Atom Interferometry with Rb Blue Transitions.

We demonstrate a novel scheme for Raman-pulse and Bragg-pulse atom interferometry based on the 5S-6P blue transitions of ^{87}Rb that provides an increase by a factor ∼2 of the interferometer phase due to accelerations with respect to the commonly used infrared transition at 780 nm. A narrow-linewidth laser system generating more than 1 W of light in the 420-422 nm range was developed for this purpose. Used as a cold-atom gravity gradiometer, our Raman interferometer attains a stability to differential acceleration measurements of 1×10^{-8} g at 1 s and 2×10^{-10} g after 2000 s of integration time. When operated on first-order Bragg transitions, the interferometer shows a stability of 6×10^{-8} g at 1 s, averaging to 1×10^{-9} g after 2000 s of integration time. The instrument sensitivity, currently limited by the noise due to spontaneous emission, can be further improved by increasing the laser power and the detuning from the atomic resonance. The present scheme is attractive for high-precision experiments as, in particular, for the determination of the Newtonian gravitational constant.

Precision measurement of the Newtonian gravitational constant using cold atoms.

About 300 experiments have tried to determine the value of the Newtonian gravitational constant, G, so far, but large discrepancies in the results have made it impossible to know its value precisely. The weakness of the gravitational interaction and the impossibility of shielding the effects of gravity make it very difficult to measure G while keeping systematic effects under control. Most previous experiments performed were based on the torsion pendulum or torsion balance scheme as in the experiment by Cavendish in 1798, and in all cases macroscopic masses were used. Here we report the precise determination of G using laser-cooled atoms and quantum interferometry. We obtain the value G = 6.67191(99) × 10(-11) m(3) kg(-1) s(-2) with a relative uncertainty of 150 parts per million (the combined standard uncertainty is given in parentheses). Our value differs by 1.5 combined standard deviations from the current recommended value of the Committee on Data for Science and Technology. A conceptually different experiment such as ours helps to identify the systematic errors that have proved elusive in previous experiments, thus improving the confidence in the value of G. There is no definitive relationship between G and the other fundamental constants, and there is no theoretical prediction for its value, against which to test experimental results. Improving the precision with which we know G has not only a pure metrological interest, but is also important because of the key role that G has in theories of gravitation, cosmology, particle physics and astrophysics and in geophysical models.

Cross-codal integration of bridging-event information in narrative understanding.

Visual narratives communicate event sequences by using different code systems such as pictures and texts. Thus, comprehenders must integrate information from different codalities. This study addressed such cross-codal integration processes by investigating how the codality of bridging-event information (i.e., pictures, text) affects the understanding of visual narrative events. In Experiment 1, bridging-event information was either present (as picture or text) or absent (i.e., not shown). The viewing times for the subsequent picture depicting the end state of the action were comparable within the absent and the text conditions. Further, the viewing times for the end-state picture were significantly longer in the text condition as compared to the pictorial condition. In Experiment 2, we tested whether replacing bridging-event information with a blank panel increases viewing times in a way similar to the text condition. Bridging event information was either present (as picture) or absent (not shown vs. blank panel). The results replicated Experiment 1. Additionally, the viewing times for the end-state pictures were longest in the blank condition. In Experiment 3, we investigated the costs related to integrating information from different codalities by directly comparing the text and picture conditions with the blank condition. The results showed that the distortion caused by the blank panel is larger than the distortion caused by cross-codal integration processes. Summarizing, we conclude that cross-codal information processing during narrative comprehension is possible but associated with additional mental effort. We discuss the results with regard to theories of narrative understanding.

Canceling the Gravity Gradient Phase Shift in Atom Interferometry.

Gravity gradients represent a major obstacle in high-precision measurements by atom interferometry. Controlling their effects to the required stability and accuracy imposes very stringent requirements on the relative positioning of freely falling atomic clouds, as in the case of precise tests of Einstein's equivalence principle. We demonstrate a new method to exactly compensate the effects introduced by gravity gradients in a Raman-pulse atom interferometer. By shifting the frequency of the Raman lasers during the central π pulse, it is possible to cancel the initial position- and velocity-dependent phase shift produced by gravity gradients. We apply this technique to simultaneous interferometers positioned along the vertical direction and demonstrate a new method for measuring local gravity gradients that does not require precise knowledge of the relative position between the atomic clouds. Based on this method, we also propose an improved scheme to determine the Newtonian gravitational constant G towards the 10 ppm relative uncertainty.

