Effect of enrichment conditions of secondary feeding on the synthesis of polyhydroxyalkanoates (PHAs) by activated sludge.

Polyhydroxyalkanoates (PHAs) are biodegradable plastics with great performance and development prospects. However, their traditional anaerobic/aerobic enrichment process requires a high concentration of dissolved oxygen (DO), resulting in high energy consumption. In this study, an anaerobic/oxygen-limited with secondary feeding enrichment mode was used to enhance the synthesis of PHAs while reducing energy consumption. The enrichment process of PHAs-synthesizing bacteria lasted up to 100 days, and the experiment was conducted to investigate the change of the PHAs synthesizing ability of the system in this mode by detecting the PHAs content and community distribution of the activated sludge under different stages. Under these conditions, the system enriched two major genera of PHAs-synthesizing bacteria, Thauera (30.21%) and Thiothrix (21.30%). The content of PHAs in the sludge increased from 4.51% to 30.87% and was able to achieve a concomitant increase in poly(3-hydroxyvalerate) (PHV) monomer content. After nitrogen limitation (C/N = 150) treatment, the content of PHAs reached 63.05%. The results showed that the enrichment mode of anaerobic/oxygen-limited with secondary feeding could enrich more PHAs-synthesizing bacteria and significantly increase the synthesis amount of PHAs, which revealed the great potential of this mode in solid waste value-added and reduce the production cost of PHAs and could provide a theoretical basis for the production of PHAs from activated sludge.

EEG-Based Epilepsy Prediction: Evaluation Metrics, Data Deficiency and Limitation of Current Methods.

Epilepsy is a disease of the brain that can do severe damage for patient's health. Due to the recurrent and unpredictable characteristics of epilepsy, it is of vital importance to develop reliable methods to predict seizures in advance. Nowadays, many researchers have developed deep learning (DL) or machine learning (ML) methods to predict epileptic seizures with electroencephalogram (EEG). But there are still many problems and challenges on the way towards a high-performance and generalized model. This study discussed and analyzed the current ML and DL techniques used in seizure prediction and summarized some challenges that remains to be solved, including the Inconsistency of the evaluation metrics, the imbalance and insufficiency of the available data and some limitations of current models. This study summarized the solutions that used to solve them and proposed some suggestions that can help improve the performance of the models. Furthermore, this review discussed some potential DL/ML methods that can be applied in the area of seizure prediction. This study aims to provide researchers with clear concepts in future works and proposed future directions.

Optimization of activated sludge polyhydroxyalkanoates(PHAs) synthesis system by performing sludge activity recovery experiments and varying the initial sludge concentration.

Polyhydroxyalkanoates(PHAs) are considered a good alternative to petroleum-based plastics because of their good biodegradability and biocompatibility. The synthesis of PHAs using activated sludge can not only solve the problem of the high cost of pure cultures but also improve the utilization value of activated sludge. In this study, sludge activity recovery experiments were firstly conducted and the effects of different initial sludge concentrations on the activated sludge PHAs synthesis system were further investigated. the initial sludge concentrations were 1#SBR (2800 ± 50) mg/L, 2#SBR (4200 ± 50) mg/L, and 3#SBR (5500 ± 50) mg/L. The results showed that the activity, sedimentation performance and PHAs synthesis capacity of activated sludge were enhanced after the sludge activity recovery experiment. At the initial sludge concentration of 4200 mg/L, the activated sludge PHAs synthesis system was operated stably and the synthesis efficiency of PHAs was enhanced. In contrast, at the initial sludge concentration of 2800 and 5500 mg/L, the steady state of the activated sludge PHAs synthesis system was damaged to different degrees at different times, and the synthesis efficiency of PHAs was greatly reduced.

Chemical digestion method to promote activated sludge cell wall breaking and optimize the polyhydroxyalkanoate (PHA) extraction process.

