Quasiparticle Poisoning of Superconducting Qubits from Resonant Absorption of Pair-Breaking Photons.

The ideal superconductor provides a pristine environment for the delicate states of a quantum computer: because there is an energy gap to excitations, there are no spurious modes with which the qubits can interact, causing irreversible decay of the quantum state. As a practical matter, however, there exists a high density of excitations out of the superconducting ground state even at ultralow temperature; these are known as quasiparticles. Observed quasiparticle densities are of order 1 µm^{-3}, tens of orders of magnitude greater than the equilibrium density expected from theory. Nonequilibrium quasiparticles extract energy from the qubit mode and can induce dephasing. Here we show that a dominant mechanism for quasiparticle poisoning is direct absorption of high-energy photons at the qubit junction. We use a Josephson junction-based photon source to controllably dose qubit circuits with millimeter-wave radiation, and we use an interferometric quantum gate sequence to reconstruct the charge parity of the qubit. We find that the structure of the qubit itself acts as a resonant antenna for millimeter-wave radiation, providing an efficient path for photons to generate quasiparticles. A deep understanding of this physics will pave the way to realization of next-generation superconducting qubits that are robust against quasiparticle poisoning.

A qualitative analysis of rural syringe service program fidelity in Appalachian Kentucky: Staff and participant perspectives.

PURPOSE: As drug-related epidemics have expanded from cities to rural areas, syringe service programs (SSPs) and other harm reduction programs have been slow to follow. The recent implementation of SSPs in rural areas demands attention to program fidelity based on core components of SSP success. METHODS: Semistructured interviews conducted with clients and staff at 5 SSPs in 5 counties within 2 Central Appalachian health districts. Interviews covered fidelity of SSP implementation to 6 core components: (1) meet needs for harm reduction supplies; (2) education and counseling for sexual, injection, and overdose risks; (3) cooperation between SSPs and local law enforcement; (4) provide other health and social services; (5) ensure low threshold access to services; and (6) promote dignity, the impact of poor fidelity on vulnerability to drug-related harms, and the risk environment's influence on program fidelity. We applied thematic methods to analyze the data. FINDINGS: Rural SSPs were mostly faithful to the 6 core components. Deviations from core components can be attributed to certain characteristics of the local rural risk environment outlined in the risk environment model, including geographic remoteness, lack of resources and underdeveloped infrastructure, and stigma against people who inject drugs (PWID) CONCLUSIONS: As drug-related epidemics continue to expand outside cities, scaling up SSPs to serve rural PWID is essential. Future research should explore whether the risk environment features identified also influence SSP fidelity in other rural areas and develop and test strategies to strengthen core components in these vulnerable areas.

Phonon downconversion to suppress correlated errors in superconducting qubits.

Quantum error correction can preserve quantum information in the presence of local errors, but correlated errors are fatal. For superconducting qubits, high-energy particle impacts from background radioactivity produce energetic phonons that travel throughout the substrate and create excitations above the superconducting ground state, known as quasiparticles, which can poison all qubits on the chip. We use normal metal reservoirs on the chip back side to downconvert phonons to low energies where they can no longer poison qubits. We introduce a pump-probe scheme involving controlled injection of pair-breaking phonons into the qubit chips. We examine quasiparticle poisoning on chips with and without back-side metallization and demonstrate a reduction in the flux of pair-breaking phonons by over a factor of 20. We use a Ramsey interferometer scheme to simultaneously monitor quasiparticle parity on three qubits for each chip and observe a two-order of magnitude reduction in correlated poisoning due to background radiation.

Antibiotic Exposure and Risk for Death or Bronchopulmonary Dysplasia in Very Low Birth Weight Infants.

We assessed the association between antibiotic exposure in the first 2 weeks of life and development of bronchopulmonary dysplasia in a cohort of very low birth weight infants. After controlling for the severity of illness, each additional day of antibiotic therapy was associated with both an increased risk for and severity of bronchopulmonary dysplasia.

Chorioamnionitis and subsequent bronchopulmonary dysplasia in very-low-birth weight infants: a 25-year cohort.

