Loss of control in pattern-directed nucleation: a theoretical study

The properties of template-directed nucleation are studied close to the transition where full nucleation control is lost and additional nucleation occurs beyond the pre-patterned regions. First, kinetic Monte Carlo simulations are performed to obtain information on a microscopic level. Here the experimentally relevant cases of 1D stripe patterns and 2D square lattice symmetry are considered. The nucleation properties in the transition region depend in a complex way on the parameters of the system, i.e. the flux, the surface diffusion constant, the geometric properties of the pattern and the desorption rate. Second, the properties of the stationary concentration field in the fully controlled case are studied to derive the remaining nucleation probability and thus to characterize the loss of nucleation control. Using the analytically accessible solution of a model system with purely radial symmetry, some of the observed properties can be rationalized. A detailed comparison to the Monte Carlo data is included

Dynamic effects on the loss of control in template-directed nucleation

Full nucleation control for deposited functional molecules on pre-patterned surfaces is of major technological relevance. To understand the nucleation behavior we combine the numerical solution for the evolution of the adatom concentration with standard nucleation theory. From the qualitative change in nucleation behavior upon variation of the pattern spacing and coverage we show why the quality of nucleation control can vary significantly in different parameter regimes. In some limits analytical expressions can be formulated for the nucleation control. Our analysis provides a theoretical explanation for previous experimental observations [Wang et al, PRL 98, 225504 (2007)]

Networks of free-living nematodes and co-extracted fungi, associated with symptoms of apple replant disease

Apple replant disease affects tree nurseries and apple production globally. After repeated planting in the same soil, apple roots show accumulation of phytoalexins, stunting, and blackening. Recently, we showed that nematodes extracted from replanted soil and co-extracted microbes triggered these symptoms, while pathogens or plant-parasitic nematodes could not explain the early disease development. To identify nematode-microbe complexes that coincide with replant disease, apple rootstocks were grown in the greenhouse in soils from five replanted sites for eight weeks. Nematodes were extracted by floatation from pots with stunted or normal plant growth, washed on a 20-μm sieve, and used for DNA extraction. Nematode communities and co-extracted fungi and bacteria were analyzed by high-throughput sequencing of amplified ribosomal fragments. The experiment was repeated in the next year. Regardless of soil type or year, the nematode and fungal communities significantly differed between pots with differential plant growth. Bacteria were not significantly associated with growth depression. Plant-parasitic nematodes or pathogens were not abundant in numbers that could explain the observed root damage. Free-living nematodes Prsimatolaimus, Acrobeles, Tylencholaimus, Acrobeloides, and Aphelenchus, and associated fungi Exophiala, Hohenbuehelia, Naganishia, Psathyrella, and unidentified members of Orbiliales, Helotiales, and Rhytismataceae significantly correlated with reduced plant growth. Isolating and investigating such disease complexes will give a chance to understand external biotic stress of apple roots and design mitigation measures. © 2021 The Author

KEM Combiners

Key-encapsulation mechanisms (KEMs) are a common stepping stone for constructing public-key encryption. Secure KEMs can be built from diverse assumptions, including ones related to integer factorization, discrete logarithms, error correcting codes, or lattices. In light of the recent NIST call for post-quantum secure PKE, the zoo of KEMs that are believed to be secure continues to grow. Yet, on the question of which is the most secure KEM opinions are divided. While using the best candidate might actually not seem necessary to survive everyday life situations, placing a wrong bet can actually be devastating, should the employed KEM eventually turn out to be vulnerable. We introduce KEM combiners as a way to garner trust from different KEM constructions, rather than relying on a single one: We present efficient black-box constructions that, given any set of `ingredient\u27 KEMs, yield a new KEM that is (CCA) secure as long as at least one of the ingredient KEMs is. As building blocks our constructions use cryptographic hash functions and blockciphers. Some corresponding security proofs require idealized models for these primitives, others get along on standard assumptions

Standard Security Does Imply Security Against Selective Opening for Markov Distributions

About three decades ago it was realized that implementing private channels between parties which can be adaptively corrupted requires an encryption scheme that is secure against selective opening attacks. Whether standard (IND-CPA) security implies security against selective opening attacks has been a major open question since. The only known reduction from selective opening to IND-CPA security loses an exponential factor. A polynomial reduction is only known for the very special case where the distribution considered in the selective opening security experiment is a product distribution, i.e., the messages are samples independent from each other. In this paper we give a reduction whose loss is quantified via the dependence graph (where message dependencies correspond to edges) of the underlying message distribution. In particular, for some concrete distributions including Markov distributions, our reduction is polynomial

