Identification and quantification of flavonoid glycosides from fenugreek (Trigonella foenum-graecum) germinated seeds by LC-DAD-ESI/MS analysis

The phenolic composition of fenugreek (Trigonella foenum-graecum) germinated seeds originating from Morocco has been investigated. After germination, extraction was performed from defatted germinated seeds by a hydromethanolic solution using an accelerated solvent extractor. HPLC coupled to negative ion electrospray ionization mass spectrometry and diode array detection was employed to identify the polyphenol in the obtained fenugreek germinated seeds extract. A total of 28 identified phenolic compounds were grouped into flavone di C-glycosides, flavonol O-diglycosides, flavone tri- and tetra O-, C-glycosides and acylated flavone O-, C-glycosides. Most of the identified flavones were apigenin and luteolin adducts, while only two kaempferol glycosides were detected as flavonols. Quantitative analysis of the identified compounds showed that the phenolic composition of the studied germinated fenugreek seeds was predominated by acylated and non-acylated flavone derivatives with apigenin as main aglycone. Germinated fenugreek seeds could be considered as a rich source of bioactive phenolic compounds. © 2014 Elsevier Inc.Peer Reviewe

Simulation of FUS Protein Condensates with an Adapted Coarse-Grained Model

Disordered proteins and nucleic acids can condense into droplets that resemble the membraneless organelles observed in living cells. MD simulations offer a unique tool to characterize the molecular interactions governing the formation of these biomolecular condensates, their physicochemical properties, and the factors controlling their composition and size. However, biopolymer condensation depends sensitively on the balance between different energetic and entropic contributions. Here, we develop a general strategy to fine-tune the potential energy function for molecular dynamics simulations of biopolymer phase separation. We rebalance protein-protein interactions against solvation and entropic contributions to match the excess free energy of transferring proteins between dilute solution and condensate. We illustrate this formalism by simulating liquid droplet formation of the FUS low-complexity domain (LCD) with a rebalanced MARTINI model. By scaling the strength of the nonbonded interactions in the coarse-grained MARTINI potential energy function, we map out a phase diagram in the plane of protein concentration and interaction strength. Above a critical scaling factor of αc ≈ 0.6, FUS-LCD condensation is observed, where α = 1 and 0 correspond to full and repulsive interactions in the MARTINI model. For a scaling factor α = 0.65, we recover experimental densities of the dilute and dense phases, and thus the excess protein transfer free energy into the droplet and the saturation concentration where FUS-LCD condenses. In the region of phase separation, we simulate FUS-LCD droplets of four different sizes in stable equilibrium with the dilute phase and slabs of condensed FUS-LCD for tens of microseconds, and over one millisecond in aggregate. We determine surface tensions in the range of 0.01-0.4 mN/m from the fluctuations of the droplet shape and from the capillary-wave-like broadening of the interface between the two phases. From the dynamics of the protein end-to-end distance, we estimate shear viscosities from 0.001 to 0.02 Pa s for the FUS-LCD droplets with scaling factors α in the range of 0.625-0.75, where we observe liquid droplets. Significant hydration of the interior of the droplets keeps the proteins mobile and the droplets fluid

Laser processing of carbon black reinforced ethylene-butylacrylate copolymer

Interest in the phenomenon of laser ablation (LA) has gained significant attention in recent years due to its potential for machining, high-precision drilling, and cutting materials, such as metals, semiconductors, and dielectrics. Here, LA of ethylene-butyl acrylate (EBA) filled with different volume fractions (4%, 8%, and 20%) of CB particles is studied. Upon irradiation with the second harmonics (532 nm) of the nanosecond pulsed Nd:YAG laser, a structuration is evidenced at the sample surface in a restricted range of fluence and at high pulse number (PN) (500 pulses, 1 Hz). The laser-ablated surface is analyzed by microtopography, scanning electron microscopy (SEM), and x-ray photoelectron spectroscopy (XPS). Collectively, our data show a lowering in ablation threshold and depth for CB volume fractions larger than the conduction threshold (8%), indicating that visible radiation primarily induces photothermal effects. After redeposition of the ablation products at the surface, XPS indicates that high CB content in the EBA matrix induces high oxidation level of the composite surface. Furthermore, our results reveal that LA produces a significant proportion of amorphous carbon. Several parameters which affect heat accumulation and CB particle shielding are discussed. Such parameters include laser fluence and repetition rate, and CB content

