A Comment on "A note on polarized light from Magnetars: QED effects and axion-like particles" by L.M. Capparelli, L. Maiani and A.D. Polosa

The recent detection of a large polarization degree in the optical emission of an isolated neutron star led to the suggestion that this has been the first evidence of vacuum polarization in a strong magnetic field, an effect predicted by quantum electrodynamics but never observed before. This claim was challanged in a paper by Capparelli, Maiani & Polosa (2017), according to whom a much higher polarization degree would be necessary to positively identify vacuum polarization. Here we show that their conclusions are biased by several inadequate assumptions and have no impact on the original claim.Comment: 10 pages, 2 figure

Evidence of vacuum birefringence from the polarisation of the optical emission from an Isolated Neutron Star

Isolated Neutron Stars are some of the most exciting stellar objects known to astronomers: they have the most extreme magnetic fields, with values up to $10^{15}$ G, and, with the exception of stellar-mass black holes, they are the most dense stars, with densities of $\approx 10^{14}$ g cm$^{-3}$. As such, they are perfect laboratories to test theories of electromagnetism and nuclear physics under conditions of magnetic field and density unattainable on Earth. In particular, the interaction of radiation with strong magnetic fields is the cause of the {\em vacuum birefringence}, an effect predicted by quantum electrodynamics in 1936 but that lacked an observational evidence until now. Here, we show how the study of the polarisation of the optical radiation from the surface of an isolated neutron star yielded such an observational evidence, opening exciting perspectives for similar studies at other wavelengths.Comment: 5 pages, 1 figure, Contributed to the 13th Patras Workshop on Axions, WIMPs and WISPs, Thessaloniki, May 15 to 19, 201

Electron localization and possible phase separation in the absence of a charge density wave in single-phase 1T-VS2_2

We report on a systematic study of the structural, magnetic and transport properties of high-purity 1T-VS$_2$ powder samples prepared under high pressure. The results differ notably from those previously obtained by de-intercalating Li from LiVS$_2$. First, no Charge Density Wave (CDW) is found by transmission electron microscopy down to 94 K. Though, \textit{ab initio} phonon calculations unveil a latent CDW instability driven by an acoustic phonon softening at the wave vector ${\bf q}_{CDW} \approx$ (0.21,0.21,0) previously reported in de-intercalated samples. A further indication of latent lattice instability is given by an anomalous expansion of the V-S bond distance at low temperature. Second, infrared optical absorption and electrical resistivity measurements give evidence of non metallic properties, consistent with the observation of no CDW phase. On the other hand, magnetic susceptibility and NMR data suggest the coexistence of localized moments with metallic carriers, in agreement with \textit{ab initio} band structure calculations. This discrepancy is reconciled by a picture of electron localization induced by disorder or electronic correlations leading to a phase separation of metallic and non-metallic domains in the nm scale. We conclude that 1T-VS$_2$ is at the verge of a CDW transition and suggest that residual electronic doping in Li de-intercalated samples stabilizes a uniform CDW phase with metallic properties.Comment: 22 pages, 10 Figures. Full resolution pictures available at http://journals.aps.org/prb/abstract/10.1103/PhysRevB.89.23512

Finite size effects on thermal denaturation of globular proteins

Finite size effects on the cooperative thermal denaturation of proteins are considered. A dimensionless measure of cooperativity, Omega, scales as N^zeta, where N is the number of amino acids. Surprisingly, we find that zeta is universal with zeta = 1 + gamma, where the exponent gamma characterizes the divergence of the susceptibility for a self-avoiding walk. Our lattice model simulations and experimental data are consistent with the theory. Our finding rationalizes the marginal stability of proteins and substantiates the earlier predictions that the efficient folding of two-state proteins requires the folding transition temperature to be close to the collapse temperature.Comment: 3 figures. Physical Review Letters (in press

Evidence for vacuum birefringence from the first optical-polarimetry measurement of the isolated neutron star RX J1856.5-3754

The "Magnificent Seven" (M7) are a group of radio-quiet Isolated Neutron Stars (INSs) discovered in the soft X-rays through their purely thermal surface emission. Owing to the large inferred magnetic fields ($B\approx 10^{13}$ G), radiation from these sources is expected to be substantially polarised, independently on the mechanism actually responsible for the thermal emission. A large observed polarisation degree is, however, expected only if quantum-electrodynamics (QED) polarisation effects are present in the magnetised vacuum around the star. The detection of a strongly linearly polarised signal would therefore provide the first observational evidence of QED effects in the strong-field regime. While polarisation measurements in the soft X-rays are not feasible yet, optical polarisation measurements are within reach also for quite faint targets, like the M7 which have optical counterparts with magnitudes $\approx 26$--$28$. Here, we report on the measurement of optical linear polarisation for the prototype, and brightest member, of the class, RX\, J1856.5$-$3754 ($V\sim 25.5$), the first ever for one of the M7, obtained with the Very Large Telescope. We measured a polarisation degree $\mathrm{P.D.} =16.43\% \pm5.26\%$ and a polarisation position angle \mathrm{P.A.}=145\fdg39\pm9\fdg44, computed east of the North Celestial Meridian. The $\mathrm{P.D.}$ that we derive is large enough to support the presence of vacuum birefringence, as predicted by QED.Comment: 9 pages, 7 figures, accepted for publication on MNRA

Ultrasound-Guided Percutaneous Tenotomy of the Long Head of Biceps Tendon in Patients with Symptomatic Complete Rotator Cuff Tear: In Vivo Non-contRolled Prospective Study

