We fabricate a Mach-Zehnder interferometer-based optical isolator using a silicon-wire waveguide with magneto-optic garnet cladding using direct bonding techniques. Using Si-wire waveguides, the size of the device is greatly reduced from that of our previous device. We investigate surface-activated direct bonding with nitrogen plasma treatment, which shows better bonding results than oxygen plasma treatment. A large magneto-optic phase shift of 0.8π and an optical isolation of 18 dB are obtained at a wavelength of 1322 nm.
Neonicotinoids have become the most widely used class of insecticides world-wide. Although numerous studies have documented neonicotinoid toxicity in bees and other insects, the effects of exposure during early development in mammals remain largely unexplored. We assessed the effects of the neonicotinoid imidacloprid (IMI) in adult male and female mice after in utero and early postnatal exposure. Pregnant mice were infused with IMI (0.5 mg/kg/day) from gestational day 4 to the end of nursing at postnatal day 21. The young adult offspring were studied in a series of biochemical and behavioral tests. To assess reproducibility, the behavioral analyses were conducted in three separate studies using multiple exposed litters. Exposure to IMI reduced fecundity, and in adult offspring, decreased body weight in male but not female pups. Offspring from IMI-treated mothers displayed lower triglycerides, elevated motor activity, enhanced social dominance, reduced depressive-like behavior, and a diminution in social aggression compared to vehicle treated controls. Low levels of IMI were detected in the brains and livers of the treated mothers, while trace levels were detected in some offspring. Our results demonstrate that transient exposure to a neonicotinoid over the early developmental period induces long-lasting changes in behavior and brain function in mice.
Although myo-inositol pyrophosphates such as diphosphoinositol pentakisphosphate (InsP) are important in biology, little quantitative information is available regarding their presence in mammalian organisms owing to the technical difficulties associated with accurately detecting these materials in biological samples. We have developed an analytical method whereby InsP and its precursor inositol hexakisphosphate (InsP) are determined directly and sensitively using tandem mass spectrometry coupled with hydrophilic interaction liquid chromatography (HILIC). InsP and InsP peak symmetry is influenced greatly by the buffer salt composition and pH of the mobile phase used in HILIC analysis. The use of 300 mM ammonium carbonate (pH 10.5) as an aqueous mobile phase resolves InsP and InsP on a polymer-based amino HILIC column with minimal peak tailing. Method validation shows that InsP and InsP can be quantitated from 20-500 pmol with minimal intra-day/inter-day variance in peak area and retention time. The concentration of InsP in C57BL/6J mouse brain (40.68 ± 3.84 pmol/mg wet weight) is successfully determined. HILIC‒MS/MS analysis using HEK293 culture cells confirms previous observations that InsP is induced by NaF treatment and ectopic expression of InsPK2, a primary kinase for InsP synthesis. Furthermore, this analysis reveals the abundance of InsP (50.46 ± 18.57 pmol/10 cells) and scarcity of InsP in human blood cells. The results demonstrate that HILIC‒MS/MS analysis can quantitate endogenous InsP and InsP in mouse and human samples, and we expect that the method will contribute to further understanding of InsP functions in mammalian pathobiology.
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