A novel protocol for the recovery of PHA from mixed-cultures proposed. In this experiment, activated sludge for PHA synthesis was investigated and a two-stage chemical digestion method was used for activated sludge to improve the yield of PHA. The highest PHA extraction combination that could be obtained in this experiment was sodium hypochlorite(NaClO) plus sodium dodecyl sulfate (SDS), and the optimal concentration of NaClO solution was 25 % (v/v), and the ratio of the dry weight of activated sludge to SDS was 1:2. The recovery and purity of PHA were 72.14 % and 54.47 %, respectively. The reaction time between NaClO and activated sludge affects the recovery of PHA, and the optimal reaction time of NaClO was experimentally obtained as 30 min. The purity of the PHA extract obtained after purification using methanol was improved.

The Value of MR-DWI and T1 Mapping in Indicating Radiation-Induced Soft Tissue Injury.

OBJECTIVE: To explore the value of MR-DWI and T1 mapping in predicting radiation-induced soft tissue fibrosis and its correlation with radiation inflammation. METHODS: ① a total of 30 C57BL/6 mice were randomly divided into a control group (Nor group), irradiation group (IR group) and irradiation plus glycyrrhetinic acid group (GA group). The IR group and GA group were treated with 6MV X-rays to irradiate the right hind limbs of mice for 30 Gy in a single shot. MRI examinations were performed before and on the 7th day after irradiation to measure the apparent diffusion coefficient (ADC) value and the longitudinal relaxation time (T1) value of the hind limb muscles of the mice. On the 90th day after irradiation, the hind limb contracture was measured, and the right hind limb muscle was taken for HE staining, masson staining, immunohistochemical staining and Western blot analysis to detect the expression of a-SMA and Fibronectin. ② The other 30 mice were grouped randomly as above. On the 7th day after irradiation, the right hind limbs of the mice were examined by MRI to measure the ADC value and T1 value of the thigh muscles, and then the right hind thigh muscles were immediately sacrificed to detect IL-1ß, IL-6, TNF-a and TGF-ß1 expression with ELISA. RESULTS: On the 7th day after irradiation, the ADC values ​​of right hind thigh muscles of mice in Nor group, IR group and GA group were (1.35 ± 0.11)*10-3mm2/s, (1.48 ± 0.07) *10-3mm2/s and (1.36 ± 0.13)*10-3mm2/s, respectively, by which the differences between the IR group and Nor group (P=0.008) and that between IR group and GA group (P=0.013) were statistically significant; T1 values ​​were (1369.7 ± 62.7)ms, (1483.7 ± 127.7)ms and (1304.1 ± 82.3)ms, respectively, with which the differences in the T1 value between the IR group and Nor group (P=0.012) and between IR group and GA group (P<0.001) were also statistically significant. On the 90th day after irradiation, the contracture lengths of the right hind limbs of the three groups of mice were (0.00 ± 0.07)cm, (2.08 ± 0.32)cm, and (1.49 ± 0.70) cm, respectively. There were statistically significant differences in the IR group compared with the Nor group (P<0.001) and the GA group (P=0.030). The ADC value (r=0.379, P=0.039) and T1 value (r=0.377, P=0.040) of the mice's hindlimbs on Day 7 after irradiation were correlated with the degree of contracture on Day 90 after irradiation; the ADC value (r=0.496, P=0.036) and T1 value (r=0.52, P=0.027) were positively correlated with the Masson staining results and with the expression of α-SMA and Fibronectin. While the ADC value was positively correlated with IL-6 (r=0.553, P=0.002), there was no obvious correlation with IL-1ß, TNF-a and TGF-ß1; the T1 value was positively correlated with IL-1ß (r=0.419, P=0.021), IL-6 (r=0.535, P=0.002) and TNF-a (r=0.540, P=0.002) but not significantly related to TGF-ß1 (r=0.155, P=0.413). CONCLUSION: The MR-DWI and T1 mapping values on the 7th day after irradiation can reflect the early condition of tissue inflammation after the soft tissue is irradiated, and the values have a certain correlation with the degree of radiofibrosis of the soft tissue in the later period and may be used as an index to predict radiofibrosis.

Selective recovery of heavy metals from wastewater by mechanically activated calcium carbonate: Inspiration from nature.

