Understanding Liquid−Solid-Like Behavior of Tetrahydrofuran Adlayers at Room Temperature between Graphene and Mica: A Born−Oppenheimer Molecular Dynamics Study

The phase behavior of adlayers of volatile small organic molecule tetrahydrofuran (THF) at room temperature has been imaged using atomic force microscopy (AFM) through graphene templating (J. Am. Chem. Soc. 2011, 133, 2334−2337). To gain more insight into the dynamical and structural properties of THF adlayers on mica and the effect of graphene templating, the Born−Oppenheimer molecular dynamics simulations (with the BLYP-D functional and a Gaussian plane-wave basis set) are performed. Without the graphene coating, the computed self-diffusion coefficients of THF molecules in the monolayer and bilayer are comparable to that in bulk THF solvent. However, with the graphene coating, the THF monolayer becomes considerably viscous. As the thickness of adlayers increases, the second adlayer of the THF bilayer exhibits even solid-like behavior, consistent with the AFM measurement. Although the motion of THF molecules becomes markedly slower with the graphene coating, the adsorbed THF molecules can still freely tilt and rotate on the mica substrate. Hence, the graphene-coated THF monolayer and bilayer are not strictly as ordered as the monoclinic THF crystal. Nevertheless, with the graphene coating, some THF molecules in the monolayer and bilayer entail certain degrees of crystalline packing as the graphene coating serves as an energy barrier to prevent the volatile THF molecules from evaporation, thereby limiting their motion in both lateral and vertical directions

Layer-wise Representation Fusion for Compositional Generalization

Despite successes across a broad range of applications, sequence-to-sequence models' construct of solutions are argued to be less compositional than human-like generalization. There is mounting evidence that one of the reasons hindering compositional generalization is representations of the encoder and decoder uppermost layer are entangled. In other words, the syntactic and semantic representations of sequences are twisted inappropriately. However, most previous studies mainly concentrate on enhancing token-level semantic information to alleviate the representations entanglement problem, rather than composing and using the syntactic and semantic representations of sequences appropriately as humans do. In addition, we explain why the entanglement problem exists from the perspective of recent studies about training deeper Transformer, mainly owing to the ``shallow'' residual connections and its simple, one-step operations, which fails to fuse previous layers' information effectively. Starting from this finding and inspired by humans' strategies, we propose \textsc{FuSion} (\textbf{Fu}sing \textbf{S}yntactic and Semant\textbf{i}c Representati\textbf{on}s), an extension to sequence-to-sequence models to learn to fuse previous layers' information back into the encoding and decoding process appropriately through introducing a \emph{fuse-attention module} at each encoder and decoder layer. \textsc{FuSion} achieves competitive and even \textbf{state-of-the-art} results on two realistic benchmarks, which empirically demonstrates the effectiveness of our proposal.Comment: work in progress. arXiv admin note: substantial text overlap with arXiv:2305.1216

Use of ITS2 Region as the Universal DNA Barcode for Plants and Animals

The internal transcribed spacer 2 (ITS2) region of nuclear ribosomal DNA is regarded as one of the candidate DNA barcodes because it possesses a number of valuable characteristics, such as the availability of conserved regions for designing universal primers, the ease of its amplification, and sufficient variability to distinguish even closely related species. However, a general analysis of its ability to discriminate species in a comprehensive sample set is lacking.In the current study, 50,790 plant and 12,221 animal ITS2 sequences downloaded from GenBank were evaluated according to sequence length, GC content, intra- and inter-specific divergence, and efficiency of identification. The results show that the inter-specific divergence of congeneric species in plants and animals was greater than its corresponding intra-specific variations. The success rates for using the ITS2 region to identify dicotyledons, monocotyledons, gymnosperms, ferns, mosses, and animals were 76.1%, 74.2%, 67.1%, 88.1%, 77.4%, and 91.7% at the species level, respectively. The ITS2 region unveiled a different ability to identify closely related species within different families and genera. The secondary structure of the ITS2 region could provide useful information for species identification and could be considered as a molecular morphological characteristic.)

MicroRNA-378 enhances inhibitory effect of curcumin on glioblastoma

Glioblastoma multiforme is the most aggressive and common primary brain tumor, and is virtually incurable due to its therapeutic resistance to radiation and chemotherapy. Curcumin is a well-known phytochemical exhibiting antitumor activity on many human cancers including glioblastoma multiforme. Given the unique miRNA expression profiles in cancer cells compared to non-cancerous cells, we investigated whether these miRNA could be used to cancer therapy. In this report we show that miR-378, a glioblastoma multiforme down regulated miRNA, may enhance the inhibitory effect of curcumin on this cancer growth. Our results indicated that the inhibitory effect of curcumin was enhanced in miR-378-expressing stable U87 cells in vitro and in vivo, compared to control cells. MiR-378 was found to target p-p38 expression, underlying the observed phenotypic changes. Thus, we concluded that miR-378 enhances the response of glioblastoma multiforme to curcumin treatment, by targeting p38

Differential Effects of Sorafenib on Liver Versus Tumor Fibrosis Mediated by Stromal-Derived Factor 1 alpha/C-X-C Receptor Type 4 Axis and Myeloid Differentiation Antigen-Positive Myeloid Cell Infiltration in Mice

