Observation of two-mode squeezing in the microwave frequency domain

Continuous variable entanglement between two modes of a radiation field is usually studied at optical frequencies. Here we demonstrate experiments that show the entanglement between microwave photons of different energy in a broadband squeezed beam. We use a Josephson parametric amplifier to generate the two-mode correlated state and detect all four quadrature components simultaneously in a two-channel heterodyne setup using amplitude detectors. Analyzing two-dimensional phase space histograms for all possible pairs of quadratures allows us to determine the full covariance matrix, which is in good agreement with the one expected for a two-mode squeezed state.

Distribution of bacteria in the epidermal layers and hair follicles of the human skin

Previous studies over recent years have revealed the presence of a resident bacterial population in the human skin throughout the entire body. However, the localization and composition of the bacteria within the epidermis and the skin appendages have not been fully investigated. Using differential tape stripping, cyanoacrylate skin surface biopsies and mapping of hair follicles, bacteria on the forearms of study participants were isolated, mapped, cultured and identified with respect to their origin within the epidermis and the hair follicles. Our studies showed that 85% of the bacteria were found within the first 6 corneocyte layers and roughly 25% of the cutaneous bacterial population were localized within the hair follicles. The microbial flora of the skin between individuals is subject to considerable fluctuations. Micrococcaceae represent the biggest fraction of hair-follicle-associated bacteria. The techniques developed for this study allowed us to selectively investigate the bacterial population within the hair follicles. Our results point out the role of skin appendages as potential microbial reservoirs and the need to develop new antiseptic formulations that sufficiently penetrate into the hair follicles.

Observation of resonant photon blockade at microwave frequencies using correlation function measurements

Creating a train of single photons and monitoring its propagation and interaction is challenging in most physical systems, as photons generally interact very weakly with other systems. However, when confining microwave frequency photons in a transmission line resonator, effective photon-photon interactions can be mediated by qubits embedded in the resonator. Here, we observe the phenomenon of photon blockade through second-order correlation function measurements. The experiments clearly demonstrate antibunching in a continuously pumped source of single microwave photons measured by using microwave beam splitters, linear amplifiers, and quadrature amplitude detectors. We also investigate resonance fluorescence and Rayleigh scattering in Mollow-triplet-like spectra.

Experimental state tomography of itinerant single microwave photons

A wide range of experiments studying microwave photons localized in superconducting cavities have made important contributions to our understanding of the quantum properties of radiation. Propagating microwave photons, however, have so far been studied much less intensely. Here we present measurements in which we reconstruct the quantum state of itinerant single photon Fock states and their superposition with the vacuum by analyzing moments of the measured amplitude distribution up to fourth order. Using linear amplifiers and quadrature amplitude detectors, we have developed efficient methods to separate the detected single photon signal from the noise added by the amplifier. From our measurement data we have also reconstructed the corresponding Wigner function.

Control and tomography of a three level superconducting artificial atom

A number of superconducting qubits, such as the transmon or the phase qubit, have an energy level structure with small anharmonicity. This allows for convenient access of higher excited states with similar frequencies. However, special care has to be taken to avoid unwanted higher-level populations when using short control pulses. Here we demonstrate the preparation of arbitrary three level superposition states using optimal control techniques in a transmon. Performing dispersive readout, we extract the populations of all three levels of the qutrit and study the coherence of its excited states. Finally we demonstrate full quantum state tomography of the prepared qutrit states and evaluate the fidelities of a set of states, finding on average 95%.

Quantum-to-classical transition in cavity quantum electrodynamics

The quantum properties of electromagnetic, mechanical or other harmonic oscillators can be revealed by investigating their strong coherent coupling to a single quantum two level system in an approach known as cavity quantum electrodynamics (QED). At temperatures much lower than the characteristic energy level spacing the observation of vacuum Rabi oscillations or mode splittings with one or a few quanta asserts the quantum nature of the oscillator. Here, we study how the classical response of a cavity QED system emerges from the quantum one when its thermal occupation-or effective temperature-is raised gradually over 5 orders of magnitude. In this way we explore in detail the continuous quantum-to-classical crossover and demonstrate how to extract effective cavity field temperatures from both spectroscopic and time-resolved vacuum Rabi measurements.

Caries Inhibition by and Safety of Lactobacillus paracasei DSMZ16671

Lactobacillus paracasei DSMZ16671, even if heat-killed, sensitively co-aggregates mutans streptococci specifically. Mutans streptococci are strongly implicated in caries induction in humans and rodents. We hypothesized: (1) that S. mutans recoveries from rats’ teeth in vivo will decrease, with an associated decrease in caries, if these lactobacilli are fed to rats in an established caries model; and (2) that toxicological assays of these lactobacilli will show them to be benign. Four groups of specific-pathogen-free rats were formed: S. mutans 10449S-inoculated/16671-supplemented diet; un-inoculated/16671-supplemented diet; S. mutans 10449S-inoculated/placebo diet; and un-inoculated/placebo diet. Standard tests of toxicity and mutagenicity of heat-killed DSMZ16671 were performed. S. mutans recoveries were significantly reduced both in mid-experiment and at termination, as were caries lesion scores for the rats inoculated by S. mutans and fed the DSMZ16671 supplement, by comparison with controls. Neither toxicity nor mutagenicity of DSMZ16671 was detected. Use of heat-killed DSMZ16671 is efficacious in rats and appears safe.

