Multiphoton Atom Interferometry via Cavity-Enhanced Bragg Diffraction.

We present a novel atom interferometer configuration that combines large momentum transfer with the enhancement of an optical resonator for the purpose of measuring gravitational strain in the horizontal directions. Using Bragg diffraction and taking advantage of the optical gain provided by the resonator, we achieve momentum transfer up to 8ℏk with mW level optical power in a cm-sized resonating waist. Importantly, our experiment uses an original resonator design that allows for a large resonating beam waist and eliminates the need to trap atoms in cavity modes. We demonstrate inertial sensitivity in the horizontal direction by measuring the change in tilt of our resonator. This result paves the way for future hybrid atom or optical gravitational wave detectors. Furthermore, the versatility of our method extends to a wide range of measurement geometries and atomic sources, opening up new avenues for the realization of highly sensitive inertial atom sensors.

Community, Time, and (Con)text: A Dynamical Systems Analysis of Online Communication and Community Health among Open-Source Software Communities.

Free and open-source software projects have become essential digital infrastructure over the past decade. These projects are largely created and maintained by unpaid volunteers, presenting a potential vulnerability if the projects cannot recruit and retain new volunteers. At the same time, their development on open collaborative development platforms provides a nearly complete record of the community's interactions; this affords the opportunity to study naturally occurring language dynamics at scale and in a context with massive real-world impact. The present work takes a dynamical systems view of language to understand the ways in which communicative context and community membership shape the emergence and impact of language use-specifically, sentiment and expressions of gratitude. We then present evidence that these language dynamics shape newcomers' likelihood of returning, although the specific impacts of different community responses are crucially modulated by the context of the newcomer's first contact with the community.

Degradation of dibutyl phthalate by Paenarthrobacter sp. Shss isolated from Saravan landfill, Hyrcanian Forests, Iran.

Phthalic acid esters are predominantly used as plasticizers and are industrially produced on the million ton scale per year. They exhibit endocrine-disrupting, carcinogenic, teratogenic, and mutagenic effects on wildlife and humans. For this reason, biodegradation, the major process of phthalic acid ester elimination from the environment, is of global importance. Here, we studied bacterial phthalic acid ester degradation at Saravan landfill in Hyrcanian Forests, Iran, an active disposal site with 800 tons of solid waste input per day. A di-n-butyl phthalate degrading enrichment culture was established from which Paenarthrobacter sp. strain Shss was isolated. This strain efficiently degraded 1 g L-1 di-n-butyl phthalate within 15 h with a doubling time of 5 h. In addition, dimethyl phthalate, diethyl phthalate, mono butyl phthalate, and phthalic acid where degraded to CO2, whereas diethyl hexyl phthalate did not serve as a substrate. During the biodegradation of di-n-butyl phthalate, mono-n-butyl phthalate was identified in culture supernatants by ultra-performance liquid chromatography coupled to electrospray ionization quadrupole time-of-flight mass spectrometry. In vitro assays identified two cellular esterase activities that converted di-n-butyl phthalate to mono-n-butyl phthalate, and the latter to phthalic acid, respectively. Our findings identified Paenarthrobacter sp. Shss amongst the most efficient phthalic acid esters degrading bacteria known, that possibly plays an important role in di-n-butyl phthalate elimination at a highly phthalic acid esters contaminated landfill.

Prevalence and differences of ideal cardiovascular health in urban and rural adolescents in the Region of Tyrol: results from the EVA Tyrol study.

