On the dependence on bias voltage of the structural evolution of magnetron- sputtered nanocrystalline Cu films during thermal annealing

The nanostructural evolution during heat treatments of DC magnetron-sputtered Cu films deposited at different substrate bias voltages was experimentally studied. A growth chamber equipped with two magnetrons and Kapton windows for in-situ X-ray diffraction was mounted on a six-circle goniometer at a synchrotron beam line. Using Bragg-Brentano X-ray diffraction, the grain size, the texture, and the lattice constant were monitored during thermal annealing. Increasing the substrate bias voltage, the grain growth rate lowered, and the change in texture with time became smaller due to a decrease in the defect concentration. Furthermore, the grain size in the as-deposited films decreased with increasing bias voltage. The activation energy for grain growth was, within experimental errors, the same in all the films.     

Results of a phase II trial with second-line cystemustine at 60 mg/m2 in advanced soft tissue sarcoma: a trial of the EORTC Early Clinical Studies Group

The aim of this phase II trial was to examine the efficacy of a new nitrosourea, cystemustine, in soft tissue sarcoma. Between January 1990 and March 1991, 32 pretreated patients with advanced soft tissue sarcoma were enrolled. Cystemustine was given every 2 weeks at 60 mg/m2 via a 15-min i.v. infusion. All eligible patients were considered evaluable for response and toxicity (WHO criteria). Of the 32 enrolled patients, 4 were ineligible, leaving 28 evaluable patients. All but 1 had been pretreated: 6 with adjuvant chemotherapy, 18 patients with first-line palliative chemotherapy without nitrosourea, 3 with both treatments, and 18 had received radiotherapy. Median age was 54 years (range 20-73) and median performance status was 1 (0-2). One partial response (PR, duration 12 weeks), 2 stable disease and 25 progressions were observed, giving an overall response rate of 3.57% (confidence interval: 0.1-18.4%). Toxicity was mild, and was mainly neutropenia (no grade 3 or 4), thrombocytopenia (3.57% grade 3 and grade 4) and nausea-vomiting (no grade 3 or 4). It should be noted that the treatment for the patient who obtained a PR was third line with no previous response. Cystemustine with this schedule appears to have a low clinical activity and toxicity in advanced soft tissue sarcoma.     

Effects of dietary fiber and salt mixtures on the cholesterol metabolism of rats

The isotopic dilution method, which permits the in vivo measurements of the rates of the processes involved in cholesterol turnover, has been applied to rats fed a commercial stock diet or a basal semipurified diet in which either the nature and proportions of the source of dietary fiber or the salt mixture were changed. The cholesterolemia was about 100 mg/100 g in rats fed agar-agar, cellulose, bran or the stock diet. Pectin addition (5%) lowered significantly the plasma concentration of cholesterol (70 mg/100 g). Changes in the source of dietary fiber or salt mixture have moderate effects on the absorption coefficient of dietary cholesterol (range 58.2%-82%). In comparison to agar-agar, cellulose at 2.3% in the diet significantly lowered this coefficient, but larger amounts of cellulose (6.8% or 12.3%), or pectin (5%) were without effect, while bran addition (10%) tended to slightly decrease cholesterol absorption. Hence, high levels of cellulose in the diet increased the absorption coefficient in comparison to a low cellulose diet. A decrease of this coefficient was also observed when the calcium content of the diet was increased. Cholesterol biosynthesis and fecal excretion were inversely correlated to the absorption coefficient of dietary cholesterol in rats fed all of the semipurified diets indicating, as previously shown, that the intestine was the major source of biosynthesized cholesterol diverted into the plasma. However, feeding a commercial stock diet greatly increased the cholesterogenesis and the fecal elimination of bile acids, suggesting a high hepatic cholesterogenesis.     

Luminescence and bandgap studies of high purity MgXZn1−XTe Ternary Alloys

High purity Mg_XZn_1−XTe alloys in the range of 0 < x < 0.45 have been prepared by the Bridgman technique. Wavelength modulated reflectivity measurements have been performed at 300 K. The structure of the spectra near the fundamen-tal edge is similar to the one for ZnTe. The bandgap va-riation versus the composition x is Eg (x) = 2.271 + 0.7 x + 0.6 x². Cathodoluminescence at 300K and 110K shows a single bandedge narrow peak. The variation with composition of the emission peak energy Ep (X) follows the same law as Eg (x). Undoped crystals are highly resistive (> 10⁵Ωcm) but when phosporus is introduced into the melt, the resis-tivity decreases to 10³ Ωcm.     

