Note: Radio frequency surface impedance characterization system for superconducting samples at 7.5 GHz

A radio frequency (RF) surface impedance characterization (SIC) system that uses a novel sapphire-loaded niobium cavity operating at 7.5 GHz has been developed as a tool to measure the RF surface impedance of flat superconducting material samples. The SIC system can presently make direct calorimetric RF surface impedance measurements on the central 0.8 cm(2) area of 5 cm diameter disk samples from 2 to 20 K exposed to RF magnetic fields up to 14 mT. To illustrate system utility, we present first measurement results for a bulk niobium sample.

Alcohol ingestion and colorectal neoplasia: a meta-analysis based on a Mendelian randomization approach

AIM

Observed associations of alcohol with colorectal cancer are prone to distortion by confounding and reverse causation. A Mendelian randomization approach provides an unbiased estimate of the association using the aldehyde dehydrogenase 2 (ALDH2) variant as a surrogate of alcohol exposure.

METHOD

A meta-analysis was performed to assess the association between the ALDH2 genotype and colorectal neoplasia, using the ALDH2 genotype as a marker of alcohol intake.

RESULTS

The pooled odds ratio (OR) of colorectal neoplasia was 1.31 (95%CI, 1.01-1.70) for the Glu/Glu vs the Lys/Lys genotype. There was no evidence of interstudy heterogeneity (P = 0.12, I² = 42.7). The overall risk for Glu/Lys heterozygotes relative to Lys/Lys homozygotes (under a fixed-effects model) was 1.13 (95%CI, 0.86-1.48). There was no evidence of publication bias for Glu/Glu or Glu/Lys analysis.

CONCLUSION

The result supports the role of alcohol in colorectal carcinogenesis based on a Mendelian randomization approach.

In vivo assessment of chitosan/β-glycerophosphate as a new liquid embolic agent

We sought to assess the feasibility of using thermosensitive chitosan/β-glycerophosphate forembolotherapy. The renal arteries in nine rabbits were embolized with chitosan/β-glycero-phosphate. The animals were studied angiographically and sacrificed at one week (n = 3), four weeks (n = 3), and eight weeks (n = 3) after embolotherapy. Histology was obtained at these three time points. Delivery of chitosan/β-glycerophosphate was successful in all cases. Complete occlusion was achieved in all cases. No recanalization was observed in the follow-up angiograms. No untoward inflammatory reactions were observed in the target renal arteries and infarcted kidneys during the histological examinations. Our preliminary feasibility evaluation in rabbit renal arteries indicates that C/GP is a satisfactory embolization agent.

Comparison of the diversity of the bacterial communities in the intestinal tract of adult Bactrocera dorsalis from three different populations

AIMS

To (i) identify the bacterial communities in the gut of oriental fruit fly (Bactrocera dorsalis) adult and (ii) determine whether the different surroundings and diets influence the bacteria composition.

METHODS AND RESULTS

Polymerase chain reaction-denaturing gradient gel electrophoresis (DGGE) fingerprinting was used to investigate bacterial diversity in the oriental fruit fly adult gut. The 16S rDNA cloned libraries from the intestinal tract of laboratory-reared (LR), laboratory sterile sugar-reared (LSSR) and field-collected (FC) populations of oriental fruit fly were compared. Phylogenetic analysis of 16S rDNA revealed that Gammaproteobacteria were dominant in the all samples (73·0-98·3%). Actinobacteria and Firmicutes were judged to be major components of a given library as they constituted 10% or more of the total clones of such library. The Flavobacteria, Deltaproteobacteria, Bacteroidetes and Alphaproteobacteria were observed in small proportions in various libraries. Further phylogenetic analyses indicated common bacterial phylotypes for all three libraries, e.g. those related to Klebsiella, Citrobacter, Enterobacter, Pectobacterium and Serratia. LIBSHUFF analysis showed that the bacterial communities of B. dorsalis from the three populations were significantly different from each other (P < 0·0085).

CONCLUSIONS

(i) The intestinal tract of B. dorsalis adult contains a diverse bacterial community, some of which are stable. (ii) Different environmental conditions and food supply could influence the diversity of the harboured bacterial communities and increase community variations.

SIGNIFICANCE AND IMPACT OF THE STUDY

Comparison of the microbial compositions and common bacterial species found in this paper may be very important for the biocontrol of B. dorsalis.

