Tetra­imidazolium piperazinediium bis­(benzene-1,3,5-tricarboxyl­ate) dihydrate

During the crystallization of the title compound, 4C3H5N2 +·C4H12N2 +·2C9H3O6 3−·2H2O, the acidic protons were transferred to the imidazole and piperazine N atoms, forming the final 4:1:2:2 hydrated mixed salt. The mean planes of the three carboxyl­ate groups in the anion are twisted with respect to the the central benzene ring, making dihedral angles of 13.5 (1), 14.5 (1) and 16.9 (1)°. In the crystal, the component ions are linked into a three-dimensional network by a combination of inter­molecular N—H⋯O, O—H⋯O and weak C—H⋯O hydrogen bonds. Further stabilization is provided by π-π stacking inter­actions with centroid–centroid distances of 3.393 (2) Å and weak C=O⋯π inter­actions [O–centroid = 3.363 (2) Å]

Contrastive Attention for Automatic Chest X-ray Report Generation

Recently, chest X-ray report generation, which aims to automatically generate descriptions of given chest X-ray images, has received growing research interests. The key challenge of chest X-ray report generation is to accurately capture and describe the abnormal regions. In most cases, the normal regions dominate the entire chest X-ray image, and the corresponding descriptions of these normal regions dominate the final report. Due to such data bias, learning-based models may fail to attend to abnormal regions. In this work, to effectively capture and describe abnormal regions, we propose the Contrastive Attention (CA) model. Instead of solely focusing on the current input image, the CA model compares the current input image with normal images to distill the contrastive information. The acquired contrastive information can better represent the visual features of abnormal regions. According to the experiments on the public IU-X-ray and MIMIC-CXR datasets, incorporating our CA into several existing models can boost their performance across most metrics. In addition, according to the analysis, the CA model can help existing models better attend to the abnormal regions and provide more accurate descriptions which are crucial for an interpretable diagnosis. Specifically, we achieve the state-of-the-art results on the two public datasets.Comment: Appear in Findings of ACL 2021 (The Joint Conference of the 59th Annual Meeting of the Association for Computational Linguistics and the 11th International Joint Conference on Natural Language Processing (ACL-IJCNLP 2021)

Electric field tunable multi-state tunnel magnetoresistances in 2D van der Waals magnetic heterojunctions

Magnetic tunnel junction (MTJ) based on van der Waals (vdW) magnetic layers has been found to present excellent tunneling magnetoresistance (TMR) property, which has great potential applications in field sensing, non-volatile magnetic random access memories, and spin logics. Although MTJs composed of multilayer vdW magnetic homojunctions have been extensively investigated, the ones composed of vdW magnetic heterojunction is still to be explored. Here we use first-principles approaches to reveal that the magnetic heterojunction MTJs have much more distinguishable TMR values than the homojunction ones. In the MTJ composed of bilayer CrI3/bilayer Cr2Ge2Te6 heterojunction, we find there are eight stable magnetic states, leading to seven distinguishable electronic resistances. As a result, six sizable TMRs larger than 600% can be obtained (the maximum TMR is up to 120,000%). The number of distinguishable memories is more than two times larger than that of a four-layered homojunction MTJ. The underlying relationships among magnetic state, spin-polarized band structures, and transmission spectrums are further revealed to explain the multiple TMR values. We also find that the magnetic states and thus TMRs can be efficiently modulated by an external electric field. This study opens an avenue to the design of high-performance MTJ devices based on vdW heterojunctions.Comment: 6 figure

Expression pattern and activity of six glutelin gene promoters in transgenic rice*

The shortage of strong endosperm-specific expression promoters for driving the expression of recombinant protein genes in cereal endosperm is a major limitation in obtaining the required level and pattern of expression. Six promoters of seed storage glutelin genes (GluA-1, GluA-2, GluA-3, GluB-3, GluB-5, and GluC) were isolated from rice (Oryza sativa L.) genomic DNA by PCR. Their spatial and temporal expression patterns and expression potential in stable transgenic rice plants were examined with β-glucuronidase (GUS) used as a reporter gene. All the promoters showed the expected spatial expression within the endosperm. The GluA-1, GluA-2, and GluA-3 promoters directed GUS expression mainly in the outer portion (peripheral region) of the endosperm. The GluB-5 and GluC promoters directed GUS expression in the whole endosperm, with the latter expressed almost evenly throughout the whole endosperm, a feature different from that of other rice glutelin gene promoters. The GluB-3 promoter directed GUS expression solely in aleurone and subaleurone layers. Promoter activities examined during seed maturation showed that the GluC promoter had much higher activity than the other promoters. These promoters are ideal candidates for achieving gene expression for multiple purposes in monocot endosperm but avoid promoter homology-based gene silencing. The GluC promoter did not contain the endosperm specificity-determining motifs GCN4, AACA, and the prolamin-box, which suggests the existence of additional regulatory mechanism in determining endosperm specificity

Thymol exerts anti-inflammatory effect in dextran sulfate sodium-induced experimental murine colitis

Purpose: To investigate the effect of thymol on dextran sulfate sodium (DSS)-induced experimental colitis in mice.Methods: Colitis in mice was induced by drinking water with 2.5 % (w/v) DSS. The levels of myeloperoxidase (MPO), malondialdehyde (MDA), glutathione (GSH) and superoxide (SOD) in colonic tissues were determined using commercial kits. Histological changes were evaluated by hematoxylin and eosin staining. The production of nitric oxide (NO) was measured by Griess assay. The levels of pro-inflammatory cytokines including TNF-α, IL-1β and IL-6 were assessed by quantitative PCR and ELISA kits. Nuclear factor-kappaB (NF-κB) pathway activation was determined by Western blot.Results: Thymol markedly reduced disease activity index (DAI) scores, and recovered the colon length. Histological damage and MPO levels in the colonic tissues were markedly inhibited (p < 0.05) by thymol, which also reduced mRNA expressions of TNF-α, IL-1β and IL-6 in the colon. In addition, it downregulated MDA level but elevated GSH and SOD levels. Moreover, in vitro data showed that thymol significantly inhibited (p < 0.05) lipopolysaccharide-induced secretion of NO, TNF-α, IL-1β and IL-6 in macrophages, and suppressed (p < 0.05) the activation of NF-κB pathway.Conclusion: Thymol attenuates experimental colitis by down-regulating the activation of NF-κB pathway. Therefore, thymol is a potential candidate drug for the management of ulcerative colitis.Keywords: Thymol, Ulcerative colitis, Dextran sulfate sodium, Macrophages, Nuclear factor-kappa

Spindle oscillations are generated in the dorsal thalamus and modulated by the thalamic reticular nucleus

Spindle waves occur during the early stage of slow wave sleep and are thought to arise in the thalamic reticular nucleus (TRN), causing inhibitory postsynaptic potential spindle-like oscillations in the dorsal thalamus that are propagated to the cortex. We have found that thalamocortical neurons exhibit membrane oscillations that have spindle frequencies, consist of excitatory postsynaptic potentials, and co-occur with electroencephalographic spindles. TRN lesioning prolonged oscillations in the medial geniculate body (MGB) and auditory cortex (AC). Injection of GABA~A~ antagonist into the MGB decreased oscillation frequency, while injection of GABA~B~ antagonist increased spindle oscillations in the MGB and cortex. Thus, spindles originate in the dorsal thalamus and TRN inhibitory inputs modulate this process, with fast inhibition facilitating the internal frequency and slow inhibition limiting spindle occurrence