4,699 research outputs found
Hexakis(1H-imidazole-κN 3)nickel(II) bis(3-thienylacetate)
In the title complex, [Ni(C3H4N2)6](C6H5O2S)2, the NiII atom displays an octahedral coordination geometry, defined by six N atoms from the imidazole ligands. Intermolecular N—H⋯O hydrogen-bonding interactions between the cationic complex and 3-thienylacetate anions form a three-dimensional network architecture. The two 3-thienylacetate anions are disordered, with occupancy ratios of circa 0.774 (1):0.226 (1) and ca 0.753 (5):0.247 (5)
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Analysis of interspecies adherence of oral bacteria using a membrane binding assay coupled with polymerase chain reaction-denaturing gradient gel electrophoresis profiling.
Information on co-adherence of different oral bacterial species is important for understanding interspecies interactions within oral microbial community. Current knowledge on this topic is heavily based on pariwise coaggregation of known, cultivable species. In this study, we employed a membrane binding assay coupled with polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) to systematically analyze the co-adherence profiles of oral bacterial species, and achieved a more profound knowledge beyond pairwise coaggregation. Two oral bacterial species were selected to serve as "bait": Fusobacterium nucleatum (F. nucleatum) whose ability to adhere to a multitude of oral bacterial species has been extensively studied for pairwise interactions and Streptococcus mutans (S. mutans) whose interacting partners are largely unknown. To enable screening of interacting partner species within bacterial mixtures, cells of the "bait" oral bacterium were immobilized on nitrocellulose membranes which were washed and blocked to prevent unspecific binding. The "prey" bacterial mixtures (including known species or natural saliva samples) were added, unbound cells were washed off after the incubation period and the remaining cells were eluted using 0.2 mol x L(-1) glycine. Genomic DNA was extracted, subjected to 16S rRNA PCR amplification and separation of the resulting PCR products by DGGE. Selected bands were recovered from the gel, sequenced and identified via Nucleotide BLAST searches against different databases. While few bacterial species bound to S. mutans, consistent with previous findings F. nucleatum adhered to a variety of bacterial species including uncultivable and uncharacterized ones. This new approach can more effectively analyze the co-adherence profiles of oral bacteria, and could facilitate the systematic study of interbacterial binding of oral microbial species
Law Article-Enhanced Legal Case Matching: a Causal Learning Approach
Legal case matching, which automatically constructs a model to estimate the
similarities between the source and target cases, has played an essential role
in intelligent legal systems. Semantic text matching models have been applied
to the task where the source and target legal cases are considered as long-form
text documents. These general-purpose matching models make the predictions
solely based on the texts in the legal cases, overlooking the essential role of
the law articles in legal case matching. In the real world, the matching
results (e.g., relevance labels) are dramatically affected by the law articles
because the contents and the judgments of a legal case are radically formed on
the basis of law. From the causal sense, a matching decision is affected by the
mediation effect from the cited law articles by the legal cases, and the direct
effect of the key circumstances (e.g., detailed fact descriptions) in the legal
cases. In light of the observation, this paper proposes a model-agnostic causal
learning framework called Law-Match, under which the legal case matching models
are learned by respecting the corresponding law articles. Given a pair of legal
cases and the related law articles, Law-Match considers the embeddings of the
law articles as instrumental variables (IVs), and the embeddings of legal cases
as treatments. Using IV regression, the treatments can be decomposed into
law-related and law-unrelated parts, respectively reflecting the mediation and
direct effects. These two parts are then combined with different weights to
collectively support the final matching prediction. We show that the framework
is model-agnostic, and a number of legal case matching models can be applied as
the underlying models. Comprehensive experiments show that Law-Match can
outperform state-of-the-art baselines on three public datasets.Comment: 10 pages accepted by SIGIR202
Diaquabis(4-carboxy-2-propyl-1H-imidazole-5-carboxylato-κ2 N 3,O 4)cobalt(II) N,N-dimethylformamide disolvate
In the title complex, [Co(C8H9N2O4)2(H2O)2]·2C3H7NO, the CoII cation (site symmetry ) is six-coordinated by two 5-carboxy-2-propyl-1H-imidazole-4-carboxylate ligands and two water molecules in a distorted octahedral environment. In the crystal structure, the complex molecules and dimethylformamide solvent molecules are linked by extensive O—H⋯O and N—H⋯O hydrogen bonding into sheets lying parallel to (21)
Aquabis(1H-imidazole-κN 3)bis(4-methylbenzoato-κ2 O,O′)cadmium(II)
In the title compound, [Cd(C8H7O2)2(C3H4N2)2(H2O)], the CdII atom is coordinated by four carboxylate O atoms from two bidentate chelating 4-methylbenzoate ligands, two N atoms from two imidazole ligands and one water molecule in a distorted pentagonal bipyramidal geometry. Intermolecular O—H⋯O hydrogen bonds between the coordinated water molecule and the carboxylate O atoms of 4-methylbenzoate lead to an infinite chain. These chains are further self-assembled into a two-dimensional layer through N—H⋯O hydrogen bonds between the imidazole ligands and carboxylate groups. One of the imidazole ligands is disordered over two positions with site-occupancy factors of 0.737 (4) and 0.263 (4)
Aquabis(4-methylbenzoato)-κO;κ2 O,O′-bis(pyridine-κN)nickel(II)
In the title mononuclear complex, [Ni(C8H7O2)2(C5H5N)2(H2O)], the NiII atom is in a distorted octahedral arrangement, coordinated by three carboxylate O atoms from one bidentate 4-methylbenzoate ligand and one monodentate 4-methylbenzoate ligand, two N atoms from pyridine ligands, axially positioned, and a water molecule. The equatorially positioned water molecule and uncoordinated carboxylate O atom form an intramolecular hydrogen bond. An intermolecular O—H⋯O hydrogen bond between the coordinated water molecule and carboxylate O atom of the 4-methylbenzoate ligand forms infinite chains along the b axis. These chains are connected by C—H⋯π interactions
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