PURPOSE: Early adoption of a healthy lifestyle has positive effects on cardiovascular health (CVH) in adulthood. In this study, we aimed to assess CVH metrics in a cohort of healthy teenagers with focus on differences between rural and urban areas. METHODS: The Early Vascular Aging (EVA) Tyrol study is a population-based non-randomized controlled trial, which prospectively enrolled 14- to 19-year-old adolescents in North Tyrol, Austria and South Tyrol, Italy between 2015 and 2018. Data from the baseline and control group (prior to health intervention) are included in the current analysis. CVH determinants (smoking, body mass index, physical activity, dietary patterns, systolic and diastolic blood pressure, total cholesterol and fasting blood glucose) were assessed and analyzed for urban and rural subgroups separately by univariate testing. Significant variables were added in a generalized linear model adjusted for living in urban or rural area with age and sex as covariates. Ideal CVH is defined according to the guidelines of the American Heart Association. RESULTS: 2031 healthy adolescents were enrolled in the present study (56.2% female, mean age 16.5 years). 792 adolescents (39.0%) were from urban and 1239 (61.0%) from rural areas. In 1.3% of adolescents living in urban vs. 1.7% living in rural areas all CVH determinants were in an ideal range. Compared to the rural group, urban adolescents reported significantly longer periods of moderate to vigorous-intensive activity (median 50.0 min/day (interquartile range 30-80) vs. median 40.0 min/day (interquartile range 25-60), p < 0.01). This observation remained significant in a generalized linear model (p < 0.01). There were no significant differences between the study groups regarding all other CVH metrics. CONCLUSION: The low prevalence of ideal CVH for adolescents living in urban as well as rural areas highlights the need for early health intervention. Geographic differences must be taken into account when defining targeted subgroups for health intervention programs.

Tailoring Multiloop Atom Interferometers with Adjustable Momentum Transfer.

Multiloop matter-wave interferometers are essential in quantum sensing to measure the derivatives of physical quantities in time or space. Because multiloop interferometers require multiple reflections, imperfections of the matter-wave mirrors create spurious paths that scramble the signal of interest. Here, we demonstrate a method of adjustable momentum transfer that prevents the recombination of the spurious paths in a double-loop atom interferometer aimed at measuring rotation rates. We experimentally study the recombination condition of the spurious matter waves, which is quantitatively supported by a model accounting for the coherence properties of the atomic source. We finally demonstrate the effectiveness of the method in building a cold-atom gyroscope with a single-shot acceleration sensitivity suppressed by a factor of at least 50. Our study will impact the design of multiloop atom interferometers that measure a single inertial quantity.

A fibered laser system for the MIGA large scale atom interferometer.

We describe the realization and characterization of a compact, autonomous fiber laser system that produces the optical frequencies required for laser cooling, trapping, manipulation, and detection of 87Rb atoms - a typical atomic species for emerging quantum technologies. This device, a customized laser system from the Muquans company, is designed for use in the challenging operating environment of the Laboratoire Souterrain à Bas Bruit (LSBB) in France, where a new large scale atom interferometer is being constructed underground - the MIGA antenna. The mobile bench comprises four frequency-agile C-band Telecom diode lasers that are frequency doubled to 780 nm after passing through high-power fiber amplifiers. The first laser is frequency stabilized on a saturated absorption signal via lock-in amplification, which serves as an optical frequency reference for the other three lasers via optical phase-locked loops. Power and polarization stability are maintained through a series of custom, flexible micro-optic splitter/combiners that contain polarization optics, acousto-optic modulators, and shutters. Here, we show how the laser system is designed, showcasing qualities such as reliability, stability, remote control, and flexibility, while maintaining the qualities of laboratory equipment. We characterize the laser system by measuring the power, polarization, and frequency stability. We conclude with a demonstration using a cold atom source from the MIGA project and show that this laser system fulfills all requirements for the realization of the antenna.

Interleaved atom interferometry for high-sensitivity inertial measurements.

Cold-atom inertial sensors target several applications in navigation, geoscience, and tests of fundamental physics. Achieving high sampling rates and high inertial sensitivities, obtained with long interrogation times, represents a challenge for these applications. We report on the interleaved operation of a cold-atom gyroscope, where three atomic clouds are interrogated simultaneously in an atom interferometer featuring a sampling rate of 3.75 Hz and an interrogation time of 801 ms. Interleaving improves the inertial sensitivity by efficiently averaging vibration noise and allows us to perform dynamic rotation measurements in a so far unexplored range. We demonstrate a stability of 3 × 10-10 rad s-1 , which competes with the best stability levels obtained with fiber-optic gyroscopes. Our work validates interleaving as a key concept for future atom-interferometry sensors probing time-varying signals, as in on-board navigation and gravity gradiometry, searches for dark matter, or gravitational wave detection.

Exploring gravity with the MIGA large scale atom interferometer.

