Strong coupling between a microwave photon and a singlet-triplet qubit

Combining superconducting resonators and quantum dots has triggered tremendous progress in quantum information, however, attempts at coupling a resonator to even charge parity spin qubits have resulted only in weak spin-photon coupling. Here, we integrate a zincblende InAs nanowire double quantum dot with strong spin-orbit interaction in a magnetic-field resilient, high-quality resonator. The quantum confinement in the nanowire is achieved using deterministically grown wurtzite tunnel barriers. Our experiments on even charge parity states and at large magnetic fields, allow us to identify the relevant spin states and to measure the spin decoherence rates and spin-photon coupling strengths. We find an anti-crossing between the resonator mode in the single photon limit and a singlet-triplet qubit with a spin-photon coupling strength of g/2π = 139 ± 4 MHz. This coherent coupling exceeds the resonator decay rate κ/2π = 19.8 ± 0.2 MHz and the qubit dephasing rate γ/2π = 116 ± 7 MHz, putting our system in the strong coupling regime.

Performance of high impedance resonators in dirty dielectric environments

High-impedance resonators are a promising contender for realizing long-distance entangling gates between spin qubits. Often, the fabrication of spin qubits relies on the use of gate dielectrics which are detrimental to the quality of the resonator. Here, we investigate loss mechanisms of high-impedance NbTiN resonators in the vicinity of thermally grown SiO2 and Al2O3 fabricated by atomic layer deposition. We benchmark the resonator performance in elevated magnetic fields and at elevated temperatures and find that the internal quality factors are limited by the coupling between the resonator and two-level systems of the employed oxides. Nonetheless, the internal quality factors of high-impedance resonators exceed 103 in all investigated oxide configurations which implies that the dielectric configuration would not limit the performance of resonators integrated in a spin-qubit device. Because these oxides are commonly used for spin qubit device fabrication, our results allow for straightforward integration of high-impedance resonators into spin-based quantum processors. Hence, these experiments pave the way for large-scale, spin-based quantum computers.

POS1324 TREATMENT OF UVEITIS ASSOCIATED WITH JUVENILE IDIOPATHIC ARTHRITIS: A SEVEN YEARS’ SINGLE-CENTRE EXPERIENCE

Background:

Uveitis (U) is one of the most common extra-articular manifestation of juvenile idiopathic arthritis (JIA). It is usually revealed in 10-20% of children with JIA, often asymptomatic and sometimes the onset of U precedes the onset of arthritis. Being inappropriately treated, U leads to vision loss in up to 20% of children. Despite the efforts of the Standardization of Uveitis Nomenclature (SUN) Working Group and the European initiative Single Hub and Access point for pediatric Rheumatology in Europe (SHARE) which optimized management of JIA-associated U [1], the actual treatment is mostly based on physicians’ experience. Initial treatment typically includes topical glucocorticoids (G) or systemic immunosuppressive therapy if topical G don’t work. Methotrexate (MTX) is the first-line systemic immunosuppressive agent, followed by tumor necrosis factor inhibitors (TNFi) [1,2].

Objectives:

To provide treatment recommendations for JIA-associated U based on monitoring of 221 patients during 7 years.

Methods:

Data collected during 2240 hospitalisations of 221 patients aged 3 - 17 years treated at the State Pediatric Medical University in years 2014 - 2020 were analyzed. U and JIA were diagnosed according to the SUN and ACR recommendations. Initial treatment of U included topical G or non-steroidal anti-inflammatory drugs (NSAIDs). Treatment of JIA included systemic NSAIDs, cytostatics (MTX, Cyclosporine or Cyclophosphamide) and biologics: Adalimumab (Ada), Infliximab (Inf), Etanercept (Eta), Abatacept (Aba), Tocilizumab (Toc), Golimumab (Gol). Statistical analysis included traditional Descriptive Statistics, Spearman Rank Order Correlation (SROC) and Multivariate Exploratory Techniques [Statistica for Windows, Statsoft].

