A load-lock compatible system for in situ electrical resistivity measurements during thin film growth.

An experimental setup designed for in situ electrical resistance measurement during thin film growth is described. The custom-built sample holder with a four-point probe arrangement can be loaded into a high-vacuum magnetron sputter-deposition chamber through a load-lock transfer system, allowing measurements on series of samples without venting the main chamber. Electrical contact is ensured with circular copper tracks inserted in a Teflon plate on a mounting holder station inside the deposition chamber. This configuration creates the possibility to measure thickness-dependent electrical resistance changes with sub-monolayer resolution and is compatible with use of sample rotation during growth. Examples are presented for metallic films with high adatom mobility growing in a Volmer-Weber mode (Ag and Pd) as well as for refractory metal (Mo) with low adatom mobility. Evidence for an amorphous-to-crystalline phase transition at a film thickness of 2.6 nm is reported during growth of Mo on an amorphous Si underlayer, supporting previous findings based on in situ wafer curvature measurements.

Inception and validation of a pressure ulcer risk scale in oncology.

OBJECTIVE: To create and validate a specific tool to evaluate the pressure ulcer risk in cancer patients. METHOD: The Pressure Ulcer Scale in Oncology (PUSO) was developed and subsequently validated against the Norton and Braden scales in order to efficiently and reliably evaluate the pressure ulcer risk in adult cancer patients, with various sites and stages of the illness (both curative and palliative phases). Two series of prevalence surveys (three surveys over two days, at two-month intervals) were conducted in one and then two French Cancer Centres in 2002 and 2009, respectively. The surveys investigated a total of 933 patients. RESULTS: Multivariate logistic regression analysis identified three key items as being predictive of the development of pressure ulcers in cancer patients (mobility, incontinence and moisture/shearing), all with similar odds ratio weighting. A score was defined using this logistic model, the PUSO score (0-3)=bedridden/chair-ridden + incontinence + moisture/shearing. CONCLUSION: The extreme simplicity of this scale may appear disconcerting, but the PUSO is a simple, reliable and validated tool, which allows standardised evaluation of each patient's risk and, thereby, rapid introduction of appropriate measures.

Influence of phase transformation on stress evolution during growth of metal thin films on silicon.

In situ stress measurements during two-dimensional growth of low mobility metal films on amorphous Si were used to demonstrate the impact of interface reactivity and phase transformation on stress evolution. Using Mo1-xSix films as examples, the results show that the tensile stress rise, which develops after the film has become crystalline, is correlated with an increase in lateral grain size. The origin of the tensile stress is attributed to the volume change resulting from the alloy crystallization, which occurs at a concentration-dependent critical thickness.

Antiphase dynamics and chaos in self-pulsing erbium-doped fiber lasers.

We present experimental evidence of antiphase dynamics in self-pulsing erbium-doped fiber lasers operating simultaneously at 1.536- and 1.55-microm wavelengths. Autonomous chaos is also observed for several ranges of pumping rates. The fractal dimension of the chaotic attractor, calculated from experimental data by use of the Procaccia method, is found to depend on the pumping ratio but always remains smaller than 4.1, regardless of the chaotic regime considered.

A comparative study of cyproheptadine and DL carnitine on psychomotor performance and memory in healthy volunteers.

This study was performed in order to investigate the extent and severity of cyproheptadine effects on psychomotor performance, mood and memory functions and to compare them to the effects of DL carnitine, another appetite stimulant. Twelve healthy volunteers received 2 doses (at 800 am and 1200 am) of 6 mg cyproheptadine, 1600 mg DL carnitine and placebo on separate days at a weekly intervals. The study followed a double-blind, latin-square design. Assessment of dependent variables was performed 1 h after the first and 1 h and 5 h after the second administration of the drug. On each of these occasions, the following measurements were performed: choice reaction time (CRT), critical flicker fusion (CFF), digit symbol substitution test (DSST), short-term memory (paired words association test), long-term memory (picture test) and 100 mm visual analogue scales of subjective ratings (VAS). Cyproheptadine significantly impaired objective measures (CFF) and subjective ratings both at 1 h and 5 h after the second dosage. Compared with cyproheptadine, DL carnitine induced a slight improvement in psychomotor performance as assessed by CRT. None of the drugs had any effect on memory and on appetite at the doses studied. In conclusion, cyproheptadine at usual doses had a sedative effect, the intensity and duration of which implied a certain risk in performing daytime functions eg when driving, or manipulating machines. DL carnitine had no effect on vigilance.