Resonant excitation of precursor molecules in improving the particle crystallinity, growth rate and optical limiting performance of carbon nano-onions

A catalyst-free and highly efficient synthetic method for growing carbon nano-onions (CNOs) in open air has been developed through the laser resonant excitation of a precursor molecule, ethylene, in a combustion process. Highly concentric CNO particles with improved crystallinity were obtained at a laser wavelength of 10.532 µm through the resonant excitation of the CH(2) wagging mode of the ethylene molecules. A higher growth rate up to 2.1 g h( - 1) was obtained, compared with that without a laser (1.3 g h( - 1)). Formation of the CNOs with ordered graphitic shells is ascribed to the decomposition of polycyclic aromatic hydrocarbons (PAHs) into C(2) species. The optical limiting performances of the CNOs grown by the combustion processes were investigated. CNOs grown at 10.532 µm laser excitation demonstrated improved optical limiting properties due to the improved crystallinity.

Effect of NF-κB signaling on apoptosis in chronic inflammation-associated carcinogenesis

The causal relationship between inflammation and cancer has been documented for sometime, but its molecular nature remains ill defined. Increasing evidence suggested that inflammatory microenvironment in and around tumors is an indispensable participant in the neoplastic process. High level of free radicals produced during inflammation significantly induces DNA damage while evading apoptosis, a hallmark of cancer, reduces the capability of tissues to eliminate damaged cells. Therefore, the mechanism by which inflammation affects the apoptosis pathway is crucial to understand inflammation-associated carcinogenesis. Nuclear factor-κB (NF-κB), a transcriptional factor, plays an important role in the regulation of inflammatory responses. NF-κB signaling, which can be activated by diverse stimuli including proinflammatory cytokines, infectious agents and cellular stresses, has been shown to involve in carcinogenesis and resistance to multiple drug therapy. In this review, we focus on the role of NF-κB signaling on the apoptotic effect in inflammation-associated carcinogenesis. These insights may help us to consider the role of NF-κB in inflammation and cancer and further on as a target of drugs for the prevention and treatment of these diseases.

Taspoglutide, a novel human once-weekly GLP-1 analogue, protects pancreatic β-cells in vitro and preserves islet structure and function in the Zucker diabetic fatty rat in vivo

AIM

Glucagon-like peptide-1 (GLP-1) has protective effects on pancreatic β-cells. We evaluated the effects of a novel, long-acting human GLP-1 analogue, taspoglutide, on β-cells in vitro and in vivo.

METHODS

Proliferation of murine pancreatic β (MIN6B1) cells and rat islets in culture was assessed by imaging of 5-ethynyl-2'-deoxyuridine-positive cells after culture with taspoglutide. Apoptosis was evaluated with the transferase-mediated 2'-deoxyuridine 5'-triphosphate nick-end labelling assay in rat insulinoma (INS-1E) cells and isolated human islets exposed to cytokines (recombinant interleukin-1β, interferon-γ, tumour necrosis factor-α) or lipotoxicity (palmitate) in the presence or absence of taspoglutide. Islet morphology and survival and glucose-stimulated insulin secretion in perfused pancreata were assessed 3-4 weeks after a single application of taspoglutide to prediabetic 6-week-old male Zucker diabetic fatty (ZDF) rats.

RESULTS

Proliferation was increased in a concentration-dependent manner up to fourfold by taspoglutide in MIN6B1 cells and was significantly stimulated in isolated rat islets. Taspoglutide almost completely prevented cytokine- or lipotoxicity-induced apoptosis in INS-1E cells (control 0.5%, cytokines alone 2.2%, taspoglutide + cytokines 0.6%, p < 0.001; palmitate alone 8.1%, taspoglutide + palmitate 0.5%, p < 0.001) and reduced apoptosis in isolated human islets. Treatment of ZDF rats with taspoglutide significantly prevented β-cell apoptosis and preserved healthy islet architecture and insulin staining intensity as shown in pancreatic islet cross sections. Basal and glucose-stimulated insulin secretion of in situ perfused ZDF rat pancreata was normalized after taspoglutide treatment.

CONCLUSIONS

Taspoglutide promoted β-cell proliferation, prevented apoptosis in vitro and exerted multiple β-cell protective effects on islet architecture and function in vivo in ZDF rats.

