Effect of maternal cold exposure and nutrient restriction on insulin-like growth factor sensitivity in adipose tissue of newborn sheep

Adipose tissue mass in the newborn is determined in part by insulin-like growth factor (IGF)s, which are dependent on the maternal nutritional and metabolic environment during late gestation. The present study was designed to determine whether maternal cold exposure (CE) commencing in mid gestation could modulate some of the adaptive effects of nutrient restriction in late gestation on adipose tissue endocrine sensitivity in the resulting offspring. Twenty eight pregnant sheep were entered into the study and were either shorn, i.e. cold exposed, from 70 days gestation (term = 147 days), or remained unshorn, and were fed either their total calculated metabolisable energy (ME) requirements for body weight and pregnancy from 110 days gestation or 50% of this amount (n=7 per group). Adipose tissue was sampled from the offspring at one day of age and the mRNA abundance for IGF-I, II their receptors (R) and GH secretagogue receptor-1a (GHSR-1a) were determined. CE mothers produced larger offspring with more perirenal adipose tissue, an adaptation prevented by maternal nutrient restriction. Nutrient restriction in unshorn mothers increased IGF-I and IIR mRNA abundance. The mRNA abundances for IGF-I, II and IIR in adipose tissue were reduced by CE, adaptations independent of maternal food intake, whereas CE plus nutrient restriction increased GHSR-1a mRNA. In conclusion, maternal nutrient restriction with or without CE has very different effects on IGF sensitivity of adipose tissue and may act to ensure adequate fat stores are present in the newborn in the face of very different maternal endocrine and metabolic environments

Asymmetric double high mesa slot waveguide to enhance the light confinement in a 90o sharp bend

In this work, we propose a technique to enhance the confinement of light at 90o sharp bend of a double high mesa slot (DHMS) waveguide based on Silicon on Insulator (SOI). These waveguides deliver high electric field and optical power density in low refractive index Nano-metric slot. The slot is displaced to the inner and outer periphery of the bend and explores the deviation in the relative power. The maximum relative power is attained by shifting the slot towards the outer periphery of the bend. This is only conceivable by choosing the precise slot position where the two evanescent tails of the high index waveguide modes have maximum overlap.This work was supported by the Federal Agency of Scientific Organizations (agreement No 007-ГЗ/ 3363/26) and Ministry of Education and Science of the Russian Federation and the Russian Foundation for Basic Research (grant No. 16-37-00241 mol_a)

Optical elements based on silicon photonics

Silicon photonics is gaining substantial impulse because it permits optical devices to be realized inexpensively using standard semiconductor fabrication techniques and integrated with microelectronic chips. In this paper, we proposed some optical elements based on silicon platform simulated using Finite Element Method (FEM)

Modeling of a Fabry-Perot filter based on TiO2 and air gap by using Eigenvectors and Eigenvalues approach

We used Eigenvectors and Eigenvalues method to obtain transmittance coefficients for each of an interference filter. The filter is based on titanium dioxide layer (n=2.26) and air (n=1.0). The transmission spectra of the FP filter in mid- IR region shows a characteristic peak with a maximum of 86 % at 4.70 μm which is the fundamental absorption wavelength of CO which makes it possible to work as a gas sensor. The layers are horizontally stacked on one side which makes it possible to use air as a low index material. This gives an opportunity to deposit high index material in single deposition step which transforms the layer thickness into line thickness. As a result complex filter designs can be fabricated with simple and low production cost.This work was supported by the Federal Agency of Scientific Organizations (agreement No 007-ГЗ/Ч3363/26)

Designing of a 1 x 8 Optical power splitter based on coupled mode theory

In this work, we designed a T-shaped 1 x 8 balanced optical power splitter design based on the Coupled-mode theory. Vertical silicon slot waveguides are employed in the design which provides the optical confinement in TE-polarization. The layout of the optical power splitter is unique and offers four output ports with each on two sides of the chip. Furthermore, the bending losses of the waveguides are lessened by ~ 80 % by moving the slot towards the outer sideline of the bend as compared to the symmetric slot waveguide

