Highly Efficient Conversion of Cellulose to Bio-Oil in Hot-Compressed Water with Ultrasonic Pretreatment

Ultrasonic pretreatment was developed to increase conversion of cellulose to bio-oil in hot-compressed water. The physical structures of cellulose were greatly changed by ultrasonic pretreatment, resulting in excellent swelling and dispersion of cellulose in the water. With the increased surface area and decreased crystallinity and degree of polymerization of cellulose, the bio-oil yield was increased remarkably. The highest bio-oil yield (61.5%) was obtained at 260 °C with a residence time of 0 min for the 1 h pretreated cellulose. Under the optimum reaction conditions, ultrasonic pretreatment increased the bio-oil yield by 22.1% and reduced residence time by 5 min. GC-MS analysis results showed that ultrasonic pretreatment affected the chemical compositions of bio-oils and significantly improved the content of 5-hydroxymethylfurfural in heavy oils

Conversion of Cornstalk to Bio-oil in Hot-Compressed Water: Effects of Ultrasonic Pretreatment on the Yield and Chemical Composition of Bio-oil, Carbon Balance, and Energy Recovery

An ultrasonic pretreatment method was developed to enhance the yield of bio-oil obtained from the liquefaction of cornstalks in hot-compressed water at different reaction temperatures (260–340 °C) and residence times (0–40 min). Influences of ultrasonic pretreatment on the physicochemical properties of cornstalks and bio-oil yields were investigated. The results show that ultrasonic pretreatment obviously increases surface areas of cornstalks, decreases crystallinities, and erodes the structures of lignin, leading to more exposure of cellulose and hemicellulose. The yield of bio-oil was increased remarkably by 10.1% for 40 min sonicated cornstalks under the optimum liquefied conditions (300 °C for 0 min of residence time). Carbon balance indicates that ultrasonic pretreatment increases the carbon conversion of cornstalks to heavy oil and water-soluble oil. Energy balance indicates that the sonicated cornstalks have positive energy efficiencies. GC-MS analyses demonstrate ultrasonic pretreatment increases the contents of the phenols in heavy oil and water-soluble oil

Ultrasensitive Detection of Aminopeptidase N Activity in Urine and Cells with a Ratiometric Fluorescence Probe

An ultrasensitive ratiometric fluorescent probe (CVN) has been designed and synthesized by incorporating alanine into the cresyl violet fluorophore. The probe shows ratiometric fluorescence response toward aminopeptidase N (APN) through the increase of fluorescent intensity ratio of 626/575 nm. The sensitivity of the probe is ultrahigh with a detection limit of 33 pg/mL, which can quantify the contents of APN in 500-fold diluted human urine samples. Furthermore, by using ratiometric fluorescence imaging, the probe reveals significantly higher contents of APN in HepG2 cells than those in LO2 cells, which has been further used to distinguish these two types of cells in mixed cocultures. The probe could be of great importance for the APN-related disease diagnosis and pathophysiology elucidation

One-Pot Conversion of Bio-oil to Diesel- and Jet-Fuel-Range Hydrocarbons in Supercritical Cyclohexane

This study demonstrates a new route for converting bio-oil, prepared from the hydrothermal liquefaction of cornstalks, to diesel- and jet-fuel-range hydrocarbons over Ni/ZrO₂ in supercritical cyclohexane. Under relatively mild conditions (573 K, 5 MPa H₂), we obtained a high yield (81.6 C%) of hydrocarbons with an excellent quality (90% of diesel- and jet-fuel-range hydrocarbons and 7% of gasoline-range hydrocarbons). Ni/ZrO₂ efficiently and stably catalyzed all types of compounds in the bio-oil to the corresponding alkanes via hydrogenation, dehydration, hydrogenolysis, decarbonylation, and isomerization, without polymerizations among the different reactive compounds in bio-oil. The activity and selectivity for diesel- and jet-fuel-range hydrocarbons of Ni/ZrO₂ showed no obvious changes after three cycles. Ni/ZrO₂ was fairly stable in supercritical cyclohexane after 72 h of reaction time. This strategy provides a novel high-efficiency pathway for the preparation of high-quality hydrocarbons from bio-oil

