Poor screening and nonadiabatic superconductivity in correlated systems

In this paper we investigate the role of the electronic correlation on the hole doping dependence of electron-phonon and superconducting properties of cuprates. We introduce a simple analytical expression for the one-particle Green's function in the presence of electronic correlation and we evaluate the reduction of the screening properties as the electronic correlation increases by approaching half-filling. The poor screening properties play an important role within the context of the nonadiabatic theory of superconductivity. We show that a consistent inclusion of the reduced screening properties in the nonadiabatic theory can account in a natural way for the $T_c$-$\delta$ phase diagram of cuprates. Experimental evidences are also discussed.Comment: 12 Pages, 6 Figures, Accepted on Physical Review

Nustar and Chandra Insight into the Nature of the 3-40 Kev Nuclear Emission in Ngc 253

We present results from three nearly simultaneous Nuclear Spectroscopic Telescope Array (NuSTAR) and Chandra monitoring observations between 2012 September 2 and 2012 November 16 of the local star-forming galaxy NGC 253. The 3-40 kiloelectron volt intensity of the inner approximately 20 arcsec (approximately 400 parsec) nuclear region, as measured by NuSTAR, varied by a factor of approximately 2 across the three monitoring observations. The Chandra data reveal that the nuclear region contains three bright X-ray sources, including a luminous (L (sub 2-10 kiloelectron volt) approximately few 10 (exp 39) erg per s) point source located approximately 1 arcsec from the dynamical center of the galaxy (within the sigma 3 positional uncertainty of the dynamical center); this source drives the overall variability of the nuclear region at energies greater than or approximately equal to 3 kiloelectron volts. We make use of the variability to measure the spectra of this single hard X-ray source when it was in bright states. The spectra are well described by an absorbed (power-law model spectral fit value, N(sub H), approximately equal to 1.6 x 10 (exp 23) per square centimeter) broken power-law model with spectral slopes and break energies that are typical of ultraluminous X-ray sources (ULXs), but not active galactic nuclei (AGNs). A previous Chandra observation in 2003 showed a hard X-ray point source of similar luminosity to the 2012 source that was also near the dynamical center (Phi is approximately equal to 0.4 arcsec); however, this source was offset from the 2012 source position by approximately 1 arcsec. We show that the probability of the 2003 and 2012 hard X-ray sources being unrelated is much greater than 99.99% based on the Chandra spatial localizations. Interestingly, the Chandra spectrum of the 2003 source (3-8 kiloelectron volts) is shallower in slope than that of the 2012 hard X-ray source. Its proximity to the dynamical center and harder Chandra spectrum indicate that the 2003 source is a better AGN candidate than any of the sources detected in our 2012 campaign; however, we were unable to rule out a ULX nature for this source. Future NuSTAR and Chandra monitoring would be well equipped to break the degeneracy between the AGN and ULX nature of the 2003 source, if again caught in a high state

The Polygenic and Monogenic Basis of Blood Traits and Diseases

Blood cells play essential roles in human health, underpinning physiological processes such as immunity, oxygen transport, and clotting, which when perturbed cause a significant global health burden. Here we integrate data from UK Biobank and a large-scale international collaborative effort, including data for 563,085 European ancestry participants, and discover 5,106 new genetic variants independently associated with 29 blood cell phenotypes covering a range of variation impacting hematopoiesis. We holistically characterize the genetic architecture of hematopoiesis, assess the relevance of the omnigenic model to blood cell phenotypes, delineate relevant hematopoietic cell states influenced by regulatory genetic variants and gene networks, identify novel splice-altering variants mediating the associations, and assess the polygenic prediction potential for blood traits and clinical disorders at the interface of complex and Mendelian genetics. These results show the power of large-scale blood cell trait GWAS to interrogate clinically meaningful variants across a wide allelic spectrum of human variation. Analysis of blood cell traits in the UK Biobank and other cohorts illuminates the full genetic architecture of hematopoietic phenotypes, with evidence supporting the omnigenic model for complex traits and linking polygenic burden with monogenic blood diseases

