Study of curtaining effect reduction methods in Inconel 718 using a plasma focused ion beam

The curtaining effect is a common challenge in focused ion beam (FIB) surface preparation. This study investigates methods to reduce this effect during plasma FIB milling of Inconel 718 (nickel-based superalloy). Platinum deposition, silicon mask and XeF2 gas injection were explored as potential solutions. These methods were evaluated for two ion beam current conditions; a high ion beam intensity condition (30 kV-1 µA) and a medium one (30 kV-100 nA) and their impact on curtaining reduction and resulting cross-section quality was assessed quantitatively thanks to topographic measurements done by atomic force microscopy (AFM). XeF2 assistance notably improved cross-section quality at medium current level. Pt deposition and Si mask individually mitigated the curtaining effect, with greater efficacy at 100 nA. Both methods also contributed to reducing cross-section curvature, with the Si mask outperforming Pt deposition. However, combining Pt deposition and Si mask with XeF2 injection led to deterioration of these protective layers and the reappearance of the curtaining effect after a quite short exposure time.

Is a quantitative risk assessment of air quality in underground parking garages possible?

Little information is available about the health risks associated with time spent in underground parking garages. The objective of this study was to determine whether it is possible to quantify the health risks associated with these garages without epidemiologic data on the subject. We followed the standard procedure for health risk assessment. We searched the literature for pollutant concentrations in the air samples of underground parking garages, the hazards associated with their inhalation, and their toxicological reference values. Conditions of occupational and user exposure were estimated by scenarios and taken into account to discuss toxicological reference values by modifying (with Haber's law) the adjustment factors for exposure frequency and duration. Risk quantification was possible for 39 pollutants. Acute exposures to CO and NO2 exceed toxicological reference values, as does chronic exposure to benzene for threshold effects. The risk of a carcinogenic effect associated with benzene may be greater than 10(-5). Excess exposure to air pollution indicators (PM and NO2) is also elevated, judging by the WHO Air Quality Guidelines, and also when comparing to levels with reported effects in epidemiologic studies. The risk associated with underground parking garages can be evaluated only in part. The information available is nonetheless sufficient to justify actions to reduce exposure.

PRACTICAL IMPLICATIONS

The risks associated with exposure in underground parking garages cannot be thoroughly evaluated because of inadequate knowledge of exposures and of the toxicity of pollutants. The available knowledge is nonetheless sufficient to advise that risk management measures should be taken to reduce both acute and chronic exposures.

Prevalence of sexual abuse among patients with functional disorders of the lower gastrointestinal tract

To evaluate the links between gastrointestinal disorders and sexual abuse, we asked 344 patients consulting in a specialized tertiary care university hospital or a gastroenterologist in private practice, if they had been sexually abused. Forty per cent of patients suffering from lower functional digestive disorder gave a history of having been victims of sexual abuse in contrast to only 10% of patients with organic diseases (P < 0.0003). The prevalence was similar in private practice and in the university hospital. Abused patients were more likely to complain of constipation (P < 0.03) and diarrhoea (P < 0.04). Anismus was more frequent in patients who had been sexually abused (P < 0.02). The prevalence of abuse was four times greater in patients with lower than with upper functional motor disorders of the gastrointestinal tract (P < 0.002). This study confirms the large prevalence of a past history of sexual abuse among patients consulting for gastrointestinal tract functional disorder, and this whatever the kind of recruitment may be. It shows the association to be much stronger in patients who have a lower rather than an upper gastrointestinal dysfunction, the major complaint of abused patients being constipation and diarrhoea.

Biofeedback re-education of faecal continence in children

The purpose of this prospective study was to see if pretreatment anorectal motility can predict successful correction of faecal incontinence with biofeedback. Forty-seven consecutive children, aged 5 to 18 years, were treated. They had been treated for idiopathic constipation with faecal impaction, but had remained incontinent (n = 15), had been operated for congenital anorectal malformations of high (n = 19) or low (n = 2) type, or had a number of organic congenital pelvic abnormalities (n = 11). This consecutive series represents our entire experience with biofeedback for faecal incontinence, in the period from January 1 1983 to December 31 1989. In each patient, at the first session, anorectal manometry was performed. Resting pressures in the rectum, upper anal canal and lower anal canal were measured. The threshold of rectal sensation during distension, the maximal pressure during voluntary sphincteric contraction and the time to half decrease of sphincteric pressure because of muscular fatigue were also noted. The patient was then asked to make a voluntary sphincteric contraction, while the rectum was being distended with the volume at threshold for rectal sensation. In subsequent sessions, the rectum was also distended but without warning the patient, who was congratulated when he or she contracted the sphincter immediately after onset of rectal distension. Full continence was the criterion used to classify re-education as a success. Improvement or no change in continence was considered as failure of the treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescents and microcomputers: sex differences, proxemics, task and stimulus variables

Questionnaires concerning attitudes toward use of microcomputers at home, in school, and at video arcades were administered to 879 high school students. Direct observations of adolescent proxemics and sex differences, and of various parameters of video games in 18 video arcades were made. A thorough and representative content analysis of sex bias of microcomputer software advertising brochures was carried out. Results supported previous findings of overrepresentation of masculine culture in the adolescent world of microcomputers, particularly regarding video games. Various types of computer-related activity were not related to socioeconomic class of the parents or to academic grades except for use of home microcomputers, which was mildly positively related to socioeconomic class (r = .124, p less than .001). Nearly half the activity in the arcades was strictly solitary. None of the arcade video games allowed for cooperative play. Most allowed only for sequential competition (86%) or simultaneous competition (7%); as many as 7% did not provide a display of the scores for a second player.

Sleep positions and postural shifts in elderly persons

The sleep characteristics and the body positions of four men and four women ranging in age from 65 to 75 yr. were monitored in the laboratory for 2 consecutive nights preceded by 2 adaptation nights. Overall, there was an average of 16 position shifts per night with duration of position averaging 33 min. The preferred trunk positions were on the right side (55%) and the least frequent on the stomach (2%) and limited to waking episodes. Back positions occurred for 19% of sleeptime and left positions for 22%. The preference for the right side and the absence of stomach postures during sleep which appear to be characteristic of elderly persons may respectively be related to cardiovascular and respiratory functions.