles was studied in response to pH gradients generated by the H+-ATPase. No pH gradient-dependent Na+ uptake was found using this approach. It is concluded from these studies that previous evidence for a tonoplast Na+/H+ antiport in red beet is artef actual. It is suggested that Na+ is passively distributed across the tonoplast in red beet

The ethos of music in ancient Greek education

This item was digitized by the Internet Archive. Thesis (M.A.)--Boston Universityhttps://archive.org/details/theethosofmusici00cla

Treatment of psoriasis with biologic agents in Malta

Introduction: Biologic therapy has revolutionalised the treatment of moderate to severe psoriasis leading to improved clinical outcomes and quality of life scores. This study aims to determine current biologic use in psoriatic patients at our Dermatology department at Sir Paul Boffa hospital, Malta. Method: All patients who were administered biologic therapy for psoriasis in Malta until the end of 2014 were included. Data included demographic details, disease duration and severity, biologic use and duration, previously attempted treatments, side effects, early and late response to biologic using Psoriasis Area Severity Index (PASI) scores and Dermatology Life Quality index (DLQI) scores. Results: A total of 36 patients were started on a biologic between 2009 and 2014 for psoriasis (M:25, F:11) with a mean age of 46.9 years. These included etanercept (n=22), infliximab (n=8), adalimumab (n=4) and ustekinumab (n=2). Secondary failure was the main reason why biologics were stopped and switched. Most patients had an improvement in their PASI scores after 2 to 4 weeks of starting the biologic and had a PASI 90 score improvement. All patients had more than a 5 point improvement in DLQI score. Discussion: Biologic use in our department is on the increase. Our patients had considerable improvements in their PASI and DLQI scores. Secondary failures have occurred usually after 2 to 4 years and switching has yielded positive results. Biologics are expensive drugs and recently we have switched to cheaper biosimilars. Doctors should be aware of the treatment options available for psoriasis patients, their possible side effects and when to refer to our department. In most cases a satisfactory response can be achieved.peer-reviewe