Proton Coulomb Blockade Effect Involving Covalent Oxygen-Hydrogen Bond Switching.

Instead of the canonical Grotthuss mechanism, we show that a knock-on proton transport process is preferred between organic functional groups (e.g., -COOH and -OH) and adjacent water molecules in biological proton channel and synthetic nanopores through comprehensive quantum and classical molecular dynamics simulations. The knock-on process is accomplished by the switching of covalent O─H bonds of the functional group under externally applied electric fields. The proton transport through the synthetic nanopore exhibits nonlinear current-voltage characteristics, suggesting an unprecedented proton Coulomb blockade effect. These findings not only enhance the understanding of proton transport in nanoconfined systems but also pave the way for the design of a variety of proton-based nanofluidic devices.

Field-Induced Hydration Shell Reorganization Enables Electro-osmotic Flow in Nanochannels.

Electro-osmotic flow is the motion of fluid driven by an applied electric field, for which an electric double layer near a charged surface is deemed essential. Here, we find that electro-osmotic flow can occur in electrically neutral nanochannels in the absence of definable electric double layers through extensive molecular dynamics simulations. An applied electric field is shown to cause an intrinsic channel selectivity between cations and anions, by reorienting the hydration shells of these confined ions. The ion selectivity then results in a net charge density in the channel that induces the unconventional electro-osmotic flow. The flow direction is amenable to manipulation by the field strength and the channel size, which will inform ongoing efforts to develop highly integrated nanofluidic systems capable of complex flow control.

Edge premelting of two-dimensional ices.

The surface of a three-dimensional ice crystal naturally has a quasi-liquid layer (QLL) at temperatures below its bulk melting point, due to a phenomenon called surface premelting. Here, we show that the edges of a two-dimensional (2D) bilayer hexagonal ice adsorbed on solid surfaces undergo premelting as well, resulting in the formation of quasi-liquid bands (QLBs) at the edges. Our extensive molecular dynamics simulations show that the QLB exhibits structure and dynamics indistinguishable from the bilayer liquid phase, acting as a lower-dimensional analog of the QLL on the bulk ice. We further find that at low temperatures, the width of the QLBs at armchair-type edges of the 2D ice is almost identical to that at zigzag-type edges but becomes far greater than the latter at temperatures near the melting point. The chirality-dependent edge premelting of 2D ices should add an important new ingredient to the heterogeneity of premelting.

Mechanical stability of a nanotube from monolayer black phosphorus with the [110] direction as the tube's circumference or generatrix.

The mechanical properties of black phosphorus (BP) are anisotropic. Correspondingly, the properties of the nanotubes formed by bending the same BP ribbon along different directions are different as well. When bending the ribbon along the [110] direction (i.e., stair direction), or along its perpendicular direction (i.e., ps-direction), s- or ps-BPNT can be obtained. The two types of BPNTs are investigated via molecular dynamics (MD) simulations on their thermal and mechanical properties. The results indicate that, for the thermal stability of the s-BPNTs with similar diameters, s-BPNT is weaker than a-BPNTs (armchair type) but stronger than ps-BPNT, and z-BPNT (zigzag type) is the weakest one. In general, a-BPNT has larger compressive or tensile strength, while s-BPNT and ps-BPNT can bear larger deformation. Under uniaxial compression, s-BPNT has two different breaking patterns at different temperatures. The peculiar properties illustrate the wider application of BPNTs in nanodevices under large deformation.

A New Analogue of Echinomycin and a New Cyclic Dipeptide from a Marine-Derived Streptomyces sp. LS298.

