The lowest singlet-triplet excitation energy of BN: a converged coupled cluster perspective

The notoriously small $X ^3\Pi-a ^1\Sigma^+$ excitation energy of the BN diatomic has been calculated using high-order coupled cluster methods. Convergence has been established in both the 1-particle basis set and the coupled cluster expansion. Explicit inclusion of connected quadruple excitations $\hat{T}_4$ is required for even semiquantitative agreement with the limit value, while connected quintuple excitations $\hat{T}_5$ still have an effect of about 60 cm$^{-1}$. Still higher excitations only account for about 10 cm$^{-1}$. Inclusion of inner-shell correlation further reduces $T_e$ by about 60 cm$^{-1}$ at the CCSDT, and 85 cm$^{-1}$ at the CCSDTQ level. Our best estimate, $T_e$=183$\pm$40 cm$^{-1}$, is in excellent agreement with earlier calculations and experiment, albeit with a smaller (and conservative) uncertainty. The dissociation energy of BN($X ^3\Pi$) is $D_e$=105.74$\pm$0.16 kcal/mol and $D_0$=103.57$\pm$0.16 kcal/mol.Comment: J. Chem. Phys., in pres

Multichannel interference mitigation methods in radio astronomy

Radio-astronomical observations are increasingly corrupted by RF interference, and online detection and filtering algorithms are becoming essential. To facilitate the introduction of such techniques into radio astronomy, we formulate the astronomical problem in an array signal processing language, and give an introduction to some elementary algorithms from that field. We consider two topics in detail: interference detection by rank estimation of short-term covariance matrices, and spatial filtering by subspace estimation and projection. We discuss experimental data collected at the Westerbork radio telescope, and illustrate the effectiveness of the space-time detection and blanking process on the recovery of a 3C48 absorption line in the presence of GSM mobile telephony interference.Comment: 39 pages, 18 figures.Enhanced figures can be downloaded from http://cas.et.tudelft.nl/~leshem/postscripts/leshem/figs34567.ps.gz To appear in Astrophysical Journal Supplements serie

Comment on: "Estimating the Hartree-Fock limit from finite basis set calculations" [Jensen F (2005) Theor Chem Acc 113:267]

We demonstrate that a minor modification of the extrapolation proposed by Jensen [(2005): Theor Chem Acc 113:267] yields very reliable estimates of the Hartree-Fock limit in conjunction with correlation consistent basis sets. Specifically, a two-point extrapolation of the form $E_{HF,L}=E_{HF,\infty}+A(L+1)\exp(-9\sqrt{L})$ yields HF limits $E_{HF,\infty}$ with an RMS error of 0.1 millihartree using aug-cc-pVQZ and aug-cc-pV5Z basis sets, and of 0.01 millihartree using aug-cc-pV5Z and aug-cc-pV6Z basis sets.Comment: Theoretical Chemistry Accounts, in pres

Design, construction and testing of a COC 3D flow-over flow-through bioreactor for hepatic cell culture

In this poster, we present the joint development efforts for a 3D microfluidic bioreactor for hepatic cell cultures. Cyclic Olefin Copolymer (COC) was selected for constructing the bioreactor, since the material has good chemical resistance, low adsorption and good optical properties, including low auto-fluorescence. A downside of COC is that it is much more difficult to structure than more traditional microfluidic materials, such as PDMS, PMMA, … Two parallel approaches were developed for structuring the COC. In a first approach, mechanical micro-milling of the channels allows for extremely fast manufacturing of new design variations, at the expense of difficulties in scalability to mass-production and a channel surface that requires post-processing to achieve sufficient optical quality. In a second approach, hot embossing using epoxy molds allows for direct structuring of optical grade channels and is scalable to mass production, at the expense of longer cycle time in the development of new channel designs. To facilitate the handling of the bioreactor, a holder was designed to provide the fluidic connections to a pump,ensuring medium exchange and sampling to down-stream sensors connected to the outlets. The design of the bioreactor was intended to maintain and expose pre-formed hepatic co-culture spheroids to toxicants for more than a week. Once seeded, spheroids rest on a polycarbonate membrane with 12 µm pore size, allowing the medium to flow-through, while flow-over is maintained to avoid an excess pressure on the cells. In a single bioreactor, 9 wells are connected to a common inlet to provide the cells with fresh culture medium or test compounds. On a first cell culture trial, it was possible to visually detect the spheroids in the wells after seeding, however, after 1 week of culture there was no possibility to accurately detect the presence and viability of the cells. In the framework of HeMiBio, significant progress has been made towards producing a 3D COC-based bioreactor for hepatic cell culture, and most technological hurdles in producing prototype reactors have been overcome. Further testing is needed to see which improvements to the reactor or the flow conditions should be made to ensure cell viability

