Magnetic-field-induced electronic instability of Weyl-like fermions in compressed black phosphorus

Revealing the role of Coulomb interaction in topological semimetals with Dirac/Weyl-like band dispersion shapes a new frontier in condensed matter physics. Topological node-line semimetals (TNLSMs), anticipated as a fertile ground for exploring electronic correlation effects due to the anisotropy associated with their node-line structure, have recently attracted considerable attention. In this study, we report an experimental observation for correlation effects in TNLSMs realized by black phosphorus (BP) under hydrostatic pressure. By performing a combination of nuclear magnetic resonance measurements and band calculations on compressed BP, a magnetic-field-induced electronic instability of Weyl-like fermions is identified under an external magnetic field parallel to the so-called nodal ring in the reciprocal space. Anomalous spin fluctuations serving as the fingerprint of electronic instability are observed at low temperatures, and they are observed to maximize at approximately 1.0 GPa. This study presents compressed BP as a realistic material platform for exploring the rich physics in strongly coupled Weyl-like fermions.Comment: 10 pages, 4 figure

A Novel Xenograft Model in Zebrafish for High-Resolution Investigating Dynamics of Neovascularization in Tumors

Tumor neovascularization is a highly complex process including multiple steps. Understanding this process, especially the initial stage, has been limited by the difficulties of real-time visualizing the neovascularization embedded in tumor tissues in living animal models. In the present study, we have established a xenograft model in zebrafish by implanting mammalian tumor cells into the perivitelline space of 48 hours old Tg(Flk1:EGFP) transgenic zebrafish embryos. With this model, we dynamically visualized the process of tumor neovascularization, with unprecedented high-resolution, including new sprouts from the host vessels and the origination from VEGFR2+ individual endothelial cells. Moreover, we quantified their contributions during the formation of vascular network in tumor. Real-time observations revealed that angiogenic sprouts in tumors preferred to connect each other to form endothelial loops, and more and more endothelial loops accumulated into the irregular and chaotic vascular network. The over-expression of VEGF165 in tumor cells significantly affected the vascularization in xenografts, not only the number and size of neo-vessels but the abnormalities of tumor vascular architecture. The specific inhibitor of VEGFR2, SU5416, significantly inhibited the vascularization and the growth of melanoma xenografts, but had little affects to normal vessels in zebrafish. Thus, this zebrafish/tumor xenograft model not only provides a unique window to investigate the earliest events of tumoral neoangiogenesis, but is sensitive to be used as an experimental platform to rapidly and visually evaluate functions of angiogenic-related genes. Finally, it also offers an efficient and cost-effective means for the rapid evaluation of anti-angiogenic chemicals

Benthic fluxes of metals into the Pearl River Estuary based on 224 Ra/ 228 Th disequilibrium: From alkaline earth (Ba) to redox sensitive elements (U, Mn, Fe)

We extended the 224Ra/228Th disequilibrium approach to examine benthic fluxes of a variety of metals, ranging from alkaline earth (Ba) to redox sensitive elements (U, Mn, and Fe), into the Pearl River Estuary (PRE), China. Depth profiles of 224Ra and 228Th in bulk sediment, as well as dissolved 224Ra and trace metals in porewater were measured along a transect within the estuary in July 2015. Significant deficit of 224Ra relative to 228Th was commonly observed in the upper 0–15 cm sediment. We took advantage of the 224Ra/228Th disequilibrium in the bottom sediments to construct a full mass balance of 224Ra in the overlying water column. We demonstrated that porewater exchange (PEX) processes with scale lengths of several centimeters are the predominant mechanism for solute transport between sediments and overlying waters in the PRE. In contrast, deep porewater flow or submarine groundwater discharge (SGD) with scale lengths of “meters to kilometers” are a negligible component in the water column budget of 224Ra. Strong correlations between dissolved 224Ra and trace metals (Ba, U, Mn, and Fe) in porewater were frequently observed in the study region. This likely reflects a fact that geochemical cycling of alkaline earth elements (e.g., Ra and Ba) and redox sensitive elements (like U) in sediments was closely linked to diagenetic reactions of manganese and iron oxides. This linkage makes it possible to quantify benthic fluxes of alkaline earth and redox sensitive metals using 224Ra/228Th disequilibrium in sediments. Benthic Ba fluxes based on 224Ra/228Th disequilibrium were found to vary from virtually nil to 320 μmol m−2 d−1 within the PRE. The highest flux was identified at salinity = 3.0–7.8 and could lead to an elevation of 54 nmol Ba l−1 in the water column, which well reproduced the Ba excess frequently observed in the low salinity domain of the estuary. Benthic fluxes of redox sensitive U ranged from −0.42 (“−” denotes flux into sediment) to 1.3 μmol m−2 d−1. This could only cause a change of −0.1 to 0.3 nmol U l−1 in the water column, which is very small when compared to the U concentration of 13–14 nmol l−1 in the northern South China Sea. We therefore predicted that water column U in the PRE must behave conservatively during mixing. This prediction is consistent with historical measurements of water column U concentration within the PRE. Large benthic fluxes of Mn and Fe were generally acquired with the 224Ra/228Th disequilibrium method. They varied from virtually nil up to 97 mmol m−2 d−1, and from zero to 27 mmol m−2 d−1, respectively. These estimates are 1–2 orders of magnitude higher than historical measurements based on the traditional incubation method in other coastal settings. Nonetheless, they are in agreement with a simple consideration of Mn and Fe mass balances in the sediment. An important implication of this study is that the role of coastal sediments in estuarine geochemistry of trace metals may need to be re-evaluated

