Mechanisms of denitrifying granular sludge disintegration and calcium ion-enhanced re-granulation in acidic wastewater treatment.

Granular sludge is an alternative technology for the direct treatment of acidic nitrate-containing wastewater. Rapid remediation of disintegrated granules is essential to achieve efficient nitrogen removal. In this study, denitrifying granules were inactivated and disintegrated when the influent nitrate-nitrogen concentration was elevated from 240 to 360 mg L-1 in acidic wastewater (pH = 4.1) in a sequencing batch reactor. Tightly bound extracellular polymeric substances (TB-EPS) decreased by 60%, and extracellular protein (PN) was the main component of the reduced EPS. The three-dimensional excitation emission matrices (3D-EEM) results confirmed that the PNs that decreased were mainly tryptophan-like, tyrosine-like, and aromatic. This study further confirmed that the decrease in PN was mainly from the destruction of C=O (amide I) and N-H functional groups. Overloading of nitrogen-inhibited denitrifying activity and the destruction and dissolution of TB-EPS by acidic pH were responsible for granule disintegration, with PNs playing a major role in maintaining granule stability. Based on this, new granules with an average particle size of 454.4 µm were formed after calcium chloride addition; EPS nearly doubled during granule formation with PN as the dominant component, accounting for 64.7-78.4% of the EPS. Atomic force microscopy (AFM) revealed that PN-PN adhesion increased by 1.6-4.9 times in the presence of calcium ions, accelerating the re-granulation of disintegrated particles. This study provides new insights into the disintegration and remediation of granular sludge under acidic conditions.

Achievement of waste sludge deep dehydration under acidic conditions with polydimethyldiallylammonium chloride and ferric chloride: performance and mechanism.

The biological treatment of wastewater generates a substantial amount of waste sludge that requires dewatering before final disposal. Efficient sludge dewatering is essential to minimize storage and transportation costs. In this study, the sludge conditioners polydimethyldiallylammonium chloride (PDMDAAC) and ferric chloride (FeCl3) were sequentially dosed, and the pH was adjusted to 3. As a result, the sludge moisture content (MC) was reduced to 59.4%, achieving deep dewatering. After conditioning, the tightly bound extracellular polymeric substances (TB-EPS) were reduced from 34.5 to 10.2 mg g-1 VSS, with the majority of the reduced fractions being composed of protein (PN). In contrast, soluble EPS increased more than 8 times. Subsequent studies revealed that the decrease in PN from TB-EPS primarily involved tryptophan and tyrosine proteins, accompanied by a significant reduction in the N-H and C[double bond, length as m-dash]C absorption peaks. These results highlight the critical role of TB-EPS dissolution in achieving deep dehydration, with the N-H in PN was identified as the key group influencing sludge dewatering. Combined with the changes in sludge particle size and morphology, the dewatering mechanism can be summarized as follows: PDMDAAC dissolves TB-EPS, simultaneously disrupting the floc structure and refining the sludge. Subsequently, FeCl3 reconstructs these elements, forming larger particle sizes. Finally, hydrochloric acid reduces TB-EPS once again, releasing bound water. This study offers alternative methods and new insights for achieving deep dewatering of waste sludge.

Denitrification for acidic wastewater treatment: Long-term performance, microbial communities, and nitrous oxide emissions.

Acidic nitrogenous wastewater often requires alkali pretreatment before biological treatment, which results in increased system complexity and operating costs. The demonstration of denitrification under acidic conditions would provide a theoretical basis for the direct treatment of such wastewater. In this study, the denitrification performance, microbial community, and nitrous oxide (N2O) emissions under acidic conditions were investigated using a sequencing batch reactor. When the influent pH decreased from 5.5 to 4.5, the sequencing batch reactor removed 99.8 ± 0.2% of the nitrate and 92.5 ± 1.6% (n = 171) of the chemical oxygen demand, and the production efficiency of N2O increased significantly to 11.45%. This was 2.6-fold higher than that observed at pH 5.5. The long-term denitrification treatment of acidic wastewater (pH 4.5) led to the formation of granular sludge, and Thauera, Allorhizobium-Neorhizobium-Parararhizobium-Rhizobium, and Diaphorobacter became the dominant microbes with a collective abundance of 81.3%. More importantly, only 0.25% of the nitrate was denitrified as N2O, and the batch test revealed that the emissions of N2O decreased with the increase in sludge size. These results indicate that denitrifying granular sludge formed under acidic conditions and denitrifying bacteria capable of N2O reduction proliferated, which both resulted in a significant reduction in the release of N2O.

Drug and therapeutics committee interventions in managing irrational drug use and antimicrobial stewardship in China.

Aim: This study aimed to investigate the key points in the transformation of the functions of the Drug and Therapeutics Committee (DTC) of the Shandong Provincial Third Hospital and how to provide full authority to its role in the control of rational drug use, especially in the management of antibiotic use. Method: A prescription review management group, antimicrobial stewardship group, and rational drug use service group were established under the DTC. From January 2016 to December 2021, each group played a role in promoting rational drug use and antimicrobial stewardship. In addition, we performed statistics on typical management cases, irrational drug use, bacterial resistance rate, and drug costs from 2015 to 2021 to evaluate the effect of management by the DTC. Results: Intervention by the DTC led to a significant reduction in prescribing errors (71.43%, p < 0.05), the intervention acceptance rate increased by 16.03%, and the problem solved rate increased by 32.41% (p < 0.05). Resistance rates of general spectrum antibiotics were reduced remarkably after the intervention. The quality of drug treatment was improved and patient drug expenses was continuously reduced. Conclusion: Giving full play to the functions of the DTC can significantly improve the level of drug treatment and reduce unreasonable drug use to save unnecessary drug expenses and slow the development of drug resistance.

