Magnetic tubular nickel@silica-graphene nanocomposites with high preconcentration capacity for organothiophosphate pesticide removal in environmental water: Fabrication, magnetic solid-phase extraction, and trace detection.

Organothiophosphate pesticides (OPPs) are the most common water contaminants, significantly endangering human health and bringing serious public safety issues. Thus, developing effective technologies for the removal or trace detection of OPPs from water is urgent. Herein, a novel graphene-based silica-coated core-shell tubular magnetic nanocomposite (Ni@SiO2-G) was fabricated for the first time and used for the efficient magnetic solid-phase extraction (MSPE) of the OPPs chlorpyrifos, diazinon, and fenitrothion from environmental water. The experimental factors affecting extraction efficiency such as adsorbent dosage, extraction time, desorption solvent, desorption mode, desorption time, and adsorbent type were evaluated. The synthesized Ni@SiO2-G nanocomposites showed a higher preconcentration capacity than the Ni nanotubes, Ni@SiO2 nanotubes, and graphene. Under the optimized conditions, 5 mg of tubular nano-adsorbent displayed good linearity within the range of 0.1-1 µg·mL-1, low limits of detection (0.04-0.25 pg·mL-1), low limits of quantification (0.132-0.834 pg·mL-1), good reusability (n = 5; relative standard deviations between 1.46% and 9.65%), low dosage (5 mg), and low real detection concentration (< 3.0 ng·mL-1). Moreover, the possible interaction mechanism was investigated by density functional theory calculation. Results showed that Ni@SiO2-G was a potential magnetic material for the preconcentration and extraction of formed OPPs at ultra-trace levels from environmental water.

[Different concentration of lidocaine used for an exodontia of the impacted mandibular third molar].

PURPOSE: To investigate the anesthesia outcomes of 1% lidocaine with 1∶100 000 epinephrine (EPI) for inferior alveolar nerve, lingual nerve and buccal nerve block, compared with 2% lidocaine with 1∶100 000 EPI. METHODS: A study with a cross-over design, with each patient also serving as their own control, was implemented to estimate the clinical outcomes. Predictor variable was 1% lidocaine with 1∶100 000 EPI versus 2% lidocaine with 1∶100 000 EPI. Outcome variables were patients' responses to pain on injection, onset time of anesthetizing, efficacy of anesthesia, and the time to sensation return for the lower lip and tongue. Patients reported pain level at every experimental stage with a 10-point Numerical Rating Scale(NRS). Three weeks later, the patients were tested with the alternate drug combinations. The same outcomes were assessed. A verification of treatment difference was performed using SPSS 17.0 software package. RESULTS: Twenty-one patients were recruited and completed the study protocol. Sixty-two percent of the patients were women and 38% were men with a median age of 24 years [interquartile range (IQR), 20-30 yr]. Patients reported significantly lower pain scores with 1% lidocaine (1.09,95%CI，0.77-1.41) on injection, compared with 2% lidocaine (1.66, 95%CI, 1.33-1.99) (P=0.010). Patients undergoing 1% lidocaine with 1∶100 000 EPI (52-63 s) had a markedly quicker onset time of anesthetizing than those using 2% lidocaine with 1∶100 000 EPI (259-335 s, P=0.000). The efficacy of anesthesia between 2 groups was not significantly different (P=0.751). Among the patients with the pain values of 1~3, there were 9 patients(100%) perceiving slight pain when splitting teeth was performed in 1% lidocaine group, while 4 patients(57%) felt slight pain when elevating soft flaps was performed and 3 patients(43%) perceived mild pain when splitting teeth was performed in 2% lidocaine group (P=0.019). The time to sensation return for the lower lip and tongue was significantly different between the 2 drug formulations (P=0.000), with an extended period of average 61 min (52-69 min) in 2% lidocaine group. CONCLUSIONS: 1% lidocaine with EPI plays a similar role in clinical outcomes for inferior alveolar nerve, lingual nerve and buccal nerve block as 2% lidocaine with EPI, which produces lower pain on injection as well as a relatively short time to sensation return. The reasons for slight pain during surgical operation are a relative lower efficacy of anesthesia on the inferior alveolar nerve in 1% lidocaine group, and on the buccal nerve anesthesia in 2% lidocaine group.

Simultaneous saccharification and high titer lactic acid fermentation of corn stover using a newly isolated lactic acid bacterium Pediococcus acidilactici DQ2.