Corrosion of beryllium exposed to celotex and water

Celotex is a commercial rigid cellulose fiberboard product primarily used in the building construction industry. Currently celotex is being used as a packing material in AL-R8 containers. Ion chromatography of celotex packing material at Lawrence Livermore National Laboratory (LLNL) has indicated that this material contains aggressive anions, including chloride, which may accelerate corrosion. It is well known that beryllium is susceptible to pitting corrosion when exposed to chloride containing environments. Levy noted pitting in beryllium at the open circuit potential when exposed to 0.1 M NaCl solution. This investigation attempts to evaluate the potential risk of accelerated beryllium corrosion from celotex and water which may occur naturally when celotex dust comes into contact with moisture from the atmosphere

A compact design of a balanced 1×4 optical power splitter based on silicon on insulator slot waveguides

In this paper, a compact design of a balanced 1×4 optical power splitter based on coupled mode theory (CMT) is presented. The design consists of seven vertically slotted waveguides based on the silicon-on-insulator platform. The 1×4 OPS is modelled using commercial finite element method (FEM) simulation tool COMSOL Multiphysics 5.1. The optimized OPS is capable of working across the whole C-band with maximum ~39 % of power decay in the wavelength range 1530 – 1565 nm.This work was partially financially supported by Ministry of Education and Science of Russian Federation, Russian Foundation for Basic Research (RFBR) (16-47-630677, 16-29-11744) and by the Federal Agency for Scientific Organizations (agreement No. 007-G7/C3363/26)

Modeling of a multilayer dielectric stack Notch filter for visible spectrum

In this work, a multilayer dielectric optical notch filters design for visible spectrum 450-700 nm is proposed based on TiO2 and SiO2 alternating layers. Titanium dioxide (TiO2) is selected for its high refractive index value (2.5) and Silicon dioxide (SiO2) as a low refractive index layer (1.45). These filters are conventionally anticipated for overpowering of powerful laser beams in research experiments, to obtain good signal-to-noise ratios in Raman laser spectroscopy. The designed filter shows a high quality with average transmission of more than 90% in 450-535 and 587-700 nm wavelength ranges. And a stop band region between 536-586 nm with a FWHM of 50 nm shows a transmission of 3% with an optical density of greater than 3, which makes it a promising element to be used as notch filter.This work was supported by the Ministry of Education and Science of the Russian Federation and the Russian Foundation for Basic Research (grant No. 16-47-630546)

Conditions of a single-mode rib channel waveguide based on dielectric TiO2/SiO2

In this paper, we propose conditions for the design of a single-mode rib channel waveguide based on dielectric materials such as titanium dioxide (TiO2) and silicon dioxide (SiO2) for the 0.633-µm visible light. We also design Y-splitter structures, which show high-degree optical confinement and low bend losses at various radii of curvatures. Small radii of curvatures are extremely desirable in integrated photonics as they permit decreasing the dimensions but can also potentially reduce power consumption in the active devices.The work was partially funded by the RF Ministry of Education and Science (# SP-4375.2016.5), a RF President's grant for support of leading scientific schools (# NSh-9498.2016.9) and RFBR (##17-47-630420, 17-47-630417, 16-47-630483, 15-07-01174)

Optical elements based on silicon photonics

Silicon photonics is gaining substantial impulse because it permits optical devices to be realized inexpensively using standard semiconductor fabrication techniques and integrated with microelectronic chips. In this paper, we designed few optical elements such as optical power splitter, polarization beam splitter and Bragg grating based on silicon platform simulated using finite element method.This work was financially supported by the Russian Foundation for Basic Research (grant No. 16-29-09528_ofi_m) for numerical calculations, by the Ministry of Science and Higher Education within the State assignment FSRC "Crystallography and Photonics" RAS (No. 007-GZ/Ch3363/26) for theoretical results