Rhopaloic acid A triggers mitochondria damage-induced apoptosis in oral cancer by JNK/BNIP3/Nix-mediated mitophagy.

BACKGROUND: Oral squamous cell carcinoma (OSCC) is a frequently occurring type of head and neck cancer with a high mortality and morbidity rate. Rhopaloic acid A (RA), a terpenoid derived from sponges, has demonstrated a promising anti-tumor activity, but its effectiveness for treating OSCC remains unknown. PURPOSE: The aim of this study was to investigate whether RA inhibits the growth of OSCC. METHODS: Cell viability was evaluated using CCK-8 assays in OSCC cells (Ca9-22, HSC-3 and SAS) and in normal cells (HGF-1) treated with RA. DAPI staining, AO staining, JC-1 staining and immunofluorescence were used to determine apoptosis, mitochondrial membrane potential and autophagy in RA-treated OSCC cells. Protein expression levels were determined by western blotting. Furthermore, the anti-tumor effect of RA was confirmed in vivo using a zebrafish oral cancer xenotransplantation model. RESULTS: OSCC cells had a significantly reduced viability after RA treatment, but normal cells were not affected. Treatment with RA caused chromatin condensation in OSCC cells, which increased their expression of autophagy- and apoptosis-related proteins. Furthermore, RA caused mitochondrial damage and increased autophagosome formation. Mitophagy was also induced by RA through the JNK/BNIP3/Nix/LC3B pathway. The JNK inhibitor SP600125 prevented both RA-mediated cell death and mitophagy of OSCC cells. A zebrafish xenograft model demonstrated that RA inhibits OSCC growth. CONCLUSION: In conclusion, RA showed a potent anticancer activity in in vitro and in in vivo oral cancer models by promoting mitochondrial damage-induced apoptosis and mitophagy, which suggests that RA may be useful as a novel and effective treatment for OSCC.

Fluorogenic Rhodamine-Based Chemigenetic Biosensor for Monitoring Cellular NADPH Dynamics.

Ratiometric biosensors employing Förster Resonance Energy Transfer (FRET) enable the real-time tracking of metabolite dynamics. Here, we introduce an approach for generating a FRET-based biosensor in which changes in apparent FRET efficiency rely on the analyte-controlled fluorogenicity of a rhodamine rather than the commonly used distance change between donor-acceptor fluorophores. Our fluorogenic, rhodamine-based, chemigenetic biosensor (FOCS) relies on a synthetic, protein-tethered FRET probe, in which the rhodamine acting as the FRET acceptor switches in an analyte-dependent manner from a dark to a fluorescent state. This allows ratiometric sensing of the analyte concentration. We use this approach to generate a chemigenetic biosensor for nicotinamide adenine dinucleotide phosphate (NADPH). FOCS-NADPH exhibits a rapid and reversible response toward NAPDH with a good dynamic range, selectivity, and pH insensitivity. FOCS-NADPH allows real-time monitoring of cytosolic NADPH fluctuations in live cells during oxidative stress or after drug exposure. We furthermore used FOCS-NADPH to investigate NADPH homeostasis regulation through the pentose phosphate pathway of glucose metabolism. FOCS-NADPH is a powerful tool for studying NADPH metabolism and serves as a blueprint for the development of future fluorescent biosensors.

Electroacupuncture alleviates myocardial ischemia-reperfusion injury by inhibiting hypothalamic paraventricular nucleus neurons projecting to the rostral ventrolateral medulla.

Accumulating evidence suggests that electroacupuncture (EA) has obvious therapeutic effects and unique advantages in alleviating myocardial ischemia-reperfusion injury (MIRI), while the underlying neuromolecular mechanisms of EA intervention for MIRI have not been fully elucidated. The aim of the study is to investigate the role of the neural pathway of hypothalamic paraventricular nucleus (PVN) neurons projecting to the rostral ventrolateral medulla (RVLM) in the alleviation of MIRI rats by EA preconditioning. MIRI models were established by ligating the left anterior descending coronary artery for 30 min followed by reperfusion for 2 h. Electrocardiogram recording, chemogenetics, enzyme-linked immunosorbent assay, multichannel physiology recording and haematoxylin-eosin and immunofluorescence staining methods were conducted to demonstrate that the firing frequencies of neurons in the PVN and the expression of c-Fos decreased by EA pretreatment. Meanwhile, EA preconditioning significantly reduced the levels of creatine kinase isoenzymes (CK-MB), cardiac troponin I (cTnI) and lactic dehydrogenase (LDH). Virus tracing showed a projection connection between PVN and RVLM. The inhibition of the PVN-RVLM neural pathway could replicate the protective effect of EA pretreatment on MIRI rats. However, the activation of the pathway weakened the effect of EA preconditioning. EA pretreatment alleviated MIRI by regulating PVN neurons projecting to RVLM. This work provides novel evidence of EA pretreatment for alleviating MIRI.