In nature, the calcium carbonate shows different interactions with different metal ions. Inspiration from this natural phenomenon, in this work, the selective recovery of heavy metals from wastewater by mechanically activated calcium carbonate was investigated. The changes in Ca2+ concentration, pH value and metals uptake ratio of solution showed that M2+ (M = Cu, Mn, Zn and Ni) were endowed with different migration rules, resulting in the various interaction with the calcium carbonate in metal-bearing solution. The combination of XRD, SEM, and stereomicroscope affirmed that the adsorbed M2+ rarely change the lattice structure of calcium carbonate, while the adsorbed Cu2+ and Zn2+ could convert the mineral phase from calcium carbonate to posnjakite and hydrozincite, respectively. As a result of phase transition, 15% Cu2+ and 6% Zn2+ were uptaken with initial concentration of 1 mM for 100 min, however, the unsatisfactory recovery prevented the efficient recycling of metal. The mechanically activated calcium carbonate had a superior solubility at the solid/liquid interface, promoting mineral phase transformation on the premise of weak displacement adsorption. Hence, the uptake ratio of Cu2+ and Zn2+ were significantly increased to 99% and 53% at the same condition. Finally, Cu2+ was recovered from polymetallic systems from complex environment with high precision. The concept of selective recycling in this research guides the development of innovative processes from natural information.

Utilization of carbonate-based tailings to remove Pb(II) from wastewater through mechanical activation.

The removal of lead in water and disposal of tailings are important environmental issues that need to be addressed urgently. This work explored the feasibility of utilizing the carbonate-based tailings (CBT) for removing lead from the simulated wastewater with the aid of wet stirred ball milling (mechanical activation). Batch experiments were performed to evaluate the influences of various experimental parameters like dosage of CBT, milling balls addition and initial concentration of lead. Under the action of mechanical activated CBT, the lead removal in the solution could reach more than 99% in 2 h, and the lead removal capacity reached 832 mg/g. The results of X-Ray Diffraction (XRD), Fourier Transform infrared spectroscopy (FTIR) and Scanning Electron Microscope-Energy Dispersive Spectra (SEM-EDS) revealed that the calcite (CaCO3) in CBT played a major role in removing lead and the lead in the solution was transferred to the precipitate as cerussite (PbCO3). The mechanical activation promoted the dissolution of calcite, reduced the particle size of CBT and peeled off the lead carbonate precipitation on the surface of calcite, thereby enabling the reaction to be efficiently and thoroughly completed. The lead content in the precipitate after the reaction reached 38.4 wt%, which made it possible for lead recovery.

Removal of Cu(II) from wastewater by using mechanochemically activated carbonate-based tailings through chemical precipitation.

This work explored the feasibility of utilizing the copper tailings (CT) for removing copper from the waste mine water based on the mechanochemical activation. Batch experiments were performed to evaluate the influences of various experimental parameters like the dosage of CT, reaction time, initial concentration of Cu, and anion species. By cogriding copper solution with CT in the stirred mill (mechanochemical activation), over 99.5% of copper was removed and the residual copper concentration in the solution was less than 0.5 mg/L, reaching the discharge limit. This reaction was a chemical precipitation process. The calcite of CT played a major role in precipitating copper and had a better removal effect on copper in the copper sulfate solution than copper nitrate solution. For copper sulfate solution, the copper deposit was mainly posnjakite (Cu4(SO4)(OH)6·H2O). In the copper nitrate solution, the copper sediment might consist mainly of basic copper nitrate. The stability of the two reaction products was measured by leaching test. The result showed that the sediment obtained by this method was relatively stable and was not hazardous wastes.

Effect of anions species on copper removal from wastewater by using mechanically activated calcium carbonate.

In this work, the wastewater containing sulfate ions, nitrate ions or chloride ions was used to investigate the performance of anions in copper removal by mechanically activated calcium carbonate. The copper removal from wastewater containing sulfate anion achieved almost 99% with the CaCO3/Cu molar ratio of 1:1. However, the copper removal from wastewater containing nitrate and chloride anions are lower than 20% and 35%, respectively. The precipitations from wastewater containing different anions were analyzed by using XRD, FTIR, SEM-EDS and XPS, respectively. Cu (II) in wastewater containing sulfate anion is precipitated in the form of posnjakite. The nitrate anion precipitates as gerhardtite, whereas chloride anion as atacamite and botallackite. The solubility of precipitation plays a decisive role in copper removal so that sulfate anions have a superior effect on Cu (II) precipitation due to relatively stable posnjakite with the lowest solubility, suggesting that this method using mechanically activated calcium carbonate is more suitable and effective for the wastewater containing sulfate anion.

