Test-Retest Reliability of Time-Domain EEG Features to Assess Cognitive Load Using a Wireless Dry-Electrode System.

Human Machine Interfaces (HMIs) can provide critical support and improve daily task functionality for prosthesis users or social interaction for patients with locked-in syndrome using an assistive communication device. One goal in the development of sophisticated HMIs is to reduce the cognitive load (CL) they place on the user to promote the use of the technology. Electroencephalogram (EEG)-derived measures collected with wired wet-electrode systems have been used to assess CL in laboratory environments and have demonstrated acceptable test-retest reliability. Assessment of CL during real-world unconstrained HMI operation, however, requires the use of a wireless dry-electrode EEG system which provides easier electrode application and untethered movement. However, the test-retest reliability of wireless dry-electrode systems to quantify CL has not been explored. Ensuring the consistent capture of CL-related signals across multiple sessions is critical if these devices are to be used to assess how improvements in HMIs affect CL. Therefore, the current study used a wireless dry-electrode EEG system to compare Evoked Response Potential (ERP) features of a simple auditory oddball task to measure CL during two separate testing sessions a week apart. ERPs of 11 subjects were recorded while participants performed a virtual task at two difficulty levels. A significant correlation was found between the P300 component of the ERPs and subjective ratings of CL during both testing sessions. Furthermore, there was a statistically significant test-retest reliability for this same ERP feature and similar signal-to-noise ratios (SNRs) across sessions.Clinical Relevance- This is an initial step in validating wireless dry-electrode EEG systems to assess cognitive load across multiple sessions. The evidence presented is critical if dry-wireless EEG systems are to be used to identify aspects of HMIs that reduce CL in clinical and real-life environments. Assessing CL in unconstrained environments can better inform clinicians and technology developers in their design of future HMIs.

Configuración radicular externa e interna. Su importancia en el éxito del tratamiento endodóntico / Inner and outer root configuration. Its importance on root canal treatment prognosis

Fueron estudiadas 394 piezas dentales de las cuales se midieron la configuración externa; la longitud total y los diámetros mesiodistal y vestibulopalatino; y la configuración interna haciendo cortes transversales de las raíces a nivel de los tercios cervical, medio y apical. Este experiencia nos permitió demostrar con fundamentos anatómicos la insuficiente preparación de los conductos que proponen muchas escuelas endodónticas al trabajar con instrumental de bajo calibre a nivel apical. Siendo conveniente utilizar calibres más importantes en toda la longitud del conducto, respetando la anatomía radicular

394 teeth were studied whose external shape, total lenght and mesiodistal and vestibular palatine diameters were measured. The internal shape was also assessed making transversal cuts of. The roots a the third levels of the cervical, middle and apical. This experience allowed us to show with anatomic grounds the non sufficient preparation of the canals that many endodontic schools propose when they work with low caliber instruments at the apical level. It is more convenient to use more important calibres alone the whole length of the canal, respecting the root anatomy

Occupational exposure to laser surgery generated air contaminants.

The objective of the review is to show that scientific evidence is lacking on the safety of laser-generated air contaminants. Further research and data collection are necessary to characterize the potential dangers associated with exposures of health care professionals to laser generated air contaminants. The article is a review of existing scientific evidence in the area of exposure risks to health care professionals. A careful search of the scientific literature both in medicine and engineering was performed, as well as contact with experts from laser standards advisory sources. These sources include: International Laser Safety Conference, National Institute of Occupational Safety and Health, American National Standard Institute, Laser Safety Institute and Rockwell Laser Industries. The review includes articles in the literature documenting cases of over-exposures to contaminants while using a class IV laser, the same class laser used in surgery. Several studies of case reports of laser-generated air contaminants from cutting on human and animal tissues are included. Articles and guidelines on this subject of laser-generated contaminants from the above listed sources were used in writing this review. The review indicates that lasers used in surgery are potential occupational health risks.

Construct validity of the Commitment to Career Choices Scale among late adolescents: another look.

In response to Stead and Watson (1992), we reassessed the construct validity of the Commitment to Career Choices Scale using an age-constrained sample from our aggregate data base. A confirmatory factor analysis yielded findings comparable to Stead and Watson's results, thereby suggesting that their findings were likely due to using a homogeneous sample with truncated scores. Given the theoretical importance of measuring the full range of the two commitment to career choices continua, it seems premature to delete items from the scales for research with South African university students. Alternatively, we encourage the use of norms to interpret scores from the scales.