Modeling pathogenesis of Huntington's disease with inducible neuroprogenitor cells

Huntington's disease (HD) is caused by an abnormal expansion of CAG trinucleotide repeats encoding polyglutamine (polyQ) in the first exon of the huntingtin (htt) gene. Despite considerable efforts, the pathogenesis of HD remains largely unclear due to a paucity of models that can reliably reproduce the pathological characteristics of HD. Here, we report a neuronal cell model of HD using the previously established tetracycline regulated rat neuroprogenitor cell line, HC2S2. Stable expression of enhanced green fluorescence protein tagged htt exon 1 (referred to as 28Q and 74Q, respectively) in the HC2S2 cells did not affect rapid neuronal differentiation. However, compared to the cells expressing wild type htt, the cell line expressing mutant htt showed an increase in time-dependent cell death and neuritic degeneration, and displayed increased vulnerability to oxidative stress. Increased protein aggregation during the process of neuronal aging or when the cells were exposed to oxidative stress reagents was detected in the cell line expressing 74Q but not in its counterpart. These results suggest that the neuroprogenitor cell lines mimic the major neuropathological characteristics of HD and may provide a useful tool for studying the neuropathogenesis of HD and for high throughput screening of therapeutic compounds.

Electronic structure and magnetic ordering of the semiconducting chromium trihalides CrCl3, CrBr3, and CrI3

We present results from an electronic structure investigation of the chromium halides CrCl(3), CrBr(3), and CrI(3), as obtained by the linearized augmented plane wave method of density functional theory. Our interest focuses on the chloride. While all three halides display strong ferromagnetic coupling within the halide-Cr-halide triple layers, our emphasis is on differences in the interlayer magnetic coupling. In agreement with experimental results, our calculations indicate ferromagnetic ordering for CrBr(3) as well as CrI(3). The antiferromagnetic state of CrCl(3) can be reproduced by introducing an on-site electron-electron repulsion. However, we observe that the ground state depends critically on the specific approach used. Our results show that a low temperature structural phase transition from monoclinic to trigonal is energetically favourable for CrCl(3).

Performance of sequential organ failure assessment, logistic organ dysfunction and multiple organ dysfunction score in severe sepsis within Chinese intensive care units

This study assessed the performance of Sequential Organ Failure Assessment, Logistic Organ Dysfunction Score and Multiple Organ Dysfunction Score in outcome prediction in severe sepsis. A total of 528 consecutive patients with a diagnosis of severe sepsis were enrolled from two surgical intensive care units of university hospitals in China. Clinical and laboratory data of patients were collected and admission and maximum values of each scoring system were calculated. Areas under the receiver operating characteristic curve, which were used to assess discrimination, were 0.80, 0.83 and 0.74 for admission Sequential Organ Failure Assessment, Logistic Organ Dysfunction Score and Multiple Organ Dysfunction Score respectively, and 0.91, 0.93 and 0.86 for corresponding maximum values respectively. Calibration assessed by the Hosmer-Lemeshow statistic was better with admission (chi2 = 18.2) and maximum Logistic Organ Dysfunction Score (chi2 = 19.6) than with admission (chi2 = 98.1) and maximum Multiple Organ Dysfunction Score (chi2 = 30.9). Brier Scores, indicating the overall performance of the scores, were 0.18, 0.17 and 0.22 for admission Sequential Organ Failure Assessment, Logistic Organ Dysfunction Score and Multiple Organ Dysfunction Score respectively, and 0.12, 0.10 and 0.15 for their maximum counterparts respectively. This study found good performance of both admission Sequential Organ Failure Assessment and Logistic Organ Dysfunction Score in severe sepsis, and a slightly weaker performance of admission Multiple Organ Dysfunction Score. Since poor calibration was observed in Logistic Organ Dysfunction Score and Multiple Organ Dysfunction Score, we suggest further study of customisation of these scores in critical illness with severe sepsis.

Multiple sequence variations in SLC5A1 gene are associated with glucose-galactose malabsorption in a large cohort of Old Order Amish

Glucose-galactose malabsorption (GGM) is an autosomal recessive disease with life-threatening newborn diarrhea caused by mutations in the Na(+) /glucose cotransporter gene SLC5A1. Because of its rarity, the clinical course of the disease has not been well studied. Here, we report 33 patients with GGM from a large Old Order Amish pedigree and the associated mutations in SLC5A1 gene. Clinically, all affected individuals presented with classic watery diarrhea and dehydration. The increased bowel sounds, distended abdomen, vigorous nursing regardless of their illness, and irritability and apathy were also noted as part of the initial presentation. Patients underwent a dramatic turnaround with an immediate cease of the diarrhea and a quick rehydration if they were correctly diagnosed and adequately managed, followed by a normal growth and development pattern afterwards; whereas a prolonged clinical course would follow if the disease was not recognized. Sequence analysis of the 15 protein-coding exons and the corresponding exon-intron boundaries of SLC5A1 gene revealed four homozygous missense mutations, c.152A>G (p.N51S), c.1231G>A (p.A411T), c.1673G>A (p.R558H), and c.1845C>G (p.H615Q), that co-segregate with the GGM phenotype in all of the affected individuals. These findings suggest that founder effect of the SLC5A1 mutations associated with the disease in Amish and a population specific genetic testing is in need to pursue an early diagnosis which is critical for a favorable outcome.

