Novel flocking materials as biocarriers in moving bed biofilm reactor for improving simultaneous nitrification and denitrification performance.

Biocarrier is the key factor for the stable operation of moving bed biofilm reactor (MBBR). To achieve efficient simultaneous nitrification and denitrification (SND), this study provided novel flocking materials as biocarriers. The biofilm formation experiment showed that longer flocking carrier was more conducive to biomass accumulation, resulting in greater oxygen uptake rate. The continuous operation results showed that the total nitrogen removal and SND performance of the MBBR with the addition of 5.0 mm flocking carriers reached 52.0 % and 70.5 %, respectively, which were 29.1 % and 33.3 % greater than those of the control. Compared with those in suspended sludge, the extracellular polymeric substances and protein components in the biocarrier were more abundant. Furthermore, the relative abundance of genera related to denitrification and the nitrogen metabolic sequence improved with the addition of the novel flocking biocarriers. This study demonstrated the effectiveness of novel flocking fillers in improving the performance of MBBR.

Use of reconstruction plates prebent on three-dimensional models to reduce the complications of mandibular reconstruction.

Background/purpose: Though the gold standard method for mandible reconstruction of the defect from segmental mandibulectomy is by osseous flap or graft, using reconstruction plates is still indicated in some cases. Traditionally, the plate is bended immediately after the segmental mandibulectomy by freehand. However, it's difficult to fit well to the original position of mandible, which may result in more complications. This study therefore aimed to investigate whether using prebent plates on computer-aided 3D printing models could reduce the complication rate. Materials and methods: Patients who received mandible reconstruction by reconstruction plate from 2018 to 2022 were enrolled and evaluated in this study. The data, including demographics, indications for surgery, pre-existed preoperative and postoperative therapies, classification of defects, and postoperative outcomes were collected and analyzed. Results: A total of 52 patients were enrolled in our study. The prebent group exhibited a significantly lower complication rate than that of the immediately bent group (P = 0.012). Other risk factors of plate complications included postoperative adjuvant radiotherapy (P = 0.017) and previous surgery (P = 0.047). The complication-free survival rate was also better in the prebent group in a 3-year follow-up period (P = 0.012). Conclusion: Prebent plates on computer-aided printing models proved to be an effective approach to reduce the complications for mandibular reconstruction in segmental mandibulectomy.

Simultaneous denitrification enhancement and sludge reduction based on novel suspended carrier modified using activated carbon and magnetite at low carbon/nitrogen ratio.

A novel suspended carrier was prepared by sticking activated carbon (AC) and magnetite (Fe3O4) onto polypropylene slices. Although this carrier could not reverse the decreased denitrification capacity trends under anoxic conditions at an influent carbon/nitrogen (C/N) ratio of 2, it enhanced denitrification by stimulating sludge reduction and accelerating electron transfer to certain extent. The carrier stuck by mixed AC/Fe3O4 exhibited better performance in terms of sludge reduction, extracellular polymeric substances (EPS) secretion, and denitrification than that merely stuck by AC and Fe3O4 at an influent C/N ratio of 2. The carrier stuck by mixed AC/Fe3O4 increased the total nitrogen removal efficiency by 24.6 % ± 12.5 % in a 72-h denitrification batch experiment compared to the common polypropylene carrier. Moreover, the carrier improved EPS secretion and nitrogen metabolism and promoted the growth of Trichococcus and some denitrifying genera. This study provides a reference for the treatment of low C/N ratio sewage.

Use of magnetic powder to effectively improve the denitrification employing the activated sludge fermentation liquid as carbon source.

