Irisin,a Link among Fatty Liver Disease,Physical Inactivity and Insulin Resistance

Nonalcoholic fatty liver disease (NAFLD) is the most common cause of chronic liver disease in industrialized countries. The increasing prevalence of NAFLD mirrors the outbreak of obesity in western countries, highlighting the connection between these two conditions. Nevertheless, there is currently no specific pharmacotherapy for its treatment. Accepted management begins with weight loss and exercise. Moreover, exercise can provide metabolic benefits independently of weight loss. It is known how long-term aerobic training produces improvements in hepatic triglycerides, visceral adipose tissue and free fatty acids, even if there is no weight reduction. A recent study from Boström et al. unravels a potential molecular mechanism that may explain how exercise, independently of weight loss, can potentially improve metabolic parameters through a new messenger system (irisin) linking muscle and fat tissue. Irisin has been proposed to act as a hormone on subcutaneous white fat cells increasing energy expenditure by means of a program of brown-fat-like development. Moreover, it was also shown that irisin plasma concentration was higher in people who exercise, suggesting a molecular mechanism by which exercise may improve metabolism. The present systematic review is based on the possibility that irisin might represent a hypothetical connection between NAFLD pathogenesis and disease progression.     

Synthesis and characterization of poly (styrene‐b‐[(butadiene)1−x‐(ethylene‐co‐butylene)x] ‐b‐styrene) star‐like molecular polymers produced by partial hydrogenation of SBS

This article reports the synthesis and characterization of four arm star‐shaped poly(styrene‐b‐[(butadiene)_1?x‐(ethylene‐co‐butylene)_x]‐b‐styrene) (SBEBS) copolymers. A series of SBEBS copolymers with different compositions of the elastomeric block were produced by hydrogenating a given poly(styrene‐b‐butadiene‐b‐styrene) (SBS) copolymer using a catalyst prepared from bis(η⁵‐cyclopentadienyl)titanium(IV) dichloride and n‐butyllithium. The characterization was accomplished by proton nuclear magnetic resonance spectroscopy (¹H NMR), infrared spectroscopy (FTIR), gel permeation chromatography (GPC), differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), and thermogravimetric analysis (TGA). The results indicate that there is a selective saturation of the polybutadiene block over the polystyrene block; this selectivity was determined by the Ti/Li molar ratio and the concentration of Ti. It was observed that the saturation rate of the 1,2‐vinyl was higher than that of the 1,4‐trans and 1,4‐cis poly(butadiene)‐b isomers. The DSC and DMA results indicate that the degree of hydrogenation had a profound effect on the polymer's relaxation behavior. All samples exhibited a biphasic system behavior with two distinct transitions corresponding to the elastomeric and polystyrene blocks. SBEBS copolymers with higher saturation levels (>33%) exhibited a crystalline character. The TGA results indicated a characteristic weight loss temperature in all samples, with slightly higher thermal degradation stabilities in the materials with higher degrees of saturation. POLYM. ENG. SCI., 54:2332–2344, 2014. © 2013 Society of Plastics Engineers     

Aerosol Process for the In Situ Coating of Nanoparticles with a Polymer Shell

This article presents a novel method to encapsulate gas-borne nanoparticles with a polymeric shell. This method implies heterogeneous condensation of monomer vapor around the surface of nanoparticles as nuclei and polymerization is then subsequently started by addition of NH₃ as aerosol initiator. Ag and SiO₂ nanoparticles were generated as inorganic core by spark discharge and nebulization, respectively, and glycidyl methacrylate (GMA) was used as organic monomer. The effect of several parameters, including vapor pressure of monomer and properties of inorganic core such as morphology, material, particle size, and production method on the thickness of polymeric shell and morphology of resulting nanocomposites has been investigated. The particle size distribution and morphology of the resulting core-shell nanoparticles have been studied via scanning mobility particle sizer (SMPS) and transmission electron microscope (TEM). Finally, the coating efficiency was determined by aerosol photoemission (APE) and the results show that monomer and polymer coating efficiency are 99% and 60%, respectively.

Copyright 2014 American Association for Aerosol Research     

Dicing of hard and brittle materials with on-machine laser-dressed metal-bonded diamond blades

The ultra-precision dicing of hard and brittle materials causes high wear on the abrasive tool which results in the deterioration of blade cross section as well as the decrease of diamond grain exposure. Resin-bonded diamond blades are used due to their in-process self-sharpening capability. Nevertheless, the shape of the blade cross section generated by self-sharpening is random which leads to poor accuracy when precise grooves need to be produced. Metal-bonded diamond blades feature higher tool lifetime and shape accuracy compared to resin-bonded blades, but are not capable of performing self-sharpening. In this study, the laser dressing of metal-bonded diamond blades is investigated to enable their use in the ultra-precision dicing of hard and brittle materials by continuous laser dressing. We investigated laser dressing with and without the presence of cooling water. The sharpness (grain exposure) after dressing is measured by the cutting face surface roughness. The dicing performance is evaluated by observing the dicing results in terms of cutting depth consistency and by monitoring the spindle power during dicing. Dicing blades which have been laser dressed in an environment with coolant feature less grain exposure than dicing blades which have been laser dressed in dry condition. The dicing results show an improvement in the sharpness and durability of laser-dressed dicing blades in comparison with new or conventionally dressed blades. The ability to apply and perform laser dressing on a dicing machine in an environment with coolant shows the feasibility of laser technology for continuous dressing.     