Whole-genome sequencing reveals host factors underlying critical COVID-19

Critical COVID-19 is caused by immune-mediated inflammatory lung injury. Host genetic variation influences the development of illness requiring critical care1 or hospitalization2,3,4 after infection with SARS-CoV-2. The GenOMICC (Genetics of Mortality in Critical Care) study enables the comparison of genomes from individuals who are critically ill with those of population controls to find underlying disease mechanisms. Here we use whole-genome sequencing in 7,491 critically ill individuals compared with 48,400 controls to discover and replicate 23 independent variants that significantly predispose to critical COVID-19. We identify 16 new independent associations, including variants within genes that are involved in interferon signalling (IL10RB and PLSCR1), leucocyte differentiation (BCL11A) and blood-type antigen secretor status (FUT2). Using transcriptome-wide association and colocalization to infer the effect of gene expression on disease severity, we find evidence that implicates multiple genes—including reduced expression of a membrane flippase (ATP11A), and increased expression of a mucin (MUC1)—in critical disease. Mendelian randomization provides evidence in support of causal roles for myeloid cell adhesion molecules (SELE, ICAM5 and CD209) and the coagulation factor F8, all of which are potentially druggable targets. Our results are broadly consistent with a multi-component model of COVID-19 pathophysiology, in which at least two distinct mechanisms can predispose to life-threatening disease: failure to control viral replication; or an enhanced tendency towards pulmonary inflammation and intravascular coagulation. We show that comparison between cases of critical illness and population controls is highly efficient for the detection of therapeutically relevant mechanisms of disease

Uterine body placenta accreta spectrum: A detailed literature review

Placenta accreta spectrum (PAS) is a major obstetrical problem whose incidence is rising. Current guidelines recommend screening of all women with placenta previa and risk factors for PAS between 20 and 24 weeks. Risk factors, diagnosis, and management of previa PAS are well established, but an apparently normal location of the placenta does not exclude PAS. Literature data are scarce on uterine body PAS, which carries a high risk of maternal and neonatal adverse outcome, but is still easily missed on prenatal ultrasound. We conducted a comprehensive review to identify possible risk factors, clinical presentations, and diagnostic modalities of uterine PAS. A total of 133 cases were found during a 70-year period (1949–2019). The vast majority of them presented with signs of uterine rupture, even prior to the viability threshold of 24 weeks (up to 45%). Major risk factors included previous cesarean delivery, uterine curettage, uterine surgery, Asherman's syndrome, manual removal of the placenta, endometritis, high parity, young maternal age, in vitro fertilization, radiotherapy, uterine artery embolization, and uterine leiomyoma. Diagnosis was pre-symptomatic in only 3% of cases. Future studies should differentiate between previa PAS and uterine body PAS.SCOPUS: ar.jDecretOANoAutActifinfo:eu-repo/semantics/publishe

Characteristics of fetal and maternal heart rate tracings during labor: A prospective observational study

BACKGROUND: Fetal well-being is assured during labor and delivery with the employment of electronic fetal heart monitoring (EFHM). In uncommon instances, maternal heart rate (MHR) instead of fetal heart rate (FHR) can be the source of signals on monitors (signal ambiguity) leading to erroneous interpretation and management. Information about MHR characteristics are comparatively inadequate. We aim to analyze and compare MHR and FHR characteristics during the first and second stages of labor. METHODS: A prospective cohort study was conducted in a single tertiary care center during a one year period. Fifty one healthy full term women with singleton pregnancies during labor were enrolled. Uterine contractions, MHR and FHR were recorded simultaneously during both stages of labor by monitors designed for twin gestation. RESULTS: When compared to FHR, MHR had significantly lower baseline rate during 1st and 2nd stages (p < 0.0001). It demonstrated also more marked beat-to-beat variability during both stages (p < 0.0001). MHR showed significantly more accelerations (p = 0.03 and p = 0.008) and less decelerations (p < 0.0001 and p = 0.021) during 1st and 2nd stages respectively. CONCLUSIONS: All characteristic parameters and patterns produced by FHR could be mimicked by MHR as well, though, at different frequencies. Understanding EFHM patterns suspected to be MHR artefacts and the employment of modern monitors that simultaneously obtain and display FHR and MHR can unmask ambiguity and avert related misinterpretation problems. Similar studies should be conducted in high-risk groups where the potential for fetal hypoxia/acidosis is increased.SCOPUS: ar.jDecretOANoAutActifinfo:eu-repo/semantics/publishe