Dynamics of the carbonate system in a large continental shelf system under the influence of both a river plume and coastal upwelling

We examined the dynamics of the carbonate system in a complex mixing scheme with enhanced biological consumption modulated by both a river plume and summer coastal upwelling in a large shelf system, the northern South China Sea (NSCS) shelf. The plume waters originated from a large flooding upstream the Pearl River, and extended from the mouth of the Pearl River estuary to the middle shelf and were characterized by low dissolved inorganic carbon (DIC) and total alkalinity (TAlk), and a high aragonite saturation state (Omega(arag)). In contrast, the upwelled water occupying the nearshore area was distinguished by high DIC and TAlk and a low Omega(arag). While the dynamics of the carbonate system were largely shaped by physical mixing through plume and upwelling processes between the plume water, the offshore subsurface water and the offshore surface water, biological consumption of DIC was observable in both the river plume and the coastal upwelling areas and contributed to the elevated Omega(arag) during their pathway. Correlations between salinity normalized TAlk and DIC indicated that organic carbon production rather than biocalcification exclusively induced the DIC removal. By using a three end-member mixing model, we estimated the net community productivity in the plume water and the upwelled water to be 36 +/- 19 mmol C m(-2) d(-1) and 23 +/- 26 mmol C m(-2) d(-1), respectively. With the combination of stoichiometric relationship analysis of the carbonate system and applying the three end-member mixing model, we successfully differentiated semiquantitatively the biologically mediated DIC variations from its overall mixing control. We also attempted to link this natural process to the carbonate saturation on the NSCS shelf, contending that at present natural factors associated with the river plume and the coastal upwelling largely modulate the dynamics of the carbonate system on the NSCS shelf, whereas anthropogenic stressors such as ocean acidification currently play a relatively minor role

Effectiveness and safety of low-dose interferon alpha-2a treatment in Behçet’s Syndrome with refractory vascular or neurological involvement: a case series

Objective: The aim of this study was to evaluate the effectiveness and safety of low-dose interferon alpha-2a (IFNα2a) in Behçet’s syndrome (BS) patients with refractory vascular/cardiac or neurological involvement. Methods: In this retrospective cohort study, we consecutively included 25 BS patients with refractory vascular/cardiac ( n  = 16) or neurological involvement ( n  = 9) who received IFNα2a treatment in our center between June 2018 and September 2021. The low-dose IFNα2a (3 million IU, every other day) was used as an add-on treatment with the continuation of glucocorticoids (GCs) and immunosuppressants. Results: In total, 25 patients (20 males, 5 females) with a mean age of 31.92 ± 9.25 years were included. IFNα2a was administered for BS patients with refractory vascular/cardiac involvement ( n  = 16) and neurological involvement ( n  = 9). Before the initiation of IFNα2a, patients had insufficient response or intolerance to conventional therapies. After a median follow-up of 23 [interquartile range (IQR), 11–30] months, all patients achieved clinical improvement. The Behçet’s disease Current Activity Form (BDCAF) score improved significantly (5 versus 0, median, p   0.05). Decrease in erythrocyte sedimentation rate [ESR; 24 (IQR, 12–43.5) versus 5 (IQR, 2.75–10.5) mm/h, p  = 0.0001] and C-reactive protein [CRP; 6.64 (IQR, 3.67–19.82) versus 1.24 (IQR, 0.24–3.12) mg/liter, p  < 0.005] was achieved effectively. The median GCs dosage tapered from 26.25 (IQR, 11.88–41.25) to 10.00 (IQR, 7.50–10.63) mg/d, p  < 0.0001. Immunosuppressants were also reduced in number ( p  < 0.005). No serious adverse events were observed during follow-up. Conclusion: Our study suggests that low-dose IFNα2a, combined with GCs and immunosuppressants, is well-tolerated and effective for BS patients with refractory vascular/cardiac or neurological involvement and has a steroid- and immunosuppressant-sparing effect

The small-molecular inhibitor of VEGFR2 inhibiting the tumor growth and neovascularization.