Results:

Of all patients with JIA-associated U the proportion of those treated with biologics during the monitoring increased from 60 to 70% (of them, Ada 79 - 93%, Inf 7 - 1%, Eta 5 - 1%, Aba 7 - 3%, Toc 7 - 0%, Gol 0 - 3%). Of all children in whom U was diagnosed later than arthritis 36% were treated with systemic NSAIDs, 25% - with cytostatics (MTX - 84%, Cyclosporine - 8%, Cyclophosphamide - 8%), 23% - with systemic G, 6% - with biologics (Eta - 83%, Toc - 17%). Of patients in whom U and arthritis were diagnosed simultaneously, 95% were treated with cytostatics (MTX - 95%, Cyclosporine - 15%), 93% - with topical G, 91% - with topical NSAIDs, 81% - with systemic G, 60% - with systemic NSAIDs. Efficacy of treatment in terms of SROK showed evidence of steady improvement already after 1 month of therapy with TNFi or with MTX (increase of r during the first year from 0.37 to 0,62, p<0.02; from 0.37 to 0.55, p<0.05 respectively), though r was never higher than 0.84 during the first 3 years of treatment. Topical NSAIDs and G were less effective: improvement was revealed after 3 months of treatment, it was not so steady and r was never higher than 0.35. Systemic NSAID’s were not effective at all.

Conclusion:

1. The likelihood of improvement of U treated with TNFi (Eta excepted) after one month, after 1 and after 3 years of therapy was 37%, 62% and 84% respectively. For MTX this likelihood was 37% after 1 month and 55% after 3 months.

2. TNFi (Eta excepted) in treatment of JIA prevents the onset of U, thereby supposing its early administration.

3. Eta neither prevents nor treats U.

4. Topical NSAIDs and G can hardly be recommended as a reliable means for treatment of U without TNFi and MTX.

5. Systemic NSAIDs neither prevent nor treat JIA-associated U.

References:

[1]Constantin T, Foeldvari I, Anton J, et al. Consensus-based recommendations for the management of uveitis associated with juvenile idiopathic arthritis: the SHARE initiative Ann Rheum Dis 2018;77:1107–1117

[2]Angeles-Han ST, Ringold S, Beukelman T, Lovell D et al., 2018 American College of Rheumatology/Arthritis Foundation Guideline for the Screening, Monitoring, and Treatment of Juvenile Idiopathic Arthritis-Associated Uveitis. Arthritis Care Res (Hoboken). 2019 June; 71(6): 703–716

Disclosure of Interests:

None declared

Determination of lumpy skin disease virus in bovine meat and offal products following experimental infection

Lumpy skin disease (LSD) has recently expanded its range northwards to include the Balkans, Turkey and Russia. Because there was no solid evidence conclusively verifying the transmission mechanism in the field and LSDV viraemic animals with overt and asymptomatic presentation of disease and their products may represent a risk as an indirect transmission pathway. In this work, we used PCR positivity and infectivity in clinical and subclinical infection to evaluate the safety of meat and offal products from cows infected with the virulent LSDV strain Russia/Dagestan/2015. At day 21 post infection, seven of the 12 animals developed the generalized disease, and four animals became subclinically infected without apparent clinical signs. Upon examination and necropsy, the animals with the generalized disease had skin lesions; noticeably enlarged lymph nodes; and lesions in the lungs, trachea and testicles; whereas subclinically ill animals exhibited only enlarged lymph nodes and fever. For both disease presentations, testing of skeletal meat by PCR and virus isolation showed that the skeletal meat did not contain live virus or viral genome, whereas in cattle with generalized disease, meat with gross pathology physically connected under the site of a skin lesion was positive for the live virus. In subclinical infection, only enlarged lymph nodes carried the infectious virus, while the other internal organs tested in both types of disease manifestation were negative except for the testicles. Overall, our findings demonstrate that clinically and subclinically infected animals are reservoirs of live LSDV in lymph nodes and testicles, whereas deep skeletal meat in both types of infection do not carry live virus and the risk of transmission through this product seems very low. The detection of LSDV in testicular tissues in subclinically ill animals is concerning because of the potential to spread infection through contaminated semen. This aspect requires reconsideration of surveillance programmes to identify these Trojan horses of LSDV infection.

