Discovery of chemosynthesis-based association on the Cretaceous basal leatherback sea turtle from Japan

We report a Late Cretaceous chemosynthetic community fueled by decomposing basal leatherback sea turtle on the ocean floor in the western Pacific. The fossil association representing this community has been recovered from the matrix of a concretion containing a single carapace of Mesodermochelys sp. from Late Cretaceous outer shelf to upper slope deposit of northern Hokkaido, Japan. The carapace displays boreholes most likely performed by boring bivalves, and is associated with molluscan shells, mainly Provanna cf. nakagawensis and Thyasira tanabei. Since this association is similar to fauna already known from Late Cretaceous hydrocarbon seeps, sunken wood, and plesiosaur-falls in Hokkaido, it is suggested that all types of chemosynthesis-based communities in the Late Cretaceous of western Pacific may have belonged to the same regional pool of animals and were not yet fully differentiated into three independent types of communities as it is known today. This finding also indicates that the sulfophilic stage of the vertebrate-fall communities was supported not only by plesiosaur carcasses, which were previously reported, but also by sea turtle carcasses. It highlights the possibility of surviving vertebrate-fall communities through the end-Cretaceous mass extinction event on carcasses of sea turtles which are the only large marine vertebrates surviving this event

Suppression of Magnetic Order by Pressure in BaFe2As2

We performed the dc resistivity and the ZF 75As-NMR measurement of BaFe2As2 under high pressure. The T-P phase diagram of BaFe2As2 determined from resistivity anomalies and the ZF 75As-NMR clearly revealed that the SDW anomaly is quite robust against P.Comment: 2 pages, 2 figure

Morphological and histological evidence for the oldest known softshell turtles from Japan

Herein we report morphologically and histologically diagnostic trionychid specimens from the Barremian–Aptian (129.4–113.0 Ma) of Japan. One specimen (FPDM-V9487) is an associated skeleton that consists of a scapula, a humerus, an ischium, and hypoplastra. The limb and girdle bones are similar in morphology to those of modern trionychids.The hypoplastron also resembles that of modern trionychids; however, it is distinctive in that it completely lacks callosities.The other three new specimens are fragmentary costals that show a reduction in the shell bones and an absence of scute sulci.Two of the newly reported costals and FPDM-V0127 were examined histologically. Bone fiber bundles organized in a plywood-like structure, which is unique to trionychids, were identified. Fossil occurrence data indicate that morphologically and histologically typical trionychids already inhabited the coastal region of Asia (e.g., western Japan) as early as the Aptian. In contrast, the Hauterivian–Aptian stem trionychid Kappachelys okurai from Japan does not show a plywood-like shell microstructure, suggesting that K. okurai could be the earliest-branching taxon of known stem trionychids or a carettochelyid. Our paleobiogeographic compilation suggests that the spread of wetlands in the Northern Hemisphere and the high global temperature during the middle Cretaceous (Aptian–Turonian, 125.0–89.8 Ma) might have contributed to the dispersal of trionychids from Asia, allowing for the establishment of this modern freshwater reptilian fauna

Growth of free-standing bulk wurtzite AlxGa1−xN layers by molecular beam epitaxy using a highly efficient RF plasma source

The recent development of group III nitrides allows researchers world-wide to consider AlGaN based light emitting diodes as a possible new alternative deep ultra–violet light source for surface decontamination and water purification. In this paper we will describe our recent results on plasma-assisted molecular beam epitaxy (PA-MBE) growth of free-standing wurtzite AlxGa1−xN bulk crystals using the latest model of Riber's highly efficient nitrogen RF plasma source. We have achieved AlGaN growth rates up to 3 µm/h. Wurtzite AlxGa1−xN layers with thicknesses up to 100 μm were successfully grown by PA-MBE on 2-inch and 3-inch GaAs (111)B substrates. After growth the GaAs was subsequently removed using a chemical etch to achieve free-standing AlxGa1−xN wafers. Free-standing bulk AlxGa1−xN wafers with thicknesses in the range 30–100 μm may be used as substrates for further growth of AlxGa1−xN-based structures and devices. High Resolution Scanning Transmission Electron Microscopy (HR-STEM) and Convergent Beam Electron Diffraction (CBED) were employed for detailed structural analysis of AlGaN/GaAs (111)B interface and allowed us to determine the N-polarity of AlGaN layers grown on GaAs (111)B substrates. The novel, high efficiency RF plasma source allowed us to achieve free-standing AlxGa1−xN layers in a single day's growth, making this a commercially viable process

