Ambient pressure x-ray photoelectron spectroscopy setup for synchrotron-based in situ and operando atomic layer deposition research.

An ambient pressure cell is described for conducting synchrotron-based x-ray photoelectron spectroscopy (XPS) measurements during atomic layer deposition (ALD) processes. The instrument is capable of true in situ and operando experiments in which it is possible to directly obtain elemental and chemical information from the sample surface using XPS as the deposition process is ongoing. The setup is based on the ambient pressure XPS technique, in which sample environments with high pressure (several mbar) can be created without compromising the ultrahigh vacuum requirements needed for the operation of the spectrometer and the synchrotron beamline. The setup is intended for chemical characterization of the surface intermediates during the initial stages of the deposition processes. The SPECIES beamline and the ALD cell provide a unique experimental platform for obtaining new information on the surface chemistry during ALD half-cycles at high temporal resolution. Such information is valuable for understanding the ALD reaction mechanisms and crucial in further developing and improving ALD processes. We demonstrate the capabilities of the setup by studying the deposition of TiO2 on a SiO2 surface by using titanium(IV) tetraisopropoxide and water as precursors. Multiple core levels and the valence band of the substrate surface were followed during the film deposition using ambient pressure XPS.

Speech sounds learned by sleeping newborns.

It is not yet clear whether humans are able to learn while they are sleeping. Here we show that full-term human newborns can be taught to discriminate between similar vowel sounds when they are fast asleep. It is possible that such sleep training soon after birth could find application in clinical or educational situations.

Fast vigilance decrement in closed head injury patients as reflected by the mismatch negativity (MMN).

Event-related potentials (ERPs) were measured from 24 chronic closed head injury (CHI) patients and 18 age- and education-matched controls. The oddball paradigm was applied while subjects were watching a silent movie. The standard (p=0.8) sound of 75 ms duration had a basic frequency of 500 Hz with harmonic partials of 1000 Hz and 1500 Hz, whereas these frequencies for the pitch deviant were each 10% higher. The frequencies of the duration deviant matched with those of the standard but was 25 ms in duration. The MMN (mismatch negativity), generated by the brain's automatic auditory change-detector mechanism, was elicited by both deviants. No significant differences in the MMN latency or amplitude for either pitch or duration deviants were found between the groups. However, the MMN amplitude for the pitch deviant decreased in the patient group during the experiment considerably faster than in controls, suggesting a faster vigilance decrement in the patients.

Increased distractibility in closed head injury as revealed by event-related potentials.

The present study demonstrates that event-related potentials (ERPs) may be used to reveal increased distractibility as a physiologically measurable condition after chronic closed head injury (CHI). ERPs were recorded from 17 chronic CHI subjects and from 17 healthy age-matched controls. Auditory stimuli consisted of variants of vowel /o/ (standards) occasionally replaced by an /e/ vowel (deviant). Subjects were instructed to ignore auditory stimuli while watching a silent movie. In the constant-standard condition, the vowel /o/ served as the standard and vowel /e/ as the deviant. In the roving-standard condition, four variants of the vowel /o/ were randomly used as standards in the same stimulus block. None of the stimuli were prototypes in the subjects' mother tongues. Deviant stimuli elicited significant MMNs in both groups in both conditions, which were significantly smaller in the roving-standard than in the constant-standard condition. CHI victims showed significantly larger P3a amplitudes than controls in both conditions, apparently reflecting their enhanced involuntary sifting of attention and thus their increased distractibility.

Event-related brain potentials reveal covert distractibility in closed head injuries.

Event-related brain potentials (ERPs) to auditory stimuli were recorded from 11 closed head injured (CHI) and 10 age-matched healthy adults. Auditory stimuli consisted of sequences of repetitive standard tones (600 Hz), occasionally replaced by deviant tones (660 Hz) or by natural novel sounds. Subjects were instructed to ignore auditory stimuli while concentrating on a demanding visuo-motor tracking task. CHI patients showed, in comparison to control subjects, significantly enhanced late P3a component in the ERPs to novel sounds. This suggests that novel stimuli cause greater distraction in CHI patients than in controls, demonstrating that ERPs provide a powerful tool to determine the physiological basis of attentional deficits in CHI patients.

Neuropsychological problems in everyday life: a 5-year follow-up study of young severely closed-head-injured patients.

The aim of this follow-up study was to examine the long-term disabilities and handicaps caused by severe head injuries and their effects on the everyday life of patients and their relatives. The group studied consisted of 19 subjects who had suffered a severe closed-head injury during 1984 and had been rehabilitated in the Käpylä Rehabilitation Center. In 1989 a thorough functional assessment of these patients was carried out. In addition, information concerning the quality of life, activities of daily living (ADL) and social situation was gathered by means of questionnaires filled in by the patient and, if possible, by a close relative. The results indicated the importance of changes in cognitive functions, personality and emotional reactions. Changes in personality and emotional reactions were especially emphasized by the relatives. We also correlated the patients' and their relatives' estimates of the occurrence of memory problems, whereas tests of visual memory, though able to discriminate the brain-injured from normal subjects, did not correlate on a statistically significant level with the estimates of patients and relatives. The implications of the results for methods of assessment and the planning of rehabilitation programmes are discussed.