Detection of vaccine-like lumpy skin disease virus in cattle and Musca domestica L. flies in an outbreak of lumpy skin disease in Russia in 2017

Since 2012, lumpy skin disease virus (LSDV) has been spreading from the Middle East to south-east Europe and Russia. Although vaccination campaigns have managed to contain LSDV outbreaks, the risk of further spread is still high. The most likely route of LSDV transmission in short distance spread is vector-borne. Several arthropod species have been suggested as potential vectors, but no proven vector has yet been identified. To check whether promiscuous-landing synanthropic flies such as the common housefly (Musca domestica) could be involved, we carried out entomological trapping at the site of a recent LSDV outbreak caused by a vaccine-like LSDV strain. The presence of vaccine-like LSDV DNA was confirmed by the assay developed herein, the assay by Agianniotaki et al. (2017) and RPO30 gene sequencing. No evidence of field LSDV strain circulation was revealed. In this study, we discovered that M. domestica flies carried vaccine-like LSDV DNA (C_t  > 25.5), whereas trapped stable flies from the same collection were negative for both field and vaccine LSDV. To check whether flies were contaminated internally and externally, 50 randomly selected flies from the same collection were washed four times and tested. Viral DNA was mainly detected in the 1st wash fluid, suggesting genome or even viral contamination on the insect cadaver. In this study, internal contamination in the insect bodies without differentiation between the body locations was also revealed; however, the clinical relevance for mechanical transmission is unknown. Further work is needed to clarify a role of M. domestica in the transmission of LSDV. To our knowledge, this is the first report demonstrating that an attenuated LSD vaccine strain has been identified in Russian cattle given the ban on the use of live attenuated vaccines against LSDV.

Epidemiological characterization of lumpy skin disease outbreaks in Russia in 2016

In 2015, the lumpy skin disease virus spread throughout the Russian Federation. Following a modified stamping-out campaign, the disease re-emerged with a greater incidence across 16 regions of Southern and Central Russia. A total of 313 outbreaks were reported to OIE. The highest outbreak frequency was observed in the republics of Chechnya (108), Kalmykiya (57), and Ingushetiya (35). The disease cases predominantly occurred in June and July 2016, starting from May to December; however, no association between outbreaks and altitudes was identified (p > .05). Samples taken from infected cattle were subjected to PCR analysis, which identified the genome of the virus most frequently in skin nodules (78%), nasal swabs (23.4%), blood (13%) and sera (14.5%). Interestingly, LSDV genome was occasionally identified in lung and milk samples. Based on the PRO30 sequence analysis, lumpy skin disease virus (LSDV) strains circulating in Russia were all identical and fell within the cluster of field LSDV found worldwide.

Experimental evaluation of speckle suppression efficiency using a moving 2D Barker code DOE

This paper reports the findings from an experimental evaluation of speckle suppression efficiency using a method based on a moving 2D Barker code diffractive optical element (DOE). The optical setup and the optical scheme parameters of the method are presented. A speckle contrast of ~4.4-5.3% and speckle suppression coefficient (coefficient of speckle contrast reduction) of k>8 was obtained in experiments. However, the experimentally obtained speckle suppression coefficient was approximately 1.5 times smaller than the theoretical prediction. It is speculated that the discrepancy between the theoretical and the experimental data is due to an inexact match between the optical setup and the optimal optical parameters of the method. Analysis of the experimental data revealed that once the optical scheme is optimized, it will be possible to obtain a speckle suppression that is closer to the theoretical prediction.

Optical schemes for speckle suppression by Barker code diffractive optical elements

A method for speckle suppression based on Barker code and M-sequence code diffractive optical elements (DOEs) is analyzed. An analytical formula for the dependence of speckle contrast on the wavelength of the laser illumination is derived. It is shown that speckle contrast has a wide maximum around the optimal wavelength that makes it possible to obtain large speckle suppression by using only one DOE for red, green, and blue laser illumination. Optical schemes for implementing this method are analyzed. It is shown that the method can use a simple liquid-crystal panel for phase rotation instead of a moving DOE; however, this approach requires a high frequency of liquid-crystal switching. A simple optical scheme is proposed using a 1D Barker code DOE and a simple 1D liquid-crystal panel, which does not require a high frequency of liquid-crystal switching or high-accuracy DOE movement.

