Respiratory Sinus Arrhythmia Acts as a Moderator of the Relationship Between Parental Marital Conflict and Adolescents’ Internalizing Problems

The present study examined the potential moderating role respiratory sinus arrhythmia (RSA) plays in the relationship between parental marital conflict and adolescents’ internalizing problems. To examine this issue, data were collected from 330 adolescents (13–14 years, 182 boys). The Chinese version of the Achenbach Youth Self-Report-2001 and the Chinese version of the Children’s Perception of Interparental Conflict were used to assess the adolescents’ internalizing problems and their perceptions of parental marital conflict. To obtain RSA data, electrocardiogram monitoring was performed on the adolescents at baseline and during a series of stress tasks (watching a film clip depicting marital conflict, a mental arithmetic task, and a speech task). The results indicated that baseline RSA and RSA reactivity to the film clip moderated the relationship between parental marital conflict and internalizing problems in early adolescents. The moderating effect of baseline RSA supported the BSCT hypothesis. Specifically, adolescents with low baseline RSA have both the highest and lowest levels of internalizing problems, depending on the level of marital conflict. In contrast, adolescents with high levels of baseline RSA have moderate levels in internalizing problems, regardless of the level of marital conflict they experience. Similarly, high marital conflict was related to internalizing problems for adolescents with less RSA suppression or RSA augmentation but not for those with greater RSA suppression. This effect was specific to stress related to marital conflict, as RSA reactivity to the mental arithmetic task and speech task did not moderate the relationship between marital conflict and internalizing problems. These findings suggest that certain profile of parasympathetic nervous activity is a risk factor for internalizing problems particularly for those who experience high-conflict environments

Biogas Production Potential and Kinetics of Microwave and Conventional Thermal Pretreatment of Grass

Pretreatment methods play an important role in the improvement of biogas production from the anaerobic digestion of energy grass. In this study, conventional thermal and microwave methods were performed on raw material, namely, Pennisetum hybrid, to analyze the effect of pretreatment on anaerobic digestion by the calculation of performance parameters using Logistic function, modified Gompertz equation, and transference function. Results indicated that thermal pretreatment improved the biogas production of Pennisetum hybrid, whereas microwave method had an adverse effect on the performance. All the models fit the experimental data with R-2&gt;0.980, and the Reaction Curve presented the best agreement in the fitting process. Conventional thermal pretreatment showed an increasing effect on maximum production rate and total methane produced, with an improvement of around 7% and 8%, respectively. With regard to microwave pretreatment, maximum production rate and total methane produced decreased by 18% and 12%, respectively.</p

An efficient magnetic carbon-based solid acid treatment for corncob saccharification with high selectivity of xylose and enhanced enzymatic digestibility

An effective method for corncob saccharification was investigated over a magnetic carbon-based solid acid (MMCSA) catalyst in the aqueous phase. MMCSA was synthesized through a simple and inexpensive impregnation-carbonization-sulfonation process. Under the optimal reaction conditions (150 °C, 2 h, 0.5 g corncob, 0.5 g catalyst and 50 ml deionized water), 74.9% of xylose yield was directly obtained from corncob, with 91.7% cellulose retention in the residue. After reaction, the MMCSA was easily separated from the residue by an external magnet and reused 4 times showing high stability and catalytic activity. The enzymatic digestibility of the pretreated residue reached 95.2%, with a total sugar yield of 90.4%. The morphologic and structural properties of the natural and treated corncobs were analyzed primarily through 3D X-ray microscopy to characterize the cell wall thickness, porosity, and pore surface area distribution. The increase of macropores (pore surface areas > 200 μm2) was beneficial to the accessibility of cellulose to cellulosic enzymes, so the enzymatic digestibility was enhanced immediately. Compared with other traditional hydrolysis methods, this two-step hydrolysis approach represents an environmentally friendly and sustainable saccharification of lignocellulose to produce xylose and glucose while achieving the same level of reaction efficiency

Preparation of reducing sugars from corncob by solid acid catalytic pretreatment combined with in situ enzymatic hydrolysis

The efficient conversion of hemicellulose and cellulose into reducing sugars remains as one major challenge for biorefinery of lignocellulosic biomass. In this work, saccharification of corncob in the aqueous phase was effectively realized via pretreatment by magnetic carbon-based solid acid (MMCSA) catalyst, combined with the subsequent in situ enzymatic hydrolysis (occurring in the same pretreatment system after separation of MMCSA). Through the combined two-step hydrolysis of corncob, the total sugar (xylose and glucose) yield of 90.03% was obtained, including a xylose yield of 86.99% and an enzymatic digestibility of pretreatment residue of 91.24% (cellulase loading of 20 FPU/g, 24 h). Compared with the traditional enzymatic hydrolysis of pretreated residue, the presented in situ enzymatic hydrolysis system can reach a comparable enzymatic digestibility in one-third reacting time with a half cellulase loading and save about 31% water consumption, which provides a more sustainable and low-cost method for the saccharification of lignocellulose

Improving methane production from Pennisetum hybrid by monitoring plant height and ensiling pretreatment

The biomass of grass-based Pennisetum hybrid commonly use for a biogas production via anaerobic digestion. However, it is necessary to determine a method to optimize the plant harvest time for high biogas production. Moreover, ensiling of biomass in the presence of diverse microbes may offer a solution to improve biogas production. In this study, whole plant of Pennisetum biomass (including stems and leaves) was collected at different harvesting time (plant heights of 70, 100, 150 cm), and then comparatively assessed for further ensiling and biogas production. Compared to leaves, stems exhibited a significant linear relationship (R2 = 0.99) with whole plants in terms of ensiling quality (i.e. pH and NH3-N). Microbial analysis further revealed that Lactobacillus was the dominant bacterial genus during ensiling of stems and whole plants, with the highest relative abundance of 50.08% obtained at the height of 100 cm. Ensiling of biomass at a height of 100 cm achieved the best digestion performance, with the methane yields of 316 ± 20 mL/g VS for leaves, 361 ± 43 mL/g VS for stems, and 356 ± 28 mL/g VS for whole plants. A harvesting time at the plant height of 100 cm was the optimal from the silage quality and anaerobic digestion performance