Quinomycin G (1), a new analogue of echinomycin, together with a new cyclic dipeptide, cyclo-(l-Pro-4-OH-l-Leu) (2), as well as three known antibiotic compounds tirandamycin A (3), tirandamycin B (4) and staurosporine (5), were isolated from Streptomyces sp. LS298 obtained from a marine sponge Gelliodes carnosa. The planar and absolute configurations of compounds 1 and 2 were established by MS, NMR spectral data analysis and Marfey's method. Furthermore, the differences in NMR data of keto-enol tautomers in tirandamycins were discussed for the first time. Antibacterial and anti-tumor activities of compound 1 were measured against 15 drug-sensitive/resistant strains and 12 tumor cell lines. Compound 1 exhibited moderate antibacterial activities against Staphylococcuse pidermidis, S. aureus, Enterococcus faecium, and E. faecalis with the minimum inhibitory concentration (MIC) values ranged from 16 to 64 µg/mL. Moreover, it displayed remarkable anti-tumor activities; the highest activity was observed against the Jurkat cell line (human T-cell leukemia) with an IC50 value of 0.414 µM.

[The anti-tumor activity and molecular mechanisms of an Aurora kinase inhibitor ZLJ213 in suppressing colon cancer growth].

The aim of this study is to evaluate anti-tumor activities and mechanism of a novel kinase inhibitor ZLJ213 which targeted Aurora A and vascular endothelial growth factor receptor (VEGFR) in vitro and in vivo against human colon cancer. Results showed that ZLJ213 inhibited cell proliferation and induced cell cycle arrest and apoptosis of HCT1 16 and SW48 cell lines. In HCT116-derived xenograft, ZLJ213 dosed at 100 mg · kg(-1) inhibited tumor growth by 73.24%. The IC50 of ZLJ213 on the expression of p-Aurora A was 0.258 µmol · L(-1) analyzed by ELISA. Under the concentration of 0.08 µmol · L(-1), ZLJ213 could inhibit the activities of Aurora A, Histone H3 and VEGFR of HCT116 and SW48 cell lines. Simultaneously, ZLJ213 induced activation of Caspase 3 and PARP cleavage. Above data suggested that ZLJ213 had the ability to inhibit cell proliferation and induce cell apoptosis both in vitro and in vivo in colon cancer, and down-regulate the expression of p-Aurora A and p-VEGFR. ZLJ213 might be a potential therapeutic agent against colon cancer.

[Development of a novel screening assay for inhibitors targeting HIF-1alpha and P300 interaction].

Hypoxia is a general characteristic of most solid malignancies and intimately related to cancer progression. Homeostatic response to hypoxia is primarily mediated by hypoxia inducible factor-1alpha (HIF-1alpha) that elicits transcriptional activity through recruitment P300 coactivator. Targeting the interaction of HIF- alpha and P300 would thus constitute a novel approach for cancer treatment by suppressing tumor angiogenesis and metastasis. Here, a screening assay was developed for inhibitors targeting the interaction between HIF-1alpha and P300. The nucleotide sequence of human HIF-1alpha and P300 were cloned into pBIND and pACT vectors, named pBIND-HIF1alpha and pACT-P300. The interaction of HIF-1alpha and P300 was identified in HEK293 cell using mammalian two-hybrid system. And compound chetomin decreased their interaction in this mammalian two-hybrid system. We further verified HIF-1 inhibition effect of chetomin in U251-HRE cells. Therefore, we established a screening assay combined HIF-1alpha and P300 mammalian two-hybrid system and U251-HRE reporter assay for HIF-1 selective inhibitors.

[Effect of a novel selective S1P1 agonist, Syl948, on mouse skin transplantation].

Syl948 is a synthesized selective S1P1 agonist with novel structure. HTRF-IP1 test indicated that Syl948-P, the active form of Syl948 in vitro, has strong activity against S1P1 (EC50: 83 +/- 16 nmol x L(-1)), but its effect on S1P3 was very weak (EC50: 1 026 +/- 90 nmol x L(-1)). In SD rats, oral administration of Syl948 10 mg x kg(-1) significantly decreased the peripheral blood lymphocytes (PBL), with the maximal PBL inhibition rate of 63%, which was as similar as equal dose of fingolimod (FTY720). Oral administration of Syl948 10 mg x kg(-1) had no effect on heart rate of SD rats, which was better than FTY720. Daily oral administration with Syl948 (2 or 4 mg x kg(-1)) significantly prolonged the survival time of the allografts of skin slice on mice. In summary, the above results demonstrated that Syl948 has great selectivity in vitro and good activity in vivo, which indicated its potential use as an anti-rejection drug in skin transplantation.

