On the proof of recursive Vogler algorithm for multiple knife-edge diffraction

We consider the problem of multiple knife-edge diffraction estimation which is a fundamental task in many wireless communication applications. So far, one of the most accurate methods for this problem is the Vogler one whose recursive implementation is efficient to reduce the high computational complexity of the direct one. However, in the original report, Vogler only presented the final result of the recursive algorithm without a rigorous mathematical proof, thus making the method difficult to understand and implement in practice. To tackle this shortcoming, we first analyze the mathematical structure of the problem and then present a formal proof of the result. To gain intuition of the proof and the key steps, we provide a simplified study case of four knife-edges. The insight from our proposed analysis and proof can be used to obtain a comprehensive interpretation, initiate a practical implementation and develop new efficient algorithms with similar structure

Normalisation to Blood Activity Is Required for the Accurate Quantification of Na/I Symporter Ectopic Expression by SPECT/CT in Individual Subjects

The utilisation of the Na/I symporter (NIS) and associated radiotracers as a reporter system for imaging gene expression is now reaching the clinical setting in cancer gene therapy applications. However, a formal assessment of the methodology in terms of normalisation of the data still remains to be performed, particularly in the context of the assessment of activities in individual subjects in longitudinal studies. In this context, we administered to mice a recombinant, replication-incompetent adenovirus encoding rat NIS, or a human colorectal carcinoma cell line (HT29) encoding mouse NIS. We used 99mTc pertechnetate as a radiotracer for SPECT/CT imaging to determine the pattern of ectopic NIS expression in longitudinal kinetic studies. Some animals of the cohort were culled and NIS expression was measured by quantitative RT-PCR and immunohistochemistry. The radioactive content of some liver biopsies was also measured ex vivo. Our results show that in longitudinal studies involving datasets taken from individual mice, the presentation of non-normalised data (activity expressed as %ID/g or %ID/cc) leads to ‘noisy’, and sometimes incoherent, results. This variability is due to the fact that the blood pertechnetate concentration can vary up to three-fold from day to day. Normalisation of these data with blood activities corrects for these inconsistencies. We advocate that, blood pertechnetate activity should be determined and used to normalise the activity measured in the organ/region of interest that expresses NIS ectopically. Considering that NIS imaging has already reached the clinical setting in the context of cancer gene therapy, this normalisation may be essential in order to obtain accurate and predictive information in future longitudinal clinical studies in biotherapy

A new MRI rating scale for progressive supranuclear palsy and multiple system atrophy: validity and reliability

AIM To evaluate a standardised MRI acquisition protocol and a new image rating scale for disease severity in patients with progressive supranuclear palsy (PSP) and multiple systems atrophy (MSA) in a large multicentre study. METHODS The MRI protocol consisted of two-dimensional sagittal and axial T1, axial PD, and axial and coronal T2 weighted acquisitions. The 32 item ordinal scale evaluated abnormalities within the basal ganglia and posterior fossa, blind to diagnosis. Among 760 patients in the study population (PSP = 362, MSA = 398), 627 had per protocol images (PSP = 297, MSA = 330). Intra-rater (n = 60) and inter-rater (n = 555) reliability were assessed through Cohen's statistic, and scale structure through principal component analysis (PCA) (n = 441). Internal consistency and reliability were checked. Discriminant and predictive validity of extracted factors and total scores were tested for disease severity as per clinical diagnosis. RESULTS Intra-rater and inter-rater reliability were acceptable for 25 (78%) of the items scored (≥ 0.41). PCA revealed four meaningful clusters of covarying parameters (factor (F) F1: brainstem and cerebellum; F2: midbrain; F3: putamen; F4: other basal ganglia) with good to excellent internal consistency (Cronbach α 0.75-0.93) and moderate to excellent reliability (intraclass coefficient: F1: 0.92; F2: 0.79; F3: 0.71; F4: 0.49). The total score significantly discriminated for disease severity or diagnosis; factorial scores differentially discriminated for disease severity according to diagnosis (PSP: F1-F2; MSA: F2-F3). The total score was significantly related to survival in PSP (p<0.0007) or MSA (p<0.0005), indicating good predictive validity. CONCLUSIONS The scale is suitable for use in the context of multicentre studies and can reliably and consistently measure MRI abnormalities in PSP and MSA. Clinical Trial Registration Number The study protocol was filed in the open clinical trial registry (http://www.clinicaltrials.gov) with ID No NCT00211224