Effects of sodium lauryl sulfate and postbiotic toothpaste on oral microecology.

The diversity and delicate balance of the oral microbiome contribute to oral health, with its disruption leading to oral and systemic diseases. Toothpaste includes elements like traditional additives such as sodium lauryl sulfate (SLS) as well as novel postbiotics derived from probiotics, which are commonly employed for maintaining oral hygiene and a healthy oral cavity. However, the response of the oral microbiota to these treatments remains poorly understood. In this study, we systematically investigated the impact of SLS, and toothpaste containing postbiotics (hereafter, postbiotic toothpaste) across three systems: biofilms, animal models, and clinical populations. SLS was found to kill bacteria in both preformed biofilms (mature biofilms) and developing biofilms (immature biofilms), and disturbed the microbial community structure by increasing the number of pathogenic bacteria. SLS also destroyed periodontal tissue, promoted alveolar bone resorption, and enhanced the extent of inflammatory response level. The postbiotic toothpaste favored bacterial homeostasis and the normal development of the two types of biofilms in vitro, and attenuated periodontitis and gingivitis in vivo via modulation of oral microecology. Importantly, the postbiotic toothpaste mitigated the adverse effects of SLS when used in combination, both in vitro and in vivo. Overall, the findings of this study describe the impact of toothpaste components on oral microflora and stress the necessity for obtaining a comprehensive understanding of oral microbial ecology by considering multiple aspects.

[Development and characteristics of a moxa floss shaping and spreading device].

This paper introduces a moxa floss shaping and spreading device for governor vessel moxibustion. This device is consisted of a storage unit and a propulsion unit, capable of automatically shaping moxa sticks for governor vessel moxibustion. The device allows for the flexible adjustment of moxa stick length, better conforming to the physiological curvature of the spine, and avoiding potential burns associated with governor vessel moxibustion. It simplifies the operational procedures for healthcare professionals, offering the advantages of ease of use, safety, and efficiency.

Increased expression of the kynurenine pathway in mice with eosinophilic meningitis caused by Angiostrongylus cantonensis infection.

Angiostrongylus cantonensis is the major cause of eosinophilic meningitis worldwide. The imbalance of neurotoxic and neuroprotective metabolites in the kynurenine pathway (KP) have been suggested to contribute to the pathogenesis of central nervous system (CNS) infection. We hypothesized that KP may also be involved in parasitic eosinophilic meningitis. BALB/c mice were orally infected with 40 A. cantonensis L3, intraperitoneal dexamethasone at a dose of 500 µg/kg/day was administered from the seventh day of infection until the end of the study. The Evans blue method was used to analyze blood-brain barrier (BBB) dysfunction, and indoleamine 2,3-dioxygenase (IDO) proteins levels was measured by Western blot, immunohistochemistry (IHC), and immunofluorescence. Tryptophan and kynurenine concentrations were analyzed by IHC and liquid chromatography-tandem mass spectrometry (LC-MS/MS). The concentrations of Evans blue, IDO, tryptophan and kynurenine in the different groups of mice were compared using the nonparametric Kruskal-Wallis test. BBB dysfunction was found in mice with eosinophilic meningitis. The administration of dexamethasone significantly decreased the amount of Evans blue. An increased IDO expression was shown in Western blot, IHC and immunofluorescence following 2-3 weeks infection. Increased tryptophan and kynurenine expressions in the brain and cerebrospinal fluid (CSF) were also found in IHC and LC-MS/MS studies. The administration of dexamethasone significantly decreased the amount of IDO, tryptophan and kynurenine. In conclusion, A. cantonensis infection inducing BBB damage, then increased the influx of tryptophan into CSF. The administration of dexamethasone significantly decreased the amount of IDO, tryptophan and kynurenine.

