The Endoscopic Retrograde Appendicitis Therapy for Acute Appendicitis in Children: A Systematic Review and Meta-Analysis.

Background: Acute appendicitis (AA) is a prevalent abdominal emergency in children, and there has been growing interest in the use of endoscopic retrograde appendicitis treatment (ERAT) over the past two decades. A meta-analysis of published retrospective studies was conducted to investigate the clinical characteristics and therapeutic efficacy of ERAT for AA in children. Methods: A systematic review and meta-analysis of retrospective studies were carried out, encompassing data from PUBMED, MEDLINE, Cochrane, China National Knowledge Infrastructure (CNKI), WanFang, and VIP Database. The search was limited to studies published between January 1, 2012, and June 31, 2022, with the final search conducted on October 31, 2022. No restrictions were imposed regarding publication or study design filters. The registration number in PROSPERO was CRD42022377739. Results: Seven retrospective cohort studies with 423 patients were included. The majority of children who underwent ERAT were male (57.6%, 95% CI 52.8%-62.4%). The ERAT procedure had a high success rate (99.5%, 95% CI 98.2%-100.0%) and averaged around 49 minutes. ERAT's efficacy for treating acute appendicitis was high (99.0%, 95% CI 96.5%-100.0%), with a low recurrence rate (4.2%, 95% CI 2.2%-6.7%). Patients typically stayed in the hospital for about 4.3 days, and the rate of postoperative complications was around 3.9% (95% CI 2.0%-6.2%). Conclusions: Despite the heterogeneity among studies, ERAT appears to be an effective treatment for acute uncomplicated appendicitis in children. It has a high success rate, a low recurrence rate, preserves the appendix's function, and causes minimal damage. ERAT could be considered a safe and effective treatment option for pediatric appendicitis.

Effects of rhubarb peony decoction combined with antibiotics in treating pediatric periappendiceal abscess.

Background/purpose: Rhubarb peony decoction (RPD) is a formula of traditional Chinese medicine that has been widely used to treat intra-abdominal inflammatory diseases. To investigate the therapeutic efficacy of RPD in pediatric periappendiceal abscess, patients who received intravenous antibiotics alone were compared with those treated with intravenous antibiotics combined with RPD. Methods: A retrospective review of children with periappendiceal abscess who received conservative treatment in our hospital between January 2013 and April 2022 was performed. The patients were divided into an intravenous antibiotic group (the control group) and an intravenous antibiotic combined with RPD group (the intervention group). Interval appendectomy (IA) was generally performed 10-12 weeks after conservative treatment. The primary outcome was the cure rate of conservative treatment, while the secondary outcomes included the recurrence rate, days of total intravenous antibiotic use, length of hospital stay (LOS), postoperative complications, and liver injury caused by RPD. Results: A total of 142 patients (77 girls and 65 boys) were included, 52 in the control group and 90 in the intervention group. The two groups were similar in demographic data and clinical characteristics (P > 0.05). The mean total course of RPD in the intervention group was 11.82 days. The intervention group had a significantly higher cure rate than the control group (93.33% vs. 80.77%, P = 0.029), and the length of total intravenous antibiotic use (P = 0.150), LOS (P = 0.077), recurrence rate (9.52% vs. 4.76%, P = 0.439), as well as the operation time (P = 0.101), LOS (P = 0.572), and postoperative complications (P = 0.549) were not significantly different between the two groups when the patients received IA. No patient had a liver injury caused by RPD during the treatment. Conclusion: Intravenous antibiotics combined with RPD demonstrated high effectiveness and safety for treating pediatric periappendiceal abscess.

[Preparation and Application of Magnetic Water Treatment Materials Based on Iron Sludge].

In recent years, solid waste iron sludge (red mud, iron-containing water treatment residues, and iron-rich sludge) has been widely used to remove pollutants in the water environment; however, the difficulty of separating powdered iron sludge from the water environment media makes it impossible to apply it as a water treatment material on a large scale, and preparing iron sludge into magnetic materials that are easy to be separated is one of the effective strategies to solve this bottleneck. According to the existing research on iron sludge-based magnetic materials at home and abroad, the preparation methods of magnetic materials using iron sludge as raw materials are summarized, including a series of methods, including the thermal decomposition method, hydrothermal and solvothermal method, co-precipitation method, reduction roasting method, and carbonization method. Additionally, it is pointed out that the currently commonly used preparation methods are thermal decomposition, hydrothermal and solvothermal, and co-precipitation. In addition, the performance and application of these magnetic materials as adsorbents or catalysts in water treatment are also summarized. In general, iron sludge-based magnetic materials can better absorb heavy metals and organic pollutants in water. The main adsorption mechanisms are complexation, electrostatic interaction, reduction, cation exchange, and precipitation. As a catalyst, it can efficiently oxidize and degrade organic pollutants by generating strong oxidizing substances:SO4-· and ·OH. Although there have been many studies on the preparation and application of iron sludge-based magnetic materials, because the raw material iron sludge contains many impurities, the magnetic materials prepared from iron sludge also have certain impurities. Therefore, it is still necessary to strengthen the research on the safety of iron sludge-based magnetic materials in the future to further ensure that they can be used as environmentally friendly materials for water environment restoration.

