128 research outputs found

    Optimizing the fast Rydberg quantum gate

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    The fast phase gate scheme, in which the qubits are atoms confined in sites of an optical lattice, and gate operations are mediated by excitation of Rydberg states, was proposed by Jaksch et al. Phys. Rev. Lett. 85, 2208 (2000). A potential source of decoherence in this system derives from motional heating, which occurs if the ground and Rydberg states of the atom move in different optical lattice potentials. We propose to minimize this effect by choosing the lattice photon frequency \omega so that the ground and Rydberg states have the same frequency-dependent polarizability \alpha(omega). The results are presented for the case of Rb.Comment: 5 pages, submitted to PR

    Survival of Chondrocytes in Rabbit Septal Cartilage After Electromechanical Reshaping

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    Electromechanical reshaping (EMR) has been recently described as an alternative method for reshaping facial cartilage without the need for incisions or sutures. This study focuses on determining the short- and long-term viability of chondrocytes following EMR in cartilage grafts maintained in tissue culture. Flat rabbit nasal septal cartilage specimens were bent into semi-cylindrical shapes by an aluminum jig while a constant electric voltage was applied across the concave and convex surfaces. After EMR, specimens were maintained in culture media for 64 days. Over this time period, specimens were serially biopsied and then stained with a fluorescent live–dead assay system and imaged using laser scanning confocal microscopy. In addition, the fraction of viable chondrocytes was measured, correlated with voltage, voltage application time, electric field configuration, and examined serially. The fraction of viable chondrocytes decreased with voltage and application time. High local electric field intensity and proximity to the positive electrode also focally reduced chondrocyte viability. The density of viable chondrocytes decreased over time and reached a steady state after 2–4 weeks. Viable cells were concentrated within the central region of the specimen. Approximately 20% of original chondrocytes remained viable after reshaping with optimal voltage and application time parameters and compared favorably with conventional surgical shape change techniques such as morselization

    Needle Electrode-Based Electromechanical Reshaping of Cartilage

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    Electromechanical reshaping (EMR) of cartilage provides an alternative to the classic surgical techniques of modifying the shape of facial cartilages. The original embodiment of EMR required surface electrodes to be in direct contact with the entire cartilage region being reshaped. This study evaluates the feasibility of using needle electrode systems for EMR of facial cartilage and evaluates the relationships between electrode configuration, voltage, and application time in effecting shape change. Flat rabbit nasal septal cartilage specimens were deformed by a jig into a 90° bend, while a constant electric voltage was applied to needle electrodes that were inserted into the cartilage. The electrode configuration, voltage (0–7.5 V), and application time (1–9 min) were varied systematically to create the most effective shape change. Electric current and temperature were measured during voltage application, and the resulting specimen shape was assessed in terms of retained bend angle. In order to demonstrate the clinical feasibility of EMR, the most effective and practical settings from the septal cartilage experimentation were used to reshape intact rabbit and pig ears ex vivo. Cell viability of the cartilage after EMR was determined using confocal microscopy in conjunction with a live/dead assay. Overall, cartilage reshaping increased with increased voltage and increased application time. For all electrode configurations and application times tested, heat generation was negligible (<1 °C) up to 6 V. At 6 V, with the most effective electrode configuration, the bend angle began to significantly increase after 2 min of application time and began to plateau above 5 min. As a function of voltage at 2 min of application time, significant reshaping occurred at and above 5 V, with no significant increase in the bend angle between 6 and 7.5 V. In conclusion, electromechanical reshaping of cartilage grafts and intact ears can be effectively performed with negligible temperature elevation and spatially limited cell injury using needle electrodes

    Classifying malware attacks in IaaS cloud environments

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    In the last few years, research has been motivated to provide a categorization and classification of security concerns accompanying the growing adaptation of Infrastructure as a Service (IaaS) clouds. Studies have been motivated by the risks, threats and vulnerabilities imposed by the components within the environment and have provided general classifications of related attacks, as well as the respective detection and mitigation mechanisms. Virtual Machine Introspection (VMI) has been proven to be an effective tool for malware detection and analysis in virtualized environments. In this paper, we classify attacks in IaaS cloud that can be investigated using VMI-based mechanisms. This infers a special focus on attacks that directly involve Virtual Machines (VMs) deployed in an IaaS cloud. Our classification methodology takes into consideration the source, target, and direction of the attacks. As each actor in a cloud environment can be both source and target of attacks, the classification provides any cloud actor the necessary knowledge of the different attacks by which it can threaten or be threatened, and consequently deploy adapted VMI-based monitoring architectures. To highlight the relevance of attacks, we provide a statistical analysis of the reported vulnerabilities exploited by the classified attacks and their financial impact on actual business processes

    Continent-wide differentiation of fitness traits and patterns of climate adaptation among European populations of Drosophila melanogaster