Sorafenib—a broad kinase inhibitor—is a standard therapy for advanced hepatocellular carcinoma (HCC) and has been shown to exert antifibrotic effects in liver cirrhosis, a precursor of HCC. However, the effects of sorafenib on tumor desmoplasia—and its consequences on treatment resistance—remain unknown. We demonstrate that sorafenib has differential effects on tumor fibrosis versus liver fibrosis in orthotopic models of HCC in mice. Sorafenib intensifies tumor hypoxia, which increases stromal-derived factor 1 alpha (SDF-1α) expression in cancer and stromal cells and, subsequently, myeloid differentiation antigen–positive (Gr-1+) myeloid cell infiltration. The SDF-1α/C-X-C receptor type 4 (CXCR4) pathway directly promotes hepatic stellate cell (HSC) differentiation and activation through the mitogen-activated protein kinase pathway. This is consistent with the association between SDF-1α expression with fibrotic septa in cirrhotic liver tissues as well as with desmoplastic regions of human HCC samples. We demonstrate that after treatment with sorafenib, SDF-1α increased the survival of HSCs and their alpha-smooth muscle actin and collagen I expression, thus increasing tumor fibrosis. Finally, we show that Gr-1+ myeloid cells mediate HSC differentiation and activation in a paracrine manner. CXCR4 inhibition, using AMD3100 in combination with sorafenib treatment, prevents the increase in tumor fibrosis—despite persistently elevated hypoxia—in part by reducing Gr-1+ myeloid cell infiltration and inhibits HCC growth. Similarly, antibody blockade of Gr-1 reduces tumor fibrosis and inhibits HCC growth when combined with sorafenib treatment. Conclusion: Blocking SDF-1α/CXCR4 or Gr-1+ myeloid cell infiltration may reduce hypoxia-mediated HCC desmoplasia and increase the efficacy of sorafenib treatment. (Hepatology 2014;59:1435-1447

Antitumor activity and mechanisms of action of total glycosides from aerial part of Cimicifuga dahurica targeted against hepatoma

<p>Abstract</p> <p>Background</p> <p>Medicinal plant is a main source of cancer drug development. Some of the cycloartane triterpenoids isolated from the aerial part of <it>Cimicifuga dahurica </it>showed cytotoxicity in several cancer cell lines. It is of great interest to examine the antiproliferative activity and mechanisms of total triterpenoid glycosides of <it>C. dahurica </it>and therefore might eventually be useful in the prevention or treatment of Hepatoma.</p> <p>Methods</p> <p>The total glycosides from the aerial part (TGA) was extracted and its cytotoxicity was evaluated in HepG2 cells and primary cultured normal mouse hepatocytes by an MTT assay. Morphology observation, Annexin V-FITC/PI staining, cell cycle analysis and western blot were used to further elucidate the cytotoxic mechanism of TGA. Implanted mouse H₂₂hepatoma model was used to demonstrate the tumor growth inhibitory activity of TGA <it>in vivo</it>.</p> <p>Results</p> <p>The IC₅₀values of TGA in HepG2 and primary cultured normal mouse hepatocytes were 21 and 105 μg/ml, respectively. TGA induced G₀/G₁cell cycle arrest at lower concentration (25 μg/ml), and triggered G₂/M arrest and apoptosis at higher concentrations (50 and 100 μg/ml respectively). An increase in the ratio of Bax/Bcl-2 was implicated in TGA-induced apoptosis. In addition, TGA inhibited the growth of the implanted mouse H₂₂tumor in a dose-dependent manner.</p> <p>Conclusion</p> <p>TGA may potentially find use as a new therapy for the treatment of hepatoma.</p

A 40–50 GHz RF Front-End with Integrated Local Oscillator Leakage Calibration

This article presents a transmitter (TX) front-end operating at frequencies covering 40–50 GHz, including a differential quadrature mixer with integrated amplitude and phase imbalance tuning, a power amplifier, and a detection mixer (DM) that supports local oscillator (LO) leakage signal or image signal calibration. Benefiting from the amplitude and phase imbalance tuning network of the in-phase quadrature (IQ) signal generator at the LO input, the TX exhibits more than 30 dBc image signal rejection over the full frequency band without any post-calibration. Based on the LO leakage signal fed back by the DM integrated at the RF output, the LO leakage of the TX has been improved by more than 10 dB through the LO leakage calibration module integrated in the quadrature mixer. When the intermediate frequency (IF) signal is fixed at 1 GHz, the TX’s 1 dB compressed output power (OP1 dB) is higher than 13.5 dBm over the operating band. Thanks to the LO leakage signal calibration unit and the IQ signal generator, the TX is compliant with the error vector magnitude (EVM) requirement of the IEEE 802.11aj standard up to the 64-quadrature amplitude modulation (QAM) operating mode

A 77-GHz Fully Integrated Power Amplifier for Automotive Radar Application in 40-nm CMOS

This paper presents a compact 77-GHz four-way differential power combined power amplifier for automotive radar application. At E-band, the insertion loss of matching network and power combining network are the limiting factor for the power amplifier's performance. In this work, the insertion loss of the matching networks is reduced by taking advantage of the proposed coplanar waveguide differential transmission line with floating substrate noise shielding grids. The voltage-current power combining method that takes care of impedance matching and power combining is adopted to decrease the insertion loss from power combining and output matching network. The power amplifier is implemented in a 40 nm CMOS process. From 69 to 85 GHz, the power amplifier delivers more than 19 dBm output power with the maximum $P_{sat}$ of 19.7 GHz at 77 GHz. The final layout power amplifier achieves 19.4 dB peak small signal gain, and the maximum PAE is 22.7 %