Community detection is often used to understand the structure of large and complex networks. One of the most popular algorithms for uncovering community structure is the so-called Louvain algorithm. ...We show that this algorithm has a major defect that largely went unnoticed until now: the Louvain algorithm may yield arbitrarily badly connected communities. In the worst case, communities may even be disconnected, especially when running the algorithm iteratively. In our experimental analysis, we observe that up to 25% of the communities are badly connected and up to 16% are disconnected. To address this problem, we introduce the Leiden algorithm. We prove that the Leiden algorithm yields communities that are guaranteed to be connected. In addition, we prove that, when the Leiden algorithm is applied iteratively, it converges to a partition in which all subsets of all communities are locally optimally assigned. Furthermore, by relying on a fast local move approach, the Leiden algorithm runs faster than the Louvain algorithm. We demonstrate the performance of the Leiden algorithm for several benchmark and real-world networks. We find that the Leiden algorithm is faster than the Louvain algorithm and uncovers better partitions, in addition to providing explicit guarantees.
Clustering scientific publications in an important problem in bibliometric research. We demonstrate how two software tools, CitNetExplorer and VOSviewer, can be used to cluster publications and to ...analyze the resulting clustering solutions. CitNetExplorer is used to cluster a large set of publications in the field of astronomy and astrophysics. The publications are clustered based on direct citation relations. CitNetExplorer and VOSviewer are used together to analyze the resulting clustering solutions. Both tools use visualizations to support the analysis of the clustering solutions, with CitNetExplorer focusing on the analysis at the level of individual publications and VOSviewer focusing on the analysis at an aggregate level. The demonstration provided in this paper shows how a clustering of publications can be created and analyzed using freely available software tools. Using the approach presented in this paper, bibliometricians are able to carry out sophisticated cluster analyses without the need to have a deep knowledge of clustering techniques and without requiring advanced computer skills.
Neither the routes through which humin byproducts are formed, nor their molecular structure have yet been unequivocally established. A better understanding of the formation and physicochemical ...properties of humins, however, would aid in making biomass conversion processes more efficient. Here, an extensive multiple‐technique‐based study of the formation, molecular structure, and morphology of humins is presented as a function of sugar feed, the presence of additives (e.g., 1,2,4‐trihydroxybenzene), and the applied processing conditions. Elemental analyses indicate that humins are formed through a dehydration pathway, with humin formation and levulinic acid yields strongly depending on the processing parameters. The addition of implied intermediates to the feedstocks showed that furan and phenol compounds formed during the acid‐catalyzed dehydration of sugars are indeed included in the humin structure. IR spectra, sheared sum projections of solid‐state 2DPASS 13C NMR spectra, and pyrolysis GC–MS data indicate that humins consist of a furan‐rich polymer network containing different oxygen functional groups. The structure is furthermore found to strongly depend on the type of feedstock. A model for the molecular structure of humins is proposed based on the data presented.
Under scrutiny: Humin byproducts formed during the acid‐catalyzed dehydration of sugars are analyzed with multiple techniques to reveal a furan‐rich network formed via hydroxymethylfurfural (see picture). Within this network, the aliphatic linkages and oxygen functionalities strongly depend on the feedstock. A representative model for the molecular structure of humins is proposed.
Solid-state batteries potentially offer increased lithium-ion battery energy density and safety as required for large-scale production of electrical vehicles. One of the key challenges toward ...high-performance solid-state batteries is the large impedance posed by the electrode-electrolyte interface. However, direct assessment of the lithium-ion transport across realistic electrode-electrolyte interfaces is tedious. Here we report two-dimensional lithium-ion exchange NMR accessing the spontaneous lithium-ion transport, providing insight on the influence of electrode preparation and battery cycling on the lithium-ion transport over the interface between an argyrodite solid-electrolyte and a sulfide electrode. Interfacial conductivity is shown to depend strongly on the preparation method and demonstrated to drop dramatically after a few electrochemical (dis)charge cycles due to both losses in interfacial contact and increased diffusional barriers. The reported exchange NMR facilitates non-invasive and selective measurement of lithium-ion interfacial transport, providing insight that can guide the electrolyte-electrode interface design for future all-solid-state batteries.