Nobiletin derivative, 5-acetoxy-6,7,8,3',4'-pentamethoxyflavone, inhibits neuroinflammation through the inhibition of TLR4/MyD88/MAPK signaling pathways and STAT3 in microglia.

OBJECTIVE: Microglia in the central nervous system regulate neuroinflammation that leads to a wide range of neuropathological alterations. The present study investigated the anti-neuroinflammatory properties of nobiletin (Nob) derivative, 5-acetoxy-6,7,8,3',4'-pentamethoxyflavone (5-Ac-Nob), in lipopolysaccharide (LPS)-activated BV2 microglia. MATERIALS AND METHODS: By using the MTT assay, Griess method, flow cytometry, and enzyme-linked immunosorbent assay (ELISA), we determined the cell viability, the levels of nitric oxide (NO), reactive oxygen species (ROS), and pro-inflammatory factors (interleukin 1 beta; IL-1ß, interleukin 6; IL-6, tumor necrosis factor alpha; TNF-α and prostaglandin E2; PGE2) in LPS-stimulated BV2 microglia. Toll-like receptor 4 (TLR4)-mediated myeloid differentiation primary response gene 88 (MyD88)/nuclear factor-kappa B (NF-κB), mitogen-activated protein kinase (MAPK) signaling pathway and signal transducer and activator of transcription 3 (STAT3) were measured by western blotting. Analysis of NO generation and mRNA of pro-inflammatory cytokines was confirmed in the zebrafish model. RESULTS: 5-Ac-Nob reduced cell death, the levels of NO, ROS, inducible nitric oxide synthase (iNOS), cyclooxygenase 2 (COX-2), and pro-inflammatory factors in LPS-activated BV-2 microglial cells. TLR4-mediated MyD88/NF-κB and MAPK pathway (p38, ERK and JNK) after exposure to 5-Ac-Nob was also suppressed. Moreover, 5-Ac-Nob inhibited phosphorylated STAT3 proteins expression in LPS-induced BV-2 microglial cells. Furthermore, we confirmed that 5-Ac-Nob decreased LPS-induced NO generation and mRNA of pro-inflammatory cytokines in the zebrafish model. CONCLUSIONS: Our findings suggest that 5-Ac-Nob represses neuroinflammatory responses by inhibiting TLR4-mediated signaling pathway and STAT3. As a result of these findings, 5-Ac-Nob has potential as an anti-inflammatory agent against microglia-mediated neuroinflammatory disorders.

The Antimicrobial Peptide Tilapia Piscidin 4 Induced the Apoptosis of Bladder Cancer Through ERK/SIRT1/PGC-1α Signaling Pathway.

Marine antimicrobial peptides have been demonstrated in numerous studies to possess anti-cancer properties. This research investigation aimed to explore the fundamental molecular mechanisms underlying the antitumor activity of Tilapia piscidin 4 (TP4), an antimicrobial peptide, in human bladder cancer. TP4 exhibited a remarkable inhibitory effect on the proliferation of bladder cancer cells through cell cycle arrest at the G2/M phase. Additionally, TP4 upregulated the expression of cleaved caspase-3, caspase-9, and PARP, leading to the activation of apoptotic pathways in bladder cancer cells. TP4 exhibit a marked rise in mitochondria reactive oxygen species, leading to the subsequent loss of potential for the mitochondrial membrane. Furthermore, the inhibition of mitochondrial oxidative phosphorylation resulted in a decrease in downstream ATP production. Meanwhile, TP4-treated bladder cancer cells showed an increase in Bax and ERK but a decrease in SIRT1, PGC-1α, and Bcl2. ERK activation, SIRT1/PGC-1α-axis, and TP4-induced apoptosis were all significantly reversed by the ERK inhibitor SCH772984. Finally, the inhibitory effect of TP4 on tumor growth has been confirmed in a zebrafish bladder cancer xenotransplantation model. These findings suggest that TP4 may be a potential agents for human bladder cancer through apoptosis induction, ERK activation, and the promotion of SIRT1-mediated signaling pathways.

Multi-Omics Analysis Reveals the Distinct Features of Metabolism Pathways Supporting the Fruit Size and Color Variation of Giant Pumpkin.