Effect of a wound cleansing solution on wound bed preparation and inflammation in chronic wounds: a single-blind RCT.

OBJECTIVE: Research into surfactant solutions for the debridement of chronic wounds suggests that surfactants may support wound bed preparation (WBP) in chronic wounds, however their efficacy has not been evaluated in randomised controlled trials (RCTs). Our aim was to assess the clinical efficacy of a propylbetaine-polihexanide (PP) solution versus normal saline (NS) solution in WBP, assessing inflammatory signs and wound size reduction in patients with pressure ulcers (PUs) or vascular leg ulcers. METHOD: In a single-blinded randomised controlled trial (RCT) patients were randomly allocated to two groups and treated with either propylbetaine-polihexanide (PP) solution (Prontosan) or NS. Wounds were assessed using the Bates-Jensen wound assessment tool (BWAT). Assessments took place at inclusion (T0), day 7 (T1), day 14 (T2), day 21 (T3), and day 28 (T4). Outcomes were analysed using a two-tailed Student's t-test. RESULTS: A total of 289 patients were included. Both groups had similar demographics, clinical status, and wound characteristics. Data analysis showed statistically significant differences between T0 and T4 for the following outcomes: BWAT total score, p=0.0248; BWAT score for inflammatory items, p=0.03; BWAT scores for wound size reduction (p=0.049) and granulation tissue improvement (p=0.043), all in favour of PP. The assessment of pain did not show any significant difference between the two groups. CONCLUSION: The study results showed significantly higher efficacy of the PP solution versus NS solution, in reducing inflammatory signs and accelerating the healing of vascular leg ulcers and PUs. This evidence supports the update of protocols for the care of chronic wounds. DECLARATION OF INTEREST: The authors have no conflict of interest regarding this research. This is an investigator initiated trial. B. Braun Milano SpA kindly provided the material under investigation for both treatment groups, and paid the Ethics Committees' application fees in all participating centres.

Measurement of the gravity-field curvature by atom interferometry.

We present the first direct measurement of the gravity-field curvature based on three conjugated atom interferometers. Three atomic clouds launched in the vertical direction are simultaneously interrogated by the same atom interferometry sequence and used to probe the gravity field at three equally spaced positions. The vertical component of the gravity-field curvature generated by nearby source masses is measured from the difference between adjacent gravity gradient values. Curvature measurements are of interest in geodesy studies and for the validation of gravitational models of the surrounding environment. The possibility of using such a scheme for a new determination of the Newtonian constant of gravity is also discussed.

Test of Einstein equivalence principle for 0-spin and half-integer-spin atoms: search for spin-gravity coupling effects.

We report on a conceptually new test of the equivalence principle performed by measuring the acceleration in Earth's gravity field of two isotopes of strontium atoms, namely, the bosonic (88)Sr isotope which has no spin versus the fermionic (87)Sr isotope which has a half-integer spin. The effect of gravity on the two atomic species has been probed by means of a precision differential measurement of the Bloch frequency for the two atomic matter waves in a vertical optical lattice. We obtain the values η=(0.2±1.6)×10(-7) for the Eötvös parameter and k=(0.5±1.1)×10(-7) for the coupling between nuclear spin and gravity. This is the first reported experimental test of the equivalence principle for bosonic and fermionic particles and opens a new way to the search for the predicted spin-gravity coupling effects.

Robust frequency stabilization of multiple spectroscopy lasers with large and tunable offset frequencies.

We have demonstrated a compact, robust device for simultaneous absolute frequency stabilization of three diode lasers whose carrier frequencies can be chosen freely relative to the reference. A rigid ULE multicavity block is employed, and, for each laser, the sideband locking technique is applied. A small lock error, computer control of frequency offset, wide range of frequency offset, simple construction, and robust operation are the useful features of the system. One concrete application is as a stabilization unit for the cooling and trapping lasers of a neutral-atom lattice clock. The device significantly supports and improves the clock's operation. The laser with the most stringent requirements imposed by this application is stabilized to a line width of 70 Hz, and a residual frequency drift less than 0.5 Hz/s. The carrier optical frequency can be tuned over 350 MHz while in lock.