HLA-B*9553: a novel HLA allele shown in three generations of a family

Human leukocyte antigen (HLA)-B*9553, a novel HLA-B allele, was identified in a volunteer hematopoietic stem cell donor. HLA-B*9553 differs from the closely related allele HLA-B*1518 in one single nucleotide substitution resulting in an amino acid substitution.

Specific Lactobacillus/Mutans Streptococcus co-aggregation

Selective interaction of mutans streptococci with benign bacteria could present an opportunity for their removal from the mouth without disruption of other oral flora. This study was conducted to find probiotic lactobacilli that could specifically co-aggregate in vitro with mutans streptococci, but not with other plaque commensals. A search of 624 lactobacilli among a large culture library revealed 6 strains, all classifiable as L. paracasei or L. rhamnosus, which met this criterion. Such novel, specific co-aggregation, however, was not a general characteristic of these species or the genus Lactobacillus. The co-aggregation by these specific lactobacilli was characterized as heat treatment (autoclaving)- and protease-resistant, lectin-independent, not inactivated by sugar substitutes, operational over a wide pH range, unaffected by whole saliva, but calcium-dependent. It is thus seen to present a potential strategy for in vivo alteration of plaque biofilm and caries.

Smell and taste disorders in polyneuropathy: a prospective study of chemosensory disorders

OBJECTIVE

The aim of the study was to assess the occurrence and the frequency of chemosensory dysfunction in patients with polyneuropathy (PNP).

METHODS

We performed a prospective observational study. Olfactory function was assessed using the standardized 'Sniffin' Sticks' test to measure odor threshold for phenyl ethyl alcohol, odor discrimination, and odor identification. Gustatory function was assessed using the standardized 'taste strips' test. In addition, we assessed etiology, neurophysiology, and severity of the PNP, and the patients' comorbidities and medication.

RESULTS

A total of 53 consecutive patients were enrolled (15 women, 38 men; mean age 61 years); 27 of them (51%) exhibited olfactory dysfunction and 23 of them (43%) gustatory dysfunction. Patients with diabetic PNP had significantly lower taste scores than patients with inflammatory, genetic, or idiopathic PNP. In addition, odor identification was negatively correlated with PNP severity.

CONCLUSION

The applied bedside tests are useful to detect chemosensory dysfunction in patients with PNP. Chemosensory dysfunction is quite frequent in these patients.

The design, physical properties and clinical utility of an iris collimator for robotic radiosurgery

Robotic radiosurgery using more than one circular collimator can improve treatment plan quality and reduce total monitor units (MU). The rationale for an iris collimator that allows the field size to be varied during treatment delivery is to enable the benefits of multiple-field-size treatments to be realized with no increase in treatment time due to collimator exchange or multiple traversals of the robotic manipulator by allowing each beam to be delivered with any desired field size during a single traversal. This paper describes the Iris variable aperture collimator (Accuray Incorporated, Sunnyvale, CA, USA), which incorporates 12 tungsten-copper alloy segments in two banks of six. The banks are rotated by 30 degrees with respect to each other, which limits the radiation leakage between the collimator segments and produces a 12-sided polygonal treatment beam. The beam is approximately circular, with a root-mean-square (rms) deviation in the 50% dose radius of <0.8% (corresponding to <0.25 mm at the 60 mm field size) and an rms variation in the 20-80% penumbra width of about 0.1 mm at the 5 mm field size increasing to about 0.5 mm at 60 mm. The maximum measured collimator leakage dose rate was 0.07%. A commissioning method is described by which the average dose profile can be obtained from four profile measurements at each depth based on the periodicity of the isodose line variations with azimuthal angle. The penumbra of averaged profiles increased with field size and was typically 0.2-0.6 mm larger than that of an equivalent fixed circular collimator. The aperture reproducibility is < or =0.1 mm at the lower bank, diverging to < or =0.2 mm at a nominal treatment distance of 800 mm from the beam focus. Output factors (OFs) and tissue-phantom-ratio data are identical to those used for fixed collimators, except the OFs for the two smallest field sizes (5 and 7.5 mm) are considerably lower for the Iris Collimator. If average collimator profiles are used, the assumption of circular symmetry results in dose calculation errors that are <1 mm or <1% for single beams across the full range of field sizes; errors for multiple non-coplanar beam treatment plans are expected to be smaller. Treatment plans were generated for 19 cases using the Iris Collimator (12 field sizes) and also using one and three fixed collimators. The results of the treatment planning study demonstrate that the use of multiple field sizes achieves multiple plan quality improvements, including reduction of total MU, increase of target volume coverage and improvements in conformality and homogeneity compared with using a single field size for a large proportion of the cases studied. The Iris Collimator offers the potential to greatly increase the clinical application of multiple field sizes for robotic radiosurgery.