[Anti-tumor activity and mechanism of T03 in vitro and in vivo].

The purpose of this study is to investigate the activity and mechanism of a new anti-tumor agent T03. MTT and colony formation assay were performed to determine anti-proliferation activity of T03 in vitro. Antitumor activity was observed by Renca xenograft model in vivo. The effect of T03 on cell cycle and apoptosis were measured by FCM analysis. Western blotting was performed to investigate the expression level of proteins in HepG2 cell lines treated with T03. T03 had anti-tumor activity by inhibiting tumor cell growth and colony formation in vitro, especially on hepatocellular carcinoma cells (HCC). At the concentration of 10 micromol x L(-1), T03 induced cell apoptosis and cell cycle arrest in HCC. Moreover, it proved that T03 reduced the tumor weight with the rate of 42.30% without any obviously side effect in Renca xenograft model. At the concentration of 2.0 micromol x L(-1), T03 was able to reduce the level of p-c-Raf (Ser259), and thus blocked Raf/MEK/ERK and AKT signaling in HepG2 cell lines. The result suggested that T03 has the potential to inhibit cell proliferation and induce cell apoptosis both in vitro and in vivo, particularly active against HCC, indicating T03 and its analogues may serve as a new anti-cancer drug against hepatocellular carcinoma.

[Design, synthesis and biological evaluation of fingolimod analogues containing diphenyl ether moiety].

A novel series of fingolimod analogues containing diphenyl ether moiety were designed and synthesized based on the modification of immunosuppressive agent fingolimod used in the treatment of multiple sclerosis. Compounds were evaluated in vivo for lymphopenic activity and heart rate affection. Most compounds showed moderate lymphopenic activity. It is worth noting that compounds 6c, 6d and 14c-14e showed considerable immunosuppressive activities comparable to fingolimod. And compound 14e had no effect on heart rate.

High-Resolution and Low-Noise Single-Molecule Sensing with Bio-Inspired Solid-State Nanopores.

Solid-state nanopores have been extensively explored as single-molecule sensors, bearing the potential for the sequencing of DNA. Although they offer advantages in terms of high mechanical robustness, tunable geometry, and compatibility with existing semiconductor fabrication techniques in comparison with their biological counterparts, efforts to sequence DNA with these nanopores have been hampered by insufficient spatial resolution and high noise in the measured ionic current signal. Here we show that these limitations can be overcome by the use of solid-state nanopores featuring a thin, narrow constriction as the sensing region, inspired by biological protein nanopores that have achieved notable success in DNA sequencing. Our extensive molecular dynamics simulations show that these bio-inspired nanopores can provide high spatial resolution equivalent to 2D material nanopores and, meanwhile, significantly inhibit noise levels. A theoretical model is also provided to assess the performance of the bio-inspired nanopore, which could guide its design and optimization.

Smartphone Distraction and Academic Anxiety: The Mediating Role of Academic Procrastination and the Moderating Role of Time Management Disposition.

The present study investigated the relationship between smartphone distraction, academic procrastination, academic anxiety, and time management disposition. A total of 474 college students were recruited to complete a survey comprising measures of smartphone distraction, academic procrastination, academic anxiety, and time management disposition. The hypothesised moderated mediation model was tested using Model 4 and Model 15 of the PROCESS macro for SPSS. Results showed that smartphone distraction was positively and significantly correlated with academic anxiety (r = 0.40, p < 0.001) and academic procrastination (r = 0.42, p < 0.001). Academic procrastination mediated the relationship between smartphone distraction and academic anxiety. Time management disposition moderated the paths from academic procrastination and smartphone distraction to academic anxiety. The present study suggests that smartphone distraction could predict increased levels of academic procrastination, which could then lead to higher academic anxiety. However, the predicting effects in this mediation model could fluctuate across individuals with different time management dispositions. Further studies are needed to explore the mechanism of smartphone distraction using different methods.

