Electric Levitation Using ε-Near-Zero Metamaterials

[EN] The ability to manufacture metamaterials with exotic electromagnetic properties has potential for surprising new applications. Here we report how a specific type of metamaterial-one whose permittivity is near zero-exerts a repulsive force on an electric dipole source, resulting in levitation of the dipole. The phenomenon relies on the expulsion of the time-varying electric field from the metamaterial interior, resembling the perfect diamagnetic expulsion of magnetostatic fields. Leveraging this concept, we study some realistic requirements for the levitation or repulsion of a polarized particle radiating at any frequency, from microwave to optics.This work is supported in part by the US Office of Naval Research (ONR) Multidisciplinary University Research Initiative (MURI) Grant No. N00014-10-1-0942. F. J. R.-F. acknowledges financial support from Grant FPI of GV and the Spanish MICINN under Contracts No. CONSOLIDER EMET CSD2008-00066 and No. TEC2011-28664-C02-02.Rodríguez Fortuño, FJ.; Vakil, A.; Engheta, N. (2014). Electric Levitation Using ε-Near-Zero Metamaterials. Physical Review Letters. 112(3):33902-1-33902-5. https://doi.org/10.1103/PhysRevLett.112.033902S33902-133902-5112

Molecular mechanisms of atherosclerosis in metabolic syndrome: role of reduced IRS2-dependent signaling

OBJECTIVE: The mechanisms underlying accelerated atherosclerosis in metabolic syndrome (MetS) patients remain poorly defined. In the mouse, complete disruption of insulin receptor substrate-2 (Irs2) causes insulin resistance, MetS-like manifestations, and accelerates atherosclerosis. Here, we performed human, mouse, and cell culture studies to gain insight into the contribution of defective Irs2 signaling to MetS-associated alterations. METHODS AND RESULTS: In circulating leukocytes from insulin-resistant MetS patients, Irs2 and Akt2 mRNA levels inversely correlate with plasma insulin levels and HOMA index and are reduced compared to insulin-sensitive MetS patients. Notably, a moderate reduction in Irs2 expression in fat-fed apolipoprotein E-null mice lacking one allele of Irs2 (apoE(-/-)Irs2(+/-)) accelerates atherosclerosis compared to apoE-null controls, without affecting plaque composition. Partial Irs2 inactivation also increases CD36 and SRA scavenger receptor expression and modified LDL uptake in macrophages, diminishes Akt2 and Ras expression in aorta, and enhances expression of the proatherogenic cytokine MCP1 in aorta and primary vascular smooth muscle cells (VSMCs) and macrophages. Inhibition of AKT or ERK1/2, a downstream target of RAS, upregulates Mcp1 in VSMCs. CONCLUSIONS: Enhanced levels of MCP1 resulting from reduced IRS2 expression and accompanying defects in AKT2 and Ras/ERK1/2 signaling pathways may contribute to accelerated atherosclerosis in MetS states

ANAIS status report

We report the status of the ANAIS (Annual modulation with NAI Scintillators) experiment focusing on the developments towards the improvement of the background level of our detectors and the reduction of the energy threshold

Patterns of impact resulting from a 'sit less, move more' web-based program in sedentary office employees.