Nitrogen removal is often limited in municipal wastewater treatment due to the lack of sufficient carbon source. Utilizing volatile fatty acids (VFAs) from waste activated sludge (WAS) fermentation broth as a carbon source is an ideal alternative to reduce the cost for wastewater treatment plants (WWTPs) and improve denitrification efficiency simultaneously. In this study, an anaerobic system was applied for simultaneous denitrification and WAS fermentation and the addition of magnetic microparticles (MMP) were confirmed to enhance both denitrification and WAS fermentation. Firstly, the addition of MMP increased the nitrate reduction rate by over 25.36% and improve the production of N2. Additionally, the equivalent chemical oxygen demand (COD) of the detected VFAs increased by 7.06%-14.53%, suggesting that MMP promoted the WAS fermentation. The electron transfer efficiency of denitrifies was accelerated by MMP via electron-transporting system (ETS) activity and cyclic voltammetry (CV) experiments, which might result in the promotional denitrification and WAS fermentation performance. Furthermore, the high-throughput sequencing displayed that, MMP enriched key microbes capable of degrading the complex organics (Chloroflexi, Synergistota and Spirochaetota) as well as the typical denitrifies (Bacteroidetes_vadinHA17 and Denitratisoma). Therefore, this study provides a novel strategy to realize simultaneous WAS utilization and denitrification for WWTPs.

Characterization of the microbial community and prediction of metabolic functions in an anaerobic/oxic system with magnetic micropolystyrene as a biocarrier.

Polystyrene (PS) and magnetic polystyrene (MPS) materials have been used extensively in wastewater treatment. In this research, a 55-day anaerobic/oxic process was carried out to evaluate the effects of PS and MPS on microorganisms under aerobic and anaerobic conditions. Scanning electron microscopy results revealed differences in the entanglement state of the sludge with the biocarrier due to differences in surface morphology. High-throughput sequencing analysis showed that the microbial communities differed considerably in the presence of PS and MPS addition under both aerobic and anaerobic conditions. The highest abundance and diversity were observed in the PS reactor, with 929 observed species and a PD_whole_tree index of 91.58 under anaerobic conditions. MPS promoted the enrichment of bacteria related to nitrogen recycling such as Nitrospirota which increased from 1.13% in the seeding sludge to 3.48% and 10.07% in the aerobic reactors with PS and MPS, respectively. Moreover, advanced analysis showed that PS inhibited many microbial functions (e.g., protein export, nitrogen metabolism), and MPS alleviated this inhibition. This study provides significant insights into the microbial effects of PS and MPS and may shed light on biocarrier selection in future studies.

miR-146a participates in the regulation of cancer stemness of oral carcinoma cells.

Background/purpose: Increasing evidence regarded the existence of cancer stem cells (CSCs) as a leading cause of therapy failure and tumor relapse due to their self-renewal and differentiation abilities. Although ectopic overexpression of micro-RNAs (miRNAs) can modulate the cancer stemness and tumor development in oral cancer, their molecular mechanism is still unclear. Therefore, in the present study, we attempt to uncover the role of miR-146a in the maintenance of oral CSCs. Materials and methods: The expression of miR-146a was determined using qRT-PCR analysis. Aldehyde dehydrogenase (ALDH) enzymic activity and sphere formation assays were used to evaluate the cancer stemness and self-renewal, respectively. Functional assays, including migration/invasion Transwell and colony formation assay, were used to evaluate the aggressive abilities. Luciferase reporter assay was performed to validate the relationship between miR-146a and Numb. Results: In the present study, we reported an increased expression of miR-146a in the oral squamous cell carcinoma (OSCC) specimen, primary OSCC cells sphere, and high ALDH1 activity population within OSCC cells. Inhibition of miR-146a significantly suppressed the ALDH1 activity, self-renewal capacity, and aggressive abilities, including migration, invasion, and colony formation. Moreover, we demonstrated that Numb is a functional target of miR-146a in OSCC-CSCs. Notably, silencing of Numb could retrieve the self-renewal and migration impaired by knockdown of miR-146a. Conclusion: Our results indicate that miR-146a can regulate the cancer stemness in OSCC by modulating Numb, and hence miR-146a/Numb axis can serve as a potential target for oral cancer therapy.