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    Funding: This research was supported by a Special Topics Network (STN) grant from the European Society of Evolutionary Biology (ESEB) to the DrosEU consortium as well as by individual grants and fellowships (grantees in alphabetical order): J.A.: Swedish Research Council (VR) grants 2015-04680 and 2020-05412; A.J.B.: European Research Council (ERC CoG TE_INVASION); S.D.: Ministry of Science, Technological Development and Innovation of the Republic of Serbia (NITRA) grant 451-03-66/2024-03/200007; K.E.: Ministry of Science, Technological Development and Innovation of the Republic of Serbia (NITRA) grant 451-03-66/2024-03/200007; P.E.: Ministry of Science, Technological Development and Innovation of the Republic of Serbia (NITRA) grant 451-03-66/2024-03/200007; P.E.: Jane Coffin Childs Memorial Fund for Medical Research 61-1673: T.F.: Swiss National Science Foundation (SNSF) grants 31003A-182262, 310030_219283, FZEB-0-214654; C.F.: Deutsche Forschungsgemeinschaft (DFG) grants 2973/5-1 and 2973/11; J.G.: Ministerio de Ciencia, Innovación y Universidades/Agencia Estatal de Investigación (MICIU/AEI/10.13039/501100011033/) grant PID2020-115874GB-I00; Ministerio de Ciencia, Innovación y Universidades/Agencia Estatal de Investigación (MICIU/AEI/10.13039/501100011033 and FEDER, UE) grant PID2023-148838NB-I00; Departament de Recerca i Universitats Generalitat de Catalunya grant 2021 SGR 00417; S.G.: Deutsche Forschungsgemeinschaft (DFG) grants 271330745 and 514085304; K.M.H.: Marie Skłodowska-Curie Individual Fellowship (H2020-MSCA-IF-2015) 701949; J.H.: Czech Ministry of Education, grant; European Research Council (ERC CZ LL2001); M.J.: Ministry of Science, Technological Development and Innovation of the Republic of Serbia (NITRA) grant 451-03-65/2024-03/200178; M.K.: Academy of Finland grant 322980; E.K.: European Molecular Biology Organization (EMBO) ALTF 248-2018; M.S.M.: ALW Open Programme grant 101185; J.P.: Deutsche Forschungsgemeinschaft (DFG) grants 255619725 (GR 4495/2-2) and 503272152 (GR 4495/4-1); E.G.P.: Russian state budget, assignment NRC “KI”; A.P.: Ministry of Science, Technological Development and Innovation of the Republic of Serbia (NITRA) grant 451-03-66/2024-03/200007; N.P.: Deutsche Forschungsgemeinschaft (DFG) grants PO 1648/7-1, PO 1648/3-1, PO 1648/3-2; M.S.V.: Ministry of Science, Technological Development and Innovation of the Republic of Serbia (NITRA) grant 451-03-65/2024-03/200178; C.S.: Austrian Science Fund (FWF) grants 10.55776/P32935, 10.55776/W1225, 10.55776/P33734; P.S.: National Institutes of Health (NIH) R01GM137430; M.S.-R.: Ministry of Science, Technological Development and Innovation of the Republic of Serbia (NITRA) grant 451-03-47/2023-01/200178; M.T.: Ministry of Science, Technological Development and Innovation of the Republic of Serbia (NITRA) grant 451-03-66/2024-03/200007; E.T.: Israel Science Foundation (ISF) 2121/23; C.V.: Agence Nationale de la Recherche (ANR) grant Longevity ANR-20-CE02-0015, J.V.: Fundação para a Ciência e a Tecnologia (FCT) UIDB/04293/2020; C.W.: Deutsche Forschungsgemeinschaft (DFG) grant WE 2652/7-1.A particularly well-studied evolutionary model is the vinegar fly Drosophila melanogaster, a cosmopolitan insect of ancestral southern-central African origin. Recent work suggests that it expanded out of Africa ∼9,000 years ago, and spread from the Middle East into Europe ∼1,800 years ago. During its global expansion, this human commensal adapted to novel climate zones and habitats. Despite much work on phenotypic differentiation and adaptation on several continents (especially North America and Australia), typically in the context of latitudinal clines, little is known about phenotypic divergence among European populations. Here, we sought to provide a continent-wide study of phenotypic differentiation among European populations of D. melanogaster. In a consortium-wide phenomics effort, we assayed 16 fitness-related traits on a panel of 173 isofemale lines from 9 European populations, with the majority of traits measured by several groups using semi-standardized protocols. For most fitness-related traits, we found significant differentiation among populations on a continental scale. Despite inevitable differences in assay conditions among labs, the reproducibility and hence robustness of our measurements were overall remarkably good. Several fitness components (e.g., viability, development time) exhibited significant latitudinal or longitudinal clines, and populations differed markedly in multivariate trait structure. Notably, populations experiencing higher humidity/rainfall and lower maximum temperature showed higher viability, fertility, starvation resistance, and lifespan at the expense of lower heat-shock survival, suggesting a pattern of local adaptation. Our results indicate that derived populations of this tropical fly have been shaped by pervasive spatially varying multivariate selection and adaptation to different climates on the European continent.Peer reviewe

