Bioconversion of Corncob Acid Hydrolysate into Microbial Oil by the Oleaginous Yeast Lipomyces starkeyi

For the first time, corncob acid hydrolysate was used for microbial oil production by the oleaginous yeast Lipomyces starkeyi. After hydrolysis by dilute sulfuric acid, corncob could turn into an acid hydrolysate with a sugar concentration of about 42.3 g/L. Detoxified by overliming and absorption with activated carbon, the corncob hydrolysate could be used by L. starkeyi efficiently that a total biomass of 17.2 g/L with a lipid content of 47.0 % (corresponding to a lipid yield of 8.1 g/L) and a lipid coefficient of 20.9 could be obtained after cultivation on the corncob hydrolysate for 8 days. Therefore, L. starkeyi is a promising strain for microbial oil production from lignocellulosic biomass. Glucose and xylose were used by L. starkeyi simultaneously during lipid fermentation while arabinose could not be utilized by it. Besides, the lipid composition of L. starkeyi was similar to that of vegetable oils; thus, it is a promising feedstock for biodiesel production.     

Enhanced Enzymatic Hydrolysis of Palm Pressed Fiber Based on the Three Main Components: Cellulose,Hemicellulose, and Lignin

The enzymatic hydrolysis of the native and the pretreated palm pressed fiber (PPF) was deeply investigated by using the enzyme cocktail ACCELLERASE 1500. Together with the spent PPF from the first hydrolysis and the further doubly-treated PPF, the proportions of three main components were determined and analyzed based on a triangle figure. The proportion (cellulose/hemicelluloses/lignin) in the spent PPF was equal to 44:23:33 and the surface morphology of the spent PPF looks very similar to the native PPF surface showing poor hydrolysis efficiency. After further double treatment, the proportion was changed evidently from the original 44:23:33 to 54:21:25 and the surface structure was significantly disrupted showing a potential to be hydrolyzed completely. Additionally, all samples were characterized by Fourier transform infrared spectroscopy and X-ray diffractogram through considerations of alkaline solution treatment, so as to understand better the nature of biomass hydrolysis, from the aspect of three biomass components.     

Morphology Evolution of Poly（vinylidene fluoride） Membranes during Supercritical CO2 Assisted Phase Inversion

A supercritical carbon dioxide（Sc CO2） assisted phase inversion was developed to produce microporous poly（vinylidene fluoride）（PVDF） membranes whose morphology characteristics arise from both liquid-liquid demixing and solid-liquid demixing（crystallization）. This result was confirmed by Fourier transform infrared spectroscopy（FTIR）, from which both α and β crystals were found. As revealed by contact angle experiment, the PVDF membranes prepared via Sc CO2 assisted phase inversion were more hydrophobic compared with the control membrane produced via conventional immersionprecipitation technique. In particular, the sample with 15 wt% PVDF prepared at 45 °C and 13 MPa exhibited a contact angle of 142°, which was mainly caused by the multilevel micro- and nano- structure. The effects of polyethylene glycol（PEG）, polyvinyl pyrrolidone（PVP） and lithium chloride（Li Cl） on the structures and crystal form were investigated. PVP promoted the formation of β phase crystal form, while PEG boosts the evolution of α phase. Li Cl restrained the crystallization degree of PVDF membrane under Sc CO2.     

Preparation of raspberry-like silica microcapsules via sulfonated polystyrene template and aniline medium assembly method

Raspberry-like composite particles and microcapsules were prepared with anionic sulfonated polystyrene (PSS) particles as templates and cationic aniline monomer as assembly medium. With the help of the sulfonated microgel shells, aniline and silica particles could not only adsorbed onto template surfaces but also go inward shells and finally form microcapsules with varied silica shell thickness. The sulfonation extent of PSS particles first climbed up and then decreased with sulfonation time due to the competition of sulfonation reaction and PSS chain detachment. The silica content in composite particles and shell thickness of microcapsules followed similar trend with sulfonation extent. The choice of aniline as assembly medium was checked by comparing with methyl methacrylate and [2-(methacryloyloxy) ethyl] trimethylammonium chloride, and it was found that the cationic and water-insoluble properties of aniline are both important for the composite efficiency.     

