4-Ketozeinoxanthin,a novel carotenoid produced in Escherichia coli through metabolic engineering using carotenogenic genes of bacterium and liverwort

In order to produce a novel keto-carotenoid in Escherichia coli, we introduced the marine bacterial carotenoid ketolase gene (crtW) into pathway-engineered E. coli producing carotenoids of plant origin, which carried the lycopene biosynthesis genes (crtE, crtB, and crtI) from soil bacterium Pantoea ananatis and the liverwort Marchantia polymorpha genes that encode lycopene β-cyclase (MpLCYb), lycopene ε-cyclase (MpLCYe), and β-carotenoid hydroxylase (MpBHY). A novel keto-carotenoid (1) was produced by these carotenoid biosynthesis genes in E. coli along with α-echinenone, adonirubin, and adonixanthin. The structure of 1 was determined as (3S,6′R)-3-hydroxy-β,ε-caroten-4-one based on Uv–vis, MS, ¹H NMR, and CD spectral data. This compound was named 4-ketozeinoxanthin and showed anti-tumor-promoting activity.     

Removal efficiency of 75Se, 51Cr and 60Co from tidal water by mangrove sediments from Sepetiba Bay (SE Brazil)

Mangrove sediment cores sampled from Sepetiba Bay (SE Brazil) were covered with tidal water spiked with ⁷⁵Se, ⁵¹Cr and ⁶⁰Co to evaluate the removal efficiency of these radiotracers by underlying sediments. Variable time-evolution trends were observed along 115 h experiments, with significant differences between removal efficiencies of all radiotracers observed only after 70 h (⁵¹Cr > ⁶⁰Co > ⁷⁵Se). After an event of ⁶⁰Co release back to overlying water, there was a general trend of lower ⁶⁰Co removal than observed for other radiotracers during the period from 20 to 54 h. After this event, alternated periods of higher ⁶⁰Co and higher ⁷⁵Se removal trends were observed, attributed to behavioural differences expected for such anionic and cationic radiotracers. While ⁷⁵Se and ⁵¹Cr showed uniform time-evolution curves, as typically found in the literature for most radiotracers, ⁶⁰Co removal rates presented oscillations, probably due to sensitivity to changes in redox conditions within underlying sediments. Results evidenced the role of mangrove sediments as trace element sinks, which have implications for coastal water quality and for possible uses of such sediments in wastewater treatment systems.     

Power dependence of Brillouin linewidths in a silica fiber

We report the dependence of Brillouin linewidths on the pump power below the threshold of Brillouin lasing in a silica fiber. The Stokes Brillouin shift in a silica fiber is nearly unchanged, and its linewidth decreases with increasing pump power. However, the anti-Stokes Brillouin shift becomes smaller and its linewidth larger with increasing pump power. We explain these experimental results by the distributed fluctuating source model.     

Study on transport of molecules in gel by surface-enhanced Raman spectroscopy

Cellulose - Surface-enhanced Raman spectroscopy (SERS)-based biosensors have recently been extensively developed because of their high sensitivity and nondestructive nature. Conventional SERS...     

The ASACUSA CUSP: an antihydrogen experiment

In order to test CPT symmetry between antihydrogen and its counterpart hydrogen, the ASACUSA collaboration plans to perform high precision microwave spectroscopy of ground-state hyperfine splitting of antihydrogen atom in-flight. We have developed an apparatus (“cusp trap”) which consists of a superconducting anti-Helmholtz coil and multiple ring electrodes. For the preparation of slow antiprotons and positrons, Penning-Malmberg type traps were utilized. The spectrometer line was positioned downstream of the cusp trap. At the end of the beamline, an antihydrogen beam detector was located, which comprises an inorganic Bismuth Germanium Oxide (BGO) single-crystal scintillator housed in a vacuum duct and surrounding plastic scintillators. A significant fraction of antihydrogen atoms flowing out the cusp trap were detected.     

Improved Crystallinity of Poly(3-hexylthiophene-2,5-diyl):[6,6]-Phenyl-C61 Butyric Acid Methyl Ester Film by Pulsed Electrospray Deposition

We investigated crystallinity parameters and ordering domains of poly(3-hexylthiophene-2,5-diyl) blended in [6,6]-phenyl-C₆₁-butyric acid methyl ester films, which were fabricated by pulsed electrospray deposition methods. The crystallinity parameter and the ordering domain were estimated from Raman and optical absorption spectra, respectively. As a result, they were improved with decreasing the off time of pulse voltage, corresponding to the slow evaporation speed of solvent. In addition, both the space-charge limited current mobility and the photoconversion efficiency showed same trend. A highest photoconversion efficiency of 1.11 % was achieved without the thermal annealing process after depositing the active layer.     

Preparation and properties of a fullerene/polysiloxane hybrid from chemically modified fullerene and polymethoxysiloxane

An organic–inorganic hybrid was prepared by simply mixing a fullerene derivative with polymethoxysiloxane. First, C₆₀ was subjected to a radical addition reaction with 4,4′-azobis(4-cyanovaleric acid) to provide a C₆₀ derivative. Polymethoxysiloxane was prepared by a controlled hydrolytic condensation of tetramethoxysilane. These two compounds were mixed and heated to provide hybrid bulk body. The hybrid bulk body showed high mechanical strength and elastic modulus compared with polymethoxysiloxane or the C₆₀/polymethoxysiloxane hybrid. The formation of a dense siloxane network was established by a homogeneous mixing of the C₆₀ derivative with polymethoxysiloxane.