Biomedical subjects
Publications and source records attributed to M W Klein.
We present magnetic metamaterials composed of 35 nm minimum feature-size gold split-ring resonators with a fundamental magnetic resonance at a wavelength of 900 nm. Corresponding calculations reveal excellent agreement with the experiments and show that the limits of size scaling have been reached.
The carrier-envelope phase of a laser pulse has recently become an important quantity in extreme nonlinear optics. Because of the topological Gouy phase, it changes while the pulse propagates through the focus of a lens. This variation is measured by a simple solid-state-based approach. The experimental results are analyzed by comparison with simple analytical model calculations.
We present an omnidirectional matter waveguide on an atom chip. The guide is based on a combination of two current-carrying wires and a bias field pointing perpendicular to the chip surface. Thermal atoms are guided for more than two complete turns along a 25-mm-long spiral path (with curve radii as short as 200 microm) at various atom-surface distances (35-450 microm). An extension of the scheme for the guiding of Bose-Einstein condensates is outlined.
We report on experiments with cold thermal (7)Li atoms confined in combined magnetic and electric potentials. A novel type of three-dimensional trap was formed by modulating a magnetic guide using electrostatic fields. We observed atoms trapped in a string of up to six individual such traps, a controlled transport of an atomic cloud over a distance of 400 microm, and a dynamic splitting of a single trap into a double well potential. Applications for quantum information processing are discussed.
Measurements of charge injection from indium tin oxide (ITO) into the organic semiconductor, tetraphenyl diamine doped polycarbonate (PC:TPD), were carried out. The current injected at the contact was measured as a function of the hole mobility in the organic semiconductor, which was varied from 10(-6) to 10(-3) cm (2)/V x s by adjusting the concentration of the hole transport agent, TPD, in the PC host. These experiments reveal that the current injected at the contact is proportional to the hole mobility in the bulk. As a result, the ITO/PC:TPD contact is found to limit current flow in all samples, regardless of the hole mobility in PC:TPD.
The goal of this study was to intraindividually compare a complete versus a fragmented, directly 99mTc-labeled, monoclonal anti-carcinoembryonic antigen (CEA) antibody, with respect to their antigen-targeting kinetics, sensitivity, and diagnostic accuracy in patients with CEA-expressing tumors. Twenty-five patients were investigated with the 99mTc-labeled anti-CEA IgG1 BW 431/26 and the F(ab')2/Fab' fragment mixture F023C5 within 7 days. For quantitative analysis, the region of interest technique was applied to planar scans, whole-body scans, and single photon emission computed tomography slices 10 min to 48 h postinjection (PI). Final correlations were performed according to the histopathology after surgery or biopsy. Earliest tumor detection was possible with complete IgG1 4 h PI (52% of finally positive lesions). Twenty-four- or even 48-h scans were necessary in 48% of finally positive lesions; tumor detection with fragments was possible in 17% at 1 h PI and in 94% at 4 h PI. With both monoclonal antibodies, in 35%, single photon emission computed tomography was necessary for tumor detection. Absolute antibody uptake in tumor lesions was higher with complete monoclonal antibodies than with fragments. The sensitivity of fragments was higher in detecting primary tumors, local recurrences, and lymph node metastases. For detection of liver metastases, sensitivity was also higher for fragments than for IgG (87 versus 73%), but in scintigraphically positive lesions, tumor:background ratios were significantly lower with fragments (1.26 +/- 0.12 versus 1.70 +/- 0.32; P < 0.01). Therefore, fragments seem to be more suitable for earlier detection of lesions known for their good vascularization, vascular permeability, and antigen accessibility, such as local recurrences, lymph node metastases, and peritoneal carcinomatoses. In liver metastases (high interstitial pressure, low vascular leakage), sensitivity of fragments is higher, but their rapid serum and whole-body clearance lead to a lower absolute antibody uptake, with the consequence of significantly lower tumor:background ratios than with IgG.
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UNLABELLED: The goal of this study was to intraindividually compare complete versus fragmented directly labeled 99mTc monoclonal anti-CEA antibody with respect to antigen targeting and tumor uptake kinetics, sensitivity and diagnostic accuracy in colorectal cancer patients. METHODS: Twenty-five patients were investigated with 99mTc-labeled anti-CEA IgG1 BW 431/26 and the F(ab')2/Fab' fragment mixture F023C5 within 7 days. For quantitative analysis, an ROI technique was applied to planar scans, whole-body scans and SPECT slices 10 min to 48 hr postinjection. Final correlations were performed according to histology after surgery or biopsy. RESULTS: Earliest tumor detection with complete IgG1 was possible 4 hr postinjection (52% of finally positive lesions); imaging at 24 hr or even 48 hr was necessary in 48%. Tumor detection with fragments was possible in 17% at 1 hr postinjection and in 94% at 4 hr postinjection. In 35%, SPECT was necessary for tumor detection with both MAbs. Absolute antibody uptake in tumor lesions was higher with complete MAbs than with fragments. CONCLUSIONS: Lesions known for their good vascularization, vascular permeability and antigen accessibility were detected earlier and with higher sensitivity with fragments than with complete MAbs due to faster background clearance despite lower absolute antibody uptake.
A large portion of the research carried out to date on juvenile delinquency and gang behavior has been concentrated on male delinquents. For example, Thrasher's study (1927) of 1,313 gangs in Chicago devoted less than a page to the question of whether or not females form gangs in the same way that males do. When females are included in delinquency studies, their behavior is almost always explained in psychological or social-psychological terms. The general reasoning is that females commit delinquent acts or join delinquent gangs because they are socially maladjusted, come from broken and unhappy homes, and do not relate well to the opposite sex. In this article, we juxtapose this theoretical perspective to a social structural explanation of both female juvenile delinquency and female gang membership, and then test these two alternative explanations for juvenile delinquency using data on black, female juveniles collected in Los Angeles during the mid-1960s.
Data on female participation in gang and non-gang delinquent activities were collected from black male delinquents in Los Angeles County Juvenile Hall by Shimota and Klein in the mid-1960s but never published. These data are presented, and are reanalyzed to show how females were systematically excluded from the planning and action phases of delinquent activities. An unexpected finding from the research is that female presence at the site of a delinquent activity had a suppressing effect on that activity. This material forms a baseline for contemporary, post-women's movement studies of female juvenile delinquency.
Sera from epileptic patients were assayed for phenobarbital and diphenylhydantoin by four different analytical procedures. Quantitative results obtained by radioimmunoassay (I) and enzyme immunoassay (II) were compared to each other and to the results obtained on aliquots of the same sample by gas-liquid chromatography (III) and ultraviolet spectrophotometry (IV). For phenobarbital the correlation coefficients were I vs. II, 0.909; I vs. III, 0.947; II vs. III, 0.917; I vs. IV, 0.950; II vs. IV, 0.953. For diphenylhydantoin the correlation coefficients were I vs. II, 0.953; I vs. III, 0.951; II vs. III, 0.957; I vs. IV, 0.862; II vs. IV, 0.898. The immunoassays can be substituted for liquid chromatography or ultraviolet spectrophotometry without changing the resulting clinical interpretations.
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