Discovery of chemosynthesis-based association on the Cretaceous basal leatherback sea turtle from Japan

金沢大学国際基幹教育院 GS教育系We report a Late Cretaceous chemosynthetic community fueled by decomposing basal leatherback sea turtle on the ocean floor in the western Pacific. The fossil association representing this community has been recovered from the matrix of a concretion containing a single carapace of Mesodermochelys sp. from Late Cretaceous outer shelf to upper slope deposit of northern Hokkaido, Japan. The carapace displays boreholes most likely performed by boring bivalves, and is associated with molluscan shells, mainly Provanna cf. nakagawensis and Thyasira tanabei. Since this association is similar to fauna already known from Late Cretaceous hydrocarbon seeps, sunken wood, and plesiosaur-falls in Hokkaido, it is suggested that all types of chemosynthesis-based communities in the Late Cretaceous of western Pacific may have belonged to the same regional pool of animals and were not yet fully differentiated into three independent types of communities as it is known today. This finding also indicates that the sulfophilic stage of the vertebrate-fall communities was supported not only by plesiosaur carcasses, which were previously reported, but also by sea turtle carcasses. It highlights the possibility of surviving vertebrate-fall communities through the end-Cretaceous mass extinction event on carcasses of sea turtles which are the only large marine vertebrates surviving this event. Copyright © 2017 R.G. Jenkins et al

75As NMR study of the ternary iron arsenide BaFe2As2

We report 75As-NMR measurements of the ternary iron arsenide BaFe2As2. 75As-NMR spectra clearly revealed that magnetic transition occurs at around 131 K in our samples, which corresponds to the emergence of spin density wave. Temperature dependence of the internal magnetic field suggests that the transition is likely of the first order. The critical-slowing-down phenomenon in the spin-lattice relaxation rate 1/T1 is not pronounced in this material.Comment: To be published in J. Phys. Soc. Jp

Antimicrobial peptide FF/CAP18 induces apoptotic cell death in HCT116 colon cancer cells via changes in the metabolic profile

Metabolic reprogramming is one of the hallmarks of cancer and can be targeted by therapeutic agents. We previously reported that cathelicidin-related or modified antimicrobial peptides, such as FF/CAP18, have antiproliferative effects on the squamous cell carcinoma cell line SAS-H1, and the colon carcinoma cell line HCT116. Although antimicrobial peptides have potential use in the development of new therapeutic strategies, their effects on the metabolism of cancer cells are poorly understood. Here, we investigated changes in the levels of metabolites in HCT116 cells caused by FF/CAP18, via capillary electrophoresis time-of-flight mass spectrometry (CE-TOFMS). Analysis of the 177 intracellular metabolites and 113 metabolites in conditioned medium that were detected by CE-TOFMS, revealed dramatic changes in the metabolic profile of HCT116 cells after treatment with FF/CAP18. The metabolic profile showed that the levels of most metabolites in the major metabolic pathways supported the rapid proliferation of cancer cells. Purine metabolism, glycolysis, and the TCA cycle, were altered in FF/CAP18-treated cells in a dose-dependent manner. Our present study provides mechanistic insights into the anticancer effects of antimicrobial peptides that show great potential as new therapies for colon cancer

Molecular beam epitaxy as a growth technique for achieving free-standing zinc-blende GaN and wurtzite AlxGa1-xN

