Stearoyl-CoA desaturase-1 (SCD1) is a key player in lipid metabolism. SCD1 catalyzes the synthesis of monounsaturated fatty acids (MUFA). MUFA are then incorporated into triacylglycerols and ...phospholipids. Previous studies have shown that
deficiency in mice induces metabolic changes in the liver characterized by a decrease in de novo lipogenesis and an increase in β-oxidation. Interestingly,
-deficient mice show a decrease in the expression and maturation of the principal lipogenic transcription factor sterol receptor element binding protein-1 (SREBP-1). The mechanisms mediating this effect on de novo lipogenesis and β-oxidation have not been fully elucidated. We evaluated the role of
on de novo lipogenesis and β-oxidation in HepG2 cells. We also used
-deficient mice and two strains of transgenic mice that produce either oleate (GLS5) or palmitoleate (GLS3) in a liver-specific manner. We demonstrate that the expression of β-oxidation markers increases in
-deficient hepatocytes and suggest that this is due to an increase in cellular polyunsaturated fatty acid content. We also show that the changes in the level of SREBP-1 expression, for both the precursor and the mature forms, are mainly due to the lack of oleate in
-deficient hepatocytes. Indeed, oleate treatment of cultured HepG2 cells or hepatic oleate production in chow-fed GLS5 mice can restore SREBP-1 expression and increase hepatic de novo lipogenesis. Finally, we show that oleate specifically increases SREBP-1 nuclear accumulation, suggesting a central role for oleate in SREBP-1 signaling activity.
•Fluorine, silicon atoms and SiF molecule adsorption process on Si(001)-p(2 × 2) surface have been studied.•The minimum energy paths for F diffusion and SiF decomposition on the silicon surface are ...explored using the nudged elastic band (NEB) method.•Our results show that the dissociative adsorption of the SiF molecule is energetically the most favorable.•We have found that it is energetically easier for the fluorine atom to diffuse from the SiF molecule towards the surface than the diffusion from a surface site to another.
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The adsorption of the F and Si atoms as well as the SiF molecule on the Si(001)-p(2×2) surface is studied using first-principle calculations. Our results show that the fluorine atom saturates the dangling bond of the surface while the silicon adatom forms two bonds with the surface atoms. For the adsorption of the SiF molecule, we obtained one dissociative state which is the most stable one and seven non-dissociative states. The minimum energy paths for F diffusion and SiF decomposition on the silicon surface are explored using the nudged elastic band (NEB) method. Our study reveals that it is energetically favorable for the fluorine atom to diffuse from the SiF molecule to a surface site than the diffusion from surface site to another one.
In this study, we have harvested natural oleaster (wild olive) fibers, processed and characterized in terms of physicochemical performance as well as mechanical properties. The main constituents of ...oleaster fibers with their weight proportions are cellulose (38.11%), lignin (19.4%), and ash (3.1%). The specific density of the oleaster fiber is measured to (1.40256 g cm
−3
). The average elastic modulus, tensile strength, and elongation at the break of composites made from polymer resin and oleaster fibers (untreated and treated with 20% acetic anhydride) have undergone an improvement in mechanical properties, respectively, an elastic modulus of 8.39 MPa for a deformation of 0.48334% against for the treated composite with the deformation of 3.95%for an elastic modulus of 55.53 MPa. Their Young moduli are 41.029 GPa for the untreated fiber composite and 93.19 GPa for the acetic anhydride treated fiber composite, respectively. We have also studied the effects of acetic anhydride treatment on the mechanical properties and structure of the fibers. When treated with 20% acetic anhydride for 2 h, the tensile strength of oleaster fibers had increased significantly. A longer treatment time did not show any appreciable improvement. However, the tensile strength remained higher than the tensile strength for untreated fibers.
Abstract
In this study, an optical filter based on a plasmonic metal-insulator-metal (MIM) coupled waveguide resonator is simulated and investigated. Using the proposed structure leads to realizing a ...filter function between targeted wavelengths by manipulating the appropriate geometrical parameters of the resonators. Two-dimensional FDTD-based simulation is implemented to analyze the filter properties. The filter proposed proves to be a potential candidate for highly integrated optical circuit applications.
SCD1 deficiency protects mice against ethanol-induced liver injury Lounis, Mohamed A.; Escoula, Quentin; Veillette, Cathy ...
Biochimica and biophysica acta. Molecular and cell biology of lipids,
November 2016, 2016-11-00, Letnik:
1861, Številka:
11
Journal Article
Recenzirano
Odprti dostop
Stearoyl-CoA desaturase 1 (SCD1) is a delta-9 fatty acid desaturase that catalyzes the synthesis of mono-unsaturated fatty acids (MUFA). SCD1 is a critical control point regulating hepatic lipid ...synthesis and β-oxidation. Scd1 KO mice are resistant to the development of diet-induced non-alcoholic fatty liver disease (NAFLD). Using a chronic-binge protocol of ethanol-mediated liver injury, we aimed to determine if these KO mice are also resistant to the development of alcoholic fatty liver disease (AFLD).
Mice fed a low-fat diet (especially low in MUFA) containing 5% ethanol for 10days, followed by a single ethanol (5g/kg) gavage, developed severe liver injury manifesting as hepatic steatosis. This was associated with an increase in de novo lipogenesis and inflammation. Using this model, we show that Scd1 KO mice are resistant to the development of AFLD. Scd1 KO mice do not show accumulation of hepatic triglycerides, activation of de novo lipogenesis nor elevation of cytokines or other pro-inflammatory markers. Incubating HepG2 cells with a SCD1 inhibitor induced a similar resistance to the effect of ethanol, confirming a role for SCD1 activity in mediating ethanol-induced hepatic injury.