A lactic acid bacterium with high tolerance of temperature and lignocellulose derived inhibitor was isolated and characterized as Pediococcus acidilactici DQ2. The strain used in the simultaneous saccharification and fermentation (SSF) for high titer lactic acid production at the high solids loading of corn stover. Corn stover was pretreated using the dry sulphuric acid pretreatment, followed by a biological detoxification to remove the inhibitors produced in the pretreatment. The bioreactor with a novel helical impeller was used to the SSF operation of the pretreated and biodetoxified corn stover. The results show that a typical SSF operation at 48 °C, pH 5.5, and near 30% (w/w) solids loading in both 5 and 50 L bioreactors was demonstrated. The lactic acid titer, yield, and productivity reached 101.9 g/L, 77.2%, and 1.06 g/L/h, respectively. The result provided a practical process option for cellulosic lactic acid production using virgin agriculture lignocellulose residues.

A simplified filter paper assay method of cellulase enzymes based on HPLC analysis.

A simplified filter paper assay (FPA) method of cellulase enzymes was proposed based on high-performance liquid chromatography (HPLC) measurement. The method was according to the sum of glucose and cellobiose concentrations measured by HPLC that was able to be correlated with filter paper units (FPU) of the cellulase enzymes assayed by the traditional FPA method, regardless of the differences in the sources, activities, and components of the cellulases. This simple and quick assay method for the cellulase enzymes provided another parameter of the ratio of glucose to cellobiose (G/C ratio) representing the capacity of cellulase enzymes degrading cellulose into fermentable monomeric sugars.

Dry pretreatment of lignocellulose with extremely low steam and water usage for bioethanol production.

Two rarely noticed but important parameters of the dilute sulfuric acid pretreatment of lignocellulose biomass, the feedstock filling ratio to the pretreatment reactor and the solids/liquid presoaking ratio, were extensively studied. The effects of the two parameters on the steam consumption, waste water generation, and pretreatment efficiency were investigated. At the full filling ratio and high solids/liquid presoaking ratio, this "dry" pretreatment method provided at least the following advantages: (1) the steam consumption was significantly reduced; (2) no aqueous acid containing waste water was generated; (3) high solids content of the pretreated materials were obtained and the consequent saccharification and fermentation was carried out at high solids loading easily. This method was applied to various lignocellulose feedstocks successfully and provided a practical means to produce ethanol economically feasible.

Utilization of dry distiller's grain and solubles as nutrient supplement in the simultaneous saccharification and ethanol fermentation at high solids loading of corn stover.

Dry distiller's grain and solubles (DDGS) is a major by-product of corn-based ethanol production and is usually used as animal feed. Here, it was added to the simultaneous saccharification and ethanol fermentation (SSF) carried out at high solids loading of steam explosion pretreated corn stover using a mutant strain Saccharomyces cerevisiae DQ1. The performance of SSF process with DDGS was comparable to those using the expensive yeast extract supplementation. With 30% (w/w) solids plus the addition of cellulase and 1g DDGS l(-1), the final ethanol reached 55 g l(-1) (7% v/v). The results indicated that the expensive supplement of yeast extract could be replaced by DDGS.

[Process strategy for ethanol production from lignocellulose feedstock under extremely low water usage and high solids loading conditions].

The massive water and steam are consumed in the production of cellulose ethanol, which correspondingly results in the significant increase of energy cost, waster water discharge and production cost as well. In this study, the process strategy under extremely low water usage and high solids loading of corn stover was investigated experimentally and computationally. The novel pretreatment technology with zero waste water discharge was developed; in which a unique biodetoxification method using a kerosene fungus strain Amorphotheca resinae ZN1 to degrade the lignocellulose derived inhibitors was applied. With high solids loading of pretreated corn stover, high ethanol titer was achieved in the simultaneous saccharification and fermentation process, and the scale-up principles were studied. Furthermore, the flowsheet simulation of the whole process was carried out with the Aspen plus based physical database, and the integrated process developed was tested in the biorefinery mini-plant. Finally, the core technologies were applied in the cellulose ethanol demonstration plant, which paved a way for the establishment of an energy saving and environment friendly technology of lignocellulose biotransformation with industry application potential.

Simultaneous saccharification and ethanol fermentation at high corn stover solids loading in a helical stirring bioreactor.

The higher ethanol titer inevitably requires higher solids loading during the simultaneous enzymatic saccharification and fermentation (SSF) using lignocellulose as the feedstock. The mixing between the solid lignocellulose and the liquid enzyme is crucially important. In this study, a bioreactor with a novel helical impeller was designed and applied to the SSF operation of the steam explosion pretreated corn stover under different solids loadings and different enzyme dosages. The performances using the helical impeller and the common Rushton impeller were compared and analyzed by measuring rheological properties and the mixing energy consumption. The results showed that the new designed stirring system had better performances in the saccharification yield, ethanol titer, and energy cost than those of the Rushton impeller stirring. The mixing energy consumption under different solids loadings and enzyme dosages during SSF operation were analyzed and compared to the thermal energy in the ethanol produced. A balance for achieving the optimal energy cost between the increased mixing energy cost and the reduced distillation energy cost at the high solids loading should be made. The potentials of the new bioreactor were tested under various SSF conditions for obtaining optimal ethanol yield and titer.