EUA and sCER phase II price drivers: Unveiling the reasons for the existence of the EUA–sCER spread

This article studies the price relationships between EU emissions allowances (EUAs) – valid under the EU Emissions Trading Scheme (EU ETS) – and secondary Certified Emissions Reductions (sCERs)—established from primary CERs generated through the Kyoto Protocol's Clean Development Mechanism (CDM). Given the price differences between EUAs and sCERs, financial and industrial operators may benefit from arbitrage strategies by buying sCERs and selling EUAs (i.e. selling the EUA–sCER spread) to cover their compliance position as industrial operators are allowed to use sCERs towards compliance with their emissions cap within the European system up to 13.4%. Our central results show that the spread is mainly driven by EUA prices and market microstructure variables and less importantly, as we would expect, by emissions-related fundamental drivers. This might be justified by the fact that the EU ETS remains the greatest source of CER demand to date.     

Nuclear reaction measurements of 95 MeV/u C interactions on PMMA for hadrontherapy

The ion dose deposition in tissues is characterized by a favorable depth dose profile (i.e. Bragg peak) and a small lateral spread. In order to keep these benefits of ions in cancer treatments, a very high accuracy is required on the dose deposition (±3%). For given target stoichiometry and geometry, the largest uncertainty on the physical dose deposition is due to the ion nuclear fragmentation. We have performed an experiment at GANIL with a 95 MeV/u ¹²C beam on thick tissue equivalent PMMA targets (thicknesses: 5, 10, 15, 20 and 25 mm). The main goals of this experiment are to provide experimental fragmentation data for benchmarking the physical models used for treatment planning. Production rates, energy and angular distributions of charged fragments have been measured. The purpose of this paper is to present the results of this experiment.     

Influence of the 316 L stainless steel interface on the stability and barrier properties of plasma fluorocarbon films

Coatings are known to be one of the more suited strategies to tailor the interface between medical devices and the surrounding cells and tissues once implanted. The development of coatings and the optimization of their adhesion and stability are of major importance. In this work, the influence of plasma etching of the substrate on a plasma fluorocarbon ultrathin coating has been investigated with the aim of improving the stability and the corrosion properties of coated medical devices. The 316 L stainless steel interface was subjected to two different etching sequences prior to the plasma deposition. These plasma etchings, with H(2) and C(2)F(6) as gas precursors, modified the chemical composition and the thickness of the oxide layer and influenced the subsequent polymerization. The coating properties were evaluated using flat substrates submitted to deformation, aging into aqueous medium and corrosion tests. X-ray photoelectron spectroscopy (XPS), time of flight-secondary ion mass spectrometry (ToF-SIMS), ellipsometry, and atomic force microscopy (AFM) were performed to determine the effects of the deformation and the aging on the chemistry and morphology of the coated samples. Analyses showed that plasma etchings were essential to promote reproducible polymerization and film growth. However, the oxide layer thinning due to the etching lowered the corrosion resistance of the substrate and affected the stability of the interface. Still, the deformed samples did not exhibited adhesion and cohesion failure before and after the aging.     

Plasma-hydrogenated low-threshold wide-band 1.3 mu m buried ridge structure laser

The plasma hydrogenation of p-type InP has been applied to the fabrication of buried ridge structure (BRS) lasers. The threshold current, output power and modulation bandwidth of the obtained devices compare favourably with those of more conventional ones fabricated by proton implantation on the same wafer.<>     

Fabrication of a new type of field-effect transistor using neutralisation of shallow donors by atomic hydrogen in n-GaAs (Si)

We describe a new process for the fabrication of GaAs field-effect transistors. This process is based on the neutralisation of shallow donors by atomic hydrogen diffused into a highly silicon-doped epilayer. This original process should be able to produce field-effect transistors with low access resistances. Better linearity and high breakdown voltage are expected owing to the active impurity gradient present in the hydrogenated layer. The first HFETs (hydrogenated FETs) show very encouraging characteristics. For a gate length of 1.2 ?m their typical transconductance is 330 mS/mm and the cutoff frequency is larger than 15 GHz.