Evaluating the effectiveness of drug and therapeutics committees (DTCs) in controlling irrational drug use: A retrospective analysis.

WHAT IS KNOWN AND OBJECTIVE: This study aimed to explore methods to optimize the function of Drug and Therapeutics Committees (DTCs) in controlling irrational drug use. Clinical pharmacologists contribute their specific knowledge and skills to DTCs and help guide rational therapeutics. The DTC is the highest organization of hospital pharmacy management. METHODS: From January 2016 to August 2021, the DTC promoted the optimization of clinical drug treatment schemes and reduced unreasonable drug use by improving the organizational framework, clarifying the division of functions, regularly monitoring drug use, organizing expert comments, scientific decision-making and functional intervention. During this time, we statistically analysed typical management cases, irrational drug use and drug cost to evaluate the effectiveness of the DTC's management. RESULTS AND DISCUSSION: The DTC's intervention led to a significant reduction in prescribing errors (65.98%, p < 0.05); the intervention acceptance rate increased by 16.37%; and the rate of problem resolution increased by 45.84% (p < 0.05). The level of drug treatment was improved, and the proportion of patients' drug expenses was reduced. WHAT IS NEW AND CONCLUSION: The DTC carried out a series of continuous improvement work that played a significant normative role in clinical drug use. Giving more power to the DTCs can significantly improve the level of drug treatment and reduce unreasonable drug use, which reduces unnecessary drug expenses.

Protective effect of neovibsanin B on spatial cognitive functions of rats with cerebrovascular hypoperfusion.

Neovibsanins are believed to be promising candidates for the development of novel therapeutic agents to treat neurological diseases like Alzheimer's disease. It has been shown that chronic cerebral hypoperfusion is linked to neurodegenerative disorders and their subsequent cognitive impairment. In the present study effect of neovibsanin B (NVB) on spatial cognitive functions of rats with lobal cerebrovascular hypoperfusion was investigated. The cerebrovascular hypoperfusion rat model was prepared by bilateral common carotid arteries occlusion (2VO). Morris water maze (MWM) test was employed to examine the effect of NVB on spatial cognitive function before and after 2VO intervention. The animals were divided into two groups; long-term memory (LTM) and short-term memory (STM) groups. Each of the groups was subdivided into 3 subgroups: control, untreated and NVB treated groups. After ten weeks of the surgery, all the subgroups were tested with MWM. The results of working memory test for both control and NVB treated groups revealed that escape latency time and total distance travelled were significantly lower compared to untreated group. Similarly, the maze test performance was observed to be significantly improved for control and NVB treated groups. Moreover, the probe memory test performance for control and NVB treated groups was markedly better than untreated group. Thus NVB has a significant effect on the spatial cognitive preservation in rats with chronic cerebral hypoperfusion. Thus NVB can be a promising agent for the spatial cognitive functions improvement.

Transplantation of human cord blood mononuclear cells and umbilical cord-derived mesenchymal stem cells in autism.

BACKGROUND: Autism is a pervasive neurodevelopmental disorder. At present there are no defined mechanisms of pathogenesis and therapy is mostly limited to behavioral interventions. Stem cell transplantation may offer a unique treatment strategy for autism due to immune and neural dysregulation observed in this disease. This non-randomized, open-label, single center phase I/II trial investigated the safety and efficacy of combined transplantation of human cord blood mononuclear cells (CBMNCs) and umbilical cord-derived mesenchymal stem cells (UCMSCs) in treating children with autism. METHODS: 37 subjects diagnosed with autism were enrolled into this study and divided into three groups: CBMNC group (14 subjects, received CBMNC transplantation and rehabilitation therapy), Combination group (9 subjects, received both CBMNC and UCMSC transplantation and rehabilitation therapy), and Control group (14 subjects, received only rehabilitation therapy). Transplantations included four stem cell infusions through intravenous and intrathecal injections once a week. Treatment safety was evaluated with laboratory examinations and clinical assessment of adverse effects. The Childhood Autism Rating Scale (CARS), Clinical Global Impression (CGI) scale and Aberrant Behavior Checklist (ABC) were adopted to assess the therapeutic efficacy at baseline (pre-treatment) and following treatment. RESULTS: There were no significant safety issues related to the treatment and no observed severe adverse effects. Statistically significant differences were shown on CARS, ABC scores and CGI evaluation in the two treatment groups compared to the control at 24 weeks post-treatment (p < 0.05). CONCLUSIONS: Transplantation of CBMNCs demonstrated efficacy compared to the control group; however, the combination of CBMNCs and UCMSCs showed larger therapeutic effects than the CBMNC transplantation alone. There were no safety issues noted during infusion and the whole monitoring period. TRIAL REGISTRATION: ClinicalTrials.gov: NCT01343511, Title "Safety and Efficacy of Stem Cell Therapy in Patients with Autism".