329 research outputs found
Hybrid silica-metalloporphyrin nanomaterials exhibiting intensive absorption of light in the red-region
Strain-induced modifications of transport in gated graphene nanoribbons
We investigate the effects of homogeneous and inhomogeneous deformations and
edge disorder on the conductance of gated graphene nanoribbons. Under
increasing homogeneous strain the conductance of such devices initially
decreases before it acquires a resonance structure, and finally becomes
completely suppressed at larger strain. Edge disorder induces mode mixing in
the contact regions, which can restore the conductance to its ballistic value.
The valley-antisymmetric pseudo-magnetic field induced by inhomogeneous
deformations leads to the formation of additional resonance states, which
either originate from the coupling into Fabry-Perot states that extend through
the system, or from the formation of states that are localized near the
contacts, where the pseudo-magnetic field is largest. In particular, the n=0
pseudo-Landau level manifests itself via two groups of conductance resonances
close to the charge neutrality point.Comment: 10 pages, 6 figure
Spin-split collinear antiferromagnets: a large-scale ab-initio study
It was recently discovered that, depending on their symmetries, collinear
antiferromagnets can actually break the spin degeneracy in momentum space, even
in the absence of spin-orbit coupling. Such systems are signalled by the
emergence of a spin-momentum texture set mainly by the crystal and magnetic
structure, relativistic effects playing a secondary role. Here we consider all
collinear =0 antiferromagnetic compounds in the MAGNDATA database allowing
for spin-split bands. Based on density-functional calculations for the
experimentally reported crystal and magnetic structures, we study more than
sixty compounds and introduce numerical measures for the average momentum-space
spin splitting. We highlight some compounds that are of particular interest,
either due to a relatively large spin splitting, such as CoF and FeSOF,
or because of their low-energy electronic structure. The latter include
LiFeF, which hosts nearly flat spin-split bands next to the Fermi
energy, as well as RuO, CrNbS, and CrSb, which are spin-split
antiferromagnetic metals
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Chirality flip of Weyl nodes and its manifestation in strained MoTe2
Due to their topological charge, or chirality, the Weyl cones present in
topological semimetals are considered robust against arbitrary perturbations.
One well-understood exception to this robustness is the pairwise creation or
annihilation of Weyl cones, which involves the overlap of two oppositely
charged nodes in energy and momentum. Here we show that their topological
charge can in fact change sign, in a process that involves the merging of not
two, but three Weyl nodes. This is facilitated by the presence of rotation and
time-reversal symmetries, which constrain the relative positions of Weyl cones
in momentum space. We analyze the chirality flip process, showing that
transport properties distinguish it from the conventional, double Weyl merging.
Moreover, we predict that the chirality flip occurs in MoTe, where
experimentally accessible strain leads to the merging of three Weyl cones close
to the Fermi level. Our work sets the stage to further investigate and observe
such chirality flipping processes in different topological materials
Spreading in Social Systems: Reflections
In this final chapter, we consider the state-of-the-art for spreading in
social systems and discuss the future of the field. As part of this reflection,
we identify a set of key challenges ahead. The challenges include the following
questions: how can we improve the quality, quantity, extent, and accessibility
of datasets? How can we extract more information from limited datasets? How can
we take individual cognition and decision making processes into account? How
can we incorporate other complexity of the real contagion processes? Finally,
how can we translate research into positive real-world impact? In the
following, we provide more context for each of these open questions.Comment: 7 pages, chapter to appear in "Spreading Dynamics in Social Systems";
Eds. Sune Lehmann and Yong-Yeol Ahn, Springer Natur
Risk of HPV-related extra-cervical cancers in women treated for cervical intraepithelial neoplasia
Preterm birth is not associated with asymptomatic/mild SARS-CoV-2 infection per se: Pre-pregnancy state is what matters
