Many body exchange effects close to the s-wave Feshbach resonance in two-component Fermi systems: Is a triplet superfluid possible?

We suggest that the exchange fluctuations close to a Feshbach resonance in a two-component Fermi gas can result in an effective p-wave attractive interaction. On the BCS side of a Feshbach resonance, the magnitude of this effective interaction is comparable to the s-wave interaction, therefore leading to a possible spin-triplet superfluid in the range of temperatures of actual experiments. We also show that the particle-hole exchange fluctuations introduce an effective scattering length which does not diverge, as the standard mean-field one does. Finally, using the effective interaction quantities we are able to model the molecular binding energy on the BEC side of the resonance.Comment: 5 pages, 5 figures,revised text version. Replaced with published versio

Current-induced spin polarization in InGaAs and GaAs epilayers with varying doping densities

The current-induced spin polarization and momentum-dependent spin-orbit field were measured in In$_{x}$Ga$_{1-x}$As epilayers with varying indium concentrations and silicon doping densities. Samples with higher indium concentrations and carrier concentrations and lower mobilities were found to have larger electrical spin generation efficiencies. Furthermore, current-induced spin polarization was detected in GaAs epilayers despite the absence of measurable spin-orbit fields, indicating that the extrinsic contributions to the spin polarization mechanism must be considered. Theoretical calculations based on a model that includes extrinsic contributions to the spin dephasing and the spin Hall effect, in addition to the intrinsic Rashba and Dresselhaus spin-orbit coupling, are found to qualitatively agree with the experimental results.Comment: 16 pages, 8 figure

Finite size Berezinski-Kosterlitz-Thouless transition at grain boundaries in solid 4^4He and role of 3^3He impurities

We analyze the complex phenomenology of the Non-Classical Rotational Inertia (NCRI) observed at low temperature in solid $^4$He within the context of a two dimensional Berezinski-Kosterlitz-Thouless transition in a premelted $^4$He film at the grain boundaries. We show that both the temperature and $^3$He doping dependence of the NCRI fraction (NCRIF) can be ascribed to finite size effects induced by the finite grain size. We give an estimate of the average size of the grains which we argue to be limited by the isotopic $^3$He impurities and we provide a simple power-law relation between the NCRIF and the $^3$He concentration.Comment: Final version, as appearing on prin

Architectures and Key Technical Challenges for 5G Systems Incorporating Satellites

Satellite Communication systems are a promising solution to extend and complement terrestrial networks in unserved or under-served areas. This aspect is reflected by recent commercial and standardisation endeavours. In particular, 3GPP recently initiated a Study Item for New Radio-based, i.e., 5G, Non-Terrestrial Networks aimed at deploying satellite systems either as a stand-alone solution or as an integration to terrestrial networks in mobile broadband and machine-type communication scenarios. However, typical satellite channel impairments, as large path losses, delays, and Doppler shifts, pose severe challenges to the realisation of a satellite-based NR network. In this paper, based on the architecture options currently being discussed in the standardisation fora, we discuss and assess the impact of the satellite channel characteristics on the physical and Medium Access Control layers, both in terms of transmitted waveforms and procedures for enhanced Mobile BroadBand (eMBB) and NarrowBand-Internet of Things (NB-IoT) applications. The proposed analysis shows that the main technical challenges are related to the PHY/MAC procedures, in particular Random Access (RA), Timing Advance (TA), and Hybrid Automatic Repeat reQuest (HARQ) and, depending on the considered service and architecture, different solutions are proposed.Comment: Submitted to Transactions on Vehicular Technologies, April 201

H3 histamine receptor-mediated activation of protein kinase calpha inhibits the growth of cholangiocarcinoma in vitro and in vivo

Histamine regulates functions via four receptors (HRH1, HRH2, HRH3, and HRH4). The D-myo-inositol 1,4,5-trisphosphate (IP(3))/Ca(2+)/protein kinase C (PKC)/mitogen-activated protein kinase pathway regulates cholangiocarcinoma growth. We evaluated the role of HRH3 in the regulation of cholangiocarcinoma growth. Expression of HRH3 in intrahepatic and extrahepatic cell lines, normal cholangiocytes, and human tissue arrays was measured. In Mz-ChA-1 cells stimulated with (R)-(alpha)-(-)-methylhistamine dihydrobromide (RAMH), we measured (a) cell growth, (b) IP(3) and cyclic AMP levels, and (c) phosphorylation of PKC and mitogen-activated protein kinase isoforms. Localization of PKC alpha was visualized by immunofluorescence in cell smears and immunoblotting for PKC alpha in cytosol and membrane fractions. Following knockdown of PKC alpha, Mz-ChA-1 cells were stimulated with RAMH before evaluating cell growth and extracellular signal-regulated kinase (ERK)-1/2 phosphorylation. In vivo experiments were done in BALB/c nude mice. Mice were treated with saline or RAMH for 44 days and tumor volume was measured. Tumors were excised and evaluated for proliferation, apoptosis, and expression of PKC alpha, vascular endothelial growth factor (VEGF)-A, VEGF-C, VEGF receptor 2, and VEGF receptor 3. HRH3 expression was found in all cells. RAMH inhibited the growth of cholangiocarcinoma cells. RAMH increased IP(3) levels and PKC alpha phosphorylation and decreased ERK1/2 phosphorylation. RAMH induced a shift in the localization of PKC alpha expression from the cytosolic domain into the membrane region of Mz-ChA-1 cells. Silencing of PKC alpha prevented RAMH inhibition of Mz-ChA-1 cell growth and ablated RAMH effects on ERK1/2 phosphorylation. In vivo, RAMH decreased tumor growth and expression of VEGF and its receptors; PKC alpha expression was increased. RAMH inhibits cholangiocarcinoma growth by PKC alpha-dependent ERK1/2 dephosphorylation. Modulation of PKC alpha by histamine receptors may be important in regulating cholangiocarcinoma growth. (Mol Cancer Res 2009;7(10):1704-13

