Limits on the production of scalar leptoquarks from Z (0) decays at LEP

A search has been made for pairs and for single production of scalar leptoquarks of the first and second generations using a data sample of 392000 Z0 decays from the DELPHI detector at LEP 1. No signal was found and limits on the leptoquark mass, production cross section and branching ratio were set. A mass limit at 95% confidence level of 45.5 GeV/c2 was obtained for leptoquark pair production. The search for the production of a single leptoquark probed the mass region above this limit and its results exclude first and second generation leptoquarks D0 with masses below 65 GeV/c2 and 73 GeV/c2 respectively, at 95% confidence level, assuming that the D0lq Yukawa coupling alpha(lambda) is equal to the electromagnetic one. An upper limit is also given on the coupling alpha(lambda) as a function of the leptoquark mass m(D0)

Drug Pricing Decisions and Insurance Coverage: Evidence from Medicare Part D

We examine whether the pricing of brand drugs, relative to estimates of their clinical value, is related to the way insurers cover those products in Medicare Part D. The net prices of drugs in our sample vary significantly relative to value-based prices from the Institute for Clinical and Economic Review (ICER), indicating meaningfully different pricing strategies. Coverage decisions, formulary placement, and use of utilization management are clearly responsive to first-order differences in costs of products generally. However, among the subset of relatively high-cost products with value-based price estimates, we observe little relationship between pricing strategies and extensive margin coverage decisions. Plans that cover larger shares of lower-value products tend to have permissive coverage policies and higher resulting premiums. Among potential explanations, we highlight institutional features that may help explain these results and propose an empirical test surrounding upcoming policy changes due to the Inflation Reduction Act

Progress in the production of CsI and diamond thin film photocathodes

The comparison between the quantum efficiency of photocathodes coated with thin CsI films obtained by thermal evaporation and, for the first time, by Ar ion-beam sputtering is reported. The sensitivity of photocathodes has been Found to be strongly dependent on the morphology and roughness of the evaporated and sputtered CsI films. The effect of surface roughness on four different substrates has been investigated and is discussed. Preliminary measurement results on the photoeinissivity of diamond films are also given. (c) 2005 Elsevier B.V. All rights reserved

Investigations on nitrogen addition in the CH4-H2 gas mixture used for fiamond deposition for a better understanding and the optimisation of the synthesis process.

International audienc

Surface functionalization of ultrananocrystalline diamond using atom transfer radical polymerization (ATRP) initiated by electro-grafted aryldiazonium salts

International audienceThe integration of organic adlayers with diamond surfaces imparts many new properties to diamond materials, including lubrication, optical response, chemical sensing, and biocompatibility. The development of new immobilization chemistries is required in which organic layers are covalently attached to the diamond surface. Poly(methyl methacrylate) and polystyrene brushes (PMMA, PS, respectively) were grown from the surfaces of ultrananocrystalline diamond (UNCD) thin films that were modified by the electrochemical reduction of the diazonium salt BF4 ~,+N2– C6H4–CH(CH3)–Br. The grafted –C6H4–CH(CH3)–Br species were effective in promoting surface initiated atom transfer radical polymerization (SI-ATRP) of the vinyl monomers. Attempts to perform SI-ATRP from undoped diamond films produced by microwave plasma assisted chemical vapour deposition (MPACVD) process was rather unsuccesful due to a very low extent of electrochemical modification by the brominated aryl diazonium salts. The formation of the polymer brushes was confirmed by XPS. The polymer brushes were further evaluated as adsorbents for human serum albumin (HSA) used as a model protein. Protein adsorption decreased in the order PS>PMMA, that is the decreasing trend of hydrophobic character

Performance analysis of poly-, nano- and single-crystalline diamond-based photocathodes

The results of the external Quantum Efficiency (QE) measurements, in the range 150-210 nm, of Poly-, Nano- and Single-Crystalline Diamond (PCD, NCD and SCD) film photocathodes (PCs) are reported and discussed. The diamond films, grown by Microwave Plasma Assisted Chemical Vapour Deposition (MPACVD) technique, have been analyzed with the aim to define which characteristics enhance their QE. It has been found that NCD film PCs, generally showing a lower QE with respect to PCD ones, enhance their photoemission if a graphitic component is present in the film. Surface hydrogenation effects on the photoemissivity of PCs have been investigated. Comparative studies between the QE of an untreated and a hydrogenated-treated diamond film PC show that the hydrogenated sample exhibits Negative Electron Affinity (NEA) properties. An ageing test of 24 h air exposure shows a stability of the hydrogenated diamond PC higher than that of the CsI one. Moreover, the PC conditioning by means of H-2 plasma allows to recover almost completely the loss of PC QE due to ageing effect caused by the air exposure of a previously hydrogenated sample. The sensitivity of PCs depends strongly on the topography of diamond films. (C) 2008 Elsevier B.V. All rights reserved

Performance analysis of poly-, nano- and single-crystalline diamond-based photocathodes

The results of the external Quantum Efficiency (QE) measurements, in the range 150-210 nm, of Poly-, Nano- and Single-Crystalline Diamond (PCD, NCD and SCD) film photocathodes (PCs) are reported and discussed. The diamond films, grown by Microwave Plasma Assisted Chemical Vapour Deposition (MPACVD) technique, have been analyzed with the aim to define which characteristics enhance their QE. It has been found that NCD film PCs, generally showing a lower QE with respect to PCD ones, enhance their photoemission if a graphitic component is present in the film. Surface hydrogenation effects on the photoemissivity of PCs have been investigated. Comparative studies between the QE of an untreated and a hydrogenated-treated diamond film PC show that the hydrogenated sample exhibits Negative Electron Affinity (NEA) properties. An ageing test of 24 h air exposure shows a stability of the hydrogenated diamond PC higher than that of the CsI one. Moreover, the PC conditioning by means of H-2 plasma allows to recover almost completely the loss of PC QE due to ageing effect caused by the air exposure of a previously hydrogenated sample. The sensitivity of PCs depends strongly on the topography of diamond films. (C) 2008 Elsevier B.V. All rights reserved