mTORC1 Inhibition via Rapamycin Promotes Triacylglycerol Lipolysis and Release of Free Fatty Acids in 3T3-L1 Adipocytes

Signaling by mTOR complex 1 (mTORC1) promotes anabolic cellular processes in response to growth factors, nutrients, and hormonal cues. Numerous clinical trials employing the mTORC1 inhibitor rapamycin (aka sirolimus) to immuno-suppress patients following organ transplantation have documented the development of hypertriglyceridemia and elevated serum free fatty acids (FFA). We therefore investigated the cellular role of mTORC1 in control of triacylglycerol (TAG) metabolism using cultured murine 3T3-L1 adipocytes. We found that treatment of adipocytes with rapamycin reduced insulin-stimulated TAG storage ~50%. To determine whether rapamycin reduces TAG storage by upregulating lipolytic rate, we treated adipocytes in the absence and presence of rapamycin and isoproterenol, a β2-adrenergic agonist that activates the cAMP/protein kinase A (PKA) pathway to promote lipolysis. We found that rapamycin augmented isoproterenol-induced lipolysis without altering cAMP levels. Rapamycin enhanced the isoproterenol-stimulated phosphorylation of hormone sensitive lipase (HSL) on Ser-563 (a PKA site), but had no effect on the phosphorylation of HSL S565 (an AMPK site). Additionally, rapamycin did not affect the isoproterenol-mediated phosphorylation of perilipin, a protein that coats the lipid droplet to initiate lipolysis upon phosphorylation by PKA. These data demonstrate that inhibition of mTORC1 signaling synergizes with the β-adrenergic-cAMP/PKA pathway to augment phosphorylation of HSL to promote hormone-induced lipolysis. Moreover, they reveal a novel metabolic function for mTORC1; mTORC1 signaling suppresses lipolysis, thus augmenting TAG storage.     

Effect of Al content on the corrosion behavior of Mg-Al alloys in aqueous solutions of different pH

The effect of systematic increase of Al content on the electrochemical behavior of the Mg-Al alloys in aqueous solutions of different pH was investigated. Different electrochemical methods such as open-circuit potential measurements, polarization techniques and electrochemical impedance spectroscopy, EIS, were used to investigate the electrochemical behavior of the alloys in aqueous solutions. The results have shown that Mg-5Al is easily corroded due to the microgalvanic effect between α-phase and β-phase, its corrosion rate is even higher than that of Mg itself. The increase of Al content increases the corrosion resistance of the alloy due to the formation of the β-phase (Mg₁₇Al₁₂) together with the Mg α-phase. The ranking of the corrosion rate of these alloys was Mg-5Al > Mg > Mg-10Al ≅ Mg-15Al. The corrosion rates of the alloys in acidic solutions are pronouncedly high compared to those measured in neutral or basic solutions. The impedance measurements are in consistence with the polarization techniques and the impedance data were fitted to theoretical data obtained according to an equivalent circuit model describing the electrode/electrolyte interface.     

Effect of ZrO2-doping of nanosized Fe2O3/MgO system on its structural,surface and catalytic properties

Fe₂O₃/MgO system was prepared by wet impregnation method followed by treatment with different amounts of Zr-dopant salt then heating at 500 and 700 °C. The dopant concentrations were 0.48, 0.95 and 1.4 mol% ZrO₂. Pure and variously doped solids were characterized using XRD, N₂-adsorption isotherms carried out at ?196 °C and catalytic decomposition of H₂O₂ in aqueous solution at 25–35 °C. The results revealed that the nanosized MgO phase was only detected in the diffractograms of pure and doped solids calcined at 500 °C. Heating pure and doped solids at 700 °C produced nanosized MgFe₂O₄ phase together with MgO phase. Pure and ZrO₂-doped solids calcined at 500 and 700 °C are mesoporous adsorbents. The doping process brought about a measurable decrease in the S_BET of Fe₂O₃/MgO system with subsequent increase in its catalytic activity. The catalytic activity of the investigated system toward H₂O₂ decomposition, expressed as reaction rate constant per unit surface area was found to increase as a function of dopant concentration. The maximum increase in the reaction rate constant per unit surface area measured for the reaction carried out at 30 °C attained 125% for the heavily doped samples. This significant increase was based on the catalytic activity of pure catalyst sample measured under the same conditions.     

