Degradation of switchgrass by Bacillus subtilis 1AJ3 and expression of a beta-glycoside hydrolase

Increasing demand for carbon neutrality has led to the development of new techniques and modes of low carbon production. The utilization of microbiology to convert low-cost renewable resources into more valuable chemicals is particularly important. Here, we investigated the ability of a cellulolytic bacterium, Bacillus subtilis 1AJ3, in switchgrass lignocellulose degradation. After 5 days of culture with the strain under 37°C, cellulose, xylan, and acid-insoluble lignin degradation rates were 16.13, 14.24, and 13.91%, respectively. Gas chromatography–mass spectrometry (GC-MS) analysis and field emission scanning electron microscopy (FE-SEM) indicated that the lignin and surface of switchgrass were degraded after incubation with the bacterial strain. Strain 1AJ3 can grow well below 60°C, which satisfies the optimum temperature (50°C) condition of most cellulases; subsequent results emphasize that acid-heat incubation conditions increase the reducing sugar content in a wide range of cellulosic biomass degraded by B. subtilis 1AJ3. To obtain more reducing sugars, we focused on β-glycoside hydrolase, which plays an important role in last steps of cellulose degradation to oligosaccharides. A β-glycoside hydrolase (Bgl-16A) was characterized by cloning and expression in Escherichia coli BL21 and further determined to belong to glycoside hydrolase (GH) 16 family. The Bgl-16A had an enzymatic activity of 365.29 ± 10.43 U/mg, and the enzyme’s mode of action was explained by molecular docking. Moreover, the critical influence on temperature (50°C) of Bgl-16A also explained the high-efficiency degradation of biomass by strain under acid-heat conditions. In terms of potential applications, both the strain and the recombinant enzyme showed that coffee grounds would be a suitable and valuable substrate. This study provides a new understanding of cellulose degradation by B. subtilis 1AJ3 that both the enzyme action mode and optimum temperature limitation by cellulases could impact the degradation. It also gave new sight to unique advantage utilization in the industrial production of green manufacturing

Acupuncture in Treatment of Chronic Functional Constipation

Constipation is not only a symptom but is a predominant presenting symptom in many diseases. The prevalence is between 3 and 27% worldwide, and is especially prevalent in the elderly population. The aetiology is multifactorial. Laxative abuse or enema use are usually a norm in patients’ constipation. Patients tend not to seek further medical aid after several unsuccessful therapies and this can seriously affect their quality of life

Magnetoelectric Effect at the Ni/HfO\u3csub\u3e2\u3c/sub\u3e Interface Induced by Ferroelectric Polarization

Driven by the technological importance of the recently discovered ferroelectric HfO2, we explore a magnetoelectric effect at the HfO2-based ferroelectric-ferromagnetic interface. Using density-functionaltheory calculations of the Ni/HfO2/Ni (001) heterostructure as a model system, we predict a stable and sizable ferroelectric polarization in a few-nm-thick HfO2 layer. For the Ni/HfO2 interface with opposite polarization directions (pointing to or away from the interface), we find a sizable difference in the interfacial Ni—O bonding, resulting in dissimilar degrees of depletion of the electron density around the interface. The latter affects the relative population of the exchange-split majority and minority spin bands at the interface and thus the interfacial magnetic moments. The sizable change in the interface magnetization with ferroelectric polarization reversal of HfO2 manifests a significant ferroelectrically induced magnetoelectric effect at the Ni/HfO2 interface. Our results reveal promising prospects of ferroelectric-ferromagnetic composite multiferroics based on HfO2-based ferroelectric materials

Developing Dipole-scheme Heterojunction Photocatalysts

The high recombination rate of photogenerated carriers is the bottleneck of photocatalysis, severely limiting the photocatalytic efficiency. Here, we develop a dipole-scheme (D-scheme for short) photocatalytic model and materials realization. The D-scheme heterojunction not only can effectively separate electrons and holes by a large polarization field, but also boosts photocatalytic redox reactions with large driving photovoltages and without any carrier loss. By means of first-principles and GW calculations, we propose a D-scheme heterojunction prototype with two real polar materials, PtSeTe/LiGaS2. This D-scheme photocatalyst exhibits a high capability of the photogenerated carrier separation and near-infrared light absorption. Moreover, our calculations of the Gibbs free energy imply a high ability of the hydrogen and oxygen evolution reaction by a large driving force. The proposed D-scheme photocatalytic model is generalized and paves a valuable route of significantly improving the photocatalytic efficiency.Comment: 10 pages, 5 figure

Meta-Analysis for the evaluation of perioperative enhanced recovery after gynaecological surgery