Fibrin-glue assisted vasoepididymostomy: a comparison to standard end-to-side microsurgical vasoepididymostomy in the rat model

PURPOSE

The use of fibrin glue for vasovasostomy has produced high patency rates in animal models. Vasoepididymostomy is a microsurgical technique that might be made easier if fibrin glue could substitute for microsutures. We evaluated the efficacy of a new vasoepididymostomy technique using fibrin glue.

MATERIALS AND METHODS

Bilateral vasoepididymostomies were performed in 24 male Sprague-Dawley rats using a conventional microsurgical technique on one side and a fibrin-glue assisted technique on the other. The rats were sacrificed 30 days after surgery and anastomotic patency was assessed by examining the vasal fluid for sperm, injecting methylene blue dye into the vas deferens and observing backflow into the epididymis by gross inspection and histological studies. Additionally, the incidence of granuloma formation was compared between the two techniques.

RESULTS

Fibrin-glue anastomoses showed a patency rate of 79% (n = 19), compared with 63% (n = 15) for the conventional suture anastomoses (p = 0.29). Among the patent anastomoses, the incidence of sperm granuloma formation between the sutured (12, 50%) and the fibrin glue anastomoses (16, 67%) did not differ significantly (p = 0.36). Morphological tissue changes were similar for the two techniques. The time required for anastomosis using fibrin glue was significantly shorter than the conventional suture technique (p < 0.001).

CONCLUSIONS

Conventional suturing techniques for vasoepididymostomy require advanced microsurgical skills. The use of fibrin glue simplifies this procedure and provides patency rates comparable to microsutured, end-to-side anastomoses.

Evaluation of nerve recovery from minimal-duration crush injury

The recovery of damaged peripheral nerves has been the subject of multiple studies. The effects of an inadvertent clamping of a nerve has not been well examined. An experiment was performed to evaluate the effects of a minimal-duration crush injury on the rat sciatic nerve and to determine if walking track analysis was useful in evaluating the short-term functional deficit. Ten Sprague-Dawley rats underwent high-pressure, short-duration crush injuries. Walking track analysis was done regularly for 3 weeks. Histological specimens for light and electron microscopy were taken at postoperative days 3, 7, 14, 21, and 42 from similar animals. There was significant decrease in function by the second week, which then improved to control levels after week 3. Toluidine blue and electron microscopic findings confirmed the clinical course, while routine histological findings tended to lag behind the return of function. Walking track analysis appears to be an effective method of evaluating the short-duration nerve crush injury.

Fibrin glue-assisted end-to-side anastomosis of rat femoral vessels: comparison with conventional suture method

Conventional methods of microvascular anastomosis using sutures cause vessel narrowing, foreign body reactions, and intravascular thrombosis. Although fibrin glue seems to be the ideal material to perform a microvascular anastomosis, its success has been limited. Excess fibrin used in some of the earlier methods has caused vessel narrowing and intravascular thrombosis. We evaluated the quality of end-to-side anastomosis using fibrin glue applied with a new technique and minimal sutures, and compared the results to those obtained with a standard suture technique. End-to-side anastomosis of femoral vessels was performed in 32 male Sprague-Dawley rats. Fibrin glue was topically applied at the anastomotic site, after inserting only two corner sutures. The fibrinogen component obtained from single donor human cryoprecipitate, was combined with bovine thrombin (500 IU per milliliter). In the control group (N = 16), the anastomosis was performed using eight to ten interrupted 10/0 nylon sutures. Fibrin glue-assisted anastomosis took less time, caused less bleeding at the anastomotic sites, and achieved a patency rate comparable to that provided by the suture technique. We have shown that a new, atraumatic technique of microvascular anastomosis with cryoprecipitate-thrombin glue and only two sutures, can produce excellent patency rates. This technique is easy to perform, inexpensive, and does not involve new equipment.

