By combining angle-resolved photoemission spectroscopy and quantum oscillation measurements, we performed a comprehensive investigation on the electronic structure of LaSb, which exhibits ...near-quadratic extremely large magnetoresistance (XMR) without any sign of saturation at magnetic fields as high as 40 T. We clearly resolve one spherical and one intersecting-ellipsoidal hole Fermi surfaces (FSs) at the Brillouin zone (BZ) center Γ and one ellipsoidal electron FS at the BZ boundary X. The hole and electron carriers calculated from the enclosed FS volumes are perfectly compensated, and the carrier compensation is unaffected by temperature. We further reveal that LaSb is topologically trivial but shares many similarities with the Weyl semimetal TaAs family in the bulk electronic structure. Based on these results, we have examined the mechanisms that have been proposed so far to explain the near-quadratic XMR in semimetals.
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CMK, CTK, FMFMET, IJS, NUK, PNG, UM
In quantum field theory, Lorentz invariance leads to three types of fermion-Dirac, Weyl and Majorana. Although the existence of Weyl and Majorana fermions as elementary particles in high-energy ...physics is debated, all three types of fermion have been proposed to exist as low-energy, long-wavelength quasiparticle excitations in condensed-matter systems. The existence of Dirac and Weyl fermions in condensed-matter systems has been confirmed experimentally, and that of Majorana fermions is supported by various experiments. However, in condensed-matter systems, fermions in crystals are constrained by the symmetries of the 230 crystal space groups rather than by Lorentz invariance, giving rise to the possibility of finding other types of fermionic excitation that have no counterparts in high-energy physics. Here we use angle-resolved photoemission spectroscopy to demonstrate the existence of a triply degenerate point in the electronic structure of crystalline molybdenum phosphide. Quasiparticle excitations near a triply degenerate point are three-component fermions, beyond the conventional Dirac-Weyl-Majorana classification, which attributes Dirac and Weyl fermions to four- and two-fold degenerate points, respectively. We also observe pairs of Weyl points in the bulk electronic structure of the crystal that coexist with the three-component fermions. This material thus represents a platform for studying the interplay between different types of fermions. Our experimental discovery opens up a way of exploring the new physics of unconventional fermions in condensed-matter systems.
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IJS, KISLJ, NUK, SBMB, UL, UM, UPUK
We report a study of the processes of e^{+}e^{-}→K^{+}D_{s}^{-}D^{*0} and K^{+}D_{s}^{*-}D^{0} based on e^{+}e^{-} annihilation samples collected with the BESIII detector operating at BEPCII at five ...center-of-mass energies ranging from 4.628 to 4.698 GeV with a total integrated luminosity of 3.7 fb^{-1}. An excess of events over the known contributions of the conventional charmed mesons is observed near the D_{s}^{-}D^{*0} and D_{s}^{*-}D^{0} mass thresholds in the K^{+} recoil-mass spectrum for events collected at sqrts=4.681 GeV. The structure matches a mass-dependent-width Breit-Wigner line shape, whose pole mass and width are determined as (3982.5_{-2.6}^{+1.8}±2.1) MeV/c^{2} and (12.8_{-4.4}^{+5.3}±3.0) MeV, respectively. The first uncertainties are statistical and the second are systematic. The significance of the resonance hypothesis is estimated to be 5.3 σ over the contributions only from the conventional charmed mesons. This is the first candidate for a charged hidden-charm tetraquark with strangeness, decaying into D_{s}^{-}D^{*0} and D_{s}^{*-}D^{0}. However, the properties of the excess need further exploration with more statistics.