Hybrid material additive manufacturing: interlocking interfaces for fused filament fabrication on laser powder bed fusion substrates

The fabrication of polymer–metal hybrids in an additive process makes it possible to further improve the geometrical and material adaption in a multi-material design. In this work, PLA is fabricated through a fused filament fabrication process on AlSi10Mg structures manufactured by laser powder bed fusion. The mechanical connection is realised by form fit, for which different geometries are examined through tensile tests. Deep penetration of the PLA into the metallic structures is achieved by optimisation of the process parameters. The penetration depth is assessed through the use of micro-computed tomography. Finally, the interplay of mechanisms leading to a firm connection is discussed

Inter-kingdom Signaling by the Legionella Quorum Sensing Molecule LAI-1 Modulates Cell Migration through an IQGAP1-Cdc42-ARHGEF9-Dependent Pathway

Small molecule signaling promotes the communication between bacteria as well as between bacteria and eukaryotes. The opportunistic pathogenic bacterium Legionella pneumophila employs LAI-1 (3-hydroxypentadecane-4-one) for bacterial cell-cell communication. LAI-1 is produced and detected by the Lqs (Legionella quorum sensing) system, which regulates a variety of processes including natural competence for DNA uptake and pathogen-host cell interactions. In this study, we analyze the role of LAI-1 in inter-kingdom signaling. L. pneumophila lacking the autoinducer synthase LqsA no longer impeded the migration of infected cells, and the defect was complemented by plasmid-borne lqsA. Synthetic LAI-1 dose-dependently inhibited cell migration, without affecting bacterial uptake or cytotoxicity. The forward migration index but not the velocity of LAI-1-treated cells was reduced, and the cell cytoskeleton appeared destabilized. LAI-1-dependent inhibition of cell migration involved the scaffold protein IQGAP1, the small GTPase Cdc42 as well as the Cdc42-specific guanine nucleotide exchange factor ARHGEF9, but not other modulators of Cdc42, or RhoA, Rac1 or Ran GTPase. Upon treatment with LAI-1, Cdc42 was inactivated and IQGAP1 redistributed to the cell cortex regardless of whether Cdc42 was present or not. Furthermore, LAI-1 reversed the inhibition of cell migration by L. pneumophila, suggesting that the compound and the bacteria antagonistically target host signaling pathway(s). Collectively, the results indicate that the L. pneumophila quorum sensing compound LAI-1 modulates migration of eukaryotic cells through a signaling pathway involving IQGAP1, Cdc42 and ARHGEF9

Routinedaten aus notaufnahmen: unterschiedliche dokumentationsanforderungen, abrechnungsmodalitäten und datenhalter bei identischem ort der leistungserbringung / Routine data from emergency departments: varying documentation standards, billing modalities and data custodians at an identical unit of care