Recoverable Photodegradation of Light-Emitting Polymers

The photodegradation of light-emitting polymers was studied by measuring the decay of the photoluminescence with exposure time to He-Cd laser beam at room temperature. It was found that the photoluminescence intensity decreases very fast initially, and then tends to saturate on the order of several tens of minutes. More interestingly, it was found that the degradation induced by laser beam can be self-healed. By stopping the exposure of the sample to the laser beam, the photoluminescence intensity recovers gradually without any treatment.

Antidiabetic effects of duodenojejunal bypass in an experimental model of diabetes induced by a high-fat diet

Background

Obese patients with type II diabetes who undergo bariatric surgery revert to normal blood glucose and insulin levels, and develop a dramatic increase in insulin sensitivity. However, the mechanisms involved are unknown. This study characterized pancreatic islet and duodenojejunal enteroendocrine cells in normal mice and those with diabetes induced by a high-fat diet (HFD) following duodenojejunal bypass (DJB).

Methods

C57BL/6J mice, fed for 8 weeks either a normal diet (n = 10) or a HFD (n = 10) resulting in a hyperglycaemic state, underwent DJB (connection of the distal end of the jejunum to the distal stomach and direction of biliopancreatic secretions to the distal jejunum). Metabolic and immunohistological analyses were carried out on the pancreas and gastrointestinal tract.

Results

A significant decrease in fasting blood glucose was observed in normal-DJB and HFD-DJB mice 1 week after the operation, with improved glucose tolerance at 4 weeks. There were no changes in pancreatic β-cell mass, but an increase in the ratio of α-cell to β-cell mass was observed in the DJB groups. Furthermore, the number of cells expressing Pdx-1, glucagon-like peptide 1, pancreatic polypeptide and synaptophysin was increased in the bypassed duodenum and/or gastrojejunum of the DJB groups.

Conclusion

Both normal and obese diabetic mice that underwent DJB displayed improved glucose tolerance and a reduction in fasting blood glucose, which mimicked findings in obese diabetic patients following bariatric surgery. The present data suggest that an increase in specific enteroendocrine cell populations may play a critical role in normalizing glucose homeostasis.

Positive and negative control of Ucp1 gene transcription and the role of β-adrenergic signaling networks

Adrenergic receptor signaling in adipocytes controls not only the hydrolysis of triglycerides as fuel for other organs but is also a driver of brown adipocyte thermogenesis and energy consumption. As the appearance of these mitochondria-rich, thermogenically active cells in 'white' adipocyte depots is correlated with resistance to overnutrition and glucose intolerance, the molecular basis of their genesis and metabolic activity needs to be understood. β-adrenergic receptors regulate the enzymatic machinery for lipolysis and fuel utilization. They also coordinately stimulate the transcription of genes that support the specific functions of white and brown adipocytes. They accomplish this through the activation of a network of signaling pathways that include cAMP-dependent protein kinase and members of the mitogen-activated protein kinase family. In brown adipocytes, these kinases control the transcription of nuclear factors such as peroxisome proliferator-activated receptor-γ coactivator-1s, as well as other molecules discovered to respond to adrenergic signals, to increase mitochondrial biogenesis and uncoupling protein-1 (UCP1) expression. However, it is also important to understand the mechanisms that may actively repress these energy-wasting processes. Toward that end, we provide evidence for an important role for the nuclear receptor LXRα as a cAMP- and oxysterol-dependent transcriptional repressor of the Ucp1 gene. Adipocytes from LXRα-null mice have increased expression of most 'markers' of brown adipocytes, increased mitochondrial mass and uncoupled respiration. These studies reveal potential new targets and directions for controlling the relative levels of white versus brown adipocytes as a means of metabolic fuel utilization in the struggle against obesity and related metabolic diseases.

