Large-Momentum-Transfer Atom Interferometers with μrad-Accuracy Using Bragg Diffraction

Large-momentum-transfer (LMT) atom interferometers using elastic Bragg scattering on light waves are among the most precise quantum sensors to date. To advance their accuracy from the mrad to the μrad regime, it is necessary to understand the rich phenomenology of the Bragg interferometer, which differs significantly from that of a standard two-mode interferometer. We develop an analytic model for the interferometer signal and demonstrate its accuracy using comprehensive numerical simulations. Our analytic treatment allows the determination of the atomic projection noise limit of a LMT Bragg interferometer and provides the means to saturate this limit. It affords accurate knowledge of the systematic phase errors as well as their suppression by 2 orders of magnitude down to a few μrad using appropriate light-pulse parameters.

Momentum Entanglement for Atom Interferometry

Compared to light interferometers, the flux in cold-atom interferometers is low and the associated shot noise is large. Sensitivities beyond these limitations require the preparation of entangled atoms in different momentum modes. Here, we demonstrate a source of entangled atoms that is compatible with state-of-the-art interferometers. Entanglement is transferred from the spin degree of freedom of a Bose-Einstein condensate to well-separated momentum modes, witnessed by a squeezing parameter of -3.1(8)  dB. Entanglement-enhanced atom interferometers promise unprecedented sensitivities for quantum gradiometers or gravitational wave detectors.

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.

Concentrations of hormones, pharmaceuticals and other micropollutants in groundwater affected by septic systems in New England and New York

Septic-system discharges can be an important source of micropollutants (including pharmaceuticals and endocrine active compounds) to adjacent groundwater and surface water systems. Groundwater samples were collected from well networks tapping glacial till in New England (NE) and sandy surficial aquifer New York (NY) during one sampling round in 2011. The NE network assesses the effect of a single large septic system that receives discharge from an extended health care facility for the elderly. The NY network assesses the effect of many small septic systems used seasonally on a densely populated portion of Fire Island. The data collected from these two networks indicate that hydrogeologic and demographic factors affect micropollutant concentrations in these systems. The highest micropollutant concentrations from the NE network were present in samples collected from below the leach beds and in a well downgradient of the leach beds. Total concentrations for personal care/domestic use compounds, pharmaceutical compounds and plasticizer compounds generally ranged from 1 to over 20 μg/L in the NE network samples. High tris(2-butoxyethyl phosphate) plasticizer concentrations in wells beneath and downgradient of the leach beds (>20 μg/L) may reflect the presence of this compound in cleaning agents at the extended health-care facility. The highest micropollutant concentrations for the NY network were present in the shoreline wells and reflect groundwater that is most affected by septic system discharges. One of the shoreline wells had personal care/domestic use, pharmaceutical, and plasticizer concentrations ranging from 0.4 to 5.7 μg/L. Estradiol equivalency quotient concentrations were also highest in a shoreline well sample (3.1 ng/L). Most micropollutant concentrations increase with increasing specific conductance and total nitrogen concentrations for shoreline well samples. These findings suggest that septic systems serving institutional settings and densely populated areas in coastal settings may be locally important sources of micropollutants to adjacent aquifer and marine systems.

[Normative Data of Pharyngeal and Upper Esophageal Sphincter High Resolution Manometry]

BACKGROUND

High resolution manometry (HRM) can provide information about the muscular contraction of the pharynx and the upper esophageal sphincter (UES) and represents an important tool in the diagnostics of dysphagia. To compare the results of swallowing studies interindividually and to identify pathological swallows, normative data are necessary. Normative data for the use of an HRM-probe with a large diameter has already been published. As previously has been shown these probes can influence the normal contraction of the pharynx and the UES. In this study comprehensive normal values are presented for small HRM-probes in diameter (2 mm), that only minimally affect pharyngeal and UES contractions.

METHOD

29 healthy volunteers underwent pharyngeal and upper esophageal HRM. All subjects performed 10 water swallows of 2 ml in an upright position. Pressure and time dependent parameters of the velopharyngeal region, the tongue base and the UES have been evaluated. Mean and median values and different percentile ranges were calculated.

RESULTS

The normative values for the key parameters were (mean±SD): maximum velopharyngeal pressure 269.9±113.1 mmHg, maximum tongue base pressure 278±93.6 mmHg, maximum UES pressure 205.8±64.0 mmHg, UES resting pressure 42.5±18.7 mmHg and relaxation time of the UES 681.6±86.8 ms. Further parameters have been measured.

CONCLUSION

Time dependent values are comparable to those already published. Especially in the UES lower pressures can be measured when a small HRM-probe is used. The normative data established in this study might help to distinguish pathological from physiological swallows using HRM.

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%.

Molecular wires – impact of π-conjugation and implementation of molecular bottlenecks

We highlight recent progress in the field of electron transport through molecular bridges as integrative parts of electron donor–bridge–acceptor conjugates.

Secondary prophylaxis in an adult patient with severe haemophilia A. Factor VIII consumption and effectiveness

Primary prophylaxis has been proven as the gold standard for preserving joint function in severe haemophilia. Secondary prophylaxis in children has also been shown to have a more beneficial effect on joint protection as on-demand treatment. The outcome of delayed secondary prophylaxis started in adulthood is rarely studied. The case of a man (age: 47 years) with severe haemophilia A demonstrates the successful switch from on-demand therapy to prophylaxis with subsequent reduction of annual bleeding rate and number of days of work lost. The small increase of factor VIII consumption (16%) and the decrease of bleeding rate are compared with data from two recently published prospective studies.

CONCLUSION

An optimal dosing schedule needs to be discussed and larger and longer prospective studies targeting the benefits of secondary prophylaxis with factor VIII started in adulthood are necessary.

Comparison of bacterial adhesion and cellular proliferation on newly developed three-dimensional scaffolds manufactured by rapid prototyping technology

Scaffolds used in the field of tissue engineering should facilitate the adherence, spreading, and ingrowth of cells as well as prevent microbial adherence. For the first time, this study simultaneously deals with microbial and tissue cell adhesion to rapid prototyping-produced 3D-scaffolds. The cell growth of human osteosarcoma cells (CAL-72) over a time period of 3-11 days were examined on three scaffolds (PLGA, PLLA, PLLA-TCP) and compared to the adhesion of salivary microorganisms and representative germs of the oral flora (Porphyromonas gingivalis, Prevotella nigrescens, Candida albicans, Enterococcus faecalis, Streptococcus mutans, and Streptococcus sanguinis). Scanning electron microscopy (SEM), cell proliferation measurements, and determination of the colony forming units (CFU) were performed. The cell proliferation rates on PLLA and PLLA-TCP after 3, 7, and 11 days of cultivation were higher than on PLGA. On day 3 the proliferation rates on PLLA and PLLA-TCP, and on day 5 on PLLA-TCP, proved to be significantly higher compared to that of the control (culture plate). The strain which showed the most CFUs on all of the investigated scaffolds was P. gingivalis, followed by E. faecalis. No significant CFU differences were determined examining P. gingivalis among the biomaterials. In contrast, E. faecalis was significantly more adherent to PLGA and PLLA compared to PLLA-TCP. The lowest CFU values were seen with C. albicans and P. nigrescens. Salivary born aerobic and anaerobic microorganisms adhered significantly more to PLGA compared to PLLA-TCP. These results supported by SEM point out the high potential of PLLA-TCP in the field of tissue engineering.