[German abstract] Hintergrund Nicht nur im Kontext der Neuordnung der Notfallversorgung in Deutschland besteht derzeit ein hoher Bedarf an Daten aus Notaufnahmen. Für die Versorgungsforschung bieten sich Daten an, welche auf gesetzlicher Grundlage generiert werden. Unterschiedliche Kostenträger und Abrechnungsmodi stellen eigene Anforderungen an die Dokumentation dieser Routinedaten. Methodische Herausforderungen Aufgrund der sektoralen Trennung gibt es keinen Datensatz oder Datenhalter, der Auskunft über alle Notaufnahmebehandlungen geben kann. Aus administrativer Sicht gilt die gesamte Notaufnahmebehandlung als ambulant oder stationär, tatsächlich wird die Entscheidung darüber erst während der Versorgung getroffen. Für die stationäre Versorgung existiert ein administratives Notfallkennzeichen, allerdings kein direktes Merkmal für Notaufnahmebehandlungen. Bei Abrechnung ambulanter Fälle über die kassenärztlichen Vereinigungen ist mindestens eine Diagnose (ICD-10-Kode) zu erfassen, versehen mit einem Kennzeichen zur Diagnosesicherheit. Es können mehrere ICD-10-Kodes ohne Hierarchie angegeben werden. Bei stationär behandelten Patienten ist eine Aufnahmediagnose und nach Behandlungsende die Hauptdiagnose und ggf. Nebendiagose(n) an die zuständige Krankenkasse zu übermitteln. Die gesetzliche Unfallversicherung hat eigene Dokumentationsanforderungen. Lösungsansätze Je nach Forschungsfrage und Studiendesign sind unterschiedliche Vorgehensweisen erforderlich. Stammen die Daten unmittelbar aus Notaufnahmen bzw. Kliniken ist eine Information über den Kostenträger und den Abrechnungsmodus hilfreich. Bei Nutzung von Krankenkassendaten muss die Identifikation von stationär behandelten Patienten in einer Notaufnahme aktuell indirekt erfolgen. Dazu können unter anderem die Parameter Aufnahmegrund und definierte „eindeutige“ Notfall-Diagnosen herangezogen werden. Die fallpauschalenbezogene Krankenhausstatistik hat eigene Limitationen, enthält dafür aber die stationären Fälle aller Kostenträger. Diskussion Die divergierenden Anforderungen an die administrative Dokumentation verursachen einen hohen Aufwand in den Kliniken. Perspektivisch ist eine Vereinheitlichung der Leistungserfassung und Dokumentation von Notfallbehandlungen aller Kostenarten auch zur Generierung von validen, vergleichbaren und repräsentativen Daten für die Versorgungsforschung erstrebenswert. Die Einführung eines eigenen Fachabteilungsschlüssels würde zur Identifikation von Notaufnahmebehandlungen beitragen. [English abstract] Background Currently, there is a big need for data on emergency department (ED) utilization in Germany. One reason is the ongoing reorganisation of emergency care. Possible sources are routine data that are being collected based on legal regulations. Different payers and compensation systems have their own requirements for data collection. Methodological challenges Due to the sectoral separation of health care services, there is no dataset or data holder to provide information on all ED treatments in Germany. From an administrative point of view, emergency care in Germany is considered ambulatory outpatient or inpatient care from the time point of admission to the ED. In contrast, clinical decision about inpatient admission can sometimes only be made towards the end of emergency care. EDs themselves cannot be identified in claims data; only the medical discipline (e. g. surgery) is classified. In the case of outpatient treatment, reimbursed by the Association of Statutory Health Insurance Physicians, at least one coded diagnosis (ICD) has to be recorded, accompanied by an additional code for the likelihood of this diagnosis. In case of multiple ICDs, a primary diagnosis cannot be specified. In the case of in-hospital treatment, an admission diagnosis must be recorded. After completion of hospital treatment, the main diagnosis and possibly secondary diagnoses are transferred to the respective health insurance fund. The statutory occupational accident insurance has its own requirements. Solutions Depending on the research question and study design, different approaches are required. If data are queried directly in emergency departments or hospitals, additional information on the designated data holder and billing mode is crucial. When using health insurance data from inpatient care, the identification of emergency departments can be estimated on the basis of the reason for hospital admission and defined "unique" emergency ICDs. The case-related hospital statistics has its own limitations, but includes inpatients of all payers. Discussion Differing requirements for the administrative documentation cause a high workload in emergency departments. A standardised data collection system for all payers for inpatient and outpatient emergency care is recommended. This would contribute to the creation of valid and comparable datasets. The introduction of a particular identifier for EDs in claims data would enhance health services research

From fossils to mind

Fossil endocasts record features of brains from the past: size, shape, vasculature, and gyrification. These data, alongside experimental and comparative evidence, are needed to resolve questions about brain energetics, cognitive specializations, and developmental plasticity. Through the application of interdisciplinary techniques to the fossil record, paleoneurology has been leading major innovations. Neuroimaging is shedding light on fossil brain organization and behaviors. Inferences about the development and physiology of the brains of extinct species can be experimentally investigated through brain organoids and transgenic models based on ancient DNA. Phylogenetic comparative methods integrate data across species and associate genotypes to phenotypes, and brains to behaviors. Meanwhile, fossil and archeological discoveries continuously contribute new knowledge. Through cooperation, the scientific community can accelerate knowledge acquisition. Sharing digitized museum collections improves the availability of rare fossils and artifacts. Comparative neuroanatomical data are available through online databases, along with tools for their measurement and analysis. In the context of these advances, the paleoneurological record provides ample opportunity for future research. Biomedical and ecological sciences can benefit from paleoneurology's approach to understanding the mind as well as its novel research pipelines that establish connections between neuroanatomy, genes and behavior