Experimental Quantum Channel Discrimination Using Metastable States of a Trapped Ion.

We present experimental demonstrations of accurate and unambiguous single-shot discrimination between three quantum channels using a single trapped ^{40}Ca^{+} ion. The three channels cannot be distinguished unambiguously using repeated single channel queries, the natural classical analogue. We develop techniques for using the six-dimensional D_{5/2} state space for quantum information processing, and we implement protocols to discriminate quantum channel analogues of phase shift keying and amplitude shift keying data encodings used in classical radio communication. The demonstrations achieve discrimination accuracy exceeding 99% in each case, limited entirely by known experimental imperfections.

High-Fidelity Ion State Detection Using Trap-Integrated Avalanche Photodiodes.

Integrated technologies greatly enhance the prospects for practical quantum information processing and sensing devices based on trapped ions. High-speed and high-fidelity ion state readout is critical for any such application. Integrated detectors offer significant advantages for system portability and can also greatly facilitate parallel operations if a separate detector can be incorporated at each ion-trapping location. Here, we demonstrate ion quantum state detection at room temperature utilizing single-photon avalanche diodes (SPADs) integrated directly into the substrate of silicon ion trapping chips. We detect the state of a trapped Sr^{+} ion via fluorescence collection with the SPAD, achieving 99.92(1)% average fidelity in 450 µs, opening the door to the application of integrated state detection to quantum computing and sensing utilizing arrays of trapped ions.

Operation of an optical atomic clock with a Brillouin laser subsystem.

Microwave atomic clocks have traditionally served as the 'gold standard' for precision measurements of time and frequency. However, over the past decade, optical atomic clocks1-6 have surpassed the precision of their microwave counterparts by two orders of magnitude or more. Extant optical clocks occupy volumes of more than one cubic metre, and it is a substantial challenge to enable these clocks to operate in field environments, which requires the ruggedization and miniaturization of the atomic reference and clock laser along with their supporting lasers and electronics4,7,8,9. In terms of the clock laser, prior laboratory demonstrations of optical clocks have relied on the exceptional performance gained through stabilization using bulk cavities, which unfortunately necessitates the use of vacuum and also renders the laser susceptible to vibration-induced noise. Here, using a stimulated Brillouin scattering laser subsystem that has a reduced cavity volume and operates without vacuum, we demonstrate a promising component of a portable optical atomic clock architecture. We interrogate a 88Sr+ ion with our stimulated Brillouin scattering laser and achieve a clock exhibiting short-term stability of 3.9 × 10-14 over one second-an improvement of an order of magnitude over state-of-the-art microwave clocks. This performance increase within a potentially portable system presents a compelling avenue for substantially improving existing technology, such as the global positioning system, and also for enabling the exploration of topics such as geodetic measurements of the Earth, searches for dark matter and investigations into possible long-term variations of fundamental physics constants10-12.

Hemorrhagic Cholecystitis: A Case of Expedited Diagnosis by Point-of-Care Ultrasound in the Emergency Department.

BACKGROUND: Hemorrhagic cholecystitis is a rare complication of acute cholecystitis and is a potentially fatal diagnosis. It may be difficult to detect because the symptoms are similar to more common diagnoses. Point-of-care ultrasound is a useful imaging technique in the emergency setting and is readily available to allow for immediate interpretation and application of the results to guide medical decision making. CASE REPORT: We report a 76-year-old man with a history of hypertension, hyperlipidemia, diabetes, atrial fibrillation on warfarin, and coronary artery disease presenting with epigastric pain radiating to the back, nausea, and vomiting who was found to have hemorrhagic cholecystitis with gallbladder perforation. Ultrasound of the abdominal right upper quadrant showed a large, hyperechoic, nonshadowing, globular structure visualized within the lumen of the gallbladder extending from the neck through the body. The gallbladder wall was noted to be 0.72 cm with wall edema, focal pericholecystic fluid, and a positive sonographic Murphy sign suggestive of acute cholecystitis. The abnormal appearance of the gallbladder contents was suspected to be blood. Computed tomography angiography was performed and confirmed the diagnosis of acute hemorrhagic cholecystitis with perforation. Blood was noted to track from the cystic duct to the gallbladder lumen. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: To our knowledge, this is a unique case of hemorrhagic cholecystitis visualized on bedside ultrasound. This case shows that the use of point-of-care ultrasound by emergency medicine providers can facilitate the rapid recognition and treatment of specific, life-threatening hepatobiliary pathology while excluding alternate diagnoses.