Effect of calcium peroxide assisted microwave irradiation pretreatment on humus formation and microbial community in straw and dairy manure composting.

In this study, the effects of four pretreatment methods on the crystallinity of maize straw were compared, and the CaO2 assisted microwave pretreatment was selected for straw and dairy manure composting. The humification and microbial community were investigated. Results showed that the pretreatment increased the initial water-soluble carbon, which favored the microbial activity, and the CO2 release increased by 15.71%. Pretreatment promoted the lignocellulose degradation, with total degradation ratio of 37.06%. The final humic acid content was 11.39 g/kg higher than the control. Spearman correlation analysis indicated that polyphenols and amino acids were significantly related to humus formation. In addition, pretreatment rendered the Firmicutes the most dominant phylum, and increased the metabolic intensity of reducing sugar metabolism, aromatic amino acid biosynthesis and carbon fixation pathways. Redundancy analysis revealed that the dominant genus of Firmicutes was significantly positively correlated with humus, while that of Actinobacteriota was correlated with CO2 release.

Is OLP potentially malignant? A clue from ZNF582 methylation.

OBJECTIVE: Whether oral lichen planus (OLP) was potentially malignant remains controversial. Here, we examined associations of ZNF582 methylation (ZNF582m ) with OLP lesions, dysplastic features and squamous cell carcinoma (OSCC). MATERIALS AND METHODS: This is a case-control study. ZNF582m was evaluated in both lesion and adjacent normal sites of 42 dysplasia, 90 OSCC and 43 OLP patients, whereas ZNF582m was evaluated only in one mucosal site of 45 normal controls. High-risk habits affecting ZNF582m such as betel nut chewing and cigarette smoking were also compared in those groups. RESULTS: OLP lesions showed significantly lower ZNF582m than those of dysplasia and OSCC. At adjacent normal mucosa, ZNF582m increased from patients of OLP, dysplasia, to OSCC. In addition, ZNF582m at adjacent normal sites in OLP patients was comparable to normal mucosa in control group. Dysplasia/OSCC patients with high-risk habits exhibited significantly higher ZNF582m than those without high-risk habits. However, ZNF582m in OLP patients was not affected by those high-risk habits. CONCLUSIONS: OLP is unlikely to be potentially malignant based on ZNF582m levels. ZNF582m may also be a potential biomarker for distinguishing OLP from true dysplastic features and OSCC, and for monitoring the malignant transformation of OLP, potentially malignant disorders with dysplastic features and OSCC.

Improved fertilization efficiency of manure compost obtained by using oil shale semicoke as the bulking agent.

Oil shale semicoke is a kind of solid waste produced during the retorting process of oil shale, which could cause environmental pollution without reasonable disposing. In our previous study, the abandoned semicoke was recycled as bulking agent to reduce the nitrogen loss and greenhouse gases emission during composting. But influences of the obtained semicoke-blended compost on soil properties and plant growth remained unclear, which would be discussed in this study. Through leaching experiments, it was found that the N/P/K retention capacity of soil mixed with semicoke-blended compost significantly increased for the good nutrients sorption capacity of oil shale semicoke. Subsequently, germination test showed the germination index of semicoke-blended compost could attain 120%, implying its low phytotoxicity. And pot experiments exhibited the biomass of cress and Brassica rapa significantly increased by 2-4 times when applying semicoke-blended compost as fertilizer, exhibiting its great benefits to plants. For the increase of crop yield, it was closely related to their elevated nutrients uptake efficiency, also might be related to the improved soil microbial community and activity as the microbial analysis indicated. Finally, results of pollutant detection showed the concentration of polycyclic aromatic hydrocarbons, Cr, As, Cd and Pb in the mature semicoke-blended compost obtained through composting was 2.82, 95.30, 5.95, 0.34 and 14.45 mg kg-1 respectively, meeting the standard for soil application. The research suggests composting could be an effective method for the harmless disposing and resource recycling of oil shale semicoke waste.

