Abstract--An environmental infrared microbalance (EIRM) cell was used to study H20 sorption on two montmorillonite samples as a function of water content and type of exchangeable cation. The vibrational spectra showed that H20 sorbed to the clay at low-water content was strongly influenced by the exchangeable" cation and by the close proximity to the clay surface. At water contents <6 H20 molecules per exchangeable cation, the H-O-H bending mode of H20 (v 2 mode) shifts to a lower frequency and is characterized by an increase in molar absorptivity. In contrast, the positions of the asymmetric and symmetric OH-stretching modes of sorbed water (vl and v3 modes) shift to higher energies. These observations indicate that H20 molecules sorbed to the clay surface at low-water content are less hydrogen bonded than in bulk H20. In addition, the vibrational-stretching and bending bands of the structural OH groups of the 2:1 layer are also strongly influenced by H20 content and type of exchangeable cation. By using the EIRM cell, the molar absorptivities of the structural OH-bending vibrations were measured as a function of H20 content. The position and molar absorptivity of the structural OH-bending bands at 920, 883, and 840 cm l are strongly influenced by H20 content and type of exchangeable cation. The molar absorptivity of the 920-cm ~ band, which is assigned to the A1A1OH group, decreased strongly at low-H20 content. This reduction in intensity is assigned to a dehydration-induced change in orientation of the structural OH groups resulting from the penetration of H20 molecules into siloxane ditrigonal cavities that are not associated with a net negative charge from isomorphous substitutions.

The photocatalytic oxidation (PCO) of 2-propanol and acetone was studied on TiO 2 powder at high coverage (>2 monolayers) at various oxygen concentrations using in situ FTIR. Two UV irradiation sources, either a continuous-wave UV lamp or an excimer laser, were applied to investigate the effect of the UV source on the PCO. It was found that higher oxygen concentrations increased the PCO rate of 2-propanol and acetone. The excimer laser source accelerated the PCO rate of 2-propanol while decelerating that of acetone as compared to the continuous-wave source. This effect was found to be larger at higher oxygen concentrations. Factors such as multiphoton adsorption or a pulsed irradiation were excluded as possible explanations for the irradiation source effect. More likely, the laser source changes the reaction mechanism by introducing an abrupt temperature increase, and hence the thermal decomposition, that is, dehydration of 2-propanol to propene, is effectively initiated on the surface. The PCO of 2-propanol was found to proceed along two routes: one was through the chemisorbed species, 2-propoxide, to form CO 2 directly; the other was through conversion of H-bonded 2-propanol to acetone, followed by thermal fragmentation of mesityl oxide (aldol condensation product of acetone) to form formate species, and finally to CO 2 . It was also found that the acetone decay rate during acetone PCO was much faster than that of acetone formed as an intermediate during 2-propanol PCO at the same oxygen concentration. This was likely due to the presence of other species competing for reaction sites on the catalyst surface.

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Arbitrary control of terahertz (THz) waves remains a significant challenge although it promises many important applications. Here, a method to tailor the reflection and scattering of THz waves in an anomalous manner by using 1‐bit coding metamaterials is presented. Specific coding sequences result in various THz far‐field reflection and scattering patterns, ranging from a single beam to two, three, and numerous beams, which depart obviously from the ordinary Snell's law of reflection. By optimizing the coding sequences, a wideband THz thin film metamaterial with extremely low specular reflection, due to the scattering of the incident wave into various directions, is demonstrated. As a result, the reflection from a flat and flexible metamaterial can be nearly uniformly distributed in the half space with small intensity at each specific direction, manifesting a diffuse reflection from a rough surface. Both simulation and experimental results show that a reflectivity less than −10 dB is achieved over a wide frequency range from 0.8 to 1.4 THz, and it is insensitive to the polarization of the incident wave. This work reveals new opportunities arising from coding metamaterials in effective manipulation of THz wave propagation and may offer widespread applications.

BackgroundProtein regulator of cytokinesis-1 (PRC1) belongs to the microtubule-associated proteins (MAPs) family, and is involved in cytokinesis. Recent investigations suggest PRC1 involvement in human carcinogenesis, including breast carcinoma, hepatocellular carcinoma and etc. However, whether PRC1 contributes to lung adenocarcinoma tumorigenesis remains unknown.MethodsQuantitative reverse-transcription polymerase chain reaction (qRT-PCR), Western blotting and Immunohistochemical staining (IHC) were used to evaluate and contrast the PRC1 expression profile in lung adenocarcinoma and adjacent normal lung tissues. We examined the clinical use of PRC1 in lung adenocarcinoma prognosis. Additionally, the tumorigenesis impact of PRC1 in lung adenocarcinoma cells was verified via in vitro and in vivo metastasis and tumorigenesis assays. Notably, Next Generation Sequencing (NGS) was performed to investigate the molecular mechanism underlying the oncogenic role of PRC1 in lung adenocarcinoma.ResultsPRC1 mRNA and protein expressions were upregulated in lung adenocarcinoma tissues compared to adjacent normal lung tissues. PRC1 protein overexpression correlated with lymph node metastasis and was an independent poor prognostic factor for lung adenocarcinoma patients. Our data implied that PRC1 depletion limited the proliferation and invasion of lung adenocarcinoma cells in vitro and lowered tumor development and lung metastasis in vivo. Remarkably, limiting PRC1 substantially prompted G2/M phase cell cycle arrest and apoptosis. Mechanistically, by conducting NGS on PRC1-depleted A549 cells and control cells, we discovered that PRC1 expression was significantly correlated with the Wnt signaling pathway.ConclusionsThis investigation offers confirmation that PRC1 is a prognostic and promising therapeutic biomarker for people with lung adenocarcinoma and takes on a key part in the activation of the Wnt/β-catenin pathway in lung adenocarcinoma development.Electronic supplementary materialThe online version of this article (doi:10.1186/s12943-017-0682-z) contains supplementary material, which is available to authorized users.

This paper studies the suppression of superconducting transition temperature (Tc) of ultrathin NbN film. We fabricated epitaxial NbN superconducting thin films of thicknesses ranging from 2.5 to 100 nm on single crystal MgO (100) substrates by dc magnetron sputtering. We performed structure analyses and measured their electric and far infrared properties. The experimental results were compared with several mechanisms of the suppression of superconductivity proposed in the literature, including the weak localization effect, the proximity effect, and quantum size effect (electron wave leakage model). We found that the electron wave leakage model matches best to the experimental data.

The phylogenetic position of the monotypic genus Wenchengia has long been controversial. It variously has been assigned to a monotypic subfamily Wenchengioideae, treated as a member of subfamily Scutellarioideae, or suggested to be related to Lamioideae or Ajugoideae. The recent rediscovery of Wenchengia alternifolia from its type locality provided an opportunity to infer its phylogenetic position using evidence from two plastid DNA regions (rbcL, ndhF), morphological data, and anatomical and cytological characters. Both the molecular data and a combination of the molecular and the morphological data suggested a close relationship of the genus to a clade consisting of Holmskioldia, Tinnea, and Scutellaria representing Scutellarioideae. This relationship is also supported by a striking similarity in gross morphological, anatomical, and cytological characters between Wenchengia and other genera of Scutellarioideae, suggesting that it should be more appropriate to treat the genus as a member of Scutellarioideae, rather than assigning it to a monotypic subfamily.

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