Association between HLA-B*27 polymorphisms and ankylosing spondylitis in Han populations: a meta-analysis

OBJECTIVES

The aim of this study was to determine whether the HLA-B*27 polymorphisms confer susceptibility to ankylosing spondylitis (AS) in Han populations by conducting a meta-analysis.

METHODS

Publications addressing the association between the HLA-B*27 polymorphisms and susceptibility to AS in Han populations were selected from the MEDLINE, EMBASE and CBMdisc databases. Data was extracted from the studies by 2 independent reviewers. The meta-analyses were performed by Review Manager Version 5.0.24 and STATA Version 9.2 software. From these data, the odds ratio (OR) with 95% confidence interval (95%CI) was calculated.

RESULTS

Fourteen studies with a total of 1900 AS cases and 831 healthy controls were retrieved. Meta-analysis results showed a positive association between B*2704 and susceptibility to AS in Han population (OR=2.20, 95%CI=1.60-3.02, p<0.00001). However, B*2705, B*2706 and B*2707 showed negative associations with susceptibility to AS in Han populations (OR=0.59, 95%CI=0.43-0.81, p=0.001; OR=0.13, 95%CI=0.05-0.37, p=0.0001; OR=0.23, 95%CI=0.11-0.46, p<0.0001; respectively). In subgroup analysis, there was a positive association between B*2704 and susceptibility to AS in the southerners of China, but not in the northerners. Negative associations between B*2705, B*2706 and susceptibility to AS were determined in the southerners of China, but also not in the northerners. Results showed obviously negative associations between B*2707 and susceptibility to AS both in the southerners and northerners of China.

CONCLUSIONS

This meta-analysis confirms that B*2704 might be a potential risk factor and B*2705, B*2706, B*2707 might be potential protective factors for AS in Han populations, especially in the southerners of China.

Study on the executive function and learning ability in first-episode schizophrenia patients

Introduction

Cognitive dysfunction was thought to be one of the core features of schizophrenia. And the executive function of the patients was paid more attention by more and more researchers and clinicians.

Objectives

To investigate the executive function and the learning ability of the patients with first-episode schizophrenia, and their relationships with psychiatric symptoms.

Methods

Fifty cases of first-episode schizophrenia patients and fifty age- and gender-matched healthy controls were tested by a computerized version of Tower of London (TOL) test. The scores of the Positive and Negative Syndrome Scale(PANSS) in the group of schizophrenia patients were over 60.

Results

The numbers of the correct answer [x1 :(14.62 ± 4.12), x2: (14.80 ± 4.70)] during the first session and the second session of the TOL test of the patients group were significantly lower than that of the control group [x1: (17.48 ± 3.79), x2:(18.68 ± 3.19)], and the reaction times [t1: (9.27 ± 4.37) seconds, t2: (9.51 ± 5.58) seconds] of the two sessions of TOL were longer than the control group [t1: (7.28 ± 2.04) seconds, t2: (6.67 ± 1.51) seconds], P < 0.01. For the control group, x2 was significantly greater than x1, and t2 shorter than t1 (P < 0.01), while for the patients group, there was no difference between the performances of the first session and the second session. The scores of TOL in the schizophrenia patients were correlated with the negative symptom score of PANSS (P < 0.05) and were not correlated with the scores of other subscales of PANSS (P > 0.05).

Conclusions

The executive function and the learning ability of schizophrenia are impaired and the cognitive dysfunction is correlated with negative symptoms.

Different anesthesia methods for laparoscopic cholecystectomy

OBJECTIVES

The aim of the study was to compare the possibility of performing laparoscopic cholecystectomy using two different anesthesia procedures (spinal anesthesia versus general anesthesia).

METHODS

The study included 68 patients with symptoms of cholelithiasis examined in the 309th Hospital of PLA from 2006 to 2009. Patients were randomly selected to undergo laparoscopic cholecystectomy with low tension pneumoperitoneum with CO(2) under general anesthesia (n=33) or spinal anesthesia (n=35). The study used propofol, fentanyl, rocuronium, sevoflurane and tracheal intubation for general anesthesia and hyperbaric 15 mg bupivacaine and 20 µg fentanyl were used to achieve a sensorial level of T(3) for spinal anesthesia. Intraoperative parameters, postoperative pain, complications, recovery, patient satisfaction and cost were compared between both groups.