Electricity generated by upstream proton diffusion in two-dimensional nanochannels.

The movement of ions along the pressure-driven water flow in narrow channels, known as downstream ionic transport, has been observed since 1859 to induce a streaming potential and has enabled the creation of various hydrovoltaic devices. In contrast, here we demonstrate that proton movement opposing the water flow in two-dimensional nanochannels of MXene/poly(vinyl alcohol) films, termed upstream proton diffusion, can also generate electricity. The infiltrated water into the channel causes the dissociation of protons from functional groups on the channel surface, resulting in a high proton concentration inside the channel that drives the upstream proton diffusion. Combined with the particularly sluggish water diffusion in the channels, a small water droplet of 5 µl can generate a voltage of ~400 mV for over 330 min. Benefiting from the ultrathin and flexible nature of the film, a wearable device is built for collecting energy from human skin sweat.

Cytotoxic triterpenoid saponins from the stems of Gordonia longicarpa.

Nine new triterpenoid saponins named longicarposides A-I (1-9), together with three known saponins (10-12), were isolated from the stems of Gordonia longicarpa. The structures of the saponins were elucidated by a combination of 1D and 2D NMR techniques, mass spectrometry, and chemical methods. They were characterized to be oleanane-type saponins with sugar moieties linked to C-3 of the aglycone. Cytotoxic activities of these saponins were evaluated against five human tumor cell lines (HCT-8, Bel-7402, BGC-823, A549, and A2780) by using the MTT in vitro assay. Compounds 5, 7, 8, 10, and 11 exhibited potent cytotoxic activity with IC50 values of 1.42-8.42 µM, while 6, 9, and 12 showed selective cytotoxic activity toward the tested cell lines.

[Mechanism about therapeutic effect of meisoindigo on psoriasis via down-regulation of the TLR4-TAK-NF-kappaB pathways].

Meisoindigo is an indigo natural derivative commonly used in anti-cancer therapy. In the clinical application, it was also found to have good therapeutic effect on psoriasis. In order to further understand its mechanism of action, human normal keratinocyte cell line HaCaT and RAW 264.7 were used to identify if meisoindigo could affect the inflammatory factors such as NO and other important cytokines which were highly involved in psoriasis. Our results indicated that meisoindigo decreased the production of NO in LPS-stimulated RAW 264.7 cells and reduced the expression of cytokines in LPS-stimulated HaCaT cells. And TLR4-TAK-NF-kappaB was a possible pathway mainly involved in the attenuation of iNOS and pro-inflammatory cytokine production by meisoindigo, which may take part in the therapeutic effect of meisoindigo on psoriasis.

Problematic social media use and mental health risks among first-year Chinese undergraduates: a three-wave longitudinal study.

Introduction: The association between social media use and mental health risks has been widely investigated over the past two decades with many cross-sectional studies reporting that problematic social media use (PSMU) is associated with higher mental health risk such as anxiety and depression. The present study examined the relationship between PSMU severity and mental health risks (depression, anxiety, stress, and loneliness) using a three-wave longitudinal design. Methods: A total of 685 first-year Chinese undergraduate students (Mean age = 19.12 years, SD = 0.92) completed surveys at three times points with intervals of 3 to 4 months. Results revealed that PSMU was positively correlated with all the mental health risk variables over the three time points. Results: The prevalence of PSMU increased over the three research waves. Cross-lagged models identified bi-directional relationships between PSMU and mental health risks, while such links were not consistent between different mental health risk variables and can change over different research intervals. Discussion: This study indicates that PSMU and mental health risks could predict each other in a vicious loop, but the differences between specific mental health risks and the research context (e.g., different term times and experiences in university) should not be ignored. Further research attention should be paid to the prevalence of PSMU and mental health conditions among Chinese first-year undergraduates who appear to have difficulties in adapting to university life.

