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This paper provides an overview of the new features of the finite element library deal.II, version 9.5. [ABSTRACT FROM AUTHOR]

This paper is concerned with the approximation of the compressible Euler equations supplemented with an arbitrary or tabulated equation of state. The proposed approximation technique is robust, formally second-order accurate in space, invariant-domain preserving, and works for every equation of state, tabulated or analytic, provided the pressure is nonnegative. An entropy surrogate functional that grows across shocks is proposed. The numerical method is verified with novel analytical solutions and then validated with several computational benchmarks seen in the literature including problems with composite waves. • Approximation technique for the compressible Euler equations supplemented with an arbitrary or tabulated equation of state. • The method is verified with novel analytical solutions and validated with computational benchmarks from the literature. [ABSTRACT FROM AUTHOR]

This paper describes in detail the implementation of a finite element technique for solving the compressible Navier–Stokes equations that is provably robust and demonstrates excellent performance on modern computer hardware. The method is second-order accurate in time and space. Robustness here means that the method is proved to be invariant domain preserving under the hyperbolic CFL time step restriction, and the method delivers results that are reproducible. The proposed technique is shown to be accurate on challenging 2D and 3D realistic benchmarks. • Second-order accurate Finite element solver for the compressible Navier-Stokes equations. • Provable invariant-domain preservation under the hyperbolic CFL time step restriction. • Detailed treatment of robust, invariant-domain preserving boundary conditions. • Demonstrated accuracy and scalability of the method on parallel computer architectures. • Source code and test vectors have been made available to allow comparison of methods. [ABSTRACT FROM AUTHOR]

deal.II is a state-of-the-art finite element library focused on generality, dimension-independent programming, parallelism, and extensibility. Herein, we outline its primary design considerations and its sophisticated features such as distributed meshes, h p -adaptivity, support for complex geometries, and matrix-free algorithms. But deal.II is more than just a software library: It is also a diverse and worldwide community of developers and users, as well as an educational platform. We therefore also discuss some of the technical and social challenges and lessons learned in running a large community software project over the course of two decades. [ABSTRACT FROM AUTHOR]

Despite the great success of the concept of doping organic compounds with BN units to access new materials with tailored properties, its use in polymer chemistry has only been realized quite recently. Herein, we present a comprehensive study of oligo- and poly(arylene iminoborane)s comprising a backbone of phenylene or thiophene moieties, as well as combinations thereof, linked via B=N units. The novel polymers can be regarded as BN analogues of poly(p-phenylene vinylene) (PPV) or poly(thiophene vinylene) (PTV) or their copolymers. Our modular synthetic approach allowed us to prepare four polymers and 12 monodisperse oligomers with modulated electronic properties. Alternating electron-releasing diaminoarylene and electron-accepting diborylarylene building blocks gave rise to a pronounced donor-acceptor character. Effective π-conjugation over the arylene iminoborane backbone is evidenced by systematic bathochromic shifts of the low-energy UV-vis absorption maximum with increasing chain length, which is furthermore supported by crystallographic and computational investigations. Furthermore, all compounds investigated show emission of visible light in the solid state and aggregation-induced emission (AIE) behavior, due to the presence of partially flexible linear B=N linkages in the backbone., (© 2023 The Authors. Chemistry - A European Journal published by Wiley-VCH GmbH.)

An unprecedented poly(thiophene iminoborane)-a boron-nitrogen analogue of the well-established conjugated organic polymer poly(thiophene vinylene)-is presented. The polymer synthesis is achieved by selective Si/B exchange polycondensation of a 2,5-diborylthiophene with a 2,5-diaminothiophene derivative. For the latter, a facile synthetic strategy is devised, which makes this versatile, strongly electron-releasing building block easily accessible. The novel polymer and a series of monodisperse thiophene iminoborane oligomers reveal systematic bathochromic shifts in their absorption with increasing chain length, and thus extended π-conjugation over the BN units along the backbone, which is further supported by TD-DFT calculations., (© 2023 The Authors. Macromolecular Rapid Communications published by Wiley-VCH GmbH.)

Treatment of an N -silyl- B -chloro-aminoborane with substoichio-metric quantities of Me 3 SiOTf afforded B-N coupling, whereas activation with 5 mol% of Ag[Al{OC(CF 3 ) 3 } 4 ] led to Cl/Me exchange between the boron and the silicon center. Combined experimental and computational studies of the latter process support a chain reaction that is initiated by nucleation-limited chloride abstraction.

Competing Interests: Disclosure The authors report no conflicts of interest in this work.

Background: The clinical effectiveness of fecal microbiota transplant (FMT) for the treatment of recurrent Clostridium difficile infections (rCDI) has been demonstrated in randomized controlled trials. To assess the current status of FMT in Germany with respect to active centers, local standards, clinical effectiveness and safety, the MicroTrans Registry (NCT02681068) was established., Methods: In a long-term retrospective multicenter observational study by the German Clinical Microbiome Study Group (GCMSG), primary and secondary cure on day 30 and 90, as well as occurrence of treatment-related adverse events were assessed. In addition to patient demographic data, we provide an overview of the FMT procedures and techniques used at different centers., Results: Overall, 133 eligible patients from 33 centers were included, of which 64.7% were female (n = 86). The mean age was 75 years (interquartile range: 59.5-81.5). Administration via the duodenal route (n = 59; 44.4%) was the most frequently applied option, followed by colonic (n = 55; 41.1%), capsule (n = 13; 9.8%), and gastric administration (n = 4; 3.0%). Primary cure on day 30 and 90 was achieved in 84.2% (n = 101/120) and 78.3% (n = 72/92) of patients, respectively. Including re-treatment, secondary response was achieved in 87.5% (d 30; n = 105/120) and 85.9% (d 90; n = 79/92), respectively. Treatment- elated adverse events were documented in 16 patients (12.0%)., Conclusion: FMT is a safe and effective treatment option for rCDI. However, FMT is currently available only in few centers in Germany, and treatment options vary from one center to another.

We present a rare cause of cervical myelopathy produced by an engorged suboccipital epidural venous plexus due to chronic cerebrospinal fluid (CSF) overdrainage. A 17-year-old boy with obstructive hydrocephalus due to a retrocerebellar cyst and secondary implantation of a ventricloperitoneal shunt (VP-shunt) presented with progressive spastic tetraparesis. MRI imaging revealed myelopathy due to significant compression of the cervical spinal cord by engorged epidural veins. Further assessment at a low-pressure setting revealed a broken shunt valve. The VP-shunt valve was changed with an additional anti-siphon device leading to a gradual increase of the intracranial pressure (ICP). After intensive physiotherapy, the patient showed slight clinical improvement. Follow-up imaging within nine days showed distinct regression of the dilated venous plexus at the cranial-cervical junction (CCJ) with the resolution of cord compression. Engorgement of the epidural venous plexus should always be considered in the differential diagnosis of myelopathy in long-term shunt patients even when classical clinical and radiological signs of overshunting are missing.