Performance and operational strategy of simultaneous nitrification, denitrification, and phosphorus removal system under the condition of low organic loading rate in wet weather.

A pilot-scale aerobic granular sequencing batch reactor (SBR) with domestic wastewater was operated to evaluate the effects of the low organic loading rate (OLR) due to wet weather flow conditions on simultaneous nitrification, denitrification, and phosphorus removal (SNDPR). As the OLR decreased from 0.85 to 0.43 kg COD m-3 d-1, the total nitrogen (TN) and total phosphorus (TP) removal efficiencies decreased from 84.0% and 94.1% to 51.3% and 73.8%, respectively, the sludge volume index (SVI) increased from 42.3 to 85.5 mL g-1, and the average granular size decreased from 1022 to 742 µm; however, no sludge disintegration and biomass loss were observed. The poor nutrient removal efficiencies and settling ability were due to the shrinking anoxic zone and substrate scarcity inside the granules, wherein the activity decay of ammonia-oxidizing bacteria and overgrowth of filamentous bacteria played an important role. Alternating the aeration intensity was effective in enhancing nitrogen removal and sludge settling by improving the anoxic activity in granules and inhibiting the proliferation of filamentous bacteria. Returning 20% of sludge from the end of one anaerobic stage to the beginning of the next anaerobic stage (midway sludge return) was beneficial for phosphorus removal as it improved phosphorus storage by phosphorus-accumulating bacteria. A smaller granular size with stronger stability and better nutrient removal performance was the new steady state of the SNDPR system under wet-weather flow conditions.

Startup and stable operation of advanced continuous flow reactor and the changes of microbial communities in aerobic granular sludge.

In this study, the granular sludge was operated under low aeration condition in sequencing batch reactor (SBR) and advanced continuous flow reactor (ACFR), respectively. Through increasing the sludge retention time (SRT) from 22 days to 33 days, the ACFR was successful startup in 30 days and achieved long term stable operation. Under SBR operation condition, the aerobic granular sludge (AGS) showed good nitrogen (60%), phosphorus (96%) and COD removal performance. During stable operation of continuous-flow, the nitrogen removal efficiency was increasing to 70%, however, the phosphorus removal efficiency could only be restored to 65%. Meanwhile, the sludge discharge volume from ACFR was about half of that in SBR. Results of high-throughput pyrosequencing illustrated that methanogenic archaea (MA), ammonia oxidizing archaea (AOA), denitrifying bacteria (DNB), denitrifying polyphosphate-accumulating organisms (DPAOs) played an important role in the removal of nutrients in ACFR. This study could have positive effect on the practical application of AGS continuous flow process for simultaneous biological nutrient removal (SBNR).

Effect of different operational modes on the performance of granular sludge in continuous-flow systems and the successions of microbial communities.

Continuous flow reactors with time intermittent operational (TIO) mode and spatial intermittent operational (SIO) mode were operated to evaluate the effects of operational modes on the removal performances, the characteristics of granules and the dynamics of microbial communities in simultaneous nitrification, denitrification and phosphorus removal (SNDPR) granular system. The results showed that the removal efficiency of TP, TN were 81.3%, 86.7% under TIO mode, and 70.6%, 77.4% under SIO mode, respectively. Meanwhile, the PN and value of PN/PS in SIO were higher than those in TIO. Besides, results of high-throughput pyrosequencing illustrated that the combination of filamentous archaea (Methanothrix) and filamentous bacteria (Thiothrix) had resulted in the increase of EPS and SVI under SIO mode. Finally, functional bacterial and archaeal species, involving HMA, AMA, AOA, DPAOs etc., were identified to reveal the effects of operational modes on the mechanism of nutrients removal in granular SNDPR continuous-flow system.

Effect of aeration modes on simultaneous nitrogen and phosphorus removal and microbial community in a continuous flow reactor with granules.