OBJECTIVE: To determine whether chorioamnionitis (CA) or sepsis were associated with bronchopulmonary dysplasia (BPD) in a 25-year cohort of very-low-birth weight (VLBW) infants. STUDY DESIGN: VLBW infants ⩽32 weeks gestation admitted to the neonatal intensive care unit between 1989 and 2014 were reviewed. BPD was defined using the National Institutes of Health consensus definition. CA was defined clinically. Logistic regression models were used for BPD prediction. RESULTS: One thousand six hundred and eighty-seven infants were included; 44% (n=740) had moderate or severe BPD. In multivariable analysis, lower gestational age (odds ratio (OR) 1.12 per week (95% confidence interval (CI) 1.11, 1.14)), sepsis (OR 2.03 (95% CI 1.49, 2.77)) and birth year ⩾1995 (OR 1.49 (95% CI 1.09, 2.04)) were significant predictors of BPD. CA was not associated with BPD (OR 1.18 (95% CI 0.66, 2.11)). CONCLUSION: Sepsis, but not CA, is associated with the development of moderate or severe BPD in VLBW infants after controlling for gestational age.

Thermal expansivity for sI and sII clathrate hydrates.

Knowledge of thermal expansivity can aid in the understanding of both microscopic and macroscopic behavior of clathrate hydrates. Diffraction studies have shown that hydrate volume changes significantly (as much as 1.5% over 50 K) as a function of temperature. It has been demonstrated previously via statistical mechanics that a minor change in hydrate volume (e.g., a 1.5% change in volume or 0.5% change in lattice parameter) can lead to a major change in the predicted hydrate formation pressure (e.g., >15% at >100 MPa for methane). Because of this sensitivity, hydrate thermal expansivity measurements, for both Structures I and II with various guests, are needed help quantify volume distortions in hydrate lattices to ensure accurate hydrate phase equilibria predictions. In addition to macroscopic phase equilibria, the thermal expansion of different hydrates can give information about the interactions between the guest molecules and the host lattice. In this work, the hydrate lattice parameters for four Structure I (C2H6, CO2, 47% C2H6 + 53% CO2, and 85% CH4 + 15% CO2) and seven Structure II (C3H8, 60% CH4 + 40% C3H8, 30% C2H6 + 70% C3H8, 18% CO2 + 82% C3H8, 87.6% CH4 + 12.4% i-C4H10, 95% CH4 + 5% C5H10O, and a natural gas mixture) systems were measured as a function of temperature. The lattice parameter measurements were combined with existing literature values. Both sI and sII hydrates, with a few exceptions, had a common thermal expansivity, independent of hydrate guest. Many guest-dependent correlations for linear thermal expansivity have been proposed. However, we present two guest-independent, structure-dependent correlations for sI and sII lattices, which have been developed to express the normalized hydrate lattice parameters (and therefore volume) as a function of temperature.

HBV DNA levels and transmission of hepatitis B by health care workers.

BACKGROUND: Laboratory-based study funded by the Research and Development Division of the Department of Health to inform the decision making on guidelines for the conduct of exposure prone procedures (EPPs) by health care workers who are hepatitis B carriers. OBJECTIVES: Define the quantity and nature of hepatitis B virus (HBV) DNA in hepatitis carriers whose serum does not contain hepatitis B e antigen (HBeAg) and in surgeons previously cleared to conduct EPPs who have transmitted HBV to their patients. STUDY DESIGN: Cross-sectional survey using HBV DNA quantification, genotyping and sequencing comparing transmitting surgeons and asymptomatic carriers. RESULTS: HBV DNA could be detected and quantified in 64.5% (136 of 211) of carriers whose serum did not contain HBeAg with a median level 3.6 log(10) copies/ml (range of 5.7 log(10) copies). Pre-core mutation appeared not to affect the HBV DNA level, however, all surgeons carried codon 28 variants and transmitted these variants to their patients. The lowest HBV DNA level in a transmitting surgeon was 4 x 10(4) copies/ml. CONCLUSIONS: Pre-core mutations are common in carriers whose serum does not contain HBeAg and do not specifically identify carriers whose HBV DNA levels are high. It was possible to define a level of virus above which transmission of hepatitis B during conduct of EPPs could not be excluded.

Adenovirus-mediated overexpression of dominant-negative mutant of c-Jun prevents intercellular adhesion molecule-1 induction by LDL: a critical role for activator protein-1 in endothelial activation.