Enhancement of biological nitrogen removal performance from low C/N municipal wastewater using novel carriers based on the nano-Fe3O4.

The aim of this work was to study the effects of the magnetic microparticles (MMP) on nitrogen removal under low C/N conditions. A 30-day anaerobic/oxic progress illustrated that nitrification and denitrification were promoted in the presence of MMP. MMP could facilitate the production of extracellular polymeric substances (EPS) and act as pH buffering in aerobic conditions. The high-throughput sequencing displayed that, compared with the sludge without MMP, the relative abundance of Dokdonella and Comamonas which are capable of both nitrifying and denitrifying were 8.7% and 1.29% higher in anaerobic sludge and 7.11% and 0.97% higher in aerobic sludge with MMP, respectively. The relative abundance of Pseudomonas with the excellent capability of EPS secretion was also observed 4.33 times higher than that without MMP in the aerobic sludge. Based on the superior performance above, MMP is a promising additive to enhance nitrogen removal efficiency for low C/N wastewater.

Improving the Diagnostic Performance by Adding Methylation Marker to Conventional Visual Examination in Identifying Oral Cancer.

BACKGROUND: Visual oral examination (VOE) is a conventional oral cancer screening method. This study aimed to evaluate the value of methylation marker to assist VOE in identifying oral epithelial dysplasia and oral squamous cell carcinoma (OED/OSCC) from non-cancerous lesions in a real-world situation. METHODS: 201 patients with high-risk personal habits who self-perceived oral anomaly were VOE examined, ZNF582 methylation (ZNF582m) tested, and histologically diagnosed. RESULTS: Among them, 132 patients (65.7%) were histologically diagnosed OED/OSCC. Using VOE, 56.1% OED/OSCC patients had possible oral cancer, whereas 37.7% non-OED/OSCC patients had leukoplakia. ZNF582m-positive was detected in 90.2% OED/OSCC patients and 44.9% non-OED/OSCC patients. Various logistic regression models were postulated to evaluate the diagnostic performance of conventional VOE and new strategies using ZNF582m. ROC analysis and its corresponding C-index demonstrated that either triage or co-testing models of VOE and ZNF582m could improve diagnostic performance and discriminative abilities compared with the VOE only approach. CONCLUSIONS: In conclusion, methylation marker test shows equivalent performance to an experienced judgment by oral maxillofacial surgeons and plays a significantly supplementary role in increasing the efficacy in identifying oral malignant lesions. ZNF582m may be an especially important tool for family physicians or general dentists to properly diagnose suspicious oral lesions.

miR-509 inhibits cancer stemness properties in oral carcinomas via directly targeting PlK1.

Background/purpose: Oral cancer is one of the common cancers worldwide. Emerging evidence has indicated that microRNAs (non-coding RNA molecules of approximately 22 nucleotides in length) are implicated in the regulation of cancer stemness. However, the functional role of microRNA-509 (miR-509) in the characteristics of oral cancer stem cells (CSCs) has not been unraveled. Materials and methods: The expression level of miR-509 in ALDH1+ and sphere oral CSCs was examined by qRT-PCR. The aldehyde dehydrogenase 1 (ALDH1) activity and CD44 expression were assessed using flow cytometry. Self-renewal, transwell migration, and colony formation assays were conducted to measure the CSC phenotypes. Besides, a luciferase reporter assay was used to confirm the direct interaction between miR-509 and its target polo-like kinase 1 (plk1). Results: We showed the expression of miR-509 was downregulated in the CSCs derived from oral cancer cells (SAS), and upregulation of miR-509 diminished the several CSCs features, including ALDH1 activity, self-renewal capacity, CD44 expression, migration, and colony-forming abilities. Moreover, the result from the luciferase reporter assay validated the direct binding of miR-509 to plk1. Conclusion: Our results suggest that the miR-509/plk1 axis may mediate the cancer stemness in oral cancer, and targeting this axis may attenuate the progression of oral cancer.