We present the MIGA experiment, an underground long baseline atom interferometer to study gravity at large scale. The hybrid atom-laser antenna will use several atom interferometers simultaneously interrogated by the resonant mode of an optical cavity. The instrument will be a demonstrator for gravitational wave detection in a frequency band (100 mHz-1 Hz) not explored by classical ground and space-based observatories, and interesting for potential astrophysical sources. In the initial instrument configuration, standard atom interferometry techniques will be adopted, which will bring to a peak strain sensitivity of [Formula: see text] at 2 Hz. This demonstrator will enable to study the techniques to push further the sensitivity for the future development of gravitational wave detectors based on large scale atom interferometers. The experiment will be realized at the underground facility of the Laboratoire Souterrain à Bas Bruit (LSBB) in Rustrel-France, an exceptional site located away from major anthropogenic disturbances and showing very low background noise. In the following, we present the measurement principle of an in-cavity atom interferometer, derive the method for Gravitational Wave signal extraction from the antenna and determine the expected strain sensitivity. We then detail the functioning of the different systems of the antenna and describe the properties of the installation site.

Validation of the GeneXpert® CT/NG Assay for use with Male Pharyngeal and Rectal Swabs.

OBJECTIVES: The GeneXpert® CT/NG (Cepheid, Sunnyvale, CA) assay is a point-of-care (POC) molecular diagnostic assay designed to rapidly test for the presence of Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (GC). However, the test is only approved for vaginal swabs, urine, and endocervical swabs. Here, we performed an evaluation of the GeneXpert® CT/NG assay to detect the presence of CT and GC on male pharyngeal and rectal swabs. METHODS: Men who have sex with men participating in an HIV and Sexually Transmitted Infection (STI) screening program providing consent were enrolled into the study. Participants were asked to self-collect two pharyngeal and two rectal swabs. One set was tested on site using GeneXpert® and the other was sent to a reference lab for molecular testing using the APTIMA® system (Hologic, San Diego, CA). RESULTS: A total of 570 swabs were collected from 144 patients. GeneXpert® detected 13/15 rectal swabs testing CT positive by the APTIMA® assay (relative sensitivity=88.2%), 1/2 pharyngeal swabs testing CT positive (relative sensitivity=50%), and 7/9 pharyngeal swabs testing NG positive (relative sensitivity =77.8%). No discordance was observed for rectal NG swabs. CONCLUSIONS: Although less sensitive than the APTIMA® assay for the molecular detection of NG and CT, GeneXpert®'s potential as a rapid POC diagnostic still make it a viable diagnostic test for STI screening. Molecular POC diagnostics, such as this, will allow more thorough screening of at risk individuals, and enhance the ability of clinics to provide same-day diagnosis and treatment.

Continuous Cold-Atom Inertial Sensor with 1 nrad/sec Rotation Stability.

We report the operation of a cold-atom inertial sensor which continuously captures the rotation signal. Using a joint interrogation scheme, where we simultaneously prepare a cold-atom source and operate an atom interferometer (AI), enables us to eliminate the dead times. We show that such continuous operation improves the short-term sensitivity of AIs, and demonstrate a rotation sensitivity of 100 nrad/sec/sqrt[Hz] in a cold-atom gyroscope of 11 cm^{2} Sagnac area. We also demonstrate a rotation stability of 1 nrad/sec at 10^{4} sec of integration time, which represents the state of the art for atomic gyroscopes. The continuous operation of cold-atom inertial sensors will lead to large area AIs at their full sensitivity potential, determined by the quantum noise limit.

Cooling of a One-Dimensional Bose Gas.

We experimentally study the dynamics of a degenerate one-dimensional Bose gas that is subject to a continuous outcoupling of atoms. Although standard evaporative cooling is rendered ineffective by the absence of thermalizing collisions in this system, we observe substantial cooling. This cooling proceeds through homogeneous particle dissipation and many-body dephasing, enabling the preparation of otherwise unexpectedly low temperatures. Our observations establish a scaling relation between temperature and particle number, and provide insights into equilibration in the quantum world.

Haemodynamic characterisation and heart catheterisation complications in children with pulmonary hypertension: Insights from the Global TOPP Registry (tracking outcomes and practice in paediatric pulmonary hypertension).

