Differential Effect of Dietary Supplementation with a Soybean Oil Enriched in Oleic Acid versus Linoleic Acid on Plasma Lipids and Atherosclerosis in LDLR-Deficient Mice

Both monounsaturated fatty acids (MUFAs) and polyunsaturated fatty acids (PUFAs) play important roles in lipid metabolism, and diets enriched with either of these two fatty acids are associated with decreased cardiovascular risk. Conventional soybean oil (CSO), a common food ingredient, predominantly contains linoleic acid (LA; C18:2), a n-6 PUFA. Recently, a modified soybean oil (MSO) enriched in oleic acid (C18:1), a n-9 MUFA, has been developed, because of its improved chemical stability to oxidation. However, the effect of the different dietary soybean oils on cardiovascular disease remains unknown. To test whether diets rich in CSO versus MSO would attenuate atherosclerosis development, LDL receptor knock-out (LDLR-KO) mice were fed a Western diet enriched in saturated fatty acids (control), or a Western diet supplemented with 5% (w/w) LA-rich CSO or high-oleic MSO for 12 weeks. Both soybean oils contained a similar amount of linolenic acid (C18:3 n-3). The CSO diet decreased plasma lipid levels and the cholesterol content of VLDL and LDL by approximately 18% (p < 0.05), likely from increased hepatic levels of PUFA, which favorably regulated genes involved in cholesterol metabolism. The MSO diet, but not the CSO diet, suppressed atherosclerotic plaque size compared to the Western control diet (Control Western diet: 6.5 ± 0.9%; CSO diet: 6.4 ± 0.7%; MSO diet: 4.0 ± 0.5%) (p < 0.05), independent of plasma lipid level changes. The MSO diet also decreased the ratio of n-6/n-3 PUFA in the liver (Control Western diet: 4.5 ± 0.2; CSO diet: 6.1 ± 0.2; MSO diet: 2.9 ± 0.2) (p < 0.05), which correlated with favorable hepatic gene expression changes in lipid metabolism and markers of systemic inflammation. In conclusion, supplementation of the Western diet with MSO, but not CSO, reduced atherosclerosis development in LDLR-KO mice independent of changes in plasma lipids.     

The lubricant migration rate on the hard disk surface

The optical surface analyzer (OSA) was found to be an excellent tool to examine the lubricant migration rate on thin film disks. Using the OSA it was found that the rate of lubricant migration increased as molecular weight decreased. An AM type perfluoropolyether with an aromatic end group and Z-Dol were also observed to have different migration rates for the same molecular weight. The migration rate of AM lubricant was increased significantly by the presence of X-1P as an additive in the lubricant system.     

Efficient Out of Core Sorting Algorithms for the Parallel Disks Model

In this paper we present efficient algorithms for sorting on the Parallel Disks Model (PDM). Numerous asymptotically optimal algorithms have been proposed in the literature. However many of these merge based algorithms have large underlying constants in the time bounds, because they suffer from the lack of read parallelism on PDM. The irregular consumption of the runs during the merge affects the read parallelism and contributes to the increased sorting time. In this paper we first introduce a novel idea called the dirty sequence accumulation that improves the read parallelism. Secondly, we show analytically that this idea can reduce the number of parallel I/O's required to sort the input close to the lower bound of [Formula: see text]. We experimentally verify our dirty sequence idea with the standard R-Way merge and show that our idea can reduce the number of parallel I/Os to sort on PDM significantly.     

Effects of spontaneous and piezoelectric polarization fields on the electronic and optical properties in GaN/AlN quantum dots: multimillion‐atom sp3d5s* tight‐binding simulations

GaN quantum dots (QDs) grown on AlN substrates are strong candidates for UV and near‐infrared applications. The wurtzite crystal symmetry in these dots induces internal fields arising from the following: (i) crystal atomicity;(ii) strained active region; (iii) piezoelectricity; and (iv) spontaneous polarization (pyroelectricity). Accurate modeling of electronic and optical properties of these QDs must capture the interplay of these atomistic and long‐range fields and the size quantization on an equal footing. In this work, single‐particle electronic structure and interband optical transition rates of a GaN/AlN QD grown along the c‐axis are studied using a coupled molecular mechanics‐atomistic 20‐band sp³d⁵s^* tight‐binding (VFF‐TB) framework. To calculate piezoelectricity, a recently reported model that takes into account both the linear and the nonlinear dependence of polarization on the strain tensors has been employed. The simulated GaN/AlN dot is realistically sized (containing ~3 million atoms) and of hexagonal disk shape having height and base length of 4.1 and 17 nm, respectively. It is found that, in contrast to the well‐studied InN/GaN systems, the pyroelectric potential in GaN/AlN dot is larger than the piezoelectric counterpart, and the effects of piezoelectric and pyroelectric fields add up. The internal fields result in a large redshift in the electronic states near the Brillouin zone center (known as quantum confined Stark effect), pronounced non‐degeneracy in the excited states, strongly suppressed optical transition, and anisotropic emission spectra. Copyright © 2014 John Wiley & Sons, Ltd.     