Pumpkin (Cucurbita maxima) is an important vegetable crop of the Cucurbitaceae plant family. The fruits of pumpkin are often used as directly edible food or raw material for a number of processed foods. In nature, mature pumpkin fruits differ in size, shape, and color. The Atlantic Giant (AG) cultivar has the world's largest fruits and is described as the giant pumpkin. AG is well-known for its large and bright-colored fruits with high ornamental and economic value. At present, there are insufficient studies that have focused on the formation factors of the AG cultivar. To address these knowledge gaps, we performed comparative transcriptome, proteome, and metabolome analysis of fruits from the AG cultivar and a pumpkin with relatively small fruit (Hubbard). The results indicate that up-regulation of gene-encoded expansins contributed to fruit cell expansion, and the increased presence of photoassimilates (stachyose and D-glucose) and jasmonic acid (JA) accumulation worked together in terms of the formation of large fruit in the AG cultivar. Notably, perhaps due to the rapid transport of photoassimilates, abundant stachyose that was not converted into glucose in time was detected in giant pumpkin fruits, implying that a unique mode of assimilate unloading is in existence in the AG cultivar. The potential molecular regulatory network of photoassimilate metabolism closely related to pumpkin fruit expansion was also investigated, finding that three MYB transcription factors, namely CmaCh02G015900, CmaCh01G018100, and CmaCh06G011110, may be involved in metabolic regulation. In addition, neoxanthin (a type of carotenoid) exhibited decreased accumulation that was attributed to the down-regulation of carotenoid biosynthesis genes in AG fruits, which may lead to pigmentation differences between the two pumpkin cultivars. Our current work will provide new insights into the potential formation factors of giant pumpkins for further systematic elucidation.

[Discussion and analysis the value of supine median³ nystagmus in the diagnosis and treatment of HC-BPPV].

Objective:To explore the clinical value of supine median³ nystagmus in the accurate diagnosis of horizontal semicircular canal benign paroxysmal positional vertigo（HC-BPPV）. Methods:A total of 187 patients with HC-BPPV admitted to the First Affiliated Hospital of Xi'an Jiaotong University from June 2020 to March 2021 were selected. Among them 42 cases of Cupulolithiasis and 145 cases of Canalithiasis. The nystagmus parameters of patients left and right supine position and supine median³ position were recorded in detail by RART. According to the direction of supine median³ nystagmus, patients were divided into three groups: group A（nystagmus to weak side）, group B（nystagmus to strong side）, group C（negative nystagmus）. The canalith repositioning manoeuvres（CRM） was carried out by utility of an automatic vestibular function diagnosis and therapy system（SRM-IV）. The cure rate of CRM in three groups of HC-BPPV patients was compared, Multivariate logistic regression analysis was performed to analyze the influencing factors of CRM for HC-BPPV. Results:The cure rates of group A, group B and group C were 81.58%, 16.13% and 56.25%, respectively. The difference among the three groups was statistically significant. Then a pairwise comparison of group A, B and C, the difference was statistically significant（χ²A-B=40.294,P<0.001,χ²B-C=14.528, P<0.001,χ²A-C=11.606, P=0.001）; the results of multivariate logistic regression analysis showed that the direction of supine median³ nystagmus and BMI were the influencing factors of CRM for HC-BPPV. Conclusion:The direction, intensity and duration of supine median³ nystagmus play an important role in determining the responsibility semicircular canal of HC-BPPV.

iJAZ-based approach to engineer lepidopteran pest resistance in multiple crop species.

The fall armyworm (FAW) poses a significant threat to global crop production. Here we showed that overexpression of jasmonate ZIM-domain (JAZ) protein GhJAZ24 confers resistance to cotton bollworm and FAW, while also causing sterility in transgenic cotton by recruiting TOPLESS and histone deacetylase 6. We identified the NGR motif of GhJAZ24 that recognizes and binds the aminopeptidase N receptor, enabling GhJAZ24 to enter cells and disrupt histone deacetylase 3, leading to cell death. To overcome plant sterility associated with GhJAZ24 overexpression, we developed iJAZ (i, induced), an approach involving damage-induced expression and a switch from intracellular to extracellular localization of GhJAZ24. iJAZ transgenic cotton maintained fertility and showed insecticidal activity against cotton bollworm and FAW. In addition, iJAZ transgenic rice, maize and tobacco plants showed insecticidal activity against their lepidopteran pests, resulting in an iJAZ-based approach for generating alternative insecticidal proteins with distinctive mechanisms of action, thus holding immense potential for future crop engineering.