A novel branched galacturonan from Gardenia jasminoides alleviates liver fibrosis linked to TLR4/NF-κB signaling.

Gardenia jasminoides (GJ) is a classic edible medicine in China of which the fruit has been proved to alleviate liver damage. We hypothesized whether polysaccharide in the fruit could have comparable bioactivity. To address this, a novel polysaccharide GJE0.2-2, is purified from the fruit of Gardenia jasminoides. Indeed, GJE0.2-2 may attenuate CCl4-induced liver fibrosis in mice and impede the expression of critical fibrogenesis associated molecules such as α-SMA, FN1, and Collagen I induced by TGF-ß in human hepatic stellate LX-2 cells. Mechanism studies suggest that this bioactivity may be implicated in TLR4/NF-κB signaling pathway via directly binding to TLR4. The structure characterization shows that the backbone of this polysaccharide is mainly composed of galacturonic acid with minor rhamnose, branched with galactose and arabinose, galacturonic acid, and esterified hexenuronic acid (HexpA). These findings provide evidence for a novel pectin-linked polysaccharide-based new drug candidate development for liver fibrosis therapy.

[Immunosuppressive effect of S1P1 receptor agonist FTY720].

FTY720 is a synthetic compound derived from the metabolites of Isaria sinclairii. Its unique chemical structure and mechanism appear to be distinctive from other known immunosuppressors. In the present study, the effect of FTY720 on immunosuppression and toxicity to heart was evaluated by detection of lymphocytes count, heart rate in rats, the survival time of the allografts of skin slice in mice and binding to S1P1 and S1P3 receptors by confocal. The results showed that FTY720 could induce lymphopenia, reduce the heart rates in rats and prolong the survival time of the allografts of skin slice in mice. The assay results on confocal showed that FTY720 can bind with S1P1 and S1P3 on surface of CHO-S1P1 and CHO-S1P3 cells. FTY720 could be developed for wide application for organ transplantation and self-immunity diseases.

The Mechanism of CP fandom Behaviors among Chinese Young Adults: A Grounded Theory Study

CP fandom behaviors or shipping, a growing popular phenomenon among Chinese young adults, refers to the activities of fans who take great satisfaction from the romantic relationships and interactions of their preferred pairings of idols or virtual characters. CP fans are regarded as a special group of fans with unique identities and interaction styles. This grounded theory study was conducted to explore the mechanism of CP fandom behaviors. Semi-structured in-depth interviews were conducted with thirty-one Chinese CP fans (twenty-eight females and three males). The antecedents, development, behavioral patterns, and consequences of shipping were identified in a comprehensive model. The reasons for CP fandom behaviors include individual factors (e.g., psychological projection, compensation, and social needs) and external factors (e.g., pop culture and internet environment). The consequences include positive emotional experiences, changed love values, and improved social interaction. CP fandom behaviors can be different in terms of the fans' degrees of engagement, and the development of shipping can be divided into three stages: exploratory stage, formation and stability stage, and rupture stage. This study contributes to the literature of CP fandom behaviors among young adults in China and proposes the directions of future studies on such topics.

[Corrigendum] The novel anti­neuroblastoma agent PF403, inhibits proliferation and invasion in vitro and in brain xenografts.

Subsequently to the publication of the above article, the authors have realized that Fig. 5D on p. 183 was published containing an error; essentially, the images chosen for the data panels representing the Fig. 5D, CAT3 Low and 5D, CAT3 High experiments were inadvertently selected from the same slide. However, the authors had retained access to their original data, and the revised version of Fig. 5 is shown on the next page, now showing the correct data for the Fig. 5D, CAT3 High panel. All the authors agree to the publication of this corrigendum, and they confirm that these data continue to support the main conclusions presented in their paper. Furthermore, the authors are grateful to the Editor of International Journal of Oncology for allowing them this opportunity to publish this Corrigendum, and they also apologize to the readership for any inconvenience caused. [International Journal of Oncology 47: 179­187, 2015; DOI: 10.3892/ijo.2015.2977].