    Sarilumab in patients admitted to hospital with severe or critical COVID-19: a randomised, double-blind, placebo-controlled, phase 3 trial

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    Background: Elevated proinflammatory cytokines are associated with greater COVID-19 severity. We aimed to assess safety and efficacy of sarilumab, an interleukin-6 receptor inhibitor, in patients with severe (requiring supplemental oxygen by nasal cannula or face mask) or critical (requiring greater supplemental oxygen, mechanical ventilation, or extracorporeal support) COVID-19. Methods: We did a 60-day, randomised, double-blind, placebo-controlled, multinational phase 3 trial at 45 hospitals in Argentina, Brazil, Canada, Chile, France, Germany, Israel, Italy, Japan, Russia, and Spain. We included adults (≥18 years) admitted to hospital with laboratory-confirmed SARS-CoV-2 infection and pneumonia, who required oxygen supplementation or intensive care. Patients were randomly assigned (2:2:1 with permuted blocks of five) to receive intravenous sarilumab 400 mg, sarilumab 200 mg, or placebo. Patients, care providers, outcome assessors, and investigators remained masked to assigned intervention throughout the course of the study. The primary endpoint was time to clinical improvement of two or more points (seven point scale ranging from 1 [death] to 7 [discharged from hospital]) in the modified intention-to-treat population. The key secondary endpoint was proportion of patients alive at day 29. Safety outcomes included adverse events and laboratory assessments. This study is registered with ClinicalTrials.gov, NCT04327388; EudraCT, 2020-001162-12; and WHO, U1111-1249-6021. Findings: Between March 28 and July 3, 2020, of 431 patients who were screened, 420 patients were randomly assigned and 416 received placebo (n=84 [20%]), sarilumab 200 mg (n=159 [38%]), or sarilumab 400 mg (n=173 [42%]). At day 29, no significant differences were seen in median time to an improvement of two or more points between placebo (12·0 days [95% CI 9·0 to 15·0]) and sarilumab 200 mg (10·0 days [9·0 to 12·0]; hazard ratio [HR] 1·03 [95% CI 0·75 to 1·40]; log-rank p=0·96) or sarilumab 400 mg (10·0 days [9·0 to 13·0]; HR 1·14 [95% CI 0·84 to 1·54]; log-rank p=0·34), or in proportions of patients alive (77 [92%] of 84 patients in the placebo group; 143 [90%] of 159 patients in the sarilumab 200 mg group; difference −1·7 [−9·3 to 5·8]; p=0·63 vs placebo; and 159 [92%] of 173 patients in the sarilumab 400 mg group; difference 0·2 [−6·9 to 7·4]; p=0·85 vs placebo). At day 29, there were numerical, non-significant survival differences between sarilumab 400 mg (88%) and placebo (79%; difference +8·9% [95% CI −7·7 to 25·5]; p=0·25) for patients who had critical disease. No unexpected safety signals were seen. The rates of treatment-emergent adverse events were 65% (55 of 84) in the placebo group, 65% (103 of 159) in the sarilumab 200 mg group, and 70% (121 of 173) in the sarilumab 400 mg group, and of those leading to death 11% (nine of 84) were in the placebo group, 11% (17 of 159) were in the sarilumab 200 mg group, and 10% (18 of 173) were in the sarilumab 400 mg group. Interpretation: This trial did not show efficacy of sarilumab in patients admitted to hospital with COVID-19 and receiving supplemental oxygen. Adequately powered trials of targeted immunomodulatory therapies assessing survival as a primary endpoint are suggested in patients with critical COVID-19. Funding: Sanofi and Regeneron Pharmaceuticals

    The influence of electric charge transferred during electro-mechanical reshaping on mechanical behavior of cartilage

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    Electromechanical reshaping (EMR) of cartilage has been suggested as an alternative to the classical surgical techniques of modifying the shape of facial cartilages. The method is based on exposure of mechanically deformed cartilaginous tissue to a low level electric field. Electro-chemical reactions within the tissue lead to reduction of internal stress, and establishment of a new equilibrium shape. The same reactions offset the electric charge balance between collagen and proteoglycan matrix and interstitial fluid responsible for maintenance of cartilage mechanical properties. The objective of this study was to investigate correlation between the electric charge transferred during EMR and equilibrium elastic modulus. We used a finite element model based on the triphasic theory of cartilage mechanical properties to study how electric charges transferred in the electro-chemical reactions in cartilage can change its mechanical responses to step displacements in unconfined compression. The concentrations of the ions, the strain field and the fluid and ion velocities within the specimen subject to an applied mechanical deformation were estimated and apparent elastic modulus (the ratio of the equilibrium axial stress to the axial strain) was calculated as a function of transferred charge. The results from numerical calculations showed that the apparent elastic modulus decreases with increase in electric charge transfer. To compare numerical model with experimental observation we measured elastic modulus of cartilage as a function of electric charge transferred in electric circuit during EMR. Good correlation between experimental and theoretical data suggests that electric charge disbalance is responsible for alteration of cartilage mechanical properties. © 2011 SPIE
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