The treatment of choroidal neovascularizations in age-related macular degeneration using either Avastin or Lucentis

BACKGROUND

Either Avastin or Lucentis was used in our clinic to treat choroidal neovascularizations in age-related macular degeneration. The number of injections necessary for drying the macular findings was especially assessed.

PATIENTS AND METHODS

From April 2006 to August 2008 324 eyes were treated with Avastin, and from January 2007 to August 2008 348 eyes were treated with Lucentis. The intravitreal injections with Avastin (1.25 mg in 0.05 mL) were performed every six weeks, and with Lucentis (0.05 mg in 0.05 mL) every four weeks until the macular findings were considered to be dry. Fluorescein angiography and optical coherence tomography were used for the diagnosis and for the checks which were carried out every twelve weeks. The visual acuity was measured with an ETDRS chart.

RESULTS

The treatment with Avastin is completed in 319 eyes with an average improvement of the visual acuity of 5.1 letters after 3.3 injections, and with Lucentis in 226 eyes with an average improvement of the visual acuity of 6.4 letters after 3.4 injections (p = 0.24; one way ANOVA).

CONCLUSION

Both of the drugs allow the drying of the macular findings in the great majority of the cases after a short time and lead to a quite similar improvement of the visual acuity. A definitive stabilization of the disease after stopping the treatment is not foreseeable.

Eignung des Tiergesundheitsdienstprogramms zur Überwachung und Bekämpfung der progressiven Rhinitis atrophicans

Gegenstand und Ziel: Im Zeitraum von 1999 bis 2005 erfolgte eine Statuserhebung über das Vorkommen der progressiven Rhinitis atrophicans (PAR) in 17 oberösterreichischen Schweinevermehrerbetrieben, um in weiterer Folge eine PAR-Freiheit und Zertifizierung zu erreichen und somit die Eignung des Tiergesundheitsdienstprogramms für diesen Zweck zu überprüfen. Material und Methoden: Entsprechend dem Tiergesundheitsdienstprogramm wurden 11 045 Nasen- und Tonsillartupferproben entnommen und mittels PCR auf Pasteurella-multocida- Toxin (PMT) untersucht. Ein Jahr nach Einstellung der ART-(Atrophic- rhinitis-toxoid-)Vakzinierung wurden 2004 und 2005 zusätzlich 179 Blutproben mittels ELISA auf Antikörper gegen PMT untersucht. Ergebnisse: 84 (0,76%) der Nasen- und Tonsillartupferproben waren PMT-positiv. Bei 43 (24,02%) Seren ergab sich ein positiver serologischer Befund, es lagen jedoch keine klinischen Symptome einer PAR vor. Bereits im Jahr 2003 war in 14 Betrieben PMT in Nasen- und Tonsillartupferproben nicht mehr nachweisbar. In 16 Betrieben gelang bis dato die Eradikation des Erregers, lediglich ein Betrieb musste aufgrund der Nichteinhaltung der Vorschriften auf den Status PAR-frei“ verzichten. Schlussfolgerung: Die Studie belegt, dass sich das empfohlene Programm, das auf einem Test-and-Removal-“(T&R-)Prinzip basiert, zur stufenweisen Bekämpfung der PAR ohne komplette Bestandsmerzung eignet. Klinische Relevanz: Das Tiergesundheitsdienstprogramm zur Überwachung und Bekämpfung der progressiven Rhinitis atrophicans konnte im Laufe dieser Studie etabliert werden und wird mittlerweile österreichweit durchgeführt.

A directional passive air sampler for monitoring polycyclic aromatic hydrocarbons (PAHs) in air mass

A passive air sampler was developed for collecting polycyclic aromatic hydrocarbons (PAHs) in air mass from various directions. The airflow velocity within the sampler was assessed for its responses to ambient wind speed and direction. The sampler was examined for trapped particles, evaluated quantitatively for influence of airflow velocity and temperature on PAH uptake, examined for PAH uptake kinetics, calibrated against active sampling, and finally tested in the field. The airflow volume passing the sampler was linearly proportional to ambient wind speed and sensitive to wind direction. The uptake rate for an individual PAH was a function of airflow velocity, temperature and the octanol-air partitioning coefficient of the PAH. For all PAHs with more than two rings, the passive sampler operated in a linear uptake phase for three weeks. Different PAH concentrations were obtained in air masses from different directions in the field test.