Low density lipoprotein (LDL) induces intercellular adhesion molecule-1 (ICAM-1) gene expression and leads to endothelial cell (EC) leukocyte adhesion. However, the transcriptional mechanism for LDL-induced EC perturbation remains to be fully explained. Activator protein-1 (AP-1) is induced after the exposure of ECs to LDL. In the present study, a regulated adenovirus expressing a dominant-negative mutant of c-Jun (TAM-67) was used to examine the role of AP-1 in the LDL-induced ICAM-1 activation. Overexpression of TAM-67 specifically inhibited AP-1 activation and prevented the LDL-activated surface expression of ICAM-1 protein in human umbilical vein ECs and human coronary artery ECs. Northern analyses and promoter transactivation assays indicated that this effect of TAM-67 was likely mediated through a suppression of the transcriptional regulation of the ICAM-1 gene. Functionally, TAM-67 attenuated leukocyte adherence to ECs in response to LDL. Furthermore, electrophoresis mobility shift assays and site-directed mutagenesis suggested that an AP-1-like motif in the promoter region of the human ICAM-1 gene was a critical cis element for LDL induction. These results, for the first time, provide evidence suggesting that AP-1 is a major regulatory mechanism leading to endothelial activation.

The effect of culture conditions on the mycelial growth and luminescence of naturally bioluminescent fungi.

The effects of temperature, light and pH on mycelial growth and luminescence of four naturally bioluminescent fungi were investigated. Cultures of Armillaria mellea, Mycena citricolor, Omphalotus olearius and Panellus stipticus were grown at 5 degrees C, 15 degrees C, 22 degrees C and 30 degrees C, under 24 h light, 12 h light/12 h dark and 24 h dark, and at a pH ranging from 3.5 to 7 in three separate experiments. Temperature and pH had a significant effect on mycelial growth and bioluminescence, however light did not. Bioluminescence and mycelial growth were optimum at 22 degrees C and pH 3-3.5, the exception being M. citricolor for which bioluminescence and growth were optimum at pH 5-6 and pH 4, respectively. With the exception of M. citricolor, bioluminescence and mycelial growth were greater under 24 h darkness. An understanding of the effect of culture conditions on mycelial growth and luminescence is necessary for the future application of bioluminescent fungi as biosensors.

Leptin enhances the calcification of vascular cells: artery wall as a target of leptin.

Leptin, the product of the ob gene, regulates food intake, energy expenditure, and other physiological functions of the peripheral tissues. Leptin receptors have been identified in the hypothalamus and in extrahypothalamic tissues. Increased circulating leptin levels have been correlated with cardiovascular disease, obesity, aging, infection with bacterial lipopolysaccharide, and high-fat diets. All these conditions have also been correlated with increased vascular calcification, a hallmark of atherosclerotic and age-related vascular disease. In addition, the differentiation of marrow osteoprogenitor cells is regulated by leptin. Thus, we hypothesized that leptin may regulate the calcification of vascular cells. In this report, we tested the effects of leptin on a previously characterized subpopulation of vascular cells that undergo osteoblastic differentiation and calcification in vitro. When treated with leptin, these calcifying vascular cells had a significant 5- to 10-fold increase in alkaline phosphatase activity, a marker of osteogenic differentiation of osteoblastic cells. Prolonged treatment with leptin enhanced the calcification of these cells, further supporting the pro-osteogenic differentiation effects of leptin. Furthermore, the presence of the leptin receptor on calcifying vascular cells was demonstrated using reverse transcriptase polymerase chain reaction, immunocytochemistry, and Western blot analysis. We also identified the presence of leptin receptor in the mouse artery wall, localized to subpopulations of medial and adventitial cells, and the expression of leptin by artery wall cells and atherosclerotic lesions in mice. Taken together, these results suggest that leptin regulates the osteoblastic differentiation and calcification of vascular cells and that the artery wall may be an important peripheral tissue target of leptin action.

Detection of Legionella pneumophila using a real-time PCR hybridization assay.

A real-time PCR hybridization assay for Legionella pneumophila is described; the assay uses LightCycler (Idaho Technology) methodology to specifically detect 2.5 CFU/reaction, equivalent to 1,000 CFU/liter of starting water sample. The assay, including DNA extraction and confirmation of product identity, is completed within 90 min of receipt of a sample.

Epidemiology of precore mutants of hepatitis B in the United Kingdom.

A point mutation assay was used to study the codon 28 and codon 1 precore mutant status of 310 chronic hepatitis B carriers (82 HBeAg positive and 228 HBeAg negative). Fourteen of 228 (6%) of HBeAg negative carriers had high levels of serum HBV DNA. Nine of these were explained by precore variants, three by core promoter variants, and two were not explained by recognised precore changes. Nested PCR detected serum HBV DNA in 36% (82/228) of HBeAg negative carriers and 63% (52/82) of these had precore variants. Four of 82 (4%) of the HBeAg positive carriers had precore variants, all as mixed mutant/wild type populations and evidence indicated that these carriers were seroconverting. Overall 23% (52/228) of HBeAg negative carriers had both serum HBV DNA and codon 1 or 28 precore mutations. A sexual transmission event from an HBeAg negative carrier with a relatively low serum HBV DNA level (10(4)-10(6) genome copies/ml) and only core promoter mutations was observed. Despite high rates of variant carriage in the antenatal sub-group perinatal transmission was not observed. The results of direct sequencing on 45 carriers validated the point mutation assay and also showed that codon 28 mutations were only seen in carriers with the genotype CCT at codon 15. For the Caucasian population a higher prevalence of codon 28 mutations (13/25 or 52%) than expected was seen. Liver biopsy data indicated that there was no link between the presence or absence of precore mutants and the severity of liver disease.