Overexpression of Salusin-α Inhibits Vascular Intimal Hyperplasia in an Atherosclerotic Rabbit Model.

Inhibiting vascular endothelial foam is the focus of clinical attention. Using SonoVue (an ultrasound contrast agent), the salusin-α gene was transfected into the arterial intima of an atherosclerotic rabbit model induced by a high-fat diet in this study. Subsequently the model of blood lipid indexes, the pathological structure of the intima, and changes in molecules regulating atherosclerosis were investigated. The high-density lipoprotein C and apolipoprotein A values in the salusin-α gene overexpression (P) group were higher than those in the salusin-α gene interference (RP) group (P < 0.05), whereas the total cholesterol, low-density lipoprotein C, and apolipoprotein B values were reversed. Rabbits in the P group showed significantly thinner vascular intimal thickness than that of other experimental groups (P < 0.05). The expression of positive regulators of atherosclerosis (ABCA1, ABCG1) was higher in the P group than that in the RP group (P < 0.05), and the opposite effect was observed for negative regulators (ACAT1, CD36). Thus, our results showed that the overexpression of salusin-α gene inhibited the proliferation of the vascular intima, thereby throwing some light on understanding the mechanism how salusin-α gene expression interfered with the foaming of vascular intimal cells.

Adsorption removal of tannic acid from aqueous solution by polyaniline: Analysis of operating parameters and mechanism.

Polyaniline (PANI) prepared by chemical oxidation was studied for adsorption removal of tannic acid (TA) from aqueous solution. Batch adsorption studies were carried out under different adsorbent dosages, pH, ionic strength, initial TA concentration and coexisting anions. Solution pH had an important impact on TA adsorption onto PANI with optimal removal in the pH range of 8-11. TA adsorption on PANI at three ionic strength levels (0.02, 0.2 and 2molL-1 NaCl) could be well described by Langmuir model (monolayer adsorption process) and the maximum adsorption capacity was 230, 223 and 1023mgg-1, respectively. Kinetic data showed that TA adsorption on PANI fitted well with pseudo-second-order model (controlled by chemical process). Among the coexisting anions tested, PO43- significantly inhibited TA adsorption due to the enhancement of repulsive interaction. Continuous flow adsorption studies indicated good flexibility and adaptability of the PANI adsorbent under different flow rates and influent TA concentrations. The mechanism controlling TA adsorption onto PANI under different operating conditions was analyzed with the combination of electrostatic interactions, hydrogen bonding, π-π interactions and Van der Waals interactions.

MicroRNA profiling in Muc2 knockout mice of colitis-associated cancer model reveals epigenetic alterations during chronic colitis malignant transformation.

Our previous studies have demonstrated that genetic deletion of the Muc2 gene causes colorectal cancers in mice. The current study further showed that at the early stage (<3 months) the Muc2 knockout mice spontaneously developed chronic inflammation in colon and rectum, similar pathological features as human colitis; and at the late stage (>3 months) the mice exhibited colorectal cancer, including a unique phenotype of rectal prolapsed (rectal severe inflammation and adenocarcinoma). Thus, the age of 3 months might be the key point of the transition from chronic inflammation to cancer. To determine the mechanisms of the malignant transformation, we conducted miRNA array on the colonic epithelial cells from the 3-month Muc2-/- and +/+ mice. MicroRNA profiling showed differential expression of miRNAs (i.e. lower or higher expression enrichments) in Muc2-/- mice. 15 of them were validated by quantitative PCR. Based on relevance to cytokine and cancer, 4 miRNAs (miR-138, miR-145, miR-146a, and miR-150) were validate and were found significantly downregulated in human colitis and colorectal cancer tissues. The network of the targets of these miRNAs was characterized, and interestedly, miRNA-associated cytokines were significantly increased in Muc2-/-mice. This is the first to reveal the importance of aberrant expression of miRNAs in dynamically transformation from chronic colitis to colitis-associated cancer. These findings shed light on revealing the mechanisms of chronic colitis malignant transformation.