The functional roles of microRNAs in the pathogenesis of oral submucous fibrosis.

Oral potentially malignant disorders (OPMD) are lesions that may precede the onset of cancers in the oral cavity, and oral submucosal fibrosis (OSF) is one of the OPMD that is usually found in the buccal mucosa. Considerable effort has been made to elucidate the pathogenesis of OSF, and emerging evidence has suggested that microRNAs may play significant roles in the development of OSF. Several studies demonstrated that aberrant expression of miRNAs is also observed in the fibrotic BMFs (fBMFs) derived from OSF tissues. For instance, it has been shown that miR-10b, miR-21, and miR-1246 are significantly elevated, and miR-29b, miR-200b, and miR-200c are reduced in fBMFs. This review systematically summarizes the current knowledge regarding the aberrant expression of microRNAs, molecular mechanisms underlying oral fibrogenesis by the dysregulated microRNAs, and how the interaction between microRNAs and long non-coding RNAs contributes to the progression of OSF. An overview of the modes of action by these microRNAs will provide a fundamental basis for clinical application.

miR-21 promotes the fibrotic properties in oral mucosa through targeting PDCD4.

Background/purpose: Oral submucous fibrosis (OSF) has been regarded as a premalignant disorder of oral cancer, and myofibroblasts are the main cells that are responsible for pathological fibrosis. Hence, elucidation of the molecular mechanism underlying myofibroblast activation is important to treat OSF. MicroRNA-21 (miR-21) is a well-known fibrosis non-coding RNA, and its role in the development of OSF remains largely unclear. Materials and methods: Luciferase reporter assay was used to confirm the direct interaction between miR-21 and its target programmed cell death 4 (PDCD4). The expression level of PDCD4 in OSF was examined by qRT-PCR. Myofibroblast activities were assessed by collagen gel contraction and transwell migration assays. Results: Our result validated the direct binding of miR-21 to PDCD4. We showed the expression of PDCD4 was downregulated in OSF specimens and negatively correlated with miR-21. Our results suggested that overexpression of PDCD4 in fibrotic buccal mucosal fibroblasts (fBMFs) mitigated the myofibroblast activities, including collagen gel contractility and migration capacity. Moreover, we showed miR-21 contributed to myofibroblast activation of BMFs through repression of PDCD4. Conclusion: Our results suggest that the miR-21/PDCD4 axis mediates the myofibroblast activation of BMFs, and targeting this axis may exert an anti-fibrosis effect.

Effective dose and radiation risk under 640-slice abdominal computed tomography examination without contrast medium injection.

BACKGROUND: Medical imaging plays a crucial role in modern medicine. In order to provide fast and accurate medical diagnosis, computed tomography (CT) is a commonly used tool in radiological examinations, and 640-slice CT is the most advanced CT imaging modality. OBJECTIVE: To evaluate the radiation dose and the risk under 640-slice abdominal CT examination. METHODS: Examinations were performed using a 640-slice CT scanner on an Alderson-Rando anthropomorphic phantom. The used scanning acquisition parameters were the same as those used on abdominal examination without contrast medium injection in clinical practice. To measure the absorbed doses, optically stimulated luminescence dosimeters (OSLDs) were put into liver, stomach, bladder, gonads, colon, small intestine, bone marrow, and skin. RESULTS: According to the 1990 Recommendations of the International Commission on Radiological Protection (ICRP Publication 60), the calculated effective doses received from this examination were 0.90 mSv in males and 0.89 mSv in females. According to the 2007 Recommendations of the International Commission on Radiological Protection (ICRP Publication 103), the calculated effective dose received from this examination was 0.83 mSv in both sexes. CONCLUSIONS: Radiation doses obtained from the abdominal 640-slice CT examination are lower than the yearly cumulative doses received from natural radiation, revealing there is no deterministic effect and radiation risk is relatively low; therefore, this CT examination is considered safe.