Objectives: To systematically evaluate the effectiveness and safety of enhanced recovery after surgery (ERAS) in gynaecological surgery and provide a scientific basis for its clinical promotion and application in the Chinese population. Material and methods: Systematic retrieval from CNKI, Wanfang, VIP database and other Chinese literature databases. Studies on ERAS application with a randomised controlled trial in gynaecological surgery were included in the present report. Outcome indicators: hospitalisation time, postoperative ambulation time, postoperative feeding time, postoperative exhaust time, postoperative defecation time, operation time, postoperative blood loss, postoperative morbidity, patient satisfaction, hospitalisation expenses, etc. The meta-analysis was performed using the Revman 5.3 software. Results: A total of 24 studies were included in the analysis. The results showed that, compared with the traditional group, the ERAS group had a lower hospitalisation time (SMD = −1.67, 95% CI = −2.03 ~ −1.30, p < 0.0001), postoperative ambulation time (SMD = −4.16, 95% CI = −5.12 ~ −3.20, p < 0.0001), postoperative feeding time (SMD = −7.36, 95% CI = −9.67 ~ −5.05, p < 0.0001), postoperative exhaust time (SMD = −2.59, 95% CI = −3.15 ~ −2.03, p < 0.0001), postoperative defecation time (SMD = −2.23, 95% CI = −2.88 ~ −1.57, p < 0.0001), postoperative morbidity (OR = 0.22, 95% CI = 0.15 ~ 0.31, p < 0.0001) and hospitalisation expenses (SMD = −0.53, 95% CI = −0.78 ~ −0.28, p < 0.0001). The patient satisfaction was significantly improved (odds ratio = 8.11, 95% CI = 4.96 ~ 13.24, p < 0.0001), and there were no significant differences in intraoperative blood loss and operation time between the two groups. Conclusions: The application of the ERAS protocol in gynaecological surgery significantly improves the effectiveness and safety of the procedure. Thus, it can be promoted and applied in clinical practice in China

Changes in element accumulation, phenolic metabolism, and antioxidative enzyme activities in the red-skin roots of Panax ginseng

AbstractBackgroundRed-skin root disease has seriously decreased the quality and production of Panax ginseng (ginseng).MethodsTo explore the disease's origin, comparative analysis was performed in different parts of the plant, particularly the epidermis, cortex, and/or fibrous roots of 5-yr-old healthy and diseased red-skin ginseng. The inorganic element composition, phenolic compound concentration, reactive oxidation system, antioxidant concentrations such as ascorbate and glutathione, activities of enzymes related to phenolic metabolism and oxidation, and antioxidative system particularly the ascorbate–glutathione cycle were examined using conventional methods.ResultsAluminum (Al), iron (Fe), magnesium, and phosphorus were increased, whereas manganese was unchanged and calcium was decreased in the epidermis and fibrous root of red-skin ginseng, which also contained higher levels of phenolic compounds, higher activities of the phenolic compound-synthesizing enzyme phenylalanine ammonia-lyase and the phenolic compound oxidation-related enzymes guaiacol peroxidase and polyphenoloxidase. As the substrate of guaiacol peroxidase, higher levels of H2O2 and correspondingly higher activities of superoxide dismutase and catalase were found in red-skin ginseng. Increased levels of ascorbate and glutathione; increased activities of l-galactose 1-dehydrogenase, ascorbate peroxidase, ascorbic acid oxidase, and glutathione reductase; and lower activities of dehydroascorbate reductase, monodehydroascorbate reductase, and glutathione peroxidase were found in red-skin ginseng. Glutathione-S-transferase activity remained constant.ConclusionHence, higher element accumulation, particularly Al and Fe, activated multiple enzymes related to accumulation of phenolic compounds and their oxidation. This might contribute to red-skin symptoms in ginseng. It is proposed that antioxidant and antioxidative enzymes, especially those involved in ascorbate–glutathione cycles, are activated to protect against phenolic compound oxidation

Wafer-scale fabrication of high-density nanoslit arrays for surface-enhanced Raman spectroscopy

Surfaces with a periodic nanostructure and controllable feature size are sought after for optical applications, and the fabrication of such surfaces in large areas with high reproducibility, good stability and low deviation is very important. We present a strategy to fabricate large-area nanoslit arrays with controllable pitches and gaps. Au nanoslit arrays with gaps down to around 10 nm and a high gap density of 2.0 ×104 cm-1 have been fabricated, which can greatly enhance the near-field electromagnetic field to achieve localized surface plasmon resonance (LSPR). An averaged surface-enhanced Raman scattering analytical enhancement factor of 8.0 ×107 has been achieved on the substrate using a 633 nm laser source and the 'coupling effect' of LSPR of the nanoslits