212 research outputs found
Terephthalic acid–4,4′-bipyridine (2/1)
In the title compound, 2C8H6O4·C10H8N2, the 4,4′-bipyridine molecule is located on an inversion centre. In the crystal structure, strong intermolecular O—H⋯N hydrogen bonds between the terephthalic acid and 4,4′-bipyridine molecules lead to the formation of chains with graph-set motif C
2
2(8) along the diagonal of the bc plane
catena-Poly[[bis(p-toluenesulfonato-κO)palladium(II)]bis(μ-1,3-di-4-pyridylpropane-κ2 N:N′)]
In the title compound, [Pd(C7H7O3S)2(C13H14N2)2]n, the metal ion, located on a twofold rotation axis, exhibits a slightly distorted octahedral coordination environment, with bond angles that deviate by at most 2.2° from an ideal geometry, completed by two O atoms from two deprotonated p-toluenesulfonic acid ligands and four N atoms from four 1,3-di-4-pyridylpropane ligands. One of the sulfonate O atoms is disordered over two positions [ratio 0.70 (5):0.30 (5)]
Bis(ethanolato-κO)(5,10,15,20-tetraphenylcalix[4]pyrrole)manganese(III) hexafluorophosphate
The title compound, [Mn(C2H5O)2(C44H28N4)]PF6, was synthesized from manganese(III) 2,4-pentanedionate and 5,10,15,20-tetraphenylcalix[4]pyrrole by a hydrothermal reaction. The MnIII atom is located on an inversion centre and the asymmetric unit comprises one half-formula unit. The MnIII ion is hexacoordinated by four N atoms from one 5,10,15,20-tetraphenylcalix[4]pyrrole ligand and two O atoms from two deprotonated ethanol molecules. The equatorially located atoms (the Mn and four N atoms) are planar. The dihedral angles between the planes of the phenyl rings and the equatorial plane are 53.3 (2) and 81.8 (2)°. One hexafluorophosphate anion balances the charge
Melatonin modulates the effects of diethylstilbestrol (DES) on the anterior pituitary of the female Wistar rat.
We studied the anti-tumorigenic effect of melatonin in diethylstilbestrol (DES)-treated anterior pituitaries in rats. Twenty-one female Wistar rats were randomly allocated into three groups: vehicle control rats, DES-treated rats, and DES-treated rats co-administrated with melatonin beginning at week 13. At the end of 16 weeks, rats were weighed and decapitated for morphological studies, including an H+E staining-based score evaluation in regard to cell proliferation, angiogenesis, immunostaining for VEGF, MMP-9, and AQP-1, and electron microscopy. Compared with vehicle, long-term treatment of DES significantly reduced rat body weight and increased H+E score, both of which were counteracted by melatonin. Administration of melatonin also reduced the expression of VEGF and MMP-9, although no changes were detected in AQP-1 expression. In rats cotreated with melatonin, the RER loosened and accumulated more secretion granules. We thus concluded that melatonin can modulate the effects of DES on the rat anterior pituitary by downregulating expression of VEGF and MMP-9 and suppressing the release of secretion granules, suggesting a therapeutic potential in estrogen-induced pituitary malfunctions
Biomass-derived carbon material as efficient electrocatalysts for the oxygen reduction reaction
Despite the abundance of carbon in nature, a significant portion of the existing biomass carbon materials in livestock, agriculture, and marine fishery industry are currently being wasted. Utilizing sustainable carbon materials as an alternative to noble Pt-based catalysts is crucial step to convert widely available and low-cost biomass resources into clean energy systems. Therefore, the rational synthesis of carbon-based catalysts for oxygen reduction reaction (ORR) has become a hot research focus in the field of electrochemistry. In this study, the recent progress in the synthesis of ORR electrocatalysts using sustainable biomass resources was reviewed; the activation and synthesis strategies of various biomass resources, as well as the microstructure and oxygen reduction performance of the prepared carbon-based catalysts were investigated. It is hoped that this review article will promote the understanding of various parameters from biomass as precursors for catalyst preparation and make contribute to the transition of biomass resources from the wasted carbon materials to the main catalysts in future energy devices.</p
PDT: Pretrained Dual Transformers for Time-aware Bipartite Graphs
Pre-training on large models is prevalent and emerging with the ever-growing
user-generated content in many machine learning application categories. It has
been recognized that learning contextual knowledge from the datasets depicting
user-content interaction plays a vital role in downstream tasks. Despite
several studies attempting to learn contextual knowledge via pre-training
methods, finding an optimal training objective and strategy for this type of
task remains a challenging problem. In this work, we contend that there are two
distinct aspects of contextual knowledge, namely the user-side and the
content-side, for datasets where user-content interaction can be represented as
a bipartite graph. To learn contextual knowledge, we propose a pre-training
method that learns a bi-directional mapping between the spaces of the user-side
and the content-side. We formulate the training goal as a contrastive learning
task and propose a dual-Transformer architecture to encode the contextual
knowledge. We evaluate the proposed method for the recommendation task. The
empirical studies have demonstrated that the proposed method outperformed all
the baselines with significant gains
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