Highlights • I-131 for DTC may cause salivary/lacrimal gland dysfunction, transient gonadal dysfunction and SPM. • I-131 therapy seems to have no deleterious effects on female reproductive outcomes. ...• Adverse effects of I-131 are associated with the given cumulative I-131 activity.
The high Li-ion conductivity of the argyrodite Li6PS5Cl makes it a promising solid electrolyte candidate for all-solid-state Li-ion batteries. For future application, it is essential to identify ...facile synthesis procedures and to relate the synthesis conditions to the solid electrolyte material performance. Here, a simple optimized synthesis route is investigated that avoids intensive ball milling by direct annealing of the mixed precursors at 550 °C for 10 h, resulting in argyrodite Li6PS5Cl with a high Li-ion conductivity of up to 4.96 × 10–3 S cm–1 at 26.2 °C. Both the temperature-dependent alternating current impedance conductivities and solid-state NMR spin–lattice relaxation rates demonstrate that the Li6PS5Cl prepared under these conditions results in a higher conductivity and Li-ion mobility compared to materials prepared by the traditional mechanical milling route. The origin of the improved conductivity appears to be a combination of the optimal local Cl structure and its homogeneous distribution in the material. All-solid-state cells consisting of an 80Li2S–20LiI cathode, the optimized Li6PS5Cl electrolyte, and an In anode showed a relatively good electrochemical performance with an initial discharge capacity of 662.6 mAh g–1 when a current density of 0.13 mA cm–2 was used, corresponding to a C-rate of approximately C/20. On direct comparison with a solid-state battery using a solid electrolyte prepared by the mechanical milling route, the battery made with the new material exhibits a higher initial discharge capacity and Coulombic efficiency at a higher current density with better cycling stability. Nevertheless, the cycling stability is limited by the electrolyte stability, which is a major concern for these types of solid-state batteries.
The development of commercial solid-state batteries has to date been hindered by the individual limitations of inorganic and organic solid electrolytes, motivating hybrid concepts. However, the ...room-temperature conductivity of hybrid solid electrolytes is still insufficient to support the required battery performance. A key challenge is to assess the Li-ion transport over the inorganic and organic interfaces and relate this to surface chemistry. Here we study the interphase structure and the Li-ion transport across the interface of hybrid solid electrolytes using solid-state nuclear magnetic resonance spectroscopy. In a hybrid solid polyethylene oxide polymer–inorganic electrolyte, we introduce two representative types of ionic liquid that have different miscibilities with the polymer. The poorly miscible ionic liquid wets the polymer–inorganic interface and increases the local polarizability. This lowers the diffusional barrier, resulting in an overall room-temperature conductivity of 2.47 × 10−4 S cm−1. A critical current density of 0.25 mA cm−2 versus a Li-metal anode shows improved stability, allowing cycling of a LiFePO4–Li-metal solid-state cell at room temperature with a Coulombic efficiency of 99.9%. Tailoring the local interface environment between the inorganic and organic solid electrolyte components in hybrid solid electrolytes seems to be a viable route towards designing highly conducting hybrid solid electrolytes.NMR measurements show that the interface between the inorganic and organic components can be tailored to design a highly conducting hybrid solid electrolyte.
Selectivity in Ru-catalyzed levulinic acid (LA) hydrogenation depends strongly on support type. Ru/TiO2 is highly selective for γ-valerolactone and very stable even in neat LA, while ...zeolite-supported catalysts give pentanoic acid in 45.8% yield in a one-pot conversion. Dealumination causes gradual deactivation. Display omitted
► A direct, one-pot conversion of levulinic acid to pentanoic acid with zeolite-supported Ru catalysts. ► Ru/TiO2 shows excellent selectivity to GVL and remarkable stability. ► Support dealumination is mainly responsible for gradual catalyst deactivation. ► Coke buildup in H-ZSM5 is found to occur preferentially in the zigzag channels.
