Low noise cryogenic system for the measurement of Casimir energy in rigid cavities

We report on preliminary results on the measurement of variations of the Casimir energy in rigid cavities through its influence on the superconducting transition of in-cavity aluminium (Al) thin films. After a description of the experimental apparatus we report on a measurement made with thermal photons, discussing its implications for the zero-point photons case. Finally we show the preliminary results for the zero-point case.Comment: 9 pages, 7 figures, Talk given at QFEXT07 Conference in Liepzig: Quantum Field Theory Under the Influence of External Condition

Optimal loading dose of meropenem before continuous infusion in critically ill patients: a simulation study

The aim of this study was to investigate optimal loading doses prior to continuous infusion of meropenem in critically ill patients. A previously published and successfully evaluated pharmacokinetic model of critically ill patients was used for stochastic simulations of virtual patients. Maintenance doses administered as continuous infusion of 1.5-6~g/24~h with preceding loading doses (administered as 30~min infusion) of 0.15-2~g were investigated. In addition to the examination of the influence of individual covariates, a best-case and worst-case scenario were simulated. Dosing regimens were considered adequate if the 5th percentile of the concentration-time profile did not drop at any time below four times the S/I breakpoint (= 2~mg/L) of Pseudomonas aeruginosa according to the EUCAST definition. Low albumin concentrations, high body weight and high creatinine clearances increased the required loading dose. A maximum loading dose of 0.33~g resulted in sufficient plasma concentrations when only one covariate showed extreme values. If all three covariates showed extreme values (= worst-case scenario), a loading dose of 0.5~g was necessary. Higher loading doses did not lead to further improvements of target attainment. We recommend the administration of a loading dose of 0.5~g meropenem over 30~min immediately followed by continuous infusion

Nanodrawing of aligned single carbon nanotubes with a nanopen

Single-walled carbon nanotubes (SWCNTs) are considered pivotal components for molecular electronics. Techniques for SWCNT lithography today lack simplicity, flexibility, and speed of direct, oriented deposition at specific target locations. In this paper SWCNTs are directly drawn and placed with chemical identification and demonstrated orientation using fountain pen nanolithography (FPN) under ambient conditions. Placement across specific electrical contacts with such alignment is demonstrated and characterized. The fundamental basis of the drawing process with alignment has potential applications for other related systems such as inorganic nanotubes, polymers, and biological molecules

Toward food analytics: fast estimation of lycopene and β-carotene content in tomatoes based on surface enhanced Raman spectroscopy (SERS)

Carotenoids are molecules that play important roles in both plant development and in the well-being of mammalian organisms. Therefore, various studies have been performed to characterize carotenoids’ properties, distribution in nature and their health benefits upon ingestion. Nevertheless, there is a gap regarding a fast detection of them at the plant phase. Within this contribution we report the results obtained regarding the application of surface enhanced Raman spectroscopy (SERS) toward the differentiation of two carotenoid molecules (namely, lycopene and β-carotene) in tomato samples. To this end, an e-beam lithography (EBL) SERS-active substrate and a 488 nm excitation source were employed, and a relevant simulated matrix was prepared (by mixing the two carotenoids in defined percentages) and measured. Next, carotenoids were extracted from tomato plants and measured as well. Finally, a combination of principal component analysis and partial least squares regression (PCA-PLSR) was applied to process the data, and the obtained results were compared with HPLC measurements of the same extracts. A good agreement was obtained between the HPLC and the SERS results for most of the tomato samples

Clinical and morphological phenotype of the filamin myopathy: a study of 31 German patients

Mutations in the filamin C gene (FLNC) cause a myofibrillar myopathy (MFM), morphologically characterized by focal myofibrillar destruction and abnormal accumulation of several proteins within skeletal muscle fibres. We studied 31 patients from four German families to evaluate the phenotype of filaminopathy. All patients harboured the same p.W2710X mutation in FLNC. Haplotype analysis suggested a founder mutation in these German filaminopathy families. The mean age at onset of clinical symptoms was 44 +/− 6 years (range, 24-57 years). Slowly progressive muscle weakness was mostly pronounced proximally, initially affecting the lower extremities and involving the upper extremities in the course of disease progression, similar to the distribution of weakness seen in limb-girdle muscular dystrophies (LGMD). Patients frequently developed respiratory muscle weakness. About one-third of the patients showed cardiac abnormalities comprising conduction blocks, tachycardia, diastolic dysfunction and left ventricular hypertrophy indicating a cardiac involvement in filaminopathy. Serum creatine kinase levels varied from normal up to 10-fold of the upper limit. Magnetic resonance imaging studies showed a rather homogenous pattern of muscle involvement in the lower extremities differing from that in other types of MFM. Myopathological features included perturbation of myofibrillar alignment, accumulation of granulofilamentous material similar to that seen in primary desminopathies and abnormal intracellular protein deposits typical of MFM. Decreased activities of oxidative enzymes and fibre hypertrophy seem to be early features, whereas dystrophic changes were present in advanced stages of filaminopathy. Rimmed vacuoles were detected in only a few cases. The intracellular aggregates were composed of a variety of proteins including filamin C, desmin, myotilin, Xin, dystrophin and sarcoglycans. Therapy is so far limited to symptomatic treatment. The German filaminopathy cohort, the largest group of patients studied so far, shares phenotypic features with LGMD and presents with characteristic histopathological findings of MF

Evaluating arbitrary strain configurations and doping in graphene with Raman spectroscopy

Raman spectroscopy is a powerful tool for characterizing the local properties of graphene. Here, we introduce a method for evaluating unknown strain configurations and simultaneous doping. It relies on separating the effects of hydrostatic strain (peak shift) and shear strain (peak splitting) on the Raman spectrum of graphene. The peak shifts from hydrostatic strain and doping are separated with a correlation analysis of the 2D and G frequencies. This enables us to obtain the local hydrostatic strain, shear strain and doping without any assumption on the strain configuration prior to the analysis. We demonstrate our approach for two model cases: Graphene under uniaxial stress on a PMMA substrate and graphene suspended on nanostructures that induce an unknown strain configuration. We measured $\omega_\mathrm{2D}/\omega_\mathrm{G} = 2.21 \pm 0.05$ for pure hydrostatic strain. Raman scattering with circular corotating polarization is ideal for analyzing strain and doping, especially for weak strain when the peak splitting by shear strain cannot be resolved

Nanoboomerang-based inverse metasurfaces—A promising path towards ultrathin photonic devices for transmission operation

Metasurfaces have revolutionized photonics due to their ability to shape phase fronts as requested and to tune beam directionality using nanoscale metallic or dielectric scatterers. Here we reveal inverse metasurfaces showing superior properties compared to their positive counterparts if transmission mode operation is considered. The key advantage of such slot-type metasurfaces is the strong reduction of light in the parallel-polarization state, making the crossed-polarization, being essential for metasurface operation, dominant and highly visible. In the experiment, we show an up to four times improvement in polarization extinction for the individual metasurface element geometry consisting of deep subwavelength nanoboomerangs with feature sizes of the order of 100 nm. As confirmed by simulations, strong plasmonic hybridization yields two spectrally separated plasmonic resonances, ultimately allowing for the desired phase and scattering engineering in transmission. Due to the design flexibility of inverse metasurfaces, a large number of highly integrated ultra-flat photonic elements can be envisioned, examples of which include monolithic lenses for telecommunications and spectroscopy, beam shaper or generator for particle trapping or acceleration or sophisticated polarization control for microscopy