Compact laser system for a laser-cooled ytterbium ion microwave frequency standard.

The development of a transportable microwave frequency standard based on the ground-state transition of 171Yb+ at ∼12.6 GHz requires a compact laser system for cooling the ions, clearing out of long-lived states and also for photoionisation. In this paper, we describe the development of a suitable compact laser system based on a 6U height rack-mounted arrangement with overall dimensions 260 × 194 × 335 mm. Laser outputs at 369 nm (for cooling), 399 nm (photoionisation), 935 nm (repumping), and 760 nm (state clearout) are combined in a fiber arrangement for delivery to our linear ion trap and we demonstrate this system by cooling of 171Yb+ ions. Additionally, we demonstrate that the lasers at 935 nm and 760 nm are close in frequency to water vapor and oxygen absorption lines, respectively; specifically, at 760 nm, we show that one 171Yb+ transition is within the pressure broadened profile of an oxygen line. These molecular transitions form convenient wavelength references for the stabilization of lasers for a 171Yb+ frequency standard.

Computer analysis of radionuclide esophageal transit studies.

For detailed examination of the esophageal transit of a swallowed radioactive liquid bolus, three computer-based techniques have been developed: (a) analysis of time-activity curves with decomposition into rapid and residual components, yielding the mean transit time for the former and the residual fraction for the latter; (b) reduction of dynamic image sequences to single condensed images, facilitating subjective assessment; and (c) tracking of the centroid of radioactivity, permitting quantification of retrograde motion. Studies were performed on 12 normal subjects and on six patients with motility disorders. Elevated residual fractions were observed in all the patients, and an abnormal degree of retrograde motion in two. Two normal and two abnormal studies exemplify the variety of patterns observed in condensed images.

Simultaneous acquisition of physiological data and nuclear medicine images.

A technique has been developed that allows the simultaneous acquisition of both image and physiological data into a standard nuclear medicine computer system. The physiological data can be displayed along with the nuclear medicine images allowing temporal correlation between the two. This technique has been used to acquire images of gastroesophageal reflux simultaneously with the intraluminal esophageal pH. The resulting data are displayed either as a standard dynamic sequence with the physiological data appearing in a corner of the image or as condensed dynamic images.

Scintigraphy versus pH probe for quantification of pediatric gastroesophageal reflux: a study using concurrent multiplexed data and acid feedings.

We performed 12 simultaneous scintigraphic and pH probe studies in children being evaluated for reflux to determine the ability of scintigraphic images in comparison to pH probe data to quantify gastroesophageal reflux in children and to identify an optimal scintigraphic framing interval. We used a multiplexor to synchronize exactly the scintigraphy and pH probe and an acid meal to avoid missing postprandial episodes with the pH probe. We reformatted the studies in both 60-sec and 10-sec images to compare the two framing intervals. The 60-sec images produced better agreement between pH probe and scintigraphy than the 10-sec images for both the number of reflux episodes and the duration of reflux. Of the 64 reflux episodes detected by either method at this coarser framing interval, scintigraphy detected 80%, the pH probe detected 63% and both methods concurrently detected 42%. Of the 681 60-sec images aggregated across patients, scintigraphy detected 55% of those with intraesophageal refluxate, the pH probe detected 96% and both tests concurrently detected 51%. Within patients, the number of positive scintigraphic images in the postprandial hour correlated with the number of images with pH < 4 during the same hour (p = 0.008, and p < 0.0001 if two patients with very rapid gastric emptying are excluded), but not with the results of the 24-hr pH probe study. A 1-hr scintigraphic study formatted in 60-sec frames provides a quantitative representation of postprandial gastroesophageal reflux for children, particularly if they do not have rapid gastric emptying.

Esophageal transit scintigraphy.

Esophageal transit scintigraphy was introduced over 20 years ago, but its exact role in the evaluation of patients with suspected esophageal motility disorders still remains controversial. The experience with this test supplies clues, if not answers, for the following key questions: "When is it useful?", "How should it be performed?", and "Are there different methods for different applications?" Opinions vary, but it seems at the very least to be useful clinically under the following conditions: (1) when esophageal manometry is unavailable or not tolerated, (2) when manometry is equivocal or negative but a reasonable suspicion of disease remains, and (3) when clinical management will be aided by monitoring for serial change or response to therapy.