Background: We prospectively tested technical feasibility and clinical outcome of percutaneous ultrasound-guided tenotomy of long head of biceps tendon (LHBT). Methods: We included 11 patients (6 women; age: 73 \ub1 8.6 years) with symptomatic full-thickness rotator cuff tear and intact LHBT, in whom surgical repair was not possible/refused. After ultrasound-guided injection of local anesthetic, the LHBT was cut with a scalpel under continuous ultrasound monitoring until it became no longer visible. Pain was recorded before and at least six months after procedure. An eight-item questionnaire was administered to patients at follow-up. Results: A median of 4 tendon cuts were needed to ensure complete tenotomy. Mean procedure duration was 65 \ub1 5.7 s. Mean length of skin incision was 5.8 \ub1 0.6 mm. Pre-tenotomy VAS score was 8.2 \ub1 0.7, post-tenotomy VAS was 2.8 \ub1 0.6 (p < 0.001). At follow-up, 5/11 patients were very satisfied, 5/11 satisfied and 1/11 neutral. One patient experienced cramping and very minimal pain in the biceps. Six patients had still moderate shoulder pain, 1/11 minimal pain, 2/11 very minimal pain, while 2/11 had no pain. No patients had weakness in elbow flexion nor limits of daily activities due to LHBT. One patient showed Popeye deformity. All patients would undergo ultrasound-guided tenotomy again. Conclusion: ultrasound-guided percutaneous LHBT tenotomy is technically feasible and effective

Regression of fetal cerebral abnormalities by primary cytomegalovirus infection following hyperimmunoglobulin therapy

Objective To assess the effects of maternal and intra-amniotic hyperimmunoglobulin (HIG) infusions among cytomegalovirus (CMV) infected fetuses with ultrasound abnormalities following a primary CMV infection. Patients and Methods The subjects were fetuses with CMV-associated cerebral and other ultrasound abnormalities. Three mothers were treated with HIG infusions during pregnancy and two were untreated. Fetal ventricle size, organ echodensity and placental thickness were measured by ultrasound before and after HIG infusions. The children were evaluated between 3 and 7 years of age. Results The ventriculomegaly of all three fetuses of HIG-treated mothers regressed and the ascites, hepatic echodensities, periventricular echodensities, and intestinal echodensities disappeared. Their sensorial, mental and motor development was normal at 4, 4.7, and 7 years of age. In contrast, both infants born of untreated mothers had signs and symptoms of severe CMV cerebropathy. Conclusion The outcomes of the infants born to HIG-treated mothers support the efficacy of HIG as a treatment for CMV-infected fetuses with ultrasound cerebral abnormalities. Copyright (C) 2008 John Wiley & Sons, Ltd

Epigenetic targeting of ovarian cancer stem cells

Emerging results indicate that cancer stem-like cells contribute to chemoresistance and poor clinical outcomes in many cancers, including ovarian cancer. As epigenetic regulators play a major role in the control of normal stem cell differentiation, epigenetics may offer a useful arena to develop strategies to target cancer stem-like cells. Epigenetic aberrations, especially DNA methylation, silence tumor-suppressor and differentiation-associated genes that regulate the survival of ovarian cancer stem-like cells (OCSC). In this study, we tested the hypothesis that DNA-hypomethylating agents may be able to reset OCSC toward a differentiated phenotype by evaluating the effects of the new DNA methytransferase inhibitor SGI-110 on OCSC phenotype, as defined by expression of the cancer stem-like marker aldehyde dehydrogenase (ALDH). We demonstrated that ALDH(+) ovarian cancer cells possess multiple stem cell characteristics, were highly chemoresistant, and were enriched in xenografts residual after platinum therapy. Low-dose SGI-110 reduced the stem-like properties of ALDH(+) cells, including their tumor-initiating capacity, resensitized these OCSCs to platinum, and induced reexpression of differentiation-associated genes. Maintenance treatment with SGI-110 after carboplatin inhibited OCSC growth, causing global tumor hypomethylation and decreased tumor progression. Our work offers preclinical evidence that epigenome-targeting strategies have the potential to delay tumor progression by reprogramming residual cancer stem-like cells. Furthermore, the results suggest that SGI-110 might be administered in combination with platinum to prevent the development of recurrent and chemoresistant ovarian cancer

Amphiregulin contained in NSCLC-exosomes induces osteoclast differentiation through the activation of EGFR pathway

Non-small cell lung cancer (NSCLC) remains the leading cause of cancer-related deaths worldwide. The majority of patients are diagnosed in advanced disease stage. Bone metastasis is the most frequent complication in NSCLC resulting in osteolytic lesions. The perfect balance between bone-resorbing osteoclasts and bone-forming osteoblasts activity is lost in bone metastasis, inducing osteoclastogenesis. In NSCLC, the epidermal growth factor receptor (EGFR) pathway is constitutively activated. EGFR binds Amphiregulin (AREG) that is overexpressed in several cancers such as colon, breast and lung. Its levels in plasma of NSCLC patients correlate with poor prognosis and AREG was recently found as a signaling molecule in exosomes derived from cancer cell lines. Exosomes have a key role in the cell-cell communication and they were recently indicated as important actors in metastatic niche preparation. In the present work, we hypothesize a role of AREG carried by exosomes derived from NSCLC in bone metastasis induction. We observed that NSCLC-exosomes, containing AREG, induce EGFR pathway activation in pre-osteoclasts that in turn causes an increased expression of RANKL. RANKL is able to induce the expression of proteolytic enzymes, well-known markers of osteoclastogenesis, triggering a vicious cycle in osteolytic bone metastasis