The catalytic performance of 1wt% Ru-based catalysts in the hydrogenation of levulinic acid (LA) has been studied at 40bar H2 and 473K. This was done by assessing the influence of the support acidity (i.e., Nb2O5, TiO2, H-β, and H-ZSM5) and solvent (i.e., dioxane, 2-ethylhexanoic acid (EHA), and neat LA). The Ru/TiO2 gave excellent selectivity to γ-valerolactone (GVL) (97.5%) at 100% conversion and was remarkably stable even under severe reaction conditions. Ru/H-ZSM5 showed a 45.8% yield of pentanoic acid (PA) and its esters in dioxane, which is the first example of this one-pot conversion directly from LA at 473K. The gradual deactivation of zeolite-supported catalysts in EHA and neat LA was mainly caused by dealumination, as confirmed by 27Al MAS NMR. Coke buildup originated from angelicalactone and, remarkably, occurred preferentially in the zigzag channels of H-ZSM5 as shown by systematic shifts in the XRD patterns. The GVL ring-opening step is considered to be the rate-determining step on the pathway to PA, necessitating an acidic support.
Abstract
BACKGROUND
Radiosurgery is the main alternative to microsurgical resection for benign meningiomas.
OBJECTIVE
To assess the long-term efficacy and safety of radiosurgery for meningiomas with ...respect to tumor growth and prevention of associated neurological deterioration. Medium- to long-term outcomes have been widely reported, but no large multicenter series with long-term follow-up have been published.
METHODS
From 15 participating centers, we performed a retrospective observational analysis of 4565 consecutive patients harboring 5300 benign meningiomas. All were treated with Gamma Knife radiosurgery at least 5 years before assessment for this study. Clinical and imaging data were retrieved from each center and uniformly entered into a database by 1 author (A.S.).
RESULTS
Median tumor volume was 4.8 cm3, and median dose to tumor margin was 14 Gy. All tumors with imaging follow-up > 24 months were excluded. Detailed results from 3768 meningiomas (71%) were analyzed. Median imaging follow-up was 63 months. The volume of treated tumors decreased in 2187 lesions (58%), remained unchanged in 1300 lesions (34.5%), and increased in 281 lesions (7.5%), giving a control rate of 92.5%. Only 84 (2.2%) enlarging tumors required further treatment. Five- and 10-year progression-free survival rates were 95.2% and 88.6%, respectively. Tumor control was higher for imaging defined tumors vs grade I meningiomas (P > .001), for female vs male patients (P > .001), for sporadic vs multiple meningiomas (P > .001), and for skull base vs convexity tumors (P > .001). Permanent morbidity rate was 6.6% at the last follow-up.
CONCLUSION
Radiosurgery is a safe and effective method for treating benign meningiomas even in the medium to long term.
Aims
Inhibition of sodium–glucose co‐transporter 2 (SGLT2) reduces the risk of death and heart failure (HF) admissions in patients with chronic HF. However, safety and clinical efficacy of SGLT2 ...inhibitors in patients with acute decompensated HF are unknown.
Methods and results
In this randomized, placebo‐controlled, double‐blind, parallel group, multicentre pilot study, we randomized 80 acute HF patients with and without diabetes to either empagliflozin 10 mg/day or placebo for 30 days. The primary outcomes were change in visual analogue scale (VAS) dyspnoea score, diuretic response (weight change per 40 mg furosemide), change in N‐terminal pro brain natriuretic peptide (NT‐proBNP), and length of stay. Secondary outcomes included safety and clinical endpoints. Mean age was 76 years, 33% were female, 47% had de novo HF and median NT‐proBNP was 5236 pg/mL. No difference was observed in VAS dyspnoea score, diuretic response, length of stay, or change in NT‐proBNP between empagliflozin and placebo. Empagliflozin reduced a combined endpoint of in‐hospital worsening HF, rehospitalization for HF or death at 60 days compared with placebo 4 (10%) vs. 13 (33%); P = 0.014. Urinary output up until day 4 was significantly greater with empagliflozin vs. placebo difference 3449 (95% confidence interval 578–6321) mL; P < 0.01. Empagliflozin was safe, well tolerated, and had no adverse effects on blood pressure or renal function.
Conclusions
In patients with acute HF, treatment with empagliflozin had no effect on change in VAS dyspnoea, diuretic response, NT‐proBNP, and length of hospital stay, but was safe, increased urinary output and reduced a combined endpoint of worsening HF, rehospitalization for HF or death at 60 days.
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