Currently there is a high level of interest in the development of ultraviolet (UV) light sources for solid state lighting, optical sensors, surface decontamination and water purification. III-V semiconductor UV LEDs are now successfully manufactured using the AlGaN material system; however, their efficiency is still low. The majority of UV LEDs require AlxGa1-xN layers with compositions in the mid-range between AlN and GaN. Because there is a significant difference in the lattice parameters of GaN and AlN, AlxGa1-xN substrates would be preferable to those of either GaN or AlN for many ultraviolet device applications. However, the growth of AlxGa1-xN bulk crystals by any standard bulk growth techniques has not been developed so far. There are very strong electric polarization fields inside the wurtzite (hexagonal) group III-nitride structures. The charge separation within quantum wells leads to a significant reduction in the efficiency of optoelectronic device structures. Therefore, the growth of non-polar and semi-polar group III-nitride structures has been the subject of considerable interest recently. A direct way to eliminate polarization effects is to use non-polar (001) zinc-blende (cubic) III-nitride layers. However, attempts to grow zinc-blende GaN bulk crystals by anystandard bulk growth techniques were not successful. Molecular beam epitaxy (MBE) is normally regarded as an epitaxial technique for the growth of very thin layers with monolayer control of their thickness. In this study we have used plasma-assisted molecular beam epitaxy (PA MBE) and have produced for the first time free-standing layers of zinc-blende GaN up to 100 μm in thickness and up to 3-inch in diameter. We have shown that our newly developed PA-MBE process for the growth of zinc-blende GaN layers can also be used to achieve free-standing wurtzite AlxGa1-xN wafers. Zinc-blende and wurtzite AlxGa1-xN polytypes can be grown on different orientations of GaAs substrates - (001) and (111)B respectively. We have subsequently removed the GaAs using a chemical etch in order to produce free-standing GaN and AlxGa1-xN wafers. At a thickness of ∼30 μm, free-standing GaN and AlxGa1-xN wafers can easily be handled without cracking. Therefore, free-standing GaN and AlxGa1-xN wafers with thicknesses in the 30–100 μm range may be used as substrates for further growth of GaN and AlxGa1 xN-based structures and devices. We have compared different RF nitrogen plasma sources for the growth of thick nitride AlxGa1-xN films including a standard HD25 source from Oxford Applied Research and a novel high efficiency source from Riber. We have investigated a wide range of the growth rates from 0.2 to 3 μm/h. The use of highly efficient nitrogen RF plasma sources makes PA-MBE a potentially viable commercial process, since free-standing films can be achieved in a single day. Our results have demonstrated that MBE may be competitive with the other group III-nitrides bulk growth techniques in several important areas including production of free-standing zinc-blende (cubic) (Al)GaN and of free-standing wurtzite (hexagonal) AlGaN

Effect of feed pressure and long-term separation performance of Pebax-ionic liquid membranes for the recovery of difluoromethane (R32) from refrigerant mixture R410A

The R410A refrigerant blend (GWP = 2088), a near azeotropic and equimass mixture of difluoromethane (R32, GWP = 675) and pentafluoroethane (R125, GWP = 3500), has been included in the HFC phase down road map established worldwide. In this context, the recovery of value-added R32 from R410A using membrane technology would be a breakthrough in the refrigeration and air conditioning sector, given that conventional distillation cannot be applied to this separation. For the first time, this work has taken advantage of the combination of ionic liquids and polymeric membranes for the separation of the constituents of the R410A mixture. Results show a remarkable improvement in terms of R32 permeability and R32/R125 selectivity in the composite membranes containing 40 wt % [C2mim][SCN] (αR32/R125 up to 14.5) and [C2mim][BF4] (αR32/R125 up to 11.0) with respect to the neat polymer membranes (αR32/R125 up to 6.9). Besides, the long-term stability was successfully tested for 25 days under high pressure conditions (7 and 12 bar), which makes these composite membranes excellent candidates for the development of membrane-based R32 separation and recovery processes.This research is supported by Project KET4F-Gas – SOE2/P1/P0823, which is co-financed by the European Regional Development Fund within the framework of Interreg Sudoe Programme, and Project PID2019-105827RB-I00, Ministerio de Ciencia e Innovación (Spain). The authors acknowledge the collaboration of Dr. Rosario Benavente (Institute of Polymer Science and Technology-CSIC) to perform the DSC experiments. Dr. Fernando Pardo, acknowledges the post-doctoral fellowship (FJCI-2017-32884, ‘Juan de la Cierva Formación’) from the Spanish Ministry of Science, Innovation and Universities