All that is silver is not toxic: silver ion and particle kinetics reveals the role of silver ion aging and dosimetry on the toxicity of silver nanoparticles

Background

When suspended in cell culture medium, nano-objects composed of soluble metals such as silver can dissolve resulting in ion formation, altered particle properties (e.g. mass, morphology, etc.), and modulated cellular dose. Cultured cells are exposed not just to nanoparticles but to a complex, dynamic mixture of altered nanoparticles, unbound ions, and ion-ligand complexes. Here, three different cell types (RAW 264.7 macrophages and bone marrow derived macrophages from wild-type C57BL/6?J mice and Scavenger Receptor A deficient (SR-A^(?/?)) mice) were exposed to 20 and 110?nm silver nanoparticles, and RAW 264.7 cells were exposed to freshly mixed silver ions, aged silver ions (ions incubated in cell culture medium), and ions formed from nanoparticle dissolution. The In Vitro Sedimentation, Diffusion, Dissolution, and Dosimetry Model (ISD3) was used to predict dose metrics for each exposure scenario.

Results

Silver nanoparticles, freshly mixed ions, and ions from nanoparticle dissolution were toxic, while aged ions were not toxic. Macrophages from SR-A^(?/?) mice did not take up 20?nm silver nanoparticles as well as wild-types but demonstrated no differences in silver levels after exposure to 110?nm nanoparticles. Dose response modeling with ISD3 predicted dose metrics suggest that amount of ions in cells and area under the curve (AUC) of ion amount in cells are the most predictive of cell viability after nanoparticle and combined nanoparticle/dissolution-formed-ions exposures, respectively.

Conclusions

Results of this study suggest that the unbound silver cation is the ultimate toxicant, and ions formed extracellularly drive toxicity after exposure to nanoparticles. Applying computational modeling (ISD3) to better understand dose metrics for soluble nanoparticles allows for better interpretation of in vitro hazard assessments.

     

Tribological Behaviour of Al6061–2SiC-xGr Hybrid Metal Matrix Nanocomposites Fabricated through Ultrasonically Assisted Stir Casting Technique

Silicon - This study deals with the tribological properties of 2&nbsp;wt.% of SiC and x wt.% of Gr (x = 0, 0.5, 1, 1.5, 2, and 3) nanoparticles reinforced Al6061 alloy fabricated...     

Tantalum—A bioactive metal for implants

Metallic biomaterials currently in use for load-bearing orthopedic applications are mostly bioinert and therefore lack sufficient osseointegration. Although bioactive ceramics such as hydroxyapatite (HA) can spontaneously bond to living bone tissue, low fracture toughness of HA limits their use as a bone substitute for load-bearing applications. Surface modification techniques such as HA coating on metals are current options to improve osseointegration in load-bearing metal implants. Over the last few decades researchers have attempted to find a bioactive metal with high mechanical strength and excellent fatigue resistance that can bond chemically with surrounding bone for orthopedic applications. Recent in vitro, in vivo, and clinical studies demonstrated that tantalum is a promising metal that is bioactive. However, tantalum applications in biomedical devices have been limited by processing challenges rather than biological performances. In this article, we provide an overview of processing aspects and biological properties of tantalum for load-bearing orthopedic applications.     

Secure emergency communication of cellular phones in ad hoc mode

In this paper we discuss the unique security characteristics of cell phones in ad hoc mode for emergency applications. We assume as first security requirements: secure authentication with non-repudiation, the need to stop the spread of malicious information as soon as possible, and the defence against potential Denial of Service.We provide solutions to the above security challenges for cell phone in ad hoc mode for emergency applications. In particular, we take advantage of the fact that cell phones were once part of a centralized network, which makes the distribution of security and trust information easier. We use identity based Cryptography to solve the problem of secure authenticated broadcast with non-repudiation.     

Spray deposition of CdTe–Te thin films using ethylene-diamine-tetra-acetic acid as a complexing agent in the precursor solution

CdTe thin films have been deposited by spray pyrolysis technique using varying concentration of Ethylene-diamine-tetra-acetic acid (EDTA) as a complexing agent (CA) in the precursor solution. Scanning electron micrographs show the films deposited with EDTA have a more homogeneous distribution of fine grains. X-ray diffraction patterns show that the films consist of a mixture of CdTe and Te, the Te peaks intensity increasing with EDTA concentration. X-ray photoelectron spectroscopy study of the surface reveals that there is a change-over in chemical environment of Te from −2 to +4 state after using CA. A broad photoluminescence peak at 1.40 eV is observed in the films without CA, which can be resolved into two peaks 1.43 and 1.40 eV. The intensities of both peaks are increased with EDTA due to formation of elemental Te and Cd vacancies. Optical study indicates that an increment in optical reflection due to Te metallic cluster formation in the film. Thus, the stoichiometry of the CdTe films can be controlled by varying EDTA concentration.