Taken together, our study shows that SCD1 is a key player in the development of AFLD and associated deleterious effects, and suggests SCD1 inhibition as a therapeutic option for the treatment of this hepatic disease.
•Chronic+binge protocol of ethanol abuse in low fat and low MUFA diet induces liver injury.•SCD1 deficiency protects mice against ethanol-induced liver injury.•SCD1 KO mice do not develop alcoholic hepatic steatosis or inflammation.•SCD1 inhibitor shows a similar effect on cultured hepatocytes.•Inhibition of SCD1 activity could represent a therapeutic target for alcoholic steatosis.
RD53 pixel chips for the ATLAS and CMS Phase-2 upgrades at HL-LHC Loddo, F.; Andreazza, A.; Arteche, F. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
October 2024, Letnik:
1067
Journal Article
Recenzirano
The Phase-2 upgrades at the High-Luminosity LHC of ATLAS and CMS experiments at CERN will require a new tracker with readout electronics operating in extremely harsh radiation environment (1 Grad), ...high hit rate (3.5 GHz/cm2) and high data rate readout (5 Gb/s). The RD53 collaboration is a joint effort between the ATLAS and CMS to qualify the chosen 65 nm CMOS technology in high radiation environment and develop the pixel readout chips of both experiments. After a half-scale demonstrator (RD53A) and full scale prototypes of the two ASICs (RD53B-ATLAS and RD53B-CMS), largely used by the two communities to characterize 3D and planar sensors, RD53 developed and submitted to foundry in 2023 the production chips. A general overview of the chip architecture will be described.
The effects of equilibrium time, solution pH, and sorption temperature of cationic methylene blue (MB) adsorption on nanoporous metallosilicoaluminophosphate ZnAPSO-34 were studied using a batch ...equilibration method. UV-Vis spectroscopy was used to obtain the adsorption isotherms at 20degreesC. The optimum period for adsorption was 300 min. In fact, MB removal increased from 82 to 95% when we double the amount of adsorbent from 0.05 to 0.1 gl super(-1). The equilibrium adsorption data were analyzed using Langmuir, Freundlich, and Temkin isotherm models. Langmuir isotherm was found to be the best-fitting model and the process followed pseudo-second-order kinetics. The results showed that ZnAPSO-34 could be employed as an alternative for the removal of dyes and colorants from aqueous solutions.
Abstract
For operation at the High Luminosity Large Hadron Collider
(LHC), the ATLAS experiment is building a new all-silicon inner
tracker (ITk). The production and testing of thousands of silicon
...pixel and strip modules is required to cover the estimated
180 m
2
of the total surface area. A compact, affordable and
robust module characterization system is required for in-situ
testing prior any test beam campaign or installation. A test bench
setup based on an infrared laser was developed at IJCLab, allowing
also for the use of micro-metric precision scanning with a
radioactive source. A detailed schema of the setup, operating
principles and testing methods are described in this paper, together
with the first results obtained with a FE-I4 silicon pixel module.
Adsorption of uranium ions from aqueous solutions onto Aleppo pine sawdust was carried out in this study. This adsorbent is untreated, modified with NaOH, and neutron irradiated. The parametric study ...of uranium(VI) adsorption from aqueous solution onto untreated Aleppo pine sawdust has been investigated using batch equilibrium method at 293 K. The removal efficiency is studied as function of the effect of pH, adsorbent ratio, and contact time. A maximum adsorption capacity was obtained at pH 5 with an adsorbent ratio of 1 g/100 and an equilibrium time of 120 min for all the initial used concentrations. The kinetics of the adsorption process followed a second-order adsorption and the biphasic nature of the plot for intraparticle diffusion, showed diffusion through a film that is followed by a diffusion in the pores. The thermodynamic constants obtained at different temperatures, such as Image omitted., Image omitted., and Image omitted. suggested that the adsorption process is exothermic and spontaneous. In order to compare the adsorption capacities, both NaOH-treated and neutron-irradiated Aleppo pine sawdust were used for uranium(VI) adsorption using the optimal parameters obtained previously. Changes in physicochemical properties of the modified adsorbents were observed with FTIR and scanning electron microscope analyses. Adsorption tests showed that both treated sawdusts gave adsorption capacities better than the untreated sawdust. Four equilibrium models (Langmuir, Freundlich, Dubinin-Radushkevich, and Temkin) were applied to the experimental data in order to determine the better model for the systems. Langmuir isotherm seems the most appropriate for the adsorption of uranium(VI) with maximum adsorption capacities of 19.56, 48.66, 35.15, and 30.98 mg/g for the untreated, treated with NaOH, and neutron-irradiated (1 H and 4 H) sawdust, respectively.
This paper presents the bending and buckling analyses of simply supported nanowires using various classical and nonclassical higher-order shear deformation theories (HSDTs). A one-dimensional ...structure is modeled with including the surface effects based on the Gurtin–Murdoch surface elasticity theory (nonclassical beam theory) and the small-scale effect based on the Eringen nonlocal theory (nonlocal beam theory); the transverse displacement is divided into two bending and shear components. A system of governing equations is derived with the help of the minimum total potential energy principle and resolved via Navier’s solutions. Several numerical results are presented and compared with those given in the literature. The results showed that the influence of the surface effects on the bending and buckling load of nanowires is more pronounced than that of the nonlocal parameter.
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