<p>(A–C) The imaging showed the obvious blockage of the specific inhibitor of VEGFR2, SU5416 (2 µM), to the neovascularization (A), tumor growth (B), and normal vascular vessels of zebrafish (C). (D,E) The quantitative analysis of the inhibiting effects of SU5416 to neovascularization (D) and tumor growth (E). (F) The result of MTT assay for B16 cells that treated by SU5416 for 48 hours <i>in vitro</i> at a concentration of 0, 1, 2 µM. Scale bar, 100 µm.</p

Dynamical observations of aniogenesis in B16 xenografts.

<p>The established microtumors (A, 3dpi and 6dpi panels) in zebrafish larvae are indicated by arrowheads. Neo-vessels are indicated by arrows (B).</p

The participation of individual VEGFR2+ endothelial cells to the initial formation of tumor vascular network.

<p>Individual VEGFR2+ endothelial cells located at the center of B16 xenograft (indicated by arrow, A). The region in white dotted box was magnified in B. With the tumor growth (C), individual endothelial cells (arrows) increased its length and fused with angiogenic sprouts (arrowheads). (D) Histogram represents (n = 12, p<0.05) the percentage of endothelial columns that originated from the individual ECs or the angiogenic sprouts. Scale bar, 100 µm (A, C) or 50 µm (B).</p

The formation of chaotic microvascular network in B16 xenografts.

<p>(<b>A</b>) The interconnection of initial endothelial cells that had penetrated into tumor tissue. (B) Schematic diagram showing the forming and formed endothelial loops. (C) The dynamic process of more and more endothelial loops assembling into a complex vascular network. Angiogenic sprouts were indicated by arrows, the formed endothelial loops were indicated by crosses. (D) Endothelial loops varied significantly in size and shape. The B16 xenograft is indicated by arrow (E). Scale bars, 200 µm.</p

Perioperative management with biologics on severe aortic valve regurgitation caused by Behçet syndrome: the experience from a single center

Background: To investigate the efficacy and safety of biologics in the perioperative management of severe aortic valve regurgitation (AR) caused by Behçet syndrome (BS). Methods: We retrospectively analyzed 20 patients with severe AR caused by BS who were all treated with biologics during the perioperative period of cardiac surgeries in our center between February 2016 and October 2020. Results: A total of 20 patients with severe AR were enrolled, including 19 males and 1 female, with a mean age of 39.1 ± 8.8 years and a median course of 8 [interquartile range (IQR) 5.25–10.00] years. Before biologic administration, 92.9% of the patients who underwent aortic valve replacement had failed conventional therapy and developed postoperative paravalvular leakage (PVL) at a median interval of 4 months. Biologics were administered with background glucocorticoids (GCs) and immunosuppressants during the perioperative period for 22 aortic valve surgeries, including preoperatively with a median interval of 3.5 (IQR 2.75–4.25) months in 13 cases and within 3 months postoperatively in 9 cases. After a median follow up of 21 (IQR 15–32) months, 2 out of 13 cases (15.4%) preoperatively, and 1 out of 9 cases (11.1%) postoperatively treated with biologics developed PVL, and the rest were event free. The Behçet’s Disease Current Activity Form score improved significantly (7 versus 0, median, p  < 0.0001). Decrease of erythrocyte sedimentation rate [25.0 (IQR 11.00–36.25) mm/h versus 6.5 (IQR 4.0–8.8) mm/h, p  < 0.001], and C-reactive protein [20.77 (IQR 7.19–29.58) mg/l versus 1.53 (IQR 0.94–2.92) mg/l, p  = 0.001] were achieved rapidly and effectively. The GC dosage tapered from 40 (IQR 30–60) mg/d to 10 (IQR 5–11.25) mg/d, p  < 0.0001. Immunosuppressants were tapered in number and dosage in 6 (30%) and 20 patients (100%), respectively. No serious adverse event was observed. Conclusion: Our study suggests that biologics were effective and well tolerated for the perioperative management of severe and refractory AR caused by BS, which significantly reduced the occurrence of postoperative PVL and had favorable GC- and immunosuppressant-sparing effect