An analysis of a puncture wound case with medical intervention

A worker noted a small wound to his thumb when leaving a work site that was undergoing decontamination because of past operations with plutonium (Pu) and americium (Am). Direct surveys of the wound site confirmed the presence of contamination. The chelating agent Ca-DTPA was administered via a nebuliser within an hour after discovery of the wound. External measurements were made of the wound site and wound dressings; 24-h urinary excretion data were collected periodically and the Pu and Am urine content was determined. Zn-DTPA was administered on three occasions. The ICRP Pu systemic model was modified to consider the enhanced urinary excretion following administration of the chelating agents. The analysis indicated that the wound resulted in an initial deposition of 400 Bq 238Pu, 2240 Bq (239/240)Pu and 1060 Bq 241Am. About 70% of the initial wound activity was removed by surgical procedures and less than 1% of the wound activity was removed by chelation therapy. This paper compares the observed urinary excretion data with that indicated by a simulation of the kinetics of the transfer from the wound site and the kinetics of the chelating agent and Pu.     

Dosimetry of radioiodine for embryo and fetus

This paper discusses the biokinetic and dosimetric models adopted in ICRP Publication 88 for the evaluation of fetal doses resulting from maternal intakes of radioiodine. The biokinetic model is used to simulate the behaviour of iodine in both the mother and the fetus. Such simulations provide the basis for the estimation of the dose to the embryo and determine the distribution of maternal iodine at the beginning of the fetal period. The model considers iodine to accumulate in the fetal thyroid from the 11th week. The dose to the fetus delivered following birth is evaluated with the biokinetic and dosimetric models described in ICRP Publication 67. Although a substantial fraction of the emitted energy of electrons and photons is less than 10 keV, conventionally assumed to be non-penetrating radiation, these emissions can escape the small fetal thyroid. Absorbed fractions for both self-dose and crossfire were evaluated for the requirements of radioiodine dosimetry in ICRP Publication 88.     

A systemic biokinetic model for polonium

Although the biokinetics of polonium has been studied extensively, interpretation of the data is complicated by potential differences with species and route of exposure and the questionable reliability of much of the reported excretion data for man. A study was undertaken to identify the data that are most likely to represent the typical behavior of polonium and apply those data to construct an improved, physiologically realistic systemic biokinetic model for polonium in man. Such a model is needed for interpretation of urinary excretion data for workers exposed to 210Po and reconstruction of the radiation doses received by those workers. This paper reviews the database on the biokinetics of polonium and describes a new systemic biokinetic model for polonium in man.     

The Ontogeny of Human Learning in Delay, Long-Delay, and Trace Eyeblink Conditioning.

The ontogeny of associative learning in delay (750-ms conditional stimulus [CS], 650-ms interstimulus interval [ISI]), long-delay (1,350-ms CS, 1,250-ms ISI), and trace (750-ms CS, 500-ms trace interval, 1,250-ms ISI) eyeblink conditioning was examined in 5-month-old human infants and adults. Infants and adults showed different acquisition rates but reached equivalent asymptotes of conditional responses (CRs) in standard delay conditioning. In long-delay and trace conditions, infants exhibited less robust conditioning than adults and minimal ability to appropriately time CRs. During infancy, the ISI, rather than the conditioning procedure, predicted rate and effectiveness of CRs. These findings suggest that higher order cognitive abilities begin emerging early in development. Across ontogeny, however, there are changes in the limits and parameters that support associative learning. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Interactive training versus reading to teach respiratory protection.

A tenet of behavioral education is that interactive training produces superior retention compared with reading. However, this has not often been directly tested and never with practical occupational information in working adults. Adults from diverse occupational backgrounds learned the principles of proper respiratory protection presented (a) in a book, (b) on a computer monitor, (c) through interactive computerized training consisting of textual information and illustrative pictures followed by quizzes and feedback, or (d) passively viewing the information and quizzes in Condition c on a computer monitor. Interactive training produced significantly more correct test answers at immediate posttraining, 1 week, and 2 months. This study demonstrated the superiority of interactive training for teaching occupational safety and health information in working adults. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Approaching and contacting the object another manipulates: A social skill of the 1-year-old.

Assigned 48 11–23 mo old infants at random to 1 of 4 groups distinguished by how an unfamiliar female adult acted on toys. The infant, in a room containing his or her mother and several toys, observed an adult who did nothing with the toys, periodically approached and sat down beside a predesignated toy either in a repetitive way for 1 group or in a varied manner for another. Contrasting which toys the infants of the different groups contacted indicated that the infants systematically went to and contacted the toy that the adult manipulated. Smiling, vocalizing, and gesturing to the adult, being near her, and contacting her were all reliably linked in time to the infants' contacting her toy. Further, the infants duplicated the adult's actions on the toy reliably more often than expected by a chance matching of activity. The findings suggest that approaching and contacting the object another manipulates is a basic social skill of the 1-yr-old; such behavior functions to facilitate the generation of social interaction. (19 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Response functions for computing absorbed dose to skeletal tissues from photon irradiation

The calculation of absorbed dose in skeletal tissues at radiogenic risk has been a difficult problem because the relevant structures cannot be represented in conventional geometric terms nor can they be visualised in the tomographic image data used to define the computational models of the human body. The active marrow, the tissue of concern in leukaemia induction, is present within the spongiosa regions of trabecular bone, whereas the osteoprogenitor cells at risk for bone cancer induction are considered to be within the soft tissues adjacent to the mineral surfaces. The International Commission on Radiological Protection (ICRP) recommends averaging the absorbed energy over the active marrow within the spongiosa and over the soft tissues within 10 microm of the mineral surface for leukaemia and bone cancer induction, respectively. In its forthcoming recommendation, it is expected that the latter guidance will be changed to include soft tissues within 50 microm of the mineral surfaces. To address the computational problems, the skeleton of the proposed ICRP reference computational phantom has been subdivided to identify those voxels associated with cortical shell, spongiosa and the medullary cavity of the long bones. It is further proposed that the Monte Carlo calculations with these phantoms compute the energy deposition in the skeletal target tissues as the product of the particle fluence in the skeletal subdivisions and applicable fluence-to-dose-response functions. This paper outlines the development of such response functions for photons.     

Nonverbal imitation and toddlers' mastery of verbal means of achieving coordinated action.

Fourteen dyads of unfamiliar peers (White, both same gender and mixed gender) were observed longitudinally at 16, 20, 24, 28, and 32 months of age. Verbalizations to the peer were analyzed for their social function with respect to the ongoing nonverbal activity and their temporal and topical coherence to prior talk. Six types of speech ( including verbal directives and topically well-connected speech) increased in frequency only after the peer partners had shown a marked increase in their readiness to imitate each other's nonverbal actions. These same types of speech occurred reliably more often when the peers were engaged in bouts of coordinated action generated largely by means of nonverbal imitative acts than during bouts of less coordinated nonverbal activity. Toddlers, through their nonverbal imitative activity, appear to create joint understandings of what they are doing together that aid in their use and development of verbal means of achieving coordinated action. (PsycINFO Database Record (c) 2010 APA, all rights reserved)