Precision and accuracy of total body bone mass and body composition measurements in the rat using x-ray-based dual photon absorptiometry

Lean body mass (LBM), total body bone mineral mass (BMC), total body bone areal density (BMD), and body fat mass (FM) were measured in rats by dual photon absorptiometry (DXA), using two different instruments. The coefficients of variation for repeated measurements of LBM and FM were about 0.4 and 2.5%, respectively, over an animal body weight range of 150 to 600 g. For BMC and BMD, the coefficients of variation were less than 2%. The correlation coefficients for LBM, FM, BMC, and BMD measured on the two densitometers were all greater than 0.94. The slope of the regression line relating LBM measured by DXA and LBM measured by carcass analysis was 0.999, and the correlation coefficient was 0.99. For FM the slope was 1.05, and the correlation coefficient was 0.98. BMC measures by DXA were falsely low in small animals. For larger animals, the correlation between BMC and ash weight was 0.93, but the slope of the regression line was 0.78. DXA measures of LBM and FM were accurate and reproducible for rats weighing between 150 and 600 g. There was a size-dependent error in BMC, which will be significant in longitudinal measurements of bone mass.     

Voltammetric and Scanning Electrochemical Microscopic Studies of the Adsorption Kinetics and Self-Assembly of n-Alkanethiol Monolayers on Gold

The adsorption kinetics and self-assembly of hexadecyl mercaptan on gold have been investigated by scanning electrochemical microscopy (SECM), chronoamperometry, and cyclic voltammetry. The developed methodology allows one to evaluate the surface coverage and the average size of the defects in the monolayer film from the effective rate constant of electron transfer. Two kinetic regimes of self-assembly were identified: a rapid initial adsorption of hexadecyl mercaptan onto a clean gold surface from 5 mM solution (more than 90% coverage obtained in 1 to 5 min), and a slower subsequent annealing of a thiol monolayer resulting in a more compact film. Typically, a long-chain-length thiol-treated gold surface acts as an electronically insulating surface after about 1 h. The SECM images of partially covered gold surfaces were always featureless, suggesting that the defects in the film were smaller than 0.5 μm for any exposure time ≥ 1 min.     

Sol-gel multimode interference power splitters

We report on the design and fabrication of 1×32 MMI power splitters through the sol-gel process. The MMI splitter is designed for 1.55-μm wavelength and characterized in terms of tolerance, wavelength response, and polarization sensitivity. The splitter is then UV-imprinted in aluminosilicate material coated on SiO₂. It is found that the responses of fabricated and designed splitter are in good agreement, with an excess loss of ~0.75 dB and power uniformity of ~0.95 dB     

Biodegradation of Medicinal Plants Waste in an Anaerobic Digestion Reactor for Biogas Production

Glycyrrhiza glabra, Mint, Cuminum cyminum, Lavender and Arctium medicinal are considered as edible plants with therapeutic properties and as medicinal plants in Iran. After extraction process of medicinal plants, residual wastes are not suitable for animal feed and are considered as waste and as an environmental threat. At present there is no proper management of waste of these plants and they are burned or buried. The present study discusses the possibility of biogas production from Glycyrrhiza Glabra Waste (GGW), Mentha Waste (MW), Cuminum Cyminum Waste (CCW), Lavender Waste (LW) and Arctium Waste (AW). 250 g of these plants with TS of 10% were digested in the batch type reactors at the temperature of 35°C. The highest biogas production rate were observed to be 13611 mL and 13471 mL for CCW and GGW (10% TS), respectively. While the maximum methane was related to GGW with a value of 9041 mL (10% TS). The highest specific biogas and methane production were related to CCW with value of 247.4 mL.(g.VS)-1 and 65.1 mL.(g.VS)-1, respectively. As an important result, it was obvious that in lignocellulose materials, it cannot be concluded that the materials with similar ratio of C/N has the similar digestion and biogas production ability.     

Crystallization of Celsian (BaAl2Si2O8) Glass

The fabrication and crystallization of stoichiometric and near-stoichiometric celsian, BaAl₂Si₂O₈ (BAS), glass made via melt and sol-gel routes is reviewed. After considering celsian polymorphism and methods of stabilizing monoclinic celsian, some new experimental results are presented which show that melt glass crystallizes predominantly via surface nucleation, but sol-gel glass via volume nucleation. Possible reasons for this behavior and the kinetics of the crystallization process are examined.     

