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Biomedical subjects

H A Klein

Publications and source records attributed to H A Klein.

At least 19 recordsLinked to original sources
PubMed2004

Hertz-level measurement of the optical clock frequency in a single 88Sr+ ion.

The frequency of the 5s 2S(1/2)-4d 2D(5/2) electric quadrupole clock transition in a single, trapped, laser-cooled 88Sr+ ion has been measured by using an optical frequency comb referenced to a cesium fountain primary frequency standard. The frequency of the transition is measured as 444,779,044,095,484.6 (1.5) hertz, with a fractional uncertainty within a factor of 3 of that of the cesium standard. Improvements required to obtain a cesium-limited frequency measurement are described and are expected to lead to a 88Sr+ optical clock with stability and reproducibility exceeding that of the primary cesium standard.

Journal Article↗
PubMed2004

Measurement of the electric quadrupole moment of the 4d2D5/2 level in 88Sr+.

The quadrupole moment of the 4d (2)D(5/2) level in 88Sr+ has been measured to be 2.6(3)ea(2)(0), where a(0) is the Bohr radius and e the elementary charge. A single laser-cooled strontium ion was confined in an end cap trap with a variable dc quadrupole potential, and measurements were made on the 5s (2)S(1/2)-4d (2)D(5/2) transition at 674 nm using a femtosecond optical frequency comb. This work shows that measurements of the unperturbed 88Sr+ transition frequency with sub-Hz uncertainty are possible and is important in understanding the reproducibility of ion trap optical frequency standards.

Journal Article↗
PubMed1997

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.

Adolescent↗
PubMed1995

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.

Deglutition↗
PubMed1995

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.

Adaptation, Psychological↗
PubMed1993

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.

Adolescent↗
PubMed1993

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.

Child↗
PubMed1992

Comparative studies of esophageal function in systemic sclerosis.

Three modalities for assessing esophageal dysfunction in patients with systemic sclerosis were prospectively compared. Seventeen patients underwent (a) esophageal manometry with measurement of distal esophageal peak contraction pressure amplitude, percentage of peristaltic waves, and lower esophageal sphincter pressure; (b) cine-esophagography with scoring based on residual contrast and the character of visualized waves; and (c) esophageal transit scintigraphy with quantification of residual swallowed tracer. Highly significant correlations were found between scintigraphic residual and cine-esophagography score, between scintigraphic residual and manometric amplitude, and indeed between all pairs of measured esophageal function parameters except those involving lower esophageal sphincter pressure. In addition, scintigraphy and cine-esophagography showed comparable ability to discriminate between patients with abnormal and normal esophageal motor function. Symptoms did not significantly correlate with quantitative parameters, nor did they have diagnostic discriminating ability. Induction of Raynaud's phenomenon in a subgroup of patients had no detectable effect on esophageal function. It was concluded that these three diagnostic modalities are approximately equivalent in their ability to detect esophageal dysmotility in systemic sclerosis and measure its severity.

Adolescent↗
PubMed1992

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.

Adaptation, Psychological↗
PubMed1990

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.

Achievement↗
PubMed1990

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.

Adult↗
PubMed1990

Colorectal carcinoma metastases: detection with In-111-labeled monoclonal antibody CCR 086.

A phase I/II clinical trial with indium-111-labeled antimucin murine monoclonal antibody (MoAb) CCR 086 was conducted. Seventeen patients with histologically proved colorectal carcinoma and known metastatic disease underwent external scintigraphy after administration of 5.5 mCi (203.5 MBq) of In-111 CCR 086 at doses of 5 and 20 mg. Of 25 known lesions, 17 were detected (sensitivity, 68%). The smallest detected lesion in the lung was 1 cm and in the liver was 1.5 cm. The serum half-life of In-111-labeled CCR 086 MoAb was approximately 64 hours. The formation of human antimouse antibody (HAMA) was detected in the serum of four of five patients who received 20 mg of MoAb. No HAMAs were detected in four patients receiving 5 mg of MoAb. No side effects were encountered. Because of effective detection of liver and lung metastases with lower doses (5-20 mg) of CCR 086 conjugated with In-111, further investigations are warranted to assess clinical and therapeutic potentials of CCR 086 in the management of colorectal cancer.

Adult↗
PubMed1989

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.

Adaptation, Psychological↗