Evidence for the real impact of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection on preterm birth is unclear, as available series report composite pregnancy outcomes and/or do not stratify patients according to disease severity. The purpose of the research was to determine the real impact of asymptomatic/mild SARS-CoV-2 infection on preterm birth not due to maternal respiratory failure. This case-control study involved women admitted to Sant Anna Hospital, Turin, for delivery between 20 September 2020 and 9 January 2021. The cumulative incidence of Coronavirus disease-19 was compared between preterm birth (case group, n = 102) and full-term delivery (control group, n = 127). Only women with spontaneous or medically-indicated preterm birth because of placental vascular malperfusion (pregnancy-related hypertension and its complications) were included. Current or past SARS-CoV-2 infection was determined by nasopharyngeal swab testing and detection of IgM/IgG antibodies in blood samples. A significant difference in the cumulative incidence of Coronavirus disease-19 between the case (21/102, 20.5%) and the control group (32/127, 25.1%) (P= 0.50) was not observed, although the case group was burdened by a higher prevalence of three known risk factors (body mass index > 24.9, asthma, chronic hypertension) for severe Coronavirus disease-19. Logistic regression analysis showed that asymptomatic/mild SARS-CoV-2 infection was not an independent predictor of spontaneous and medically-indicated preterm birth due to pregnancy-related hypertension and its complications (0.77; 95% confidence interval, 0.41-1.43). Pregnant patients without comorbidities need to be reassured that asymptomatic/mild SARS-CoV-2 infection does not increase the risk of preterm delivery. Preterm birth and severe Coronavirus disease-19 share common risk factors (i.e., body mass index > 24.9, asthma, chronic hypertension), which may explain the high rate of indicated preterm birth due to maternal conditions reported in the literature
From Uterus to Brain: An Update on Epidemiology, Clinical Features, and Treatment of Brain Metastases From Gestational Trophoblastic Neoplasia
In this review, we provide the state of the art about brain metastases (BMs) from gestational trophoblastic neoplasia (GTN), a rare condition. Data concerning the epidemiology, clinical presentation, innovations in therapeutic modalities, and outcomes of GTN BMs are comprehensively presented with particular attention to the role of radiotherapy, neurosurgery, and the most recent chemotherapy regimens. Good response rates have been achieved thanks to multi-agent chemotherapy, but brain involvement by GTNs entails significant risks for patients’ health since sudden and extensive intracranial hemorrhages are possible. Moreover, despite the evolution of treatment protocols, a small proportion of these patients ultimately develops a resistant disease. To tackle this unmet clinical need, immunotherapy has been recently proposed. The role of this novel option for this subset of patients as well as the achieved results so far are also discussed
Is there a place for immune checkpoint inhibitors in vulvar neoplasms? A state of the art review
Vulvar cancer (VC) is a rare neoplasm, usually arising in postmenopausal women, although human papilloma virus (HPV)-associated VC usually develop in younger women. Incidences of VCs are rising in many countries. Surgery is the cornerstone of early-stage VC management, whereas therapies for advanced VC are multimodal and not standardized, combining chemotherapy and radiotherapy to avoid exenterative surgery. Randomized controlled trials (RCTs) are scarce due to the rarity of the disease and prognosis has not improved. Hence, new therapies are needed to improve the outcomes of these patients. In recent years, improved knowledge regarding the crosstalk between neoplastic and tumor cells has allowed researchers to develop a novel therapeutic approach exploiting these molecular interactions. Both the innate and adaptive immune systems play a key role in anti-tumor immunesurveillance. Immune checkpoint inhibitors (ICIs) have demonstrated efficacy in multiple tumor types, improving survival rates and disease outcomes. In some gynecologic cancers (e.g., cervical cancer), many studies are showing promising results and a growing interest is emerging about the potential use of ICIs in VC. The aim of this manuscript is to summarize the latest developments in the field of VC immunoncology, to present the role of state-of-the-art ICIs in VC management and to discuss new potential immunotherapeutic approaches
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