PURPOSE: Encouraging office workers to 'sit less and move more' encompasses two public health priorities. However, there is little evidence on the effectiveness of workplace interventions for reducing sitting, even less about the longer term effects of such interventions and still less on dual-focused interventions. This study assessed the short and mid-term impacts of a workplace web-based intervention (Walk@WorkSpain, W@WS; 2010-11) on self-reported sitting time, step counts and physical risk factors (waist circumference, BMI, blood pressure) for chronic disease. METHODS: Employees at six Spanish university campuses (n=264; 42±10 years; 171 female) were randomly assigned by worksite and campus to an Intervention (used W@WS; n=129; 87 female) or a Comparison group (maintained normal behavior; n=135; 84 female). This phased, 19-week program aimed to decrease occupational sitting time through increased incidental movement and short walks. A linear mixed model assessed changes in outcome measures between the baseline, ramping (8 weeks), maintenance (11 weeks) and follow-up (two months) phases for Intervention versus Comparison groups. RESULTS: A significant 2 (group) × 2 (program phases) interaction was found for self-reported occupational sitting (F[3]=7.97, p=0.046), daily step counts (F[3]=15.68, p=0.0013) and waist circumference (F[3]=11.67, p=0.0086). The Intervention group decreased minutes of daily occupational sitting while also increasing step counts from baseline (446±126; 8,862±2,475) through ramping (+425±120; 9,345±2,435), maintenance (+422±123; 9,638±3,131) and follow-up (+414±129; 9,786±3,205). In the Comparison group, compared to baseline (404±106), sitting time remained unchanged through ramping and maintenance, but decreased at follow-up (-388±120), while step counts diminished across all phases. The Intervention group significantly reduced waist circumference by 2.1cms from baseline to follow-up while the Comparison group reduced waist circumference by 1.3cms over the same period. CONCLUSIONS: W@WS is a feasible and effective evidence-based intervention that can be successfully deployed with sedentary employees to elicit sustained changes on "sitting less and moving more"

Factors that influence bile fluid microbiology in cholecystectomized patients

Introducción y objetivo: Las vías biliares son normalmente estériles, aunque puede existir cultivo positivo hasta en el 4.2% de las personas sanas. Existen ciertas circunstancias que lo favorecen, como pueden ser las litiasis o la manipulación de la vía biliar. El objetivo del estudio fue determinar los factores que influyen en la presencia de bacteriobilia, así como su implicación en la práctica clínica. Material y métodos: Estudio prospectivo de los cultivos de bilis obtenidos de los pacientes colecistectomizados en nuestro centro desde 2013 a 2015. Resultados: Se recogieron un total de 196 pacientes (42.3% mujeres y 57.7% hombres) a los que se había realizado colecistectomía tanto abierta como laparoscópica tomando muestra del líquido biliar. Se analizaron las características clínicas, epidemiológicas y analíticas de los pacientes, así como la indicación quirúrgica (cirugía urgente o programada). Respecto a la microbiología, en el 47% los cultivos de bilis recogidos fueron positivos: 56.5% con un microorganismo, 25% con dos y 18.5% con tres o más. También se incluyeron los antibióticos empleados tanto para tratamiento como para profilaxis. Conclusión: El análisis de la microbiología de la bilis no debería realizarse de forma sistemática, ya que solamente en casos en los que se demuestren los factores de riesgo estudiados su resultado puede llegar a ser relevante. En estos mismos casos también resulta imprescindible para establecer un tratamiento antibiótico adecuado tanto en lo referente al espectro como a la duración del mismo, con el fin de evitar complicaciones y el aumento de resistencias.Introduction and aim: Normally, the bile ducts are sterile, but up to 4.2% of healthy persons can present with positive cultures. Certain circumstances favor that situation, such as gallstones or biliary tree manipulation. The aim of the present study was to determine the factors that influence the presence of bacteriobilia, as well as its implications for clinical practice. Materials and methods: A prospective study was conducted on bile cultures from patients that underwent cholecystectomy at our hospital center within the time frame of 2013 to 2015. Results: The study included 196 patients (42.3% women and 57.7% men) that underwent either open or laparoscopic cholecystectomy and in whom bile fluid samples were taken. The clinical, epidemiologic, and laboratory test characteristics of the patients were analyzed, as well as the surgical indication (urgent surgery or programmed surgery). With respect to microbiology, 47% of the bile cultures were positive: 56.5% presented with one microorganism, 25% with two, and 18.5% with three or more. Conclusion: Microbiologic bile analysis should not be systematically performed, given that its result is relevant only in cases that present with demonstrated risk factors. However, in those cases, said analysis is essential to establish adequate antibiotic treatment, in relation to activity spectrum and duration, to prevent complications and an increase in microbial resistance

Chirality of nanophotonic waveguide with embedded quantum emitter for unidirectional spin transfer