In this study, a continuous flow reactor with simultaneous nitrification, denitrification and phosphorus removal (SNDPR) granular sludge was operated in the continuous aeration (CA) and intermittent aeration (IA) modes to examine the effect of aeration on the performance of continuous-flow system. Then the experimental results showed that the IA1 mode (4 h aeration and 1 h non-aeration) could improve the simultaneous nitrogen and phosphorus removal and the settleability of granules in continuous flow system. Results of high-throughput pyrosequencing illustrated that the methanogens, AOA, ANAMMOX, DNB, denitrifying polyphosphate-accumulating organisms (DPAOs) were the important participant of simultaneous biological nutrients removal (SBNR), meanwhile, the IA1 mode could effectively inhibit the growth of filamentous microorganisms (Thiothrix and Acinetobacter). Finally, a conceptual model of the SNDPR granular microbial ecosystem under IA1 mode was proposed as a base for analyzing the mechanism of simultaneous nutrient removal in continuous flow system.

Effect of sludge retention time on continuous-flow system with enhanced biological phosphorus removal granules at different COD loading.

The effect of sludge retention time (SRT) on the continuous-flow system with enhanced biological phosphorus removal (EBPR) granules at different COD loading was investigated during the operation of more than 220days. And the results showed that when the system operated at long SRT (30days) and low COD loading (200mg·L(-1)), it could maintain excellent performance. However, long SRT and high COD loading (300mg·L(-1)) deteriorated the settling ability of granules and the performance of system and resulted in the overgrowth of filamentous bacteria. Meanwhile, the transformation of poly-ß-hydroxyalkanoates (PHAs) and glycogen in metabolism process was inhibited. Moreover, the results of pyrosequencing indicated that filamentous bacteria had a competitive advantage over polyphosphate-accumulating organisms (PAOs) at high COD loading and long SRT. The PAOs specious of Candidatus_Accumlibater and system performance increased obviously when the SRT was reduced to 20days at high COD loading.

Long term operation of continuous-flow system with enhanced biological phosphorus removal granules at different COD loading.

In this study, a continuous-flow system with enhanced biological phosphorus removal (EBPR) granules was operated at different COD concentrations (200, 300 and 400mgL(-)(1)) to investigate the effect of COD loading on this system. The results showed that when the COD concentration in influent was increased to 400mgL(-)(1), the anaerobic COD removal efficiency and total phosphorus removal efficiency reduced obviously and the settling ability of granules deteriorated due to the proliferation of filamentous bacteria. Moreover, high COD loading inhibited the EPS secretion and destroyed the stability of granules. Results of high-through pyrosequencing indicated that filamentous bacteria had a competitive advantage over polyphosphate-accumulating organisms (PAOs) at high COD loading. The performance of system, settling ability of granules and proportion of PAOs gradually recovered to the initial level after the COD concentration was reduced to 200mgL(-)(1) on day 81.

Optimized hydraulic retention time for phosphorus and COD removal from synthetic domestic sewage with granules in a continuous-flow reactor.

In continuous-flow reactor (CFR), suboptimal hydraulic retention time (HRT) can affect the substrate loading, anaerobic time and aerobic time and further affect the performance and characteristics of granules, thus different HRTs (7.5, 6.0, 4.5 and 5.2h) were tested to improve the phosphorus (P) and carbon (COD) removal of the continuous-flow system with granules in this study. When HRT was below 6.0h, the COD removal efficiency in anaerobic zone and the P removal efficiency in aerobic zone reduced obviously, and the settling ability of EBPR granules deteriorated. The residual COD in anaerobic zone resulted in the proliferation of filamentous bacteria on the granules surface. Pyrosequencing analysis revealed that Proteobacteria was the dominant phylum in this system. The dominant class transformed from Betaproteobacteria to Gammaproteobacteria when HRT was reduced from 6.0h to 4.5h.

Startup and long term operation of enhanced biological phosphorus removal in continuous-flow reactor with granules.

The startup and long term operation of enhanced biological phosphorus removal (EBPR) in a continuous-flow reactor (CFR) with granules were investigated in this study. Through reducing the settling time from 9min to 3min gradually, the startup of EBPR in a CFR with granules was successfully realized in 16days. Under continuous-flow operation, the granules with good phosphorus and COD removal performance were stably operated for more than 6months. And the granules were characterized with particle size of around 960µm, loose structure and good settling ability. During the startup phase, polysaccharides (PS) was secreted excessively by microorganisms to resist the influence from the variation of operational mode. Results of relative quantitative PCR indicated that granules dominated by polyphosphate-accumulating organisms (PAOs) were easier accumulated in the CFR because more excellent settling ability was needed in the system.