Apoptosis in BEL-7402 cells induced by ruthenium(II) complexes through a ROS-mediated mitochondrial pathway

Three Ru(II) polypyridyl complexes [Ru(dmb)₂(HMSPIP)](ClO₄)₂ (1), [Ru(phen)₂(HMSPIP)](ClO₄)₂ (2) and [Ru(dmp)₂(HMSPIP)](ClO₄)₂ (3) were synthesized and characterized. The cytotoxicity in vitro, apoptosis, cell cycle arrest, reactive oxygen species and mitochondrial membrane potential were assayed. The IC₅₀ values of complexes 1, 2 and 3 toward BEL-7402, A549, MG-63 and SK-BR-3 cell lines ranged from 10.9 ± 1.6 to 42.0 ± 3.4 μM. Complexes 1, 2 and 3 can effectively induce apoptosis and inhibit the growth of BEL-7402 cells at the G2/M phase. These complexes can enhance the level of reactive oxygen species and induce decrease in the mitochondrial membrane potential. Additionally, complex 2 can down-regulate the expression of antiapoptotic protein of Bcl-2 protein and up-regulate the levels of proapoptotic protein Bim in BEL-7402 cells.     

Crystal structures, magnetic, dielectric and ferroelectric properties of two copper(II) complexes with m-nitrobenzoic acid

Reactions of CuCl₂, m-nitrobenzoic acid (HNBA) and NaOH with 2,2′-bipyridine (bpy) or 1,10-phenanthroline (phen) in aqueous ethanol afforded two Cu(II) complexes Cu(bpy)(NBA)₂, 1, and [Cu(phen)(H₂O)₂(NBA)](NBA), 2. The monomolecular Cu(bpy)(NBA)₂ moieties are both bridged by hydrogen bonding interactions and interlayer π ^*–π ^*stacking interactions to form a 3D (3,4,6)-connected supramolecular architecture with the Schäfli symbol of (4⁴·6²)(4⁴·6⁶·8⁵)(6³)₂. Complex 2 crystallizes in a noncentrosymmetric space group P2₁ where all molecules show the same orientation along the polar b axis. Preliminary investigations suggest that 2 exhibits ferroelectric hysteresis loops at room temperature with remanent polarization (P _r) of ca. 0.09 μC cm^?2 and coercive electric fields of 2.53 kV cm^?1, respectively. It may be a potential ferroelectric with a relatively large spontaneous polarization (P _s) of 0.22 μC cm^?2. Furthermore, permittivity property measurements reveal a dielectric constant (ε _r) of 6.36. Variable-temperature (2–300 K) magnetic susceptibility measurements showed the presence of weak ferromagnetic interactions between the Cu(II) ions for both 1 and 2.     

Hydrogen bond induced chiral symmetry breaking in the crystallization of nickel(II) complexes

A pair of enantiomers formulated as {Δ-cis-[Ni(en)₂OAc][ClO₄]} _n (Δ-1) and {Λ-cis-[Ni(en)₂OAc][ClO₄]} _n (Λ-1) (en = diaminoethane, OAc^? = acetate anion) were obtained when nickel acetate was reacted with diaminoethane and sodium perchlorate in the absence of any chiral source, whereas the reactions of nickel acetate with 1,3-propanediamine and sodium perchlorate only gave a centrosymmetric complex [Ni(1,3-pn)₂OAc][ClO₄] (2) (1,3-pn = 1,3-propanediamine). Single-crystal X-ray diffraction analyses of all three complexes indicated that the central Ni(II) atoms all have a distorted octahedral coordination geometry, being coordinated by four nitrogen atoms of the diamine ligands, plus two oxygen atoms of OAc^?. In complexes Δ-1 and Λ-1, the monomers of {Δ-cis-[Ni(en)₂OAc]}⁺ and {Λ-cis-[Ni(en)₂OAc]}⁺ are connected through intermolecular hydrogen bonds to generate one-dimensional right- and left-handed homochiral helical chains, respectively, while the monomers of [Ni(1,3-pn)₂OAc]⁺ are linked by similar intermolecular hydrogen bonds to form one-dimensional zigzag chains instead of helical chains. The chiral natures of complexes Δ-1 and Λ-1 have been confirmed by circular dichroism spectroscopy.     

Effects of nonlinearity of restoring springs on propulsion performance of wave glider

Nonlinear Dynamics - Wave glider is an unmanned surface vehicle that can directly convert wave energy into forward propulsion and fulfill long-term marine monitoring. A previous study suggested...     

Nonlinear oscillation of active magnetic bearing–rotor systems with a time-delayed proportional–derivative controller

Nonlinear Dynamics - A time-delayed proportional–derivative controller is applied to suppress the nonlinear vibration of a rigid rotor suspended by the active magnetic bearing (AMB) subjected...