Scalable quantum technologies may be achieved by faithful conversion between matter qubits and photonic qubits in integrated circuit geometries. Within this context, quantum dots possess well-defined spin states (matter qubits), which couple efficiently to photons. By embedding them in nanophotonic waveguides, they provide a promising platform for quantum technology implementations. In this paper, we demonstrate that the naturally occurring electromagnetic field chirality that arises in nanobeam waveguides leads to unidirectional photon emission from quantum dot spin states, with resultant in-plane transfer of matter-qubit information. The chiral behaviour occurs despite the non-chiral geometry and material of the waveguides. Using dot registration techniques, we achieve a quantum emitter deterministically positioned at a chiral point and realize spin-path conversion by design. We further show that the chiral phenomena are much more tolerant to dot position than in standard photonic crystal waveguides, exhibit spin-path readout up to 95±5% and have potential to serve as the basis of spin-logic and network implementations

The T-REX project: Micromegas for rare event searches

The T-REX project aims at developing novel readout techniques for Time Projection Chambers for experiments searching for Rare Events. The Micromegas detectors are a good option, because of their good performance regarding low background levels, energy and time resolution, gain and stability of operation. In the present we will shortly refer to two particular cases, on one hand their performance in the CAST experiment and on the other the studies carried out within NEXT, a neutrinoless double-beta decay experiment

Influence of acute pancreatitis on the in vitro responsiveness of rat mesenteric and pulmonary arteries

<p>Abstract</p> <p>Background</p> <p>Acute pancreatitis is an inflammatory disease characterized by local tissue injury and systemic inflammatory response leading to massive nitric oxide (NO) production and haemodynamic disturbances. Therefore, the aim of this work was to evaluate the vascular reactivity of pulmonary and mesenteric artery rings from rats submitted to experimental pancreatitis.</p> <p>Male Wistar rats were divided into three groups: saline (SAL); tauracholate (TAU) and phospholipase A₂(PLA₂). Pancreatitis was induced by administration of TAU or PLA₂from <it>Naja mocambique mocambique </it>into the common bile duct of rats, and after 4 h of duct injection the animals were sacrificed. Concentration-response curves to acetylcholine (ACh), sodium nitroprusside (SNP) and phenylephrine (PHE) in isolated mesenteric and pulmonary arteries were obtained. Potency (pEC₅₀) and maximal responses (E_MAX) were determined. Blood samples were collected for biochemical analysis.</p> <p>Results</p> <p>In mesenteric rings, the potency for ACh was significantly decreased from animals treated with TAU (about 4.2-fold) or PLA₂(about 6.9-fold) compared to saline group without changes in the maximal responses. Neither pEC₅₀nor E_MAXvalues for Ach were altered in pulmonary rings in any group. Similarly, the pEC₅₀and the E_MAXvalues for SNP were not changed in both preparations in any group. The potency for PHE was significantly decreased in rat mesenteric and pulmonary rings from TAU group compared to SAL group (about 2.2- and 2.69-fold, for mesenteric and pulmonary rings, respectively). No changes were seen in the E_MAXfor PHE. The nitrite/nitrate (NO_x^-) levels were markedly increased in animals submitted to acute pancreatitis as compared to SAL group, approximately 76 and 68% in TAU and PLA₂protocol, respectively.</p> <p>Conclusion</p> <p>Acute pancreatitis provoked deleterious effects in endothelium-dependent relaxing response for ACh in mesenteric rings that were strongly associated with high plasma NO_x^-levels as consequence of intense inflammatory responses. Furthermore, the subsensitivity of contractile response to PHE in both mesenteric and pulmonary rings might be due to the complications of this pathological condition in the early stage of pancreatitis.</p

Lateral forces on circularly polarizable particles near a surface

Optical forces allow manipulation of small particles and control of nanophotonic structures with light beams. While some techniques rely on structured light to move particles using field intensity gradients, acting locally, other optical forces can push particles on a wide area of illumination but only in the direction of light propagation. Here we show that spin orbit coupling, when the spin of the incident circularly polarized light is converted into lateral electromagnetic momentum, leads to a lateral optical force acting on particles placed above a substrate, associated with a recoil mechanical force. This counterintuitive force acts in a direction in which the illumination has neither a field gradient nor propagation. The force direction is switchable with the polarization of uniform, plane wave illumination, and its magnitude is comparable to other optical forces.This work has been supported, in part, by EPSRC (UK). 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