Ratiometric Fluorescent Probe for Imaging of Pantetheinase in Living Cells

Pantetheinase, which catalyzes the cleavage of pantetheine to pantothenic acid (vitamin B5) and cysteamine, is involved in the regulation of oxidative stress, pantothenate recycling and cell migration. However, further elucidating the cellular function of this enzyme is largely limited by the lack of a suitable fluorescence imaging probe. By conjugating pantothenic acid with cresyl violet, herein we develop a new fluorescence probe CV-PA for the assay of pantetheinase. The probe not only possesses long analytical wavelengths but also displays linear ratiometric (<i>I</i>_628/582 nm) fluorescence response to pantetheinase in the range of 5–400 ng/mL with a detection limit of 4.7 ng/mL. This probe has been used to evaluate the efficiency of different inhibitors and quantitatively detect pantetheinase in serum samples, revealing that pantetheinase in fetal bovine serum and new born calf serum is much higher than that in normal human serum. Notably, with the probe the ratiometric imaging and in situ quantitative comparison of pantetheinase in different living cells (LO2 and HK-2) have been achieved for the first time. It is found that the level of pantetheinase in LO2 cells is much larger than that in HK-2 cells, as further validated by Western blot analysis. The proposed probe may be useful to better understand the specific function of pantetheinase in the pantetheinase-related pathophysiological processes

Analytical model.

<p>Figure 1 illustrated the unit cell adopted for plane strain conditions. The change of flow occurred in the <i>z</i> direction and <i>x</i> direction. (A) <i>dQ</i>_x demonstrated the flow in the <i>x</i> direction of the drain from the entrance to the exit of the unit cell. (B) The total change in flow from the entrance face to the exit face of the unit cell was given by <i>Q</i>_z. (C) Considering the incompressibility of water, <i>dQ</i>_x was equal to–<i>dQ</i>_z. The equation can be established according to plane strain unit cell.</p

Comparison of analytical result and measures result.

<p>The trends of the mean measured value and the mean analytical value processes were comparable. The mean analytical result agreed well with the mean measured value during the first 5 h. Different value appeared 5 h later, when the mean measured result was larger than the mean analytical result. Electrolytic exothermic and chemical reactions among ions can give rise to changes in the pore-water pressure, which was neglected by the analytical derivation The final mean measured value was about 61 kPa.</p

Inkjet Printing Patterns of Highly Conductive Pristine Graphene on Flexible Substrates

Highly conductive pristine graphene electrodes were fabricated by inkjet printing using ethyl cellulose-stabilized ink prepared from pristine graphene. Pristine graphene was generated by exfoliation from graphite using ultrasound-assisted supercritical CO₂. The ink, at concentrations up to 1 mg/mL, was stable for more than 9 months and had compatible fluidic characteristics for efficient and reliable inkjet printing. The inkjet printing patterns of the graphene on diverse substrates were uniform and continuous. After 30 printing passes and annealing at 300 °C for 30 min, the printed films developed a high conductivity of 9.24 × 10³ S/m. The resistivity of the printed electrodes on the flexible substrates increased by less than 5% after 1000 bending cycles and by 5.3% under a folding angle of 180°. The presented exfoliated pristine graphene and the corresponding efficient methods for formulating the ink and fabricating conductive electrodes are expected to have high potential in applications involving graphene-based flexible electronic devices

Unravelling Doping Effects on PEDOT at the Molecular Level: From Geometry to Thermoelectric Transport Properties

Tuning carrier concentration via chemical doping is the most successful strategy to optimize the thermoelectric figure of merit. Nevertheless, how the dopants affect charge transport is not completely understood. Here we unravel the doping effects by explicitly including the scattering of charge carriers with dopants on thermoelectric properties of poly­(3,4-ethylenedioxythiophene), PEDOT, which is a p-type thermoelectric material with the highest figure of merit reported. We corroborate that the PEDOT exhibits a distinct transition from the aromatic to quinoid-like structure of backbone, and a semiconductor-to-metal transition with an increase in the level of doping. We identify a close-to-unity charge transfer from PEDOT to the dopant, and find that the ionized impurity scattering dominates over the acoustic phonon scattering in the doped PEDOT. By incorporating both scattering mechanisms, the doped PEDOT exhibits mobility, Seebeck coefficient and power factors in very good agreement with the experimental data, and the lightly doped PEDOT exhibits thermoelectric properties superior to the heavily doped one. We reveal that the thermoelectric transport is highly anisotropic in ordered crystals, and suggest to utilize large power factors in the direction of polymer backbone and low lattice thermal conductivity in the stacking and lamellar directions, which is viable in chain-oriented amorphous nanofibers