N=1 G_2 SYM theory and Compactification to Three Dimensions

We study four dimensional N=2 G_2 supersymmetric gauge theory on R^3\times S^1 deformed by a tree level superpotential. We will show that the exact superpotential can be obtained by making use of the Lax matrix of the corresponding integrable model which is the periodic Toda lattice based on the dual of the affine G_2 Lie algebra. At extrema of the superpotential the Seiberg-Witten curve typically factorizes, and we study the algebraic equations underlying this factorization. For U(N) theories the factorization was closely related to the geometrical engineering of such gauge theories and to matrix model descriptions, but here we will find that the geometrical interpretation is more mysterious. Along the way we give a method to compute the gauge theory resolvent and a suitable set of one-forms on the Seiberg-Witten curve. We will also find evidence that the low-energy dynamics of G_2 gauge theories can effectively be described in terms of an auxiliary hyperelliptic curve.Comment: 27 pages, late

In2_{2}O3_{3}:H-Based Hole-Transport-Layer-Free Tin/Lead Perovskite Solar Cells for Efficient Four-Terminal All-Perovskite Tandem Solar Cells

Narrow-band gap (NBG) Sn–Pb perovskites with band gaps of ∼1.2 eV, which correspond to a broad photon absorption range up to ∼1033 nm, are highly promising candidates for bottom solar cells in all-perovskite tandem photovoltaics. To exploit their potential, avoiding optical losses in the top layer stacks of the tandem configuration is essential. This study addresses this challenge in two ways (1) removing the hole-transport layer (HTL) and (2) implementing highly transparent hydrogen-doped indium oxide In2O3:H (IO:H) electrodes instead of the commonly used indium tin oxide (ITO). Removing HTL reduces parasitic absorption loss in shorter wavelengths without compromising the photovoltaic performance. IO:H, with an ultra-low near-infrared optical loss and a high charge carrier mobility, results in a remarkable increase in the photocurrent of the semitransparent top and (HTL-free) NBG bottom perovskite solar cells when substituted for ITO. As a result, an IO:H-based four-terminal all-perovskite tandem solar cell (4T all-PTSCs) with a power conversion efficiency (PCE) as high as 24.8% is demonstrated, outperforming ITO-based 4T all-PTSCs with PCE up to 23.3%

Immune Modulation by Design: Using Topography to Control Human Monocyte Attachment and Macrophage Differentiation

© 2020 The Authors. Published by WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim Macrophages play a central role in orchestrating immune responses to foreign materials, which are often responsible for the failure of implanted medical devices. Material topography is known to influence macrophage attachment and phenotype, providing opportunities for the rational design of “immune-instructive” topographies to modulate macrophage function and thus foreign body responses to biomaterials. However, no generalizable understanding of the inter-relationship between topography and cell response exists. A high throughput screening approach is therefore utilized to investigate the relationship between topography and human monocyte–derived macrophage attachment and phenotype, using a diverse library of 2176 micropatterns generated by an algorithm. This reveals that micropillars 5–10µm in diameter play a dominant role in driving macrophage attachment compared to the many other topographies screened, an observation that aligns with studies of the interaction of macrophages with particles. Combining the pillar size with the micropillar density is found to be key in modulation of cell phenotype from pro to anti-inflammatory states. Machine learning is used to successfully build a model that correlates cell attachment and phenotype with a selection of descriptors, illustrating that materials can potentially be designed to modulate inflammatory responses for future applications in the fight against foreign body rejection of medical devices

Genome analysis of the necrotrophic fungal pathogens Sclerotinia sclerotiorum and Botrytis cinerea

Sclerotinia sclerotiorum and Botrytis cinerea are closely related necrotrophic plant pathogenic fungi notable for their wide host ranges and environmental persistence. These attributes have made these species models for understanding the complexity of necrotrophic, broad host-range pathogenicity. Despite their similarities, the two species differ in mating behaviour and the ability to produce asexual spores. We have sequenced the genomes of one strain of S. sclerotiorum and two strains of B. cinerea. The comparative analysis of these genomes relative to one another and to other sequenced fungal genomes is provided here. Their 38–39 Mb genomes include 11,860–14,270 predicted genes, which share 83% amino acid identity on average between the two species. We have mapped the S. sclerotiorum assembly to 16 chromosomes and found large-scale co-linearity with the B. cinerea genomes. Seven percent of the S. sclerotiorum genome comprises transposable elements compared t