RESULTS

All surgical procedures were completed with the chosen method with the exception of one case, in which spinal anesthesia was converted to general anesthesia. Shoulder pain was significantly less frequent in the spinal anesthesia group (6%) compared with the general anesthesia group (24%). The level of pain at 2, 4, and 6 h after the procedure under spinal anesthesia was significantly lower than that under general anesthesia. At 12 h both groups had the same evaluation in the visual analogue scale. In the spinal anesthesia group all patients recovered 6 h after surgery, while patients in the general anesthesia group spent more time in recovery. All patients were discharged from hospital after 24 h. In the postoperative evaluation all patients were satisfied with the spinal anesthesia and would recommend this procedure, while only 78.9% of patients were very satisfied in the general anesthesia group. The cost of spinal anesthesia was significantly lower than that of general anesthesia.

CONCLUSIONS

Laparoscopic cholecystectomy with low pressure pneumoperitoneum with CO(2) can be safely performed under spinal anesthesia. Spinal anesthesia was associated with an extremely low level of postoperative pain, better recovery and lower cost than general anesthesia.

Hypoxia-excited neurons in NTS send axonal projections to Kölliker-Fuse/parabrachial complex in dorsolateral pons

Hypoxic respiratory and cardiovascular responses in mammals are mediated by peripheral chemoreceptor afferents which are relayed centrally via the solitary tract nucleus (NTS) in dorsomedial medulla to other cardiorespiratory-related brainstem regions such as ventrolateral medulla (VLM). Here, we test the hypothesis that peripheral chemoafferents could also be relayed directly to the Kölliker-Fuse/parabrachial complex in dorsolateral pons, an area traditionally thought to subserve pneumotaxic and cardiovascular regulation. Experiments were performed on adult Sprague-Dawley rats. Brainstem neurons with axons projecting to the dorsolateral pons were retrogradely labeled by microinjection with choleras toxin subunit B (CTB). Neurons involved in peripheral chemoreflex were identified by hypoxia-induced c-Fos expression. We found that double-labeled neurons (i.e. immunopositive to both CTB and c-Fos) were localized mostly in the commissural and medial subnuclei of NTS and to a lesser extent in the ventrolateral NTS subnucleus, VLM and ventrolateral pontine A5 region. Extracellular recordings from the commissural and medial NTS subnuclei revealed that some hypoxia-excited NTS neurons could be antidromically activated by electrical stimulations at the dorsolateral pons. These findings demonstrate that hypoxia-activated afferent inputs are relayed to the Kölliker-Fuse/parabrachial complex directly via the commissural and medial NTS and indirectly via the ventrolateral NTS subnucleus, VLM and A5 region. These pontine-projecting peripheral chemoafferent inputs may play an important role in the modulation of cardiorespiratory regulation by dorsolateral pons.

Deposition Of Aluminium Nitride Film By Ion Beam Enhanced Reactive Magnetron Sputtering

Aluminium nitride film has been synthesized at substrate temperatures lower than 100 °C by using ion beam enhanced reactive magnetron sputtering. The growth rate was much higher than that obtained by usual physical vapor deposition at low substrate temperatures. The stoichiometry of the film was controlled by varying the resultant current of the ion beam used and identified by X-ray diffraction analysis. The optical properties of the film were also studied.

Fast tunable coupler for superconducting qubits

A major challenge in the field of quantum computing is the construction of scalable qubit coupling architectures. Here, we demonstrate a novel tunable coupling circuit that allows superconducting qubits to be coupled over long distances. We show that the interqubit coupling strength can be arbitrarily tuned over nanosecond time scales within a sequence that mimics actual use in an algorithm. The coupler has a measured on/off ratio of 1000. The design is self-contained and physically separate from the qubits, allowing the coupler to be used as a module to connect a variety of elements such as qubits, resonators, amplifiers, and readout circuitry over distances much larger than nearest-neighbor. Such design flexibility is likely to be useful for a scalable quantum computer.

Deterministic entanglement of photons in two superconducting microwave resonators

Quantum entanglement, one of the defining features of quantum mechanics, has been demonstrated in a variety of nonlinear spinlike systems. Quantum entanglement in linear systems has proven significantly more challenging, as the intrinsic energy level degeneracy associated with linearity makes quantum control more difficult. Here we demonstrate the quantum entanglement of photon states in two independent linear microwave resonators, creating N-photon NOON states (entangled states |N0> + |0N>) as a benchmark demonstration. We use a superconducting quantum circuit that includes Josephson qubits to control and measure the two resonators, and we completely characterize the entangled states with bipartite Wigner tomography. These results demonstrate a significant advance in the quantum control of linear resonators in superconducting circuits.