Dislocation-mediated relaxation in nanograined columnar palladium films revealed by on-chip time-resolved HRTEM testing

The high-rate sensitivity of nanostructured metallic materials demonstrated in the recent literature is related to the predominance of thermally activated deformation mechanisms favoured by a large density of internal interfaces. Here we report time-resolved high-resolution electron transmission microscopy creep tests on thin nanograined films using on-chip nanomechanical testing. Tests are performed on palladium, which exhibited unexpectedly large creep rates at room temperature. Despite the small 30-nm grain size, relaxation is found to be mediated by dislocation mechanisms. The dislocations interact with the growth nanotwins present in the grains, leading to a loss of coherency of twin boundaries. The density of stored dislocations first increases with applied deformation, and then decreases with time to drive additional deformation while no grain boundary mechanism is observed. This fast relaxation constitutes a key issue in the development of various micro- and nanotechnologies such as palladium membranes for hydrogen applications.

Nanostructured metallic materials involve a high rate sensitivity usually resulting from grain boundary related mechanisms. Here, the authors report mechanical tests on freestanding Pd thin films and show that creep is associated with dislocations rather than grain boundaries.

CAGE, RAPS4, RAPS4-QF and AUDIT screening tests for men and women admitted for acute alcohol intoxication to an emergency department: are standard thresholds appropriate?

AIMS

A number of screening instruments are routinely used in Emergency Department (ED) situations to identify alcohol-use disorders (AUD). We wished to study the psychometric features, particularly concerning optimal thresholds scores (TSs), of four assessment scales frequently used to screen for abuse and/or dependence, the cut-down annoyed guilty eye-opener (CAGE), Rapid Alcohol Problem Screen 4 (RAPS4), RAPS4-quantity-frequency and AUD Identification Test (AUDIT) questionnaires, particularly in the sub-group of people admitted for acute alcohol intoxication (AAI).

METHODS

All included patients [AAI admitted to ED (blood alcohol level ≥0.8 g/l)] were assessed by the four scales, and with a gold standard (alcohol dependence/abuse section of the Mini International Neuropsychiatric Interview), to determine AUD status. To investigate the TSs of the scales, we used Youden's index, efficiency, receiver operating characteristic (ROC) curve techniques and quality ROC curve technique for optimized TS (indices of quality).

RESULTS

A total of 164 persons (122 males, 42 females) were included in the study. Nineteen (11.60%) were identified as alcohol abusers alone and 128 (78.1%) as alcohol dependents (DSM-IV). Results suggest a statistically significant difference between men and women (P < 0.05) in performance of the screening tests RAPS4 (≥1) and CAGE (≥2) for detecting abuse. Also, in this population, we show an increase in TSs of RAPS4 (≥2) and CAGE (≥3) for detecting dependence compared with those typically accepted in non-intoxicated individuals. The AUDIT test demonstrates good performance for detecting alcohol abuse and/or alcohol-dependent patients (≥7 for women and ≥12 for men) and for distinguishing alcohol dependence (≥11 for women and ≥14 for men) from other conditions.

CONCLUSION

Our study underscores for the first time the need to adapt, taking into account gender, the thresholds of tests typically used for detection of abuse and dependence in this population.

Hospital morbidity of alcohol use disorders in the center of France

BACKGROUND

The Auvergne region of central France has the third highest mortality rate in the country for alcohol-related disorders and the highest level of alcohol consumption among young people.

METHODS

An exhaustive cross-sectional study of regional hospital morbidity related to alcohol was undertaken on a single day in May 1998, including 9,552 hospital beds. All inpatients age 16 and older in the Departments of Medicine, Surgery, Obstetrics and Gynecology, Psychiatry, and Medium-Stay Services were studied. The aim was to define alcohol-related behavior patterns (by using the Diagnostic and Statistical Manual of Mental Disorders [DSM-IV] criteria of abuse and dependence and the CAGE questionnaire) and to measure the proportion of nonsomatic alcohol-related care dispensed in hospital.

RESULTS AND CONCLUSIONS

The prevalence of alcohol use disorders in all wards was 20%. Half of these patients were alcohol dependent, a quarter were diagnosed as alcohol abusers, and a quarter had an alcohol-related problem that was not identified during the stay. Alcohol use disorders were more common in male inpatients (34% vs. 8% in female inpatients) and in certain age groups. One male subject in two and one female subject in five between 34 and 45 years had an alcohol-related problem. Almost 25% of male inpatients studied between the ages of 16 and 20 years had an alcohol-related problem, but only half had been diagnosed previously. Hospital care for alcohol-related health problems was seriously inadequate. On average, 38% of patients diagnosed with an alcohol use disorder received relevant nonsomatic alcohol care, of which 13% were alcohol abusers and 50% were alcohol-dependent patients.

SIGNIFICANCE

This exhaustive study demonstrates the degree of alcohol-related morbidity among hospitalized patients, which is particularly high in men, in the Auvergne region of France. The study emphasizes the lack of diagnosis, particularly for the young, and the apparent deficiencies in the hospital management of these patients.