Antimicrobial and antioxidant activity of Majorana syriaca in Yellowfin tuna

The antimicrobial and antioxidant effect of Majorana syriaca extract, obtained by ethyl acetate, to Yellowfin tuna was examined. The extract was added to refined corn oil at different concentrations (0–3900 ppm). Minced tuna was mixed with corn oil containing the extract (tuna/oil: 3/1 w/w); the mixture was packed aerobically and stored at 0 °C. Microbial growth and lipid oxidation were determined periodically. Majorana syriaca extract delayed the microbial growth (total viable count, Pseudomonas sp. and lactic acid bacteria) as compared with pure minced tuna, with an increasing effect as concentration increased. Oxidation was monitored through measurement of peroxide value and thiobarbituric acid-reactive substances. Both tests showed inhibition of tuna oxidation as the concentration of the extract increased. The results of the study show the potential of M. syriaca extract in extending the shelf life of tuna fish.     

An object-oriented multimedia database system for a news-on-demand application

We describe the design of a multimedia database management system for a distributed news-on-demand multimedia information system. News-on-demand is an application that uses broadband network services to deliver news articles to subscribers in the form of multimedia documents. Different news providers insert articles into the database, which are then accessed by users remotely, over a broadband, asynchronous transfer-mode (ATM) network. The particulars of our design are an object-oriented approach and strict adherence to international standards, in particular the Standard Generalized Mark-up Language (SGML) and Hy-Time. The multimedia database system has a visual query facility, which is also described in this paper. The visual query interface provides three major facilities for end users: presentation, navigation, and querying of multimedia news documents. The main focus, however, is the querying of multimedia objects stored in the database.     

A donor-supply electrode (DSE) for colloidal quantum dot photovoltaics

The highest-performing colloidal quantum dot (CQD) photovoltaics (PV) reported to date have relied on high-temperature (>500°C) annealing of electron-accepting TiO2. Room-temperature processing reduces energy payback time and manufacturing cost, enables flexible substrates, and permits tandem solar cells that integrate a small-bandgap back cell atop a low-thermal-budget larger-bandgap front cell. Here we report an electrode strategy that enables a depleted-heterojunction CQD PV device to be fabricated entirely at room temperature. We find that simply replacing the high-temperature-processed TiO2 with a sputtered version of the same material leads to poor performance due to the low mobility of the sputtered oxide. We develop instead a two-layer donor-supply electrode (DSE) in which a highly doped, shallow work function layer supplies a high density of free electrons to an ultrathin TiO2 layer via charge-transfer doping. Using the DSE we build all-room-temperature-processed small-bandgap (1 eV) colloidal quantum dot solar cells having 4% solar power conversion efficiency and high fill factor. These 1 eV bandgap cells are suitable for use as the back junction in tandem solar cells. The DSE concept, combined with control over TiO2 stoichiometry in sputtering, provides a much-needed tunable electrode to pair with quantum-size-effect CQD films.     

Ethoxylation of Fatty Acids Fractions of Overused Vegetable Oils

Unsaturated and saturated fatty acids fractions were separated from overused sunflower and olein oils, which are considered to be a waste, in order to use them in the preparation of valuable ethoxylated fatty derivatives with low cost of preparation. Fatty acid fractions were ethoxylated using ethylene oxide gas in the presence of 1% K₂CO₃ catalyst at 120 and 180 °C for 5, 6 and 7 h. Also fresh stearic acid and a fresh mixture of stearic acid:sunflower oil (1:1 wt/wt) were ethoxylated at 180 °C for 6 h for comparison. Results showed that effective fatty derivatives could be obtained from overused oils which may give an economic retrieval. Also, reaction conditions have different effects on the properties of the produced derivatives where the best results were obtained for samples prepared at 180 °C for 6 and 7 h. Ethoxylating the saturated fatty acids fraction of both overused oils especially olein oil gave better results than those of the unsaturated fraction, the ethoxylated fresh stearic acid and the ethoxylated fresh mixture of stearic acid:sunflower oil (1:1 wt/wt).     

PPG-based human identification using Mel-frequency cepstral coefficients and neural networks

Multimedia Tools and Applications - One of the known problems in security systems is to identify persons based on certain signatures. Biometrics have been adopted in security systems to identify...     

Sequencing and Welding of Molecular Single‐Crystal Optical Waveguides

Molecular crystals are promising anisotropic optical transducing media for next‐generation optoelectronic microdevices that will be capable of secure transduction of information and impervious to external electromagnetic interference. However, their full potential has not been explored yet due to their poor processability, low mechanical compliance, pronounced brittleness and high proneness to cracking that often result in irrecoverable damage. These issues are detrimental to their ability to transduce light. Here, a novel strategy is presented based on 3D epitaxial crystal growth of organic/inorganic crystals based on charge‐assisted hydrogen bonds that can be used to efficiently weld broken molecular single‐crystalline optical waveguides and restore their light‐transducing capability. This approach can also be applied to prepare asymmetric multidomain crystalline heterostructures starting from isostructural molecular tectons, resulting in novel opto/electro/mechanical functionalities in the hybrid materials. It also removes an important obstacle toward wider application of molecular crystals in the next‐generation optoelectronics.