Assessing the infectivity of hepatitis B carriers.

The infectivity of 310 hepatitis B carriers (among antenatal and genitourinary medicine clinic attendees, blood donors, and patients of a liver disease unit) was assessed using three different assays: chemiluminescent molecular hybridisation assay (Murex Digene), column-based solution hybridisation assay (Abbott Genostics) and in-house polymerase chain reaction (PCR). PCR was found to be at least 100 times more sensitive (1 x 10(4) copies/mL) than Murex Digene (3.2 x 10(6) copies/mL) and Abbott Genostics (3.7 x 10(7) copies/mL). Comparison of the hepatitis B e antigen (HBeAg)/anti-HBe status and hepatitis B virus (HBV) DNA level confirmed an association between these two variables. The overall detection rate of HBV DNA by Murex Digene was 28% (87/310): 89% (73/82) in the HBeAg positive group, 10% (4/40) in the HBeAg/anti HBe negative group, and 5% (10/188) in the anti-HBe positive group. The detection rate by PCR increased to 53% (163/310): 98% (80/82) in the HBeAg positive group, 38% (15/40) in the HBeAg/anti-HBe negative group, and 36% (67/188) in the anti-HBe positive group. HBV DNA detection rates by all three assays in 97 liver disease unit patients were higher, particularly in anti-HBe positive patients, than in the cohort overall, probably reflecting a higher rate of active liver disease in these patients. HBV DNA was detected at the lowest rate in the antenatal clinic group. We suggest that HBeAg negative patients who are positive by PCR but negative by either Murex Digene or Abbott Genostics are still infectious. A cut-off serum HBV DNA level of 10(4) copies/mL is proposed, below which transmission is unlikely to occur, but further studies using quantitative PCR are needed to refine the cut-off level.

Colourimetric point mutation assay: for detection of precore mutants of hepatitis B.

A colourimetric assay for the analysis of point mutations in PCR amplified DNA fragments from hepatitis B virus (HBV) is described. The method was applied for analysis of the single point mutation in codon 28 of the precore gene of HBV, which inhibits expression of HBe antigen. The assay, which uses a microtitre plate formate, incorporates fluorescein-labelled dideoxynucleotides as opposed to radioactively-labelled deoxynucleotides used in methods described previously. Synthetic control wild type and mutant oligonucleotides were tested to optimise the reaction conditions. The assay was thus shown to yield both qualitative and quantitative data on the relative proportions of wild type and mutant sequences within a given sample. Amplicons from clinical specimens of known sequence were analysed to validate the assay. Sixteen chronic carriers of HBV were tested using the codon 28 point mutation assay, and the results were confirmed by direct sequencing. The method described is suitable for applications where point mutations are of interest.

A comparison of the level of hope in patients with newly diagnosed and recurrent cancer.

PURPOSE/OBJECTIVES: To compare levels of hope in patients with newly diagnosed and recurrent cancer. DESIGN: Descriptive study. SETTING: Three oncology practices in two urban areas of the southern United States. SAMPLE: Convenience sample of 20 newly diagnosed patients with cancer and 16 patients with recurrent cancer (mean age = 56 years). The majority of the patients were Caucasian, female, and married; had a high school degree; and had a religious affiliation. METHODS: Subjects completed the Herth Hope Scale and answered the open-ended question "What gives you the most hope at the present time?" Analysis included descriptive statistics (i.e., frequency, means, standard deviations, percents), t-tests, Chi-square, and analysis of variance. MAIN RESEARCH VARIABLES: Level of hope each subject had in relation to the stage of the cancer at the time of diagnosis. FINDINGS: Contrary to expectations, patients with newly diagnosed and recurrent cancer did not differ in regard to their level of hope. However, significant differences were found related to the type of hope utilized. Married patients and male patients experienced higher levels of hope. Recurrent themes in response to the open-ended question were family support, nonfamily support, faith, outlook, and health professionals/care. CONCLUSIONS: Patients with newly diagnosed cancer use their treatment and nurses, physicians, and other healthcare professionals as sources of hope and support. Patients with recurrent cancer reported drawing hope from faith. IMPLICATIONS AND NURSING PRACTICE: Heightened awareness of the patient-healthcare professional relationship will enable healthcare professionals to provide care that is more sensitive to one congruent with patients' needs. Healthcare professionals need to assess the meaning of faith for each individual patient and offer services to foster this source of hope.