BACKGROUND: The TOPP Registry has been designed to provide epidemiologic, diagnostic, clinical, and outcome data on children with pulmonary hypertension (PH) confirmed by heart catheterisation (HC). This study aims to identify important characteristics of the haemodynamic profile at diagnosis and HC complications of paediatric patients presenting with PH. METHODS AND RESULTS: HC data sets underwent a blinded review for confirmation of PH (defined as mean pulmonary arterial pressure ≥ 25 mmHg, pulmonary capillary wedge pressure ≤ 12 mmHg and pulmonary vascular resistance index [PVRI] of >3 WU × m(2)). Of 568 patients enrolled, 472 who fulfilled the inclusion criteria and had sufficient data from HC were analysed. A total of 908 diagnostic and follow-up HCs were performed and complications occurred in 5.9% of all HCs including five (0.6%) deaths. General anaesthesia (GA) was used in 53%, and conscious sedation in 47%. Complications at diagnosis were more likely to occur if GA was used (p=0.04) and with higher functional class (p=0.02). Mean cardiac index (CI) was within normal limits at diagnosis when analysed for the entire group (3.7 L/min/m(2); 95% confidence interval 3.4-4.1), as was right atrial pressure despite a severely increased PVRI (16.6 WU × m(2,) 95% confidence interval 15.6-17.76). However, 24% of the patients had a CI of <2.5L/min/m(2) at diagnosis. A progressive increase in PVRI and decrease in CI was observed with age (p<0.001). CONCLUSION: In TOPP, haemodynamic assessment was remarkable for preserved CI in the majority of patients despite severely elevated PVRI. HC-related complication incidence was 5.9%, and was associated with GA and higher functional class.

Power-dependent Raman analysis of highly strained Si nanobridges.

Strain analysis of complex three-dimensional nanobridges conducted via Raman spectroscopy requires careful experimentation and data analysis supported by simulations. A method combining micro-Raman spectroscopy with finite element analysis is presented, enabling a detailed understanding of strain-sensitive Raman data measured on Si nanobridges. Power-dependent measurements are required to account for the a priori unknown scattering efficiency related to size and geometry. The experimental data is used to assess the validity of previously published phonon deformation potentials.

Multimode dynamics and emergence of a characteristic length scale in a one-dimensional quantum system.

We study the nonequilibrium dynamics of a coherently split one-dimensional Bose gas by measuring the full probability distribution functions of matter-wave interference. Observing the system on different length scales allows us to probe the dynamics of excitations on different energy scales, revealing two distinct length-scale-dependent regimes of relaxation. We measure the crossover length scale separating these two regimes and identify it with the prethermalized phase-correlation length of the system. Our approach enables a direct observation of the multimode dynamics characterizing one-dimensional quantum systems.

Dual-wavelength laser source for onboard atom interferometry.

We present a compact and stable dual-wavelength laser source for onboard atom interferometry with two different atomic species. It is based on frequency-doubled telecom lasers locked on a femtosecond optical frequency comb. We take advantage of the maturity of fiber telecom technology to reduce the number of free-space optical components, which are intrinsically less stable, and to make the setup immune to vibrations and thermal fluctuations. The source provides the frequency agility and phase stability required for atom interferometry and can easily be adapted to other cold atom experiments. We have shown its robustness by achieving the first dual-species K-Rb magneto-optical trap in microgravity during parabolic flights.

Detecting inertial effects with airborne matter-wave interferometry.

Inertial sensors relying on atom interferometry offer a breakthrough advance in a variety of applications, such as inertial navigation, gravimetry or ground- and space-based tests of fundamental physics. These instruments require a quiet environment to reach their performance and using them outside the laboratory remains a challenge. Here we report the first operation of an airborne matter-wave accelerometer set up aboard a 0g plane and operating during the standard gravity (1g) and microgravity (0g) phases of the flight. At 1g, the sensor can detect inertial effects more than 300 times weaker than the typical acceleration fluctuations of the aircraft. We describe the improvement of the interferometer sensitivity in 0g, which reaches 2 x 10-4 ms-2 / √Hz with our current setup. We finally discuss the extension of our method to airborne and spaceborne tests of the Universality of free fall with matter waves.

[Use of a mechatronic robotic camera holding system in head and neck surgery]. / Anwendung eines aktiven Haltearms in der endoskopischen Kopf-Hals-Chirurgie.

BACKGROUND: It has been shown that a third hand is useful for holding the endoscope during endoscopic surgery so that both hands of the surgeon are free for instrumentation. MATERIAL AND METHODS: Experimental tests were performed with the mechatronic robotic camera holding system Soloassist on anatomical specimens in the area of the nose, nasopharynx and larynx. RESULTS: An ergonomic set-up and the practical application are easily possible. The third hand enables a still and clear picture without undesired camera movement and all instruments can be controlled by the surgeon. There would appear to be some room for improvement as the working area is limited due to an additional instrument. The camera holding system shows a very high velocity for head and neck surgery. CONCLUSION: Until the active holder can be used regularly in clinical practice in the field of head and neck surgery, more technical modifications have to be implemented.