Precision measurement of gravity with cold atoms in an optical lattice and comparison with a classical gravimeter.

We report on a precision measurement of gravitational acceleration using ultracold strontium atoms confined in an amplitude-modulated vertical optical lattice. An uncertainty Δg/g ≈ 10(-7) is reached by measuring at the 5th harmonic of the Bloch frequency. The value obtained with this microscopic quantum system is consistent with the one measured with a classical gravimeter. Using lattice modulation to prepare the atomic sample, we also achieve high visibility of Bloch oscillations for ∼ 20 s. These results can be of relevance for testing gravitational redshift and Newtonian law at micrometer scale.

Source mass and positioning system for an accurate measurement of G.

We report on a system of well-characterized source masses and their precision positioning system for a measurement of the Newtonian gravitational constant G using atoms as probes. The masses are 24 cylinders of 50 mm nominal radius, 150.2 mm nominal height, and mass of about 21.5 kg, sintered starting from a mixture of 95.3% W, 3.2% Ni, and 1.5% Cu. Density homogeneity and cylindrical geometry have been carefully investigated. The positioning system independently moves two groups of 12 cylinders along the vertical direction by tens of centimeters with a reproducibility of a few microns. The whole system is compatible with a resolution DeltaG/G<10(-4).

Quantum test of the equivalence principle for atoms in coherent superposition of internal energy states.

The Einstein equivalence principle (EEP) has a central role in the understanding of gravity and space-time. In its weak form, or weak equivalence principle (WEP), it directly implies equivalence between inertial and gravitational mass. Verifying this principle in a regime where the relevant properties of the test body must be described by quantum theory has profound implications. Here we report on a novel WEP test for atoms: a Bragg atom interferometer in a gravity gradiometer configuration compares the free fall of rubidium atoms prepared in two hyperfine states and in their coherent superposition. The use of the superposition state allows testing genuine quantum aspects of EEP with no classical analogue, which have remained completely unexplored so far. In addition, we measure the Eötvös ratio of atoms in two hyperfine levels with relative uncertainty in the low 10-9, improving previous results by almost two orders of magnitude.

Fandom Biases Retrospective Judgments Not Perception.

Attitudes and motivations have been shown to affect the processing of visual input, indicating that observers may see a given situation each literally in a different way. Yet, in real-life, processing information in an unbiased manner is considered to be of high adaptive value. Attitudinal and motivational effects were found for attention, characterization, categorization, and memory. On the other hand, for dynamic real-life events, visual processing has been found to be highly synchronous among viewers. Thus, while in a seminal study fandom as a particularly strong case of attitudes did bias judgments of a sports event, it left the question open whether attitudes do bias prior processing stages. Here, we investigated influences of fandom during the live TV broadcasting of the 2013 UEFA-Champions-League Final regarding attention, event segmentation, immediate and delayed cued recall, as well as affect, memory confidence, and retrospective judgments. Even though we replicated biased retrospective judgments, we found that eye-movements, event segmentation, and cued recall were largely similar across both groups of fans. Our findings demonstrate that, while highly involving sports events are interpreted in a fan dependent way, at initial stages they are processed in an unbiased manner.

Laser sources for precision spectroscopy on atomic strontium.

We present a new laser setup designed for high-precision spectroscopy on laser cooled atomic strontium. The system, which is entirely based on semiconductor laser sources, delivers 200 mW at 461 nm for cooling and trapping atomic strontium from a thermal source, 4 mW at 497 nm for optical pumping from the metastable P23 state, 12 mW at 689 nm on linewidth less than 1 kHz for second-stage cooling of the atomic sample down to the recoil limit, 1.2 W at 922 nm for optical trapping close to the "magic wavelength" for the 0-1 intercombination line at 689 nm. The 689 nm laser was already employed to perform a frequency measurement of the 0-1 intercombination line with a relative accuracy of 2.3 x 10(-11), and the ensemble of laser sources allowed the loading in a conservative dipole trap of multi-isotopes strontium mixtures. The simple and compact setup developed represents one of the first steps towards the realization of a transportable optical standards referenced to atomic strontium.

