Quantitative ultraviolet measurements on wetted thin-layer chromatography plates using a charge-coupled device camera

This paper presents the first study of the UV imaging of spots on thin-layer chromatographic plates whilst still wet with solvent. Imaging of spots of benzophenone during and after development was carried out using a charge-coupled device camera. Limits of detection were found to be 5 ng on a wetted plate and 3 ng for a dry plate and the relationship between peak area and sample loading was found to be linear in the low nanograrn range over an order of magnitude for both wet and dry modes with r(2) values > 0.99. It was found that UV measurements on wet glass-backed plates suffer from low sensitivity; however, the use of aluminium-backed plates gave increased sensitivity. The apparent absorption coefficient (epsilon(app)) of 10AU m(2) g(-1) at 254 nm is consistent with reflection of the light from the aluminium surface with a double pass through the sorbent layer, and suggests that use of aluminium-backed plates should enable monitoring of separations by UV absorbance during TLC development. (c) 2008 Elsevier B.V. All rights reserved

Judge Learned Hand and the Limits of Judicial Discretion

Learned Hand stands among the great judges of the Anglo-American legal tradition. He is preeminently the judge\u27s judge. His long judicial career, spanning one of the crucial periods in the development of American law, and his long service on the bench in a circuit where crucial legal issues come into final focus and where a major part of the commercial law of the nation is first enunciated and explained, peculiarly fit him for the task of explaining the judge\u27s function in the American system of law and the court\u27s role in our jural order. His own legal experience, his non-official writings, brief as they are, and his official opinions are the sources from which his views as to the limits of judicial discretion may be determined. Sir Frederic Pollock has said that the duty of the courts is to keep the rules of law in harmony with the enlightened, common sense of the nation, \u27 for the accomplishment of which caution and valor are both needed, caution in making advances which have not become generally acceptable and valor in dispensing with technical difficulties and in overriding what is merely a show of authority on the part of current opinion. If this be the true measure of judicial activity, certainly Judge Learned Hand has filled nicely the judge\u27s role. He has achieved this happy balance between caution and valor which is at once the hallmark and the insignium of merit of great judges

Judge Hand\u27s Views on the Free Speech Problem

Judge Learned Hand has been for many years a lawyer\u27s lawyer. His opinions are liberally sprinkled through the case books; commentaries on legal matters cite his opinions with increasing respect and admiration; but to many people he is the judge who upheld the conviction of the eleven communists in New York on a question involving the limits of free speech. Scholars of parts and even some lawyers do not know that he anticipated the Supreme Court\u27s clear and present danger test by two years, or that his contribution to the law of free speech is by no means confined to his holding in the communist conspiracy case. Judge Hand has dealt with many aspects of this difficult and controversial problem. His early opinions were liberal but restrained; his later opinions applied the law as he understood it to operate within an industrial context; his final opinion distilled from long experience and a mature philosophy of law is now the law of the land. It fulfilled his early promise and exemplified his greatest gift and in the final analysis the object lesson of his judicial career-- judges must compromise and balance contending interests, even as legislatures whose surrogates they are, but in so doing they must take heed of the social values underlying legal principles and weigh against each other interests of similar kind, pitting social interest against social interest and individual interest against individual interest to the end that justice shall flourish and the law be vindicated

Two-dimensional magnetism in the pnictide superconductor parent material SrFeAsF probed by muon-spin relaxation

We report muon-spin relaxation measurements on SrFeAsF, which is the parent compound of a newly discovered iron-arsenic-fluoride based series of superconducting materials. We find that this material has very similar magnetic properties to LaFeAsO, such as separated magnetic and structural transitions (TN = 120 K, Ts = 175 K), contrasting with SrFe2As2 where they are coincident. The muon oscillation frequencies fall away very sharply at TN, which suggests that the magnetic exchange between the layers is weaker than in comparable oxypnictide compounds. This is consistent with our specific heat measurements, which find that the entropy change S = 0.05 J/mol/K largely occurs at the structural transition and there is no anomaly at TN.Comment: 4 pages, 3 figure