Inductively coupled probe for the measurement of partial discharges

Partial discharges are a transient phenomena whose measurement is remarkably important for electrical equipment diagnosis and maintenance. These discharges appear in the measurement circuit as very narrow current pulses of some nanoseconds. Therefore, discharge pulse detection is a particularly difficult problem, especially because they are superposed on the high voltage waveforms that cause them. In this paper, we present an inductively coupled probe able to measure this physical phenomenon by means of a very simple and inexpensive device that can be installed in the equipment under test. After modeling the probe, its response will be compared to that of commercial devices using both calibrated discharges and partial discharges occurring at real power.     

Nanotribological properties of novel lubricants for magnetic tapes

Two classes of novel lubricants, perfluoropolyethers (PFPE) and ionic liquids (ILs), were deposited on metal film magnetic tapes. The adhesive force and coefficient of friction of lubricated and unlubricated tapes were investigated at the nanoscale with an atomic force microscope (AFM) as a function of various humidity and temperature conditions. Microscale tests with a ball-on-flat tribometer were also performed in order to study the length-scale effects on friction. Wear at ultralow loads was simulated and the lubricant removal mechanism was investigated by monitoring the friction force, surface potential and contact resistance with the AFM. Fourier transform infrared (FTIR) spectroscopy and X-ray photoelectron spectroscopy (XPS) experiments were conducted to determine the chemical species that affect intermolecular bonding and as an aid in interpreting how the lubricant film tribological properties vary with the environmental conditions. Z-TETRAOL, one of the PFPEs, was found to exhibit the lowest adhesion and friction among the lubricant films studied. The ionic liquid 1,1′-(pentane-1,5-diyl)bis(3-hydroxyethyl-1H-imidazolium-1-yl) di[bis(trifluoromethanesulfonyl)imide)] exhibited comparable nanotribological properties with the PFPEs. This is attributed to the presence of hydroxyl groups at its chain ends, which can hydrogen bond with the surface similar to PFPEs.     

Fatty and resin acids of spanishpinus pinaster Ait. Subspecies

The qualitative and quantitative composition of the acid fraction of wood extractives from three SpanishPinus pinaster Ait. subspecies (Atlantic, mountain Mediterranean and plain Mediterranean) were studied. Seven samples of each subspecies were prepared according to Technical Association of Pulp and Paper Standards, extracted with petroleum ether (b.p. 40–60°C) in a Soxhlet apparatus and saponified with ethanolic 0.4N potassium hydroxide. The acid fraction was methylated with diazomethane and studied by combined gas chromatography/mass spectrometry. The major constituents found were palmitic, oleic and linoleic among the fatty acids and pimaric, sandaracopimaric, levopimaric, isopimaric, abietic and dehydroabietic among the resin acids. Neoabietic and palustric acids were not found. Variations in the quantitative composition of the acid fraction enable us to distinguish the three subspecies. Main quantitative differences are found between the Atlantic subspecies and the two Mediterranean subspecies.     

Induction charge detector with multiple sensing stages

An induction charge detector yields the net charge and the time of flight of a particle. The unique ability to independently measure these two parameters sets apart this rather simple detection technique. The main shortcoming of this instrument is its high charge detection limit, resulting from the intrinsic noise of the detector electronics and the low signal associated with the charge to measure. The goal of the present work is to lower the detection limit of this detector. This article describes an induction charge detector whose main novelty is a sequence of aligned cylindrical electrodes for measuring the charge of a particle n times. In a time domain analysis, this feature reduces both the detection limit and the standard error of the charge measurement by factors of square root of 2 and square root of n. More importantly, sensing stages could be added to arbitrarily lower the detection limit in a frequency domain analysis.     

A portable wireless biometric multi-channel system

This article presents an 8-channel system for capturing bioelectric signals and transmitting them by the ZigBee protocol. It is a small, portable system with optimised power supply so that it can be battery fed. One of its main advantages is its versatility, since it enables each channel to be configured, in a dynamic and individualised way. This makes it possible to capture diverse bioelectric signals simultaneously, such as electrocardiogram (ECG), electroencephalogram (EEG), electrooculogram (EOG), etc. The developed system can be easily integrated into a Wireless Sensor Network based on ZigBee technology.     

Accuracy evaluation for sub-aperture interferometry measurements of a synchrotron mirror using virtual experiments

We present a virtual experiment for the accuracy assessment of the sub-aperture interferometric measurement of a synchrotron mirror involving several thousand sub-aperture topographies. The virtual experiment simulates the measurement process and accounts for the influence of positioning device errors, interferometer errors, non-perfect calibration of machine geometry as well as errors in the interferometer reference. Two principles are considered for reconstructing the form of a test specimen from the conducted sub-aperture topographies, a stitching procedure and a direct measurement method. The virtual experiments are applied to the task of absolute form measurement (including its radius of curvature) of a synchrotron mirror with a length of 30 cm, a width of 4 cm, a maximum curvature of about 44 mm⁻¹ and a peak-to-valley of 5 mm. As a result, reconstruction accuracies can be expected to be in the range of 100 nm when the stitching method is applied, which outperforms the direct measurement method by a factor of about 3.