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CMK, CTK, FMFMET, IJS, NUK, PNG, UM
Abstract Induced pluripotent stem cells (iPSCs) hold great promise as a cell source for regenerative medicine yet its culture, maintenance of pluripotency and induction of differentiation remain ...challenging. Conversely, graphene (G) and graphene oxide (GO) have captured tremendous interests in the fields of materials science, physics, chemistry and nanotechnology. Here we report on that G and GO can support the mouse iPSCs culture and allow for spontaneous differentiation. Intriguingly, G and GO surfaces led to distinct cell proliferation and differentiation characteristics. In comparison with the glass surface, iPSCs cultured on the G surface exhibited similar degrees of cell adhesion and proliferation while iPSCs on the GO surface adhered and proliferated at a faster rate. Moreover, G favorably maintained the iPSCs in the undifferentiated state while GO expedited the differentiation. The iPSCs cultured on both G and GO surfaces spontaneously differentiated into ectodermal and mesodermal lineages without significant disparity, but G suppressed the iPSCs differentiation towards the endodermal lineage whereas GO augmented the endodermal differentiation. These data collectively demonstrated that the different surface properties of G and GO governed the iPSCs behavior and implicate the potentials of graphene-based materials as a platform for iPSCs culture and diverse applications.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Abstract Our aim was to differentiate IgG4-related sialadenitis, primary Sjögren syndrome, and chronic obstructive submandibular sialadenitis by analysing clinical, radiographic, and pathological ...features. Fifty-five patients, 50, and 50 were enrolled, respectively and their baseline characteristics and serological, sialographic, and pathological findings compared. The male:female ratio for IgG4-related sialadenitis was 1:1.2 for primary Sjögren syndrome 1:15.7, and for chronic obstructive submandibular sialadenitis1:0.92. Numbers with enlarged salivary glands were 55, 16, and 50; with xerostomia 26, 48, and 0; with a history of allergy 26, 4, and 6, and with coexisting systemic disease 12, 19, and 0 (p = 0.14). Mean (SD) serum IgG4 concentrations were 109.1 (97.9), 4.9. (1.9) g/L, and 5.3 (1.6) g/L, p < 0.001 in all cases. Sialography showed enlargement of the gland, dilatation of the duct, and slightly decreased secretory function in IgG4-related disease; obvious sialectasia and decreased secretory function in Sjögren syndrome; and dilatation of Wharton’s duct and filling defects in obstructive sialadenitis. Histopathological examination showed lymphoplasmacytic infiltration with storiform fibrosis, lymphoplasmacytic inflammation and lymphoepithelial lesions, and dilatation of the duct with epithelial metaplasia in the three groups, respectively. The number of IgG4-positive plasma cells was 123 (45)/HPF, 8 (3)/HPF, and 5 (4)/HPF, while the IgG4-/IgG-positive cell ratio was 71.7 (13.9)%, 4.6 (2.5)%, 18.9 (19.7)%, respectively (p < 0.001). The three conditions have different clinical, radiographic, and pathological features that provide important clues to the differential diagnosis. Serological and histological tests are important, and comprehensive consideration is necessary.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
6.
Isostructural metal-insulator transition in VO2 Lee, D; Chung, B; Shi, Y ...
Science (American Association for the Advancement of Science),
11/2018, Volume:
362, Issue:
6418
Journal Article
Peer reviewed
Open access
Separating structure and electrons in VO2Above 341 kelvin—not far from room temperature—bulk vanadium dioxide (VO2) is a metal. But as soon as the material is cooled below 341 kelvin, VO2 turns into ...an insulator and, at the same time, changes its crystal structure from rutile to monoclinic. Lee et al. studied the peculiar behavior of a heterostructure consisting of a layer of VO2 placed underneath a layer of the same material that has a bit less oxygen. In the VO2 layer, the structural transition occurred at a higher temperature than the metal-insulator transition. In between those two temperatures, VO2 was a metal with a monoclinic structure—a combination that does not occur in the absence of the adjoining oxygen-poor layer.Science, this issue p. 1037The metal-insulator transition in correlated materials is usually coupled to a symmetry-lowering structural phase transition. This coupling not only complicates the understanding of the basic mechanism of this phenomenon but also limits the speed and endurance of prospective electronic devices. We demonstrate an isostructural, purely electronically driven metal-insulator transition in epitaxial heterostructures of an archetypal correlated material, vanadium dioxide. A combination of thin-film synthesis, structural and electrical characterizations, and theoretical modeling reveals that an interface interaction suppresses the electronic correlations without changing the crystal structure in this otherwise correlated insulator. This interaction stabilizes a nonequilibrium metallic phase and leads to an isostructural metal-insulator transition. This discovery will provide insights into phase transitions of correlated materials and may aid the design of device functionalities.