Occult purulent pericarditis detected by indium-111 leukocyte imaging.

Leukocyte imaging with indium-111 is a relatively new technique which, to this point in time, has been discussed almost exclusively in the radiologic literature. Although this procedure has been used mainly to detect intra-abdominal infection, the thorax is routinely imaged along with the abdomen, and therefore detection of cardiac disease may be feasible. This case report is of a young woman after liver transplantation who developed occult purulent pericarditis initially detected by a leukocyte scan with indium-111. This case demonstrates that striking pericardial uptake on a whole-body indium-111 leukocyte scan can occur with purulent pericarditis, and it reemphasizes how insidiously purulent pericarditis may present in an immunosuppressed patient.

The effect of projection in esophageal transit scintigraphy.

Data from esophageal transit scintigraphy with swallowing of Tc-99m sulfur colloid in water in the supine position were studied to determine the effect of posterior as compared with anterior imaging. Net attenuation was less with the anterior projection. Nonetheless, the posterior projection is favored because of more uniform attenuation.

Applications of condensed dynamic images.

In appropriate cases, information from a dynamic series of nuclear images may be condensed into a single image with one spatial and one temporal dimension. A useful elaboration of the method consists of the masking out of undesired spatial regions. The versatility of such condensed dynamic images is illustrated by examples derived from gastroesophageal and pulmonary studies. Advantages of the method include obviating the need to examine and comprehend multiple images as well as enabling economical archiving of image data. Its diagnostic potential is particularly evident in esophageal transit and infant gastroesophageal reflux studies.

The scope of false-positive iodine-131 images for thyroid carcinoma.

Iodine-131 is used to detect and treat functioning lesions of papillary and follicular carcinoma of the thyroid. False-positive images although rare, do occur, with major categories being 1) body secretions, 2) pathologic transudates and inflammation, 3) nonspecific mediastinal uptake, and 4) neoplasms of nonthyroidal origin. The authors present eight cases that fall into the first three categories, including three types not previously reported--a lymphoepithelial cyst, a scrotal hydrocele, and a skin burn. The classification of mediastinal uptake as false positive is tentative. High-dose images and those exploiting therapeutic doses have an increased detection rate for both true and spurious lesions. Appropriate caution is advised in the interpretation of I-131 images.

Vertebral hyperemia associated with bone marrow insult and recovery.

A 15-year-old boy with rhabdoid sarcoma received chemotherapy, which was followed by bone marrow depression, massive nosebleeds and, finally, hematologic recovery. On both hepatobiliary and renal scintigraphy, prominent vertebral activity was present in early images. Correlation with his clinical course suggests that the findings reflect hyperemia due to marrow insult and recovery. Radionuclide imaging to detect hyperemia may be a useful probe for drug effects on hematopoietic bone marrow.

Radioxenon ventilation studies with disposable apparatus: technique and application.

Modification of commercially supplied disposable apparatus for radioxenon ventilation imaging solved several problems: occasional poor inhalation of the initial bolus of gas, awkward initiation of the wash-out phase, and building up of pressure against which the patient must exhale in the wash-out phase. Two cases illustrate results of ventilation and perfusion imaging in chronic obstructive pulmonary disease and pulmonary embolism. A third case illustrates results before and after bullectomy, including quantitative data analysis of the wash-out phase. Although long-range economy is possible with permanent equipment, the use of the modified disposable apparatus may be preferable in certain circumstances.

Temperament and self-esteem in late adolescence.

The purpose of this study was to investigate the relationship between temperament and self-esteem (or social competence) among late adolescents. The Dimensions of Temperament Scale and the Short Form of the Texas Social Behavior Inventory were administered to 186 students. It was found that Adaptability, Attention/Distractibility, and Reactivity all showed significant correlations with self-esteem. An interactive framework suggested that temperament may mediate how each individual perceives and experiences social demands and constraints, thereby influencing the level of positive regard and success during development.

Self-perception in late adolescence: an interactive perspective.

Self-perception during late adolescence was examined as a correlate of individual temperament. Harter's Self-Perception Scale for College Students and the Adult Form of the Dimensions of Temperament Survey-Revised were administered to 111 college students. It was found that positive self-perception was generally associated with an approaching, flexible, and positive mood pattern, and with high task orientation. Different aspects of self-perception showed distinct relationships with specific temperament dimensions. Self-perception differences for men and women also were noted. An interactive model was used to explain the research outcomes and to suggest environmental features that might be related to the development of positive self-perception.