Surgical anatomy of the celiac artery and portal vein of the rat

The study of liver function and diseases requires detailed knowledge of the regional anatomy of and surgical approach to the vascular supply of the liver. The objective of this study was to systematically describe the regional anatomy of the circulation to the rat liver to facilitate the planning and performance of future studies of the liver in this animal. Twelve adult rats underwent general anesthesia and vivisection of the celiac axis and portal vein using an operating microscope. The major vessels of these vascular systems were evaluated for their origin, course, relationship with neighboring structures, diameter, and length. All vessels were easily visualized by a ventral approach after mobilization of the intermediate lobe of the liver and its papillary process. The origin and course of the major vessels are similar to those of humans, and variability in vessel origin was identified in this small number of animals. Median vessel diameters were between 0.5 and 1 mm (range, 0.25 to 1 mm) for the celiac artery and its branches, and 3 mm for the portal vein (range, 2 to 3 mm). Median vessel length was between 3 and 7 mm (range, 2 to 8 mm) for the celiac artery and its branches, and 7 mm for the portal vein (range, 4 to 8 mm). The anatomic description obtained in this study is important for the appropriate selection of vessels for cannulation or ligation during study design, as well as vessel isolation during performance of the study. The diameter and length of vessels are important in the selection of appropriately sized catheters and perivascular devices.

Two metric solutions to three-dimensional reconstruction for an eye in pure rotations

A problem in space perception concerns how a mobile observer acquires information about the structure of objects. Earlier research derived the optic-flow equations for an eye undergoing pure rotations. It was suggested that, by utilizing three points and two views, one can recover the distance of points and the motion parameters. The radius of the eyeball was the metric unit. Yet the common view regards this problem as indeterminate. We derived a unique solution in the discrete case, which required three points and two views. However, when we observed a single bright point, a substantial amount of visual stability existed. We therefore derived a solution in the differential approach for a single point, which is based on a distinction that we made between mathematical and visual points. Both solutions were checked with a computer simulation and were found to be accurate, supporting the space perception in navigation (SPIN) theory.

Continuous rat intravenous infusion

Hypovolemic shock and ischemic injury to the graft commonly cause death in small animals after organ transplantation. A venous line must be readily available to replace fluids before fatal complications occur. To establish a venous line, researchers expose a vein by preliminary surgery. This time-consuming procedure adds unnecessary trauma to the recipient and worsens the results. The possibility of long-term fluid transfusion in small animals by serial injections at close intervals is quite limited. We describe a simple technique of continuous i.v. infusion by catheterization of the rat dorsal penile vein with a 24-gauge, 3/4-inch catheter. This easy-to-learn technique has permitted us to establish a venous line quickly without trauma in 148 rats while doing donor and recipient procedures for small bowel and ileocecal segment transplantation. The technique we describe has eliminated one of the most frequent causes of postoperative mortality after organ transplantation-hypovolemic shock. We would like to emphasize that other measures, including avoiding massive bleeding and reducing operative and warm ischemic time, are also very important in preventing this complication. The massive i.v. infusion alone may not totally eliminate hypovolemic shock if other factors are neglected. The use of this technique has allowed us to perform small bowel transplantation with 90% success.

A simple arteriotomy method for microsurgical end-to-side anastomoses: technical aspects of use in training and laboratory applications

An experiment was carried out to show the patency rates of microsurgical carotid artery bypasses with femoral artery grafts, using a single-cut arteriotomy in rats. A bypass was done on 127 Sprague-Dawley rats. Of these, 125 were patent after 20 min, and all of these were patent after the animals were sacrificed at 3 days, for a 98 percent patency rate. The method of performing the arteriotomies, as well as the bypass itself, is described. The benefits of using the end-to-side anastomosis are explained. The authors conclude that the single-cut arteriotomy is convenient and easy to perform. The end-to-side anastomosis is a worthwhile technique and should encourage the proficiency of every student of microsurgery.