Summary
Background
Autophagy and neutrophil extracellular DNA traps (NETs) are implicated in asthma; however, their roles in asthma pathogenesis have not been elucidated.
Objectives
We compared ...autophagy and NET production levels from peripheral blood neutrophils (PBNs) of patients with severe asthma (SA) and non‐severe asthma (NSA). Additionally, we investigated the inflammatory effects of NETs on human airway epithelial cells (AECs) and peripheral blood eosinophils (PBEs).
Methods
Peripheral blood neutrophils from patients with SA (n = 30) and NSA (n = 38) were treated with interleukin (IL)‐8 (100 ng/mL). Autophagy (light chain 3‐II expression) and NET production levels were evaluated by Western blot, immunofluorescence microscopy, and PicoGreen assay. The effects of NETs on AECs were assessed by investigating cell death, cell detachment, expression of occludin and claudin‐1, and IL‐8 production; the effects of NETs on PBEs were examined by investigating the activation and release of eosinophil cationic protein (ECP) and eosinophil‐derived neurotoxin (EDN).
Results
Untreated and IL‐8‐treated PBNs from the SA group produced higher autophagy and NET levels compared with those from the NSA group (P < 0.01). IL‐8 increased autophagy and NET levels in PBNs from the SA group, but not from the NSA group. NET levels were correlated with autophagy levels in PBNs (P < 0.001). IL‐8‐induced NET production levels negatively were correlated with FEV1/FVC (r = −0.700, P = 0.016). NETs induced cell death, detachment, degradation of occludin and claudin‐1, and IL‐8 production from AECs. Higher levels of NET‐induced ECP and EDN were released from PBEs in SA compared with NSA groups.
Conclusions and Clinical Relevance
Neutrophil autophagy and NETs could enhance asthma severity by damaging airway epithelium and triggering inflammatory responses of AECs and PBEs. Modulating neutrophil autophagy and NET production may be a new target therapy for SA.
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BFBNIB, DOBA, FZAB, GIS, IJS, IZUM, KILJ, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBMB, SIK, UILJ, UKNU, UL, UM, UPUK
This systematic review and meta-analysis estimated the global, regional prevalence, and risk factors of osteoporosis. Prevalence varied greatly according to countries (from 4.1% in Netherlands to ...52.0% in Turkey) and continents (from 8.0% in Oceania to 26.9% in Africa). Osteoporosis is a common metabolic bone disorder in the elderly, usually resulting in bone pain and an increased risk of fragility fracture, but few summarized studies have guided global strategies for the disease. Therefore, we pooled the epidemiologic data to estimate the global, regional prevalence, and potential risk factors of osteoporosis. We conducted a comprehensive literature search through PubMed, EMBASE, Web of Science, and Scopus, to identify population-based studies that reported the prevalence of osteoporosis based on the World Health Organization (WHO) criteria. Meta-regression and subgroup analyses were used to explore the sources of heterogeneity. The study was registered in the PROSPERO database (CRD42021285555). Of the 57,933 citations evaluated, 108 individual studies containing 343,704 subjects were included. The global prevalence of osteoporosis and osteopenia was 19.7% (95%CI, 18.0%–21.4%) and 40.4% (95%CI, 36.9%–43.8%). Prevalence varied greatly according to countries (from 4.1% in Netherlands to 52.0% in Turkey) and continents (from Oceania 8.0% to 26.9% in Africa). The prevalence was higher in developing countries (22.1%, 95%CI, 20.1%–24.1%) than in developed countries (14.5%, 95%CI, 11.5%–17.7%). Our study indicates a considerable prevalence of osteoporosis among the general population based on WHO criteria, and the prevalence varies substantially between countries and regions. Future studies with robust evidence are required to explore risk factors to provide effective preventive strategies for the disease.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
This phase II, open-label study evaluated the efficacy and safety of erlotinib as second-line therapy in non-small-cell lung cancer (NSCLC) patients with brain metastases (BM).