Electroporation- and mechanical ventilation-mediated gene transfer to the lung.

Our laboratory has previously demonstrated that cytoplasmic trafficking and subsequent nuclear entry of nonviral plasmid DNA can be significantly enhanced through the application of cyclic stretch after transfection in vitro. In this study, we show that cyclic stretching of the murine lung using ventilation immediately after endotracheal administration and transthoracic electroporation of plasmid DNA increases exogenous gene expression up to fourfold in mice that were not ventilated after plasmid administration and transfection by electroporation in vivo. This increase is both time and sequence specific (that is, the ventilation must occur immediately after the transfection event). The ventilation-enhanced gene transfer is also amplitude dependent, confirming similar studies completed in vitro, and is mediated, at least in part, through the cytoplasmic tubulin deacetylase, HDAC6. Using immunohistochemistry, we show that this increase in expression is due to an increase in the number of cells expressing the exogenous protein rather than an increase in the amount of protein produced per cell. These studies show the potential mechanical stimulation has in vivo in significantly increasing nonviral DNA gene expression, and may ultimately pave the way for more successful clinical trials using this type of therapy in the future.

Tubulin acetylation and histone deacetylase 6 activity in the lung under cyclic load.

Previous studies from our lab have demonstrated that upon exposure to physiologic levels of cyclic stretch, alveolar epithelial cells demonstrate a significant decrease in the amount of polymerized tubulin (Geiger et al., Gene Therapy 2006;13:725-731). However, not all microtubules are disassembled, although the mechanisms or implications of this were unknown. Using immunofluorescence microscopy, Western blotting, and immunohistochemistry approaches, we have compared the levels of acetylated tubulin in stretched and unstretched A549 cells and in murine lungs. In cultured cells exposed to cyclic stretch (10% change in basement membrane surface area at 0.25 Hz), nearly all of the remaining microtubules were acetylated, as demonstrated using immunofluorescence microscopy. In murine lungs ventilated for 20 minutes at 12 to 20 ml/kg followed by 48 hours of spontaneous breathing or for 3 hours at 16 to 40 ml/kg, levels of acetylated tubulin were increased in the peripheral lung. In both our in vitro and in vivo studies, we have found that mild to moderate levels of cyclic stretch significantly increases tubulin acetylation in a magnitude- and duration-dependent manner. This appears to be due to a decrease in histone deacetylase 6 activity (HDAC6), the major tubulin deacetylase. Since it has been previously shown that acetylated microtubules are positively correlated to a more stable population of microtubules, this result suggests that microtubule stability may be increased by cyclic stretch, and that tubulin acetylation is one way in which cells respond to changes in exogenous mechanical forces.

Microtubule acetylation through HDAC6 inhibition results in increased transfection efficiency.

The success of viral and nonviral gene delivery relies on the ability of DNA-based vectors to traverse the cytoplasm and reach the nucleus. We, as well as other researchers, have shown that plasmids utilize the microtubule network and its associated motor proteins to traffic toward the nucleus. While disruption of microtubules with nocodazole was shown to greatly inhibit cytoplasmic plasmid trafficking, it did not abolish it. It has been demonstrated that a pool of stabilized post-translationally acetylated microtubules exists in cells, and that this acetylation may play a role in protein trafficking. In order to determine whether this modification could account for the residual DNA trafficking in nocodazole-treated cells, we inhibited or knocked down the levels of the tubulin deacetylase, histone deacetylase 6 (HDAC6), thereby generating higher levels of acetylated microtubules. Electroporation of plasmids into cells with inhibited or silenced HDAC6 resulted in increased gene transfer. This increased transfection efficiency was not because of increased transcriptional activity, but rather, because of increased cytoplasmic trafficking. When plasmids were cytoplasmically microinjected into HDAC6-deficient cells, they entered the nucleus within 5 minutes of injection, almost 10 times faster than in wild-type cells. Taken together, these results suggest that modulation of HDAC6 and the microtubule network can increase the efficiency of gene transfer.