Laser processing of carbon black reinforced ethylene‐butyl acrylate copolymer

International audienceInterest in the phenomenon of laser ablation (LA) has gained significant attention in recent years due to its potential for machining, high‐precision drilling, and cutting materials, such as metals, semiconductors, and dielectrics. Here, LA of ethylene‐butyl acrylate (EBA) filled with different volume fractions (4%, 8%, and 20%) of CB particles is studied. Upon irradiation with the second harmonics (532 nm) of the nanosecond pulsed Nd:YAG laser, a structuration is evidenced at the sample surface in a restricted range of fluence and at high pulse number (PN) (500 pulses, 1 Hz). The laser‐ablated surface is analyzed by microtopography, scanning electron microscopy (SEM), and x‐ray photoelectron spectroscopy (XPS). Collectively, our data show a lowering in ablation threshold and depth for CB volume fractions larger than the conduction threshold (8%), indicating that visible radiation primarily induces photothermal effects. After redeposition of the ablation products at the surface, XPS indicates that high CB content in the EBA matrix induces high oxidation level of the composite surface. Furthermore, our results reveal that LA produces a significant proportion of amorphous carbon. Several parameters which affect heat accumulation and CB particle shielding are discussed. Such parameters include laser fluence and repetition rate, and CB content

Laser processing of carbon black reinforced ethylene-butylacrylate copolymer

Interest in the phenomenon of laser ablation (LA) has gained significant attention in recent years due to its potential for machining, high-precision drilling, and cutting materials, such as metals, semiconductors, and dielectrics. Here, LA of ethylene-butyl acrylate (EBA) filled with different volume fractions (4%, 8%, and 20%) of CB particles is studied. Upon irradiation with the second harmonics (532 nm) of the nanosecond pulsed Nd:YAG laser, a structuration is evidenced at the sample surface in a restricted range of fluence and at high pulse number (PN) (500 pulses, 1 Hz). The laser-ablated surface is analyzed by microtopography, scanning electron microscopy (SEM), and x-ray photoelectron spectroscopy (XPS). Collectively, our data show a lowering in ablation threshold and depth for CB volume fractions larger than the conduction threshold (8%), indicating that visible radiation primarily induces photothermal effects. After redeposition of the ablation products at the surface, XPS indicates that high CB content in the EBA matrix induces high oxidation level of the composite surface. Furthermore, our results reveal that LA produces a significant proportion of amorphous carbon. Several parameters which affect heat accumulation and CB particle shielding are discussed. Such parameters include laser fluence and repetition rate, and CB content

Laser processing of carbon black reinforced ethylene-butylacrylate copolymer

Interest in the phenomenon of laser ablation (LA) has gained significant attention in recent years due to its potential for machining, high-precision drilling, and cutting materials, such as metals, semiconductors, and dielectrics. Here, LA of ethylene-butyl acrylate (EBA) filled with different volume fractions (4%, 8%, and 20%) of CB particles is studied. Upon irradiation with the second harmonics (532 nm) of the nanosecond pulsed Nd:YAG laser, a structuration is evidenced at the sample surface in a restricted range of fluence and at high pulse number (PN) (500 pulses, 1 Hz). The laser-ablated surface is analyzed by microtopography, scanning electron microscopy (SEM), and x-ray photoelectron spectroscopy (XPS). Collectively, our data show a lowering in ablation threshold and depth for CB volume fractions larger than the conduction threshold (8%), indicating that visible radiation primarily induces photothermal effects. After redeposition of the ablation products at the surface, XPS indicates that high CB content in the EBA matrix induces high oxidation level of the composite surface. Furthermore, our results reveal that LA produces a significant proportion of amorphous carbon. Several parameters which affect heat accumulation and CB particle shielding are discussed. Such parameters include laser fluence and repetition rate, and CB content

Laser processing of carbon black reinforced ethylene-butylacrylate copolymer

Interest in the phenomenon of laser ablation (LA) has gained significant attention in recent years due to its potential for machining, high-precision drilling, and cutting materials, such as metals, semiconductors, and dielectrics. Here, LA of ethylene-butyl acrylate (EBA) filled with different volume fractions (4%, 8%, and 20%) of CB particles is studied. Upon irradiation with the second harmonics (532 nm) of the nanosecond pulsed Nd:YAG laser, a structuration is evidenced at the sample surface in a restricted range of fluence and at high pulse number (PN) (500 pulses, 1 Hz). The laser-ablated surface is analyzed by microtopography, scanning electron microscopy (SEM), and x-ray photoelectron spectroscopy (XPS). Collectively, our data show a lowering in ablation threshold and depth for CB volume fractions larger than the conduction threshold (8%), indicating that visible radiation primarily induces photothermal effects. After redeposition of the ablation products at the surface, XPS indicates that high CB content in the EBA matrix induces high oxidation level of the composite surface. Furthermore, our results reveal that LA produces a significant proportion of amorphous carbon. Several parameters which affect heat accumulation and CB particle shielding are discussed. Such parameters include laser fluence and repetition rate, and CB content