Acoustic attenuation probe for fermion superfluidity in ultracold atom gases

Dilute gas Bose-Einstein condensates (BEC's), currently used to cool fermionic atoms in atom traps, can also probe the superfluidity of these fermions. The damping rate of BEC-acoustic excitations (phonon modes), measured in the middle of the trap as a function of the phonon momentum, yields an unambiguous signature of BCS-like superfluidity, provides a measurement of the superfluid gap parameter and gives an estimate of the size of the Cooper-pairs in the BEC-BCS crossover regime. We also predict kinks in the momentum dependence of the damping rate which can reveal detailed information about the fermion quasi-particle dispersion relation.Comment: 4 pages, 2 figures. Revised versio

Occurrence and transformation of illicit drugs in wastewater treatment plants.

Illicit drugs (IDs) and their metabolites have been recently recognized as a new group of water emerging contaminants (ECs) with potent psychoactive properties and unknown effects to the aquatic environment (Pal et al., 2013). IDs are excreted via urine and feces and arrive at wastewater treatment plants (WWTPs) where can reach ppb levels (Castiglioni et al., 2006). Over the past few years, it has been demonstrated that conventional biological processes in WWTPs are not or scarcely able to remove IDs. Thus, they are discharged into water bodies through the treated effluent (Postigo et al., 2011). Therefore, monitoring the IDs concentration in WWTPs can have a twofold advantage: i. increase knowledge on the amount of IDs discharged in the environment and estimate their effect; ii. estimating indirectly the community level consumption (Senta et al., 2014). The objective of this paper is to provide a comprehensive analysis of the occurrence and behaviour of illicit drugs and their metabolites in two Sicilian WWTPs. Specifically, two WWTPs (namely, WWTP-1 and WWTP-2) located at the north-western Sicilian coast have been monitored for 5 months (one sampling per week). The two WWTPs have a conventional scheme and mainly differ for their potentiality. Indeed, the average daily flow expressed as m3d-1 for WWTP-1 and WWTP-2 was equal to 153,600 and 19,704, respectively. Samples were analyzed for total suspended solids (TSS), illicit drugs and their metabolites (metham-phetamine; COC = cocaine; MDMA = 3,4-methylenedioxymethamphetamine; METH = methadone; EDDP = 2-ethylidene-1,5-dimethyl-3,3-diphenylpyrrolidine; MDA = 3,4-methylenedioxy amphetamine; MDEA = 3,4-methylenedioxy ethylamphetamine; THC-COOH = 11-nor-9-carboxy-\u3949-tetrahydrocannabinol; BEG= Benzoylecgonine). In order to provide a fast and sensitive approach to quantify IDs, an automated online sample preparation method has been developed. The method uses a Thermo Scientific Transcend TLX-1 system powered by TurboFlowTM technology coupled with a TSQ Quantiva Triple Quadrupole Mass Spectrometer. Specifically, THC-COOH has been extracted from 75 \ub5L of pre-filtered water (using 7 and 0.4 \ub5m paper filters) by an online sample extraction method and quantified using an isotopic dilution approach between 30 and 2000 ng L-1

Anti-endothelin drugs in solid tumors

Importance of the field: The endothelin (ET) axis, which includes the biological functions of ETs and their receptors, has played a physiological role in normal tissue, acting as a modulator of vasomotor tone, tissue differentiation and development, cell proliferation and hormone production. Interestingly, it also functions in the growth and progression of various tumors. Several researchers have identified the blockade of the ET-1 receptor as a promising therapeutic approach. Areas covered in this review: The clinical investigation of an orally bioavailable ET antagonist, atrasentan, in prostate cancer, is encouraging. In this neoplasia, it has shown antitumor activity, bone metastasis control and amelioration of cancer-related pain but improvement in time to progression and overall survival has still not been demonstrated. The clinical trials of other ET antagonists are reported. Literature research was performed by Pubmed and Pharmaprojects. What the reader will gain: A comprehensive view about the use of atrasentan in the treatment of castration-resistant prostate cancer (CRPC) is provided together with the scientific rationale based on the function of ET and its receptor in various cancer development mechanisms. Take home message: Atrasentan seems to be active in CRPC, although strong scientific evidence is still to be found. Interesting clinical findings regard zibotentan