Forty-eight patients ...aged 18–75 years with Eastern Cooperative Oncology Group performance status 0–2, confirmed adenocarcinoma or activating epidermal growth factor receptor (EGFR) mutation-positive NSCLC, and asymptomatic BM without extracranial progressive disease after first-line platinum-doublet chemotherapy were recruited. Treatment comprised erlotinib 150 mg/day. The primary end point was progression-free survival (PFS) determined by RECIST.
The median PFS was 10.1 months 95% confidence interval (CI) 7.1–12.3 for intracranial progression and 9.7 months (95% CI 2.5–17.8) for intracranial and systemic progression. Patients with EGFR mutation-positive disease had significantly longer median PFS versus EGFR wild-type disease 15.2 months (95% CI 8.3–22.2) versus 4.4 months (95% CI 0.0–11.6); P = 0.02. The median overall survival was 18.9 months (95% CI 14.4–23.4); 6-month and 1-year survival rates were 85% and 73%, respectively. Overall response rate was 58.3%. Most common adverse events were rash (77.1%), paronychia (20.8%), hyperbilirubinemia (16.7%), and diarrhea (14.6%); these were predominantly of grade 1/2.
Single-agent erlotinib was active and well tolerated in NSCLC patients with BM. Further studies are warranted.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Summary
Background
A multidrug regimen including isoniazid, rifampicin, pyrazinamide and ethambutol is commonly used as first‐line treatment for tuberculosis. However, this regimen can occasionally ...result in severe adverse drug reactions, such as drug reaction with eosinophilia and systemic symptoms (DRESS) syndrome and drug‐induced liver injury. The culprit drug and mechanistic basis for the hypersensitive reaction are unknown.
Objectives
To investigate drug‐specific T‐cell responses in patients with antituberculosis drug (ATD)‐induced cutaneous hypersensitivity and its underlying mechanism.
Methods
We enrolled eight patients with ATD‐induced maculopapular exanthema and DRESS and performed a lymphocyte transformation test. Subsequently, drug‐specific T‐cell clones were generated from four of the patients who showed proliferation in response to ATDs. We measured the drug‐specific proliferative responses and counted the drug‐specific interferon (IFN)‐γ/granzyme B‐producing cells after drug stimulation. Antihuman leukocyte antigen (HLA) class I and class II blocking antibodies were used to analyse human leukocyte antigen‐restricted T‐cell responses.
Results
Positive proliferative responses to ATDs were mostly found in patients with cutaneous hypersensitivity. Furthermore, we isolated isoniazid/rifampicin‐specific T cells from patients, which consisted primarily of CD4+ T cells. Drug‐specific CD4+ T cells proliferated and secreted IFN‐γ/granzyme B when stimulated with isoniazid or rifampicin, respectively. Isoniazid‐responsive T‐cell clones did not proliferate in the presence of rifampicin and vice versa. Drug‐specific T‐cell responses were blocked in the presence of anti‐HLA class II antibodies.
Conclusions
This study identifies the presence of isoniazid/rifampicin‐specific T cells in patients with ATD‐induced maculopapular exanthema and DRESS. Furthermore, it highlights the important role of drug‐specific T‐cell immune responses in the pathogenesis of these reactions.
What's already known about this topic?
Antituberculosis drug (ATD) treatment often induces severe adverse drug reactions including hepatotoxicity, drug reaction with eosinophilia and systemic symptoms (DRESS) syndrome and maculopapular exanthema.
What does this study add?
This study identified an isoniazid/rifampicin‐specific T‐cell response in patients with ATD‐induced maculopapular exanthema and DRESS.
This study describes the nature of isoniazid/rifampicin‐specific CD4+ T cells and the mechanism of drug‐specific T‐cell activation in ATD‐induced maculopapular exanthema and DRESS syndrome.
What is the translational message?
As the first‐line treatment for tuberculosis is a combination regimen, the culprit drug is frequently not identified.
A lymphocyte transformation test for ATDs would be beneficial to assess the risk of drug hypersensitivity reaction.
Linked Comment: Pavlos et al. Br J Dermatol 2017; 176:292–293.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
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