Multidimensional self-perception: linkages to parental nurturance.

Childhood experiences are important for developing self-perception. The present study examined the relationship between parental nurturance and Harter's (1988) multidimensional domains of self-perception as well as gender differences in patterns of perceived nurturance. We had 207 college students complete the Neemann & Harter's Self-Perception Profile for College Students (1986) and Buri's Parental Nurturance Scale (1989). Both men and women saw their mothers as more nurturant than they saw their fathers. We found, consistent with previous findings, a positive relationship between parental nurturance and global self-worth. Nurturance also showed a positive relationship with several dimensions of self-perception. This research underscores the importance of nurturance in the development of self-esteem and the usefulness of a multidimensional construct of self-perception.

Parental conflict and self-esteem: the rest of the story.

Previous research has supported the hypothesis that high levels of marital conflict are related to lower self-esteem in children. In this study, 122 young adults completed the Rosenberg Self-Esteem Questionnaire and the Student Interparental Conflict Scale, as well as the Parental Nurturance Scale and the Parental Authority Questionnaire. One parent of each young adult completed the Parent Interparental Conflict Scale, the O'Leary-Porter Overt Hostility Scale, and a modified Parental Authority Questionnaire. Perceived interparental conflict and parental style discrepancies in nurturance and in authoritarianism were significantly and negatively related to self-esteem, but the best predictors of self-esteem were the parental styles themselves. Warm, nurturant parents were more likely to have high self-esteem children and demonstrated less conflict in marital partnerships. Correlations between marital conflict and self-esteem may reflect parental characteristics.

Aging and memory in skilled language performance.

The issue of irreversible decrements versus developmental plasticity with aging was explored for skilled language users. Fifteen English teachers (22 to 31 years of age) and 15 retired English teachers (50 to 83 years of age) were tested for language memory, using a 2 X 2 X 2 (Recall vs. Recognition X Meaningful vs. Nonmeaningful X Incidental vs. Intentional) design, and for overall grammar-skill memory, using speed and error measures. On the language-memory test, experimental variables (but not the age variable) were related to performance. On the grammar-skill test, the older subjects showed longer completion times but no decrements in accuracy. The results provided support for developmental plasticity in language memory and suggested an optimistic view of memory for skilled content areas.

Transformation of stimulus information from very short-term memory.

Observers were shown a simple stimulus pattern, a mask pattern, and a test pattern on each trial. Different types of test patterns were used to assess transformations of material from very short-term memory. The durations of the initial stimulus pattern and the mask pattern were also varied. Significant differences in average response data were found between types of test pattern over exposure durations; however, sensitivity measures showed minimal differences between types of test pattern. This suggested some distinctions between input processing and response selection in the paradigm. Selective feature analysis seems to be a characteristic of response selection.

The relationship of temperament and adjustment in Japanese schools.

We hypothesized that children whose temperaments match the features, demands, and values of their environment will demonstrate a better fit or adjustment to that environment. Culture is one factor that influences the environment. This study examined the temperament ideal held by Japanese teachers (N = 18) as well as the relationship between judged temperament and the adjustment of children (N = 108) in kindergarten, first-, and second-grade Japanese classrooms. A questionnaire assessed a range of temperament for both ideal and actual judgments. Temperament ideals were consistent with previous sociological research. Good adjustment was significantly related to high task orientation, persistence, and flexibility, as well as to an approaching (as opposed to a withdrawing) style and a positive mood. The child who fit the cultural ideal of a "good child" was also perceived as better adjusted to the programs, and to the adults and peers in Japanese schools.

Correlates of life satisfaction among military wives.

Military life includes constant change. This study explored the relationship of life satisfaction among military wives with the individual attitudinal and personality variables of perceived social support, locus of control, and temperament. Sixty wives of noncommissioned military personnel were selected as participants. Life satisfaction was found to be related to high levels of perceived social support from family and from friends, to an internal locus of control, and to low levels of emotionality-stress and emotionality-fear. The results supported the role of individual resources for mediating adjustment and enhancing life satisfaction during the changes inherent in military life. Implications for identifying and helping high-risk women emerged.