Traditional and complementary therapies used together in the treatment, relief and control of Chron's disease and polyarthritis.

A diagnosis of polyarthritis and later Chron's disease was initially treated by traditional treatments and medicines, which was later supported by aromatherapy and acupuncture, but the turning point to a full recovery followed from a visit to a naturopath and the commencement of an individual/personal diet regime. Over the months of the acute phase of the illness, a valuable insight was gained to the challenges of a physical disability and the difficulties of immobility, and the loss of independence. Also, the experience of being a patient rather than a nursing practitioner, gave first hand experience of the different situations patients meet on a daily basis throughout the health care services, both traditional and complementary, from a patient's perspective rather than from a nursing point of view. The following paper will hopefully help others to consider a fresh individual situations, reflect on the collaboration of traditional and complementary treatments, and treatment of underlying cause as well as symptoms.

Genomic concatemerization/deletion in rotaviruses: a new mechanism for generating rapid genetic change of potential epidemiological importance.

Three variants of group A rotavirus with large changes in their gene 5 structures have been analyzed at the molecular level. The first of these, P9 delta 5, was obtained during plaque purification undertaken as part of the biological cloning of a field isolate of virus. The gene 5 homolog in this isolate migrated just ahead of the normal segment 6 RNA, giving an estimated size of 1,300 bp. Molecular cloning and sequencing of this homolog revealed it to have a single 308-bp deletion in the center of the normal gene 5 sequence extending between nucleotides 460 and 768 of the normal gene sequence. This deletion caused a frameshift in the gene such that a stop codon was encountered 8 amino acids downstream of the deletion point, giving a predicted size for the protein product of this gene of 150 amino acids compared with the 490 amino acids of its normal-size counterpart. Attempts to detect this shortened protein in virus-infected cells were not successful, indicating that it was much less stable than the full-length protein and/or had suffered a large change in its antigenicity. The second two variants, brvA and brvE, were generated in an earlier study following the high-multiplicity passage of the UKtc strain of bovine rotavirus. Polyacrylamide gel electrophoresis analysis of these nondefective variants showed that brvA had a gene 5 homolog approximately equal in size to the normal RNA segment 2 (approximately 2,700 bp) and that brvE had a size of approximately 2,300 bp. Both variants showed changes in their gene 5 protein products, with brvA mimicking P9 delta 5 in failing to produce a detectable product whereas brvE produced a new virus-specific protein approximately 80 kDa in size. Full-length cDNA clones of the brvE gene 5 homolog were isolated, and analysis of their structure revealed a head-to-tail concatemerization of the normal gene 5 sequence with the first copy of the concatemer covering nucleotides 1 to 808 and the second covering nucleotides 92 to 1579, giving a total length of 2,296 bp. Sequencing across the junction region of the two copies of the gene showed that they were joined in frame to give a predicted combined open reading frame of 728 amino acids with the amino-terminal region consisting of amino acids 1 to 258 fused at the carboxy terminus to amino acids 21 to 490.(ABSTRACT TRUNCATED AT 400 WORDS)

Pro-453 to Ser mutation in CYP21 is associated with nonclassic steroid 21-hydroxylase deficiency.

Steroid 21-hydroxylase deficiency is the leading cause of impaired cortisol synthesis in congenital adrenal hyperplasia (CAH), with the nonclassic form (NC) comprising approximately 1% of the Caucasian population. The structure of the CYP21 gene was studied in 13 unrelated NC-CAH patients, three affected siblings, and 55 blood donors using polymerase chain reaction. In addition to the Leu-281 and Leu-30 mutations previously associated with NC-CAH, the finding of a Pro-453 to Ser mutation in exon-10 of CYP21 in the NC-CAH patients is reported. Ser-453 was found in 46.2% of unrelated NC-CAH patients, but only 7.7% and 3.6% of salt-wasting CAH patients and blood donors, respectively. In contrast to the Leu-281 and Leu-30 mutations, Ser-453 has not been previously detected in the CYP21 pseudogene (CYP21P) and, therefore, has not likely arisen by gene conversion.