Highly flexible all-optical wavelength conversion at 2.488 Gbits/s using a multi-output-wavelength laser

An integrated multiwavelength grating cavity (MGC) laser fabricated by selective area regrowth is demonstrated. In addition to allowing wavelength conversion, the device can perform various important network functions such as space switching and multiplexing. The use of the device for these functions offers several advantages from a wavelength division multiplexing (WDM) network, such as flexibility, reduced component count, size, and the associated cost reduction.

The transition mechanism of highly-loaded LP turbine blades

A detailed experimental investigation was conducted into the interaction of a converted wake and a separation bubble on the rear suction surface of a highly loaded low-pressure (LP) turbine blade. Boundary layer measurements, made with 2D LDA, revealed a new transition mechanism resulting from this interaction. Prior to the arrival of the wake, the boundary layer profiles in the separation region are inflexional. The perturbation of the separated shear layer caused by the converting wake causes an inviscid Kelvin-Helmholtz rollup of the shear layer. This results in the breakdown of the laminar shear layer and a rapid wake-induced transition in the separated shear layer.

A new low-power highly linear mixer design using differential derivative superposition

This paper presents the analysis and design of a new low power and highly linear mixer topology based on a newly reported differential derivative superposition method. Volterra series and harmonic balance are employed to investigate its linearisation mechanism and to optimise the design. A prototype mixer has been designed and is being implemented in 0.18μm CMOS technology. Simulation shows this mixer achieves 19.7dBm IIP3 with 10.5dB conversion gain, 13.2dB noise figure at 2.4GHz and only 3.8mW power consumption. This performance is competitive with already reported mixers.

A highly active anticomplement factor from the venom of Naja kaouthia

A highly active anticomplement factor (cobra venom factor) from the venom of Naja kaouthia in South Yunnan, China was isolated by sequential column chromatography (SP-Sephadex-C25, Q Sepharose HP and Sephadex G-150). It displays strong anticomplement acti

Dichotomains A and B: Two new highly oxygenated phenolic derivatives from Dicranopteris dichotoma

Dichotomains A (1) and B (2), two new highly oxygenated phenolic derivatives that feature a spirodilactone moiety in their structures, were isolated from the fronds of Dicranopteris dichotoma. Their structures were elucidated on the basis of NMR and MS sp

Sphenalactones A-D, a new class of highly oxygenated trinortriterpenoids from Schisandra sphenanthera

Four novel highly oxygenated trinortriterpenoids, sphenalactones A-D (1-4), were isolated from the leaves and stems of Schisandra sphenanthera and their structures were elucidated by extensive analysis of 1D and 2D NMR data. Compounds 1-4 featured a C-27

Single base-resolution methylome of the silkworm reveals a sparse epigenomic map

Epigenetic regulation in insects may have effects on diverse biological processes. Here we survey the methylome of a model insect, the silkworm Bombyx mori, at single-base resolution using Illumina high-throughput bisulfite sequencing (MethylC-Seq). We conservatively estimate that 0.11% of genomic cytosines are methylcytosines, all of which probably occur in CG dinucleotides. CG methylation is substantially enriched in gene bodies and is positively correlated with gene expression levels, suggesting it has a positive role in gene transcription. We find that transposable elements, promoters and ribosomal DNAs are hypomethylated, but in contrast, genomic loci matching small RNAs in gene bodies are densely methylated. This work contributes to our understanding of epigenetics in insects, and in contrast to previous studies of the highly methylated genomes of Arabidopsis(1) and human(2), demonstrates a strategy for sequencing the epigenomes of organisms such as insects that have low levels of methylation.

Velleratretraol, an unusual highly functionalized lactarane sesquiterpene from Lactarius vellereus

An unusual highly functionalized lactarane sesquiterpene, named velleratretraol (1), was isolated from the ethanol extract of the fruiting body of the mushroom Lactarius vellereus. Its structure was determined through spectroscopic analysis and single-cry

Highly Functionalized Daphnane Diterpenoids from Trigonostemon thyrsoideum

Trigonothyrins A-C (1-3), which are highly functionalized daphnane diterpenoids, were isolated from the stems of Trigonostemon thyrsoideum. Compounds 1-3 represent the first examples of daphnanes with an oxygen-bridged four-membered-ring system, and a linkage mode of 12,13,14-orthoester. Compound 3 was observed to inhibit HIV-1 induced cytopathic effects. The EC50 value was 2.19 mu g/mL, and the therapeutic index (TI) was more than 90.