Atom-Chip Fountain Gravimeter

We demonstrate a quantum gravimeter by combining the advantages of an atom chip for the generation, delta-kick collimation, and coherent manipulation of freely falling Bose-Einstein condensates (BECs) with an innovative launch mechanism based on Bloch oscillations and double Bragg diffraction. Our high-contrast BEC interferometer realizes tens of milliseconds of free fall in a volume as little as a one centimeter cube and paves the way for measurements with sub-μGal accuracies in miniaturized, robust devices.

Double Bragg Interferometry

We employ light-induced double Bragg diffraction of delta-kick collimated Bose-Einstein condensates to create three symmetric Mach-Zehnder interferometers. They rely on (i) first-order, (ii) two successive first-order, and (iii) second-order processes which demonstrate the scalability of the corresponding momentum transfer. With respect to devices based on conventional Bragg scattering, these symmetric interferometers double the scale factor and feature a better suppression of noise and systematic uncertainties intrinsic to the diffraction process. Moreover, we utilize these interferometers as tiltmeters for monitoring their inclination with respect to gravity.

Composite-light-pulse technique for high-precision atom interferometry

We realize beam splitters and mirrors for atom waves by employing a sequence of light pulses rather than individual ones. In this way we can tailor atom interferometers with improved sensitivity and accuracy. We demonstrate our method of composite pulses by creating a symmetric matter-wave interferometer which combines the advantages of conventional Bragg- and Raman-type concepts. This feature leads to an interferometer with a high immunity to technical noise allowing us to devise a large-area Sagnac gyroscope yielding a phase shift of 6.5 rad due to the Earth's rotation. With this device we achieve a rotation rate precision of 120  nrad s(-1) Hz(-1/2) and determine the Earth's rotation rate with a relative uncertainty of 1.2%.

Interferometry with Bose-Einstein condensates in microgravity

Atom interferometers covering macroscopic domains of space-time are a spectacular manifestation of the wave nature of matter. Because of their unique coherence properties, Bose-Einstein condensates are ideal sources for an atom interferometer in extended free fall. In this Letter we report on the realization of an asymmetric Mach-Zehnder interferometer operated with a Bose-Einstein condensate in microgravity. The resulting interference pattern is similar to the one in the far field of a double slit and shows a linear scaling with the time the wave packets expand. We employ delta-kick cooling in order to enhance the signal and extend our atom interferometer. Our experiments demonstrate the high potential of interferometers operated with quantum gases for probing the fundamental concepts of quantum mechanics and general relativity.

Amino acid uptake by wild and commercial yeasts in single fermentations and co-fermentations

Musts require nitrogen-containing compounds in order to ensure yeast development. This study examined the nitrogen-nutrient requirements of two commercial yeasts and three wild strains isolated from inoculated fermentations. The results showed that wild strains generally consumed lower amounts of amino acids than commercial yeasts. Most amino acids were assimilated during the exponential growth phase; only a few - including asparagine and histidine - were metabolized until the end of fermentation. The study also sought to determine whether industrial drying affected yeast nitrogen requirements.

DNA flow cytometry in node-positive breast cancer. Prognostic value and correlation with morphologic and clinical factors

OBJECTIVE

To help clarify the possible usefulness of nuclear DNA content and S-phase fraction (SPF) as additional prognostic factors in node-positive breast cancer patients because there is increased interest in the development of new factors that might provide more detailed prognostic information.

STUDY DESIGN

We performed a DNA and SPF analysis by flow cytometry using a multivariate statistical model on a group of 139 node-positive breast cancer patients with clearly defined inclusion and exclusion criteria.

RESULTS

The percentage of aneuploidy increased with the number of involved nodes. Aneuploid tumors were more often found among grade 3 and among receptor-negative tumors. Univariate analysis showed a strong effect on recurrence-free survival (RFS) for the number of involved nodes (P < .001) and for tumor size (P = .013). Grade 3 and receptor-negative tumors showed a nonsignificant trend toward increased risk. The relative risk of aneuploid tumors was 1.19 (95% confidence interval, 0.75-1.87). Multivariate analysis revealed only the number of involved nodes to be an independent prognostic factor (P = .002); ploidy showed no effect (P = .684). SPF did not show any significant effect on RFS, even in a univariate analysis.

CONCLUSION

These results suggest that nuclear DNA content and SPF correlate with morphologic factors. Their routine clinical use, however, in node-positive breast cancer patients receiving adjuvant therapy seems to have no clinical relevance and therefore can be omitted.

Steroid receptors in carcinoma of the breast. Results of immunocytochemical and biochemical determination and their effects on short-term prognosis

A group of 241 nonpretreated breast carcinomas was studied for estrogen receptor (ER) and progesterone receptor (PR) content by both immunocytochemistry (ICC) and biochemical analysis (dextran-coated charcoal [DCC]). While the tumors were judged to be ER positive in 67.6% and PR positive in 65.6% by ICC, DCC analysis showed positive results in 77.6% for both ER and PR. There was only a moderate correlation between the semiquantitative results of ER and PR ICC and the corresponding values for DCC receptor determination. Among tumors shown to be steroid receptor positive by ICC, a majority showed a wide spectrum of staining intensity, from negative to intensely positive (type C staining pattern, ER 87.7%, PR 73.4%). Less frequently, carcinomas showing uniform, intense staining of all epithelial tumor cells were observed (type A staining pattern, ER 11.7%, PR 18.4%). Finally, only very few tumors had both clearly negative and distinctly positive cells (type B staining pattern, ER 0.6%, PR 8.2%). On analyzing the relationship between the expression of steroid receptors (ICC and DCC) and the prognostic factors axillary node status, tumor size, tumor histology, grade and patient age, only a significant correlation between patient age and ER (ICC, r = .46; DCC, r = .43), a weakly significant negative correlation between node involvement and ER, and a weakly significant negative correlation between tumor grade and ER (ICC only) as well as between tumor grade and PR were found. Among all patients, the recurrence-free interval was significantly longer in patients with ER- or PR-positive carcinomas (ICC and DCC).(ABSTRACT TRUNCATED AT 250 WORDS)

Single-loop polarization stabilization for single-mode fiber

A simple active control system is described that maintains the output of a single-mode fiber at prescribed polarization and intensity, thus counteracting erratic birefringeance effects in the fiber that are due to temperature drift and mechanical disturbances. Whereas the system of Ulrich [Appl. Phys. Lett. 35, 840 (1979)] controls two polarization parameters by means of two interdependent control loops, ours controls only one parameter and requires only a single control loop. The resulting considerable reduction of optical and electronic system complexity is realized at the expense of about 30-50% of input light intensity.