How safe is high‐order repeat cesarean delivery? An 8‐year single‐center experience in Lebanon

Aim: To quantify the impact of the number of prior cesarean deliveries (CD) on operative complications and preterm birth. Then to investigate the presence of a threshold, beyond which complications tend to be disproportionately dangerous. Methods: This was a retrospective cohort observational study, where data corresponding to all CD done at our service, during an 8-year period, were collected and analyzed. In total, 1840 CD were performed. Patients were divided into five categories that corresponded to the number of CD. Primary outcome was the composite adverse maternal outcome, while preterm birth and individual complications were secondary outcomes. Results: The composite adverse maternal outcome, preterm birth, as well as all individual complications related to CD, except for placental abruption, showed a significant rise in frequency that paralleled the increase in the number of CD. Furthermore, this increase tended to be continuous as the number of CD increased, with an evident surge after the fourth. Conclusion: In our population, increasing number of prior CD was a risk factor for a parallel increase in the rate of composite adverse maternal outcome, preterm birth and almost all intraoperative complications attributable to CD. Decreasing exposure to such surgeries by limiting family size to four offspring should be considered seriously in patient counseling.SCOPUS: ar.jDecretOANoAutActifinfo:eu-repo/semantics/publishe

How safe is high-order repeat cesarean delivery? An 8-year single-center experience in Lebanon

Aim: To quantify the impact of the number of prior cesarean deliveries (CD) on operative complications and preterm birth. Then to investigate the presence of a threshold, beyond which complications tend to be disproportionately dangerous. Methods: This was a retrospective cohort observational study, where data corresponding to all CD done at our service, during an 8-year period, were collected and analyzed. In total, 1840 CD were performed. Patients were divided into five categories that corresponded to the number of CD. Primary outcome was the composite adverse maternal outcome, while preterm birth and individual complications were secondary outcomes. Results: The composite adverse maternal outcome, preterm birth, as well as all individual complications related to CD, except for placental abruption, showed a significant rise in frequency that paralleled the increase in the number of CD. Furthermore, this increase tended to be continuous as the number of CD increased, with an evident surge after the fourth. Conclusion: In our population, increasing number of prior CD was a risk factor for a parallel increase in the rate of composite adverse maternal outcome, preterm birth and almost all intraoperative complications attributable to CD. Decreasing exposure to such surgeries by limiting family size to four offspring should be considered seriously in patient counseling.SCOPUS: ar.jDecretOANoAutActifinfo:eu-repo/semantics/publishe

Shock-wave processing of C60 in hydrogen

International audienceContext. Interstellar carbonaceous particles and molecules are subject to intense shocks in astrophysical environments. Shocks induce a rapid raise in temperature and density which strongly affects the chemical and physical properties of both the gas and solid phases of the interstellar matter.Aims. The shock-induced thermal processing of C60 particles in hydrogen has been investigated in the laboratory under controlled conditions up to 3900 K with the help of a material shock-tube.Methods. The solid residues generated by the exposure of a C60/H2 mixture to a millisecond shock wave were collected and analyzed using X-ray diffraction, scanning electron microscopy, transmission electron microscopy, Raman micro-spectroscopy, and infrared micro-spectroscopy. The gaseous products were analyzed by Gas Chromatography and Cavity Ring Down Spectroscopy. Results. Volatile end-products appear above reflected shock gas temperatures of ~2540 K and reveal the substantial presence of small molecules with one or two C atoms. These observations confirm the role played by the C2 radical as a major product of C60 fragmentation and less expectedly highlight the existence of a single C atom loss channel. Molecules with more than two carbon atoms are not observed in the post-shock gas. The analysis of the solid component shows that C60 particles are rapidly converted into amorphous carbon with a number of aliphatic bridges.Conclusions. The absence of aromatic CH stretches on the IR spectra indicates that H atoms do not link directly to aromatic cycles. The fast thermal processing of C60 in H2 over the 800–3400 K temperature range leads to amorphous carbon. The analysis hints at a collapse of the cage with the formation of a few aliphatic connections. A low amount of hydrogen is incorporated into the carbon material. This work extends the range of applications of shock tubes to studies of astrophysical interest