Lepidic intrapulmonary growth of malignant mesothelioma presenting as recurrent hydropneumothorax.

We report a case of malignant mesothelioma with unusual clinical and histological findings. The patient presented with recurrent hydropneumothorax and minimal pleural thickening on chest computed tomography (CT). Histologically, the pleura was involved by the malignant mesothelioma, albeit to a limited degree. Unexpectedly, the lung parenchyma from two different lobes showed focal nests of mesothelioma cells filling the alveolar spaces and growing on the luminal surface of the alveolar septa, closely resembling the multicentric growth pattern of bronchioloalveolar adenocarcinoma. Immunohistochemical and ultrastructural studies confirmed that the pulmonary lesions were an extension of the malignant mesothelioma. This case illustrates clinically, the importance of a high index of suspicion for malignancy in older patients with unexplained recurrent hydropneumothorax; and histologically the potential of malignant mesothelioma to invade the lung at an early stage of growth.

Coexistent asthma and functional upper airway obstruction. Case reports and review of the literature.

Three asthmatic patients with dyspnea and episodes of apparent bronchospasm unresponsive to conventional therapy are described. During these episodes variable extrathoracic upper airway obstruction and airflow limitation typical of bronchial asthma were demonstrated by spirometry test results. In one patient, paradoxical vocal cord motion was identified by fiberoptic laryngoscopy. We believe these patients represent an unusual subgroup of asthmatic subjects who manifest laryngeal dysfunction. Recognition of this upper airway component to airflow limitation in some asthmatic patients may help physicians avoid potentially unnecessary therapy with systemic steroids and endotracheal intubation.

Tension pneumoperitoneum associated with a pleural-peritoneal shunt.

The differential diagnosis of pneumoperitoneum is broad. We report a case of tension pneumoperitoneum in a patient on mechanical ventilation with initially unrecognized pneumothorax who had an indwelling pleural-peritoneal shunt. The patient developed ventilatory and hemodynamic collapse as air was diverted from the pleural space into the peritoneal cavity. Subsequent abdominal exploration revealed the source of the intra-abdominal air. Placement of a chest thoracostomy tube and removal of the pleural-peritoneal catheter resulted in significant clinical improvement. We suggest that it is important to recognize that pleural-peritoneal catheters may cause tension pneumoperitoneum without obvious concurrent pneumothorax.

Bilateral lung volume reduction surgery for advanced emphysema. A comparison of median sternotomy and thoracoscopic approaches.

STUDY OBJECTIVES: To compare short-term outcomes following bilateral lung volume reduction surgery performed by median sternotomy (MS) and video-assisted thoracoscopic surgery (VATS). METHODS: Bilateral lung volume reduction surgery was performed by MS in 80 patients and by VATS in 40. All patients underwent preoperative assessment with pulmonary function testing, arterial blood gas determination, and 6-min walk test (6MWT). Pulmonary function testing and 6MWT were repeated at 3 to 6 months postoperatively. RESULTS: The mean age of the VATS group was lower than that of the MS group (59.3 +/- 9.4 vs 62.4 +/- 6.9 years; p = 0.001), but there were no differences in baseline functional parameters of disease severity (FEV1, FVC, residual volume [RV], arterial PCO2, or 6MWT). All patients in both groups were extubated at the completion of surgery, but 17.5% of patients in the MS group and 2.5% in the VATS group (p = 0.02) subsequently required reintubation at some point during the postoperative course. Thirty-day operative mortality was 4.2% for the MS group and 2.5% for the VATS group (p = not significant). However, total in-hospital mortality was 13.8% for the MS group, while it remained 2.5% for the VATS group (p = 0.05). Mortality was largely confined to patients 65 years of age or older. There was no significant difference in duration of air leaks or length of hospital stay between the two groups. Functional outcomes achieved with the two techniques were similar. Specifically, there was no difference between the two groups in mean postoperative FEV1, FVC, RV, or 6MWT, or in the magnitude of change in these parameters over preoperative values. CONCLUSIONS: Bilateral lung volume reduction surgery performed by either MS and VATS approaches leads to similar improvements in pulmonary function and exercise tolerance. VATS is associated with a significantly lower incidence of respiratory failure and a trend toward decreased in-hospital mortality and may be the preferred technique, particularly for high-risk patients.