Pyomyositis Diagnosed by Point-of-Care Ultrasound in the Emergency Department.

BACKGROUND: Currently, the role of ultrasound in diagnosing superficial abscesses is well validated, however, its role for deep space infections and intramuscular pathology is limited. Distinguishing between simple cellulitis and abscess is critical for emergency physicians (EP), as the treatment is very different. Management of cellulitis relies on antibiotic therapy, whereas abscess treatment requires incision and drainage. It is important that EPs can accurately distinguish between the two entities. CASE REPORT: We report a case of a 41-year-old man with a history of high blood pressure and poorly controlled diabetes who presented with right lateral thigh redness, warmth, and tenderness. A point-of-care ultrasound (POCUS) of the patient's right lateral thigh with a high-frequency linear (8 MHz) ultrasound probe showed a 2.93 × 3.38 × 6.0-cm complex fluid collection deep to the fascial plane, approximately 3.0 cm from the skin surface, that contained mixed echogenicities with posterior acoustic enhancement consistent with an intramuscular abscess of the vastus lateralis. The patient was diagnosed with pyomyositis of his vastus lateralis. He was started on vancomycin and admitted to the surgical service for antibiotic treatment and surgical drainage. WHY SHOULD EMERGENCY PHYSICIANS BE AWARE OF THIS?: This case demonstrates that the use of POCUS by EPs can facilitate the rapid recognition and treatment of a disease that is challenging to diagnose on physical examination and can be potentially life-threatening if missed. EPs can consider performing a POCUS when evaluating skin infections to ensure rapid diagnosis and appropriate medical care for a potentially severe condition.

A cell-based infection assay identifies efflux pump modulators that reduce bacterial intracellular load.

Bacterial efflux pumps transport small molecules from the cytoplasm or periplasm outside the cell. Efflux pump activity is typically increased in multi-drug resistant (MDR) pathogens; chemicals that inhibit efflux pumps may have potential for antibiotic development. Using an in-cell screen, we identified three efflux pump modulators (EPMs) from a drug diversity library. The screening platform uses macrophages infected with the human Gram-negative pathogen Salmonella enterica (Salmonella) to identify small molecules that prevent bacterial replication or survival within the host environment. A secondary screen for hit compounds that increase the accumulation of an efflux pump substrate, Hoechst 33342, identified three small molecules with activity comparable to the known efflux pump inhibitor PAßN (Phe-Arg ß-naphthylamide). The three putative EPMs demonstrated significant antibacterial activity against Salmonella within primary and cell culture macrophages and within a human epithelial cell line. Unlike traditional antibiotics, the three compounds did not inhibit bacterial growth in standard microbiological media. The three compounds prevented energy-dependent efflux pump activity in Salmonella and bound the AcrB subunit of the AcrAB-TolC efflux system with KDs in the micromolar range. Moreover, the EPMs display antibacterial synergy with antimicrobial peptides, a class of host innate immune defense molecules present in body fluids and cells. The EPMs also had synergistic activity with antibiotics exported by AcrAB-TolC in broth and in macrophages and inhibited efflux pump activity in MDR Gram-negative ESKAPE clinical isolates. Thus, an in-cell screening approach identified EPMs that synergize with innate immunity to kill bacteria and have potential for development as adjuvants to antibiotics.

Enhancing radical molecular beams by skimmer cooling.

A high-intensity supersonic beam source has been a key component in studies of molecular collisions, molecule-surface interaction, chemical reactions, and precision spectroscopy. However, the molecular density available for experiments in a downstream science chamber is limited by skimmer clogging, which constrains the separation between a valve and a skimmer to at least several hundred nozzle diameters. A recent experiment (Sci. Adv., 2017, 3, e1602258) has introduced a new strategy to address this challenge: when a skimmer is cooled to a temperature below the freezing point of the carrier gas, skimmer clogging can be effectively suppressed. We go beyond this proof-of-principle work in several key ways. Firstly, we apply the skimmer cooling approach to discharge-produced radical and metastable beams entrained in a carrier gas. We also identify two different processes for skimmer clogging mitigation-shockwave suppression at temperatures around the carrier gas freezing point and diffusive clogging at even lower temperatures. With the carrier clogging removed, we now fully optimize the production of entrained species such as hydroxyl radicals, resulting in a gain of 30 in density over the best commercial devices. The gain arises from both clogging mitigation and favorable geometry with a much shorter valve-skimmer distance.