Valley-addressable polaritons in atomically thin semiconductors

The locking of the electron spin to the valley degree of freedom in transition metal dichalcogenide (TMD) monolayers has seen these materials emerge as a promising platform in valleytronics. When embedded in optical microcavities, the large oscillator strengths of excitonic transitions in TMDs allow the formation of polaritons that are part-light part-matter quasiparticles. Here, we report that polaritons in MoSe2 show an efficient retention of the valley pseudospin contrasting them with excitons and trions in this material. We find that the degree of the valley pseudospin retention is dependent on the photon, exciton and trion fractions in the polariton states. This allows us to conclude that in the polaritonic regime, cavity-modified exciton relaxation inhibits loss of the valley pseudospin. The valley-addressable exciton-polaritons and trion-polaritons presented here offer robust valley-polarized states with the potential for valleytronic devices based on TMDs embedded in photonic structures and valley-dependent nonlinear polariton–polariton interactions

Nurses' perceptions of aids and obstacles to the provision of optimal end of life care in ICU

Contains fulltext : 172380.pdf (publisher's version ) (Open Access

Comparaison de différents modèles de diffraction dans la bande UHF

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Domains of high Ca2+ beneath the plasma membrane of living A7r5 cells.

Theoretical models and indirect experimental observations predict that Ca2+ concentrations at the inner surface of the plasma membrane may reach, upon stimulation, values much higher than those of the bulk cytosol. In the past few years, we have shown that the Ca2+-sensitive photoprotein aequorin can be intracellularly targeted and utilized for specifically monitoring the [Ca2+] of various organelles. In this work, we extend this approach to the study of the cytoplasmic rim beneath the plasma membrane. We have constructed a new aequorin chimera by fusing the photoprotein with SNAP-25, a neuronal protein which is recruited to the plasma membrane after the post-translational addition of a lipid anchor. The SNAP-25-aequorin chimera, expressed in the rat aortic smooth muscle cell line A7r5, appears correctly sorted as revealed by immunocytochemistry. Using this probe, we demonstrate that the mean [Ca2+] of this cytoplasmic region ([Ca2+]pm) can reach values >10-fold higher than those of the bulk cytosol ([Ca2+]c) upon activation of Ca2+ influx through plasma membrane channels. In unstimulated cells, the mean [Ca2+]pm appears also to be higher than the bulk cytosol, presumably reflecting the existence of microdomains of high [Ca2+]

Domains of high Ca2+ beneath the plasma membrane of living A7r5 cells.

Theoretical models and indirect experimental observations predict that Ca2+ concentrations at the inner surface of the plasma membrane may reach, upon stimulation, values much higher than those of the bulk cytosol. In the past few years, we have shown that the Ca2+-sensitive photoprotein aequorin can be intracellularly targeted and utilized for specifically monitoring the [Ca2+] of various organelles. In this work, we extend this approach to the study of the cytoplasmic rim beneath the plasma membrane. We have constructed a new aequorin chimera by fusing the photoprotein with SNAP-25, a neuronal protein which is recruited to the plasma membrane after the post-translational addition of a lipid anchor. The SNAP-25-aequorin chimera, expressed in the rat aortic smooth muscle cell line A7r5, appears correctly sorted as revealed by immunocytochemistry. Using this probe, we demonstrate that the mean [Ca2+] of this cytoplasmic region ([Ca2+]pm) can reach values >10-fold higher than those of the bulk cytosol ([Ca2+]c) upon activation of Ca2+ influx through plasma membrane channels. In unstimulated cells, the mean [Ca2+]pm appears also to be higher than the bulk cytosol, presumably reflecting the existence of microdomains of high [Ca2+]