Diffuse airway narrowing from carcinoma metastatic to the bronchial submucosa: identification by chest CT.

The differential diagnosis of dyspnea in patients with prior malignancy and nondiagnostic chest radiographs is broad. We report a case of breast carcinoma diffusely metastatic to the bronchial submucosa presenting as obstructive airway disease. Chest radiographs failed to suggest metastatic disease as the cause of dyspnea. CT, however, revealed the unusual finding of diffusely thickened and narrowed airways. Carcinoma confined to airway submucosa was identified using bronchial biopsy. We suggest that diffuse airway narrowing from submucosal metastasis can be demonstrated by CT and should be added to the differential diagnosis of dyspnea in cancer patients with nondiagnostic chest radiographs and evidence of airflow obstruction.

Comparison of short-term functional outcomes following unilateral and bilateral lung volume reduction surgery.

STUDY OBJECTIVES: To compare short-term functional outcomes following unilateral and bilateral lung volume reduction surgery (LVRS) performed in patients with advanced emphysema. METHODS: LVRS was performed unilaterally in 32 patients and bilaterally in 119 patients. Pulmonary function testing and 6-min walk test (6MWT) were performed preoperatively and repeated at 3 to 6 months postoperatively. RESULTS: Bilateral LVRS was associated with increased in-hospital mortality (10% vs 0%, p<0.05) and a higher incidence of postoperative respiratory failure (12.6% vs 0%; p<0.05) compared with unilateral LVRS. There was no significant difference in duration of air leaks between unilateral and bilateral groups, but the mean hospital stay was significantly longer following bilateral LVRS (21.1+/-32.0 days vs 14.2+/-14.0 days; p<0.05). Preoperatively, there was no significant difference between the unilateral and bilateral groups with respect to FEV1, FVC, residual volume, or 6MWT distance. However, for all of these parameters, the magnitude of improvement was significantly greater following bilateral LVRS. Notably, the magnitude of improvement in each parameter following unilateral LVRS exceeded half that following bilateral LVRS, suggesting that functional outcomes after the unilateral procedure were disproportionate to the amount of tissue resected. Serial functional assessment of seven patients undergoing staged unilateral procedures (two unilateral procedures separated in time by at least 3 months) demonstrated somewhat unpredictable responses; failure to achieve a favorable response to the initial procedure did not necessarily portend a similar outcome with the contralateral side, and vise versa. CONCLUSIONS: Bilateral LVRS produces a greater magnitude of short-term functional improvement than does the unilateral procedure and should be considered the procedure of choice for most patients. Unilateral LVRS should be reserved for patients in whom factors contraindicating entrance into one hemithorax exist.

Apical perfusion fraction as a predictor of short-term functional outcome following bilateral lung volume reduction surgery.

STUDY OBJECTIVES: To examine whether relative hypoperfusion to the apical one third of the lungs as determined by lung scintigraphy predicts a favorable functional outcome following bilateral lung volume reduction surgery (LVRS). METHODS: We performed a retrospective analysis of 128 patients who underwent bilateral LVRS. An apical perfusion fraction (AP%), defined as the percentage of total lung perfusion to the apical one third of both lungs, was derived for each patient by quantitative scintigraphy technique. Pulmonary function testing and 6-min walk test (6MWT) data were obtained preoperatively and 3 to 6 months postoperatively. RESULTS: The mean (+/- SD) improvement in FEV(1) was 309 +/- 240 mL, 209 +/- 293 mL, and 116 +/- 224 mL for patients with an AP% of 20%, respectively (p = 0.01, analysis of variance [ANOVA]). The likelihood of experiencing an increase in FEV(1) >or= 200 mL was 68% for those with an AP% 20%. Preoperative and postoperative 6MWT data were available for 109 of 128 patients. Improvement was 250 +/- 252 feet, 205 +/- 299 feet, and 77 +/- 200 feet for patients with AP% 20%, respectively (p = 0.04, ANOVA). While 50% of those with an AP% or= 180 feet, only 21% of those with an AP% > 20% did so. CONCLUSION: This retrospective analysis suggests that quantification of apical perfusion by nuclear scintigraphy assists in predicting the likelihood of short-term functional improvement after LVRS.