Microstructural evolution during fabrication of alumina via laser stereolithography technique

Application of additive manufacturing (AM) technology in production of ceramic parts is considered as a state-of-the-art technique which has been recently introduced to industry. In the current study the imperative microstructural characteristics of the alumina manufactured via laser stereolithography (SLA) has been investigated. The microstructural characteristics of the developed ceramic parts and components are still unknown and require detailed investigation. A combination of optical microscopy and scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), image analysis, X-ray diffraction (XRD) analysis, transmission electron microscopy (TEM) and micro-computed tomography (micro-CT) scans was used to evaluate the microstructural features of the alumina samples after each step of the manufacturing process (i.e. printing, debinding and sintering). In addition, the apparent density of each sample was measured using water displacement method. Results indicated that the porosity of printed alumina samples was significantly reduced after sintering process. EDS analysis confirmed elimination of binder material after debinding and sintering processes. XRD analysis detected existence of α-Al₂O₃ in initial printed samples which was not changed during debinding and sintering processes. Due to detection of identical peaks for all samples, only one set of lattice parameters ($\mathrm{a}$ and $\mathrm{c}$) was calculated from XRD patterns of all samples which was close to the ones reported in literature for alumina. TEM micrographs and corresponding diffraction patterns confirmed polycrystalline structure from different layers of the samples. High resolution transmission electron microscopy (HRTEM) and diffraction patterns from single layers were used to calculate lattice parameters for each sample. A slight increase was noticed in unit cell and grain size after sintering process. The obtained results help for better understanding of the properties through microstructural characteristics of the 3D printed ceramic parts.     

Implementation of IEEE 802.16e Standard on Xilinx ZC706: A C-RAN Prototype

Wireless Personal Communications - In this paper, we propose an architecture to implement IEEE 802.16e transmitter and receiver physical (PHY) layer on field programmable gate arrays. Several...     

Numerical simulation of planar shear flow passing a rotating cylinder at low Reynolds numbers

Two-dimensional shear flow over a rotating circular cylinder is investigated using lattice Boltzmann method. Simulations are performed at a fixed blockage ratio (B = 0.1) while the Reynolds number, nondimensional shear rate (K) and absolute rotational speed range as 80 ≤ Re ≤ 180, 0 ≤ K ≤ 0.2 and −2 ≤ β ≤ 2, respectively. To verify the simulation, the results are compared to previous experimental and numerical data. Quantitative information about the flow variables such as drag and lift coefficients, pressure coefficient and vorticity distributions on the cylinders is highlighted. It is found that, generally, with the increment in |β|, the absolute value of time average lift coefficient increases and time average drag coefficient decreases, and beyond a certain magnitude of β, the vortex shedding vanishes. It is also revealed that the drag coefficient decreases as the Reynolds number increases while the effect of the Reynolds number on lift is almost negligible. At the end, correlations for drag and lift coefficients ([`(C<sub>D</sub> )] ,[`(C_L )]){(\overline {C_D } ,\overline {C_L })} are extracted from the numerical data.     

Camellia sinensis tea melanin suppresses transformation of the aryl hydrocarbon receptor and prevents against dioxin-induced toxicity in mice

The suppressive effects of Camellia sinensis tea melanin (CSTM) on transformation of aryl hydrocarbon receptor (AhR) induced by 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) were disclosed for the first time. CSTM strongly inhibited TCDD-induced toxicity with IC₅₀ equalling 20.4 μg mL⁻¹. Daily administration of CSTM (40 mg kg⁻¹, p.o.) prevented TCDD-induced body weight loss, ameliorated TCDD-induced mortality and prevented TCDD-induced hepatomegaly and thymic atrophy. Co-administration of CSTM significantly inhibited TCDD-induced hepatic CYP1 A1 activity. CSTM retarded transformation of AhR in vitro. In animals treated with CSTM, the antibody-secreting cells produced significantly (P < 0.05) more antibodies (32–34%) than the antigen control. Administration of TCDD caused a suppression of antibody-forming cells of 29–33% against the antigen control level. Co-administration of CSTM restored immunity to the control level. We demonstrated that CSTM directly competed with TCDD during the transformation of AhR and suppressed the downstream activation of genes associated with TCDD toxicity.