Electroacupuncture pretreatment mediates sympathetic nerves to alleviate myocardial ischemia-reperfusion injury via CRH neurons in the paraventricular nucleus of the hypothalamus.

BACKGROUND: Myocardial ischemia-reperfusion can further exacerbate myocardial injury and increase the risk of death. Our previous research found that the paraventricular nucleus (PVN) of the hypothalamus plays a crucial role in the improvement of myocardial ischemia-reperfusion injury (MIRI) by electroacupuncture (EA) pretreatment, but its mechanism of action is still unclear. CRH neurons exhibit periodic concentrated expression in PVN, but further research is needed to determine whether they are involved in the improvement of MIRI by EA pretreatment. Meanwhile, numerous studies have shown that changes in sympathetic nervous system innervation and activity are associated with many heart diseases. This study aims to investigate whether EA pretreatment improves MIRI through sympathetic nervous system mediated by PVNCRH neurons. METHODS: Integrated use of fiber-optic recording, chemical genetics and other methods to detect relevant indicators: ECG signals were acquired through Powerlab standard II leads, and LabChart 8 calculated heart rate, ST-segment offset, and heart rate variability (HRV); Left ventricular ejection fraction (LVEF), left ventricular short-axis shortening (LVFS), left ventricular end-systolic internal diameter (LVIDs) and interventricular septal thickness (IVSs) were measured by echocardiography; Myocardial infarct area (IA) and area at risk (AAR) were calculated by Evans-TTC staining. Pathological changes in cardiomyocytes were observed by HE staining; Changes in PVNCRH neuronal activity were recorded by fiber-optic photometry; Sympathetic nerve discharges were recorded for in vivo electrophysiology; NE and TH protein expression was assayed by Western blot. RESULTS: Our data indicated that EA pretreatment can effectively alleviate MIRI. Meanwhile, we found that in the MIRI model, the number and activity of CRH neurons co labeled with c-Fos in the PVN area of the rat brain increased, and the frequency of sympathetic nerve discharge increased. EA pretreatment could reverse this change. In addition, the results of chemical genetics indicated that inhibiting PVNCRH neurons has a similar protective effect on MIRI as EA pretreatment, and the activation of PVNCRH neurons can counteract this protective effect. CONCLUSION: EA pretreatment can inhibit PVNCRH neurons and improve MIRI by inhibiting sympathetic nerve, which offers fresh perspectives on the application of acupuncture in the management of cardiovascular disease.

Heterologous expression of taxane genes confers resistance to fall armyworm in Nicotiana benthamiana.

KEY MESSAGE: Taxadiene synthase, taxadiene-5α-hydroxylase, and taxane 13α-hydroxylase genes were introduced into Nicotiana benthamiana, and the improved resistance to lepidoptera pest fall armyworm was reported. Fall armyworm (FAW) is a serious agricultural pest. Genetic engineering techniques have been used to create pest-resistant plant varieties for reducing pest damage. Paclitaxel is a diterpenoid natural metabolite with antineoplastic effects in medicine. However, the effects of taxanes on the growth and development of lepidoptera pests, such as the FAW, are unknown. Here, selected paclitaxel precursor biosynthesis pathway genes, taxadiene synthase, taxane 5α-hydroxylase, and taxane 13α-hydroxylase, were engineered in the heterologous host Nicotiana benthamiana plants. Bioassay experiments showed that the transgenic N. benthamiana plants displayed improved resistance to FAW infestation, with degeneration of gut tissues and induced expression of apoptosis-related genes. Cytotoxicity experiment showed that the paclitaxel precursor, 10-deacetylbaccatin III, is cytotoxic to Sf9 cells, causing cell cycle arrest at the G2/M phase and disorder of the cytoskeleton. Metabolome analysis showed that heterologous expression of taxane genes in N. benthamiana affected the digestive system, steroid hormone and purine metabolism pathways of FAW larvae. In summary, this study provides a candidate approach for FAW control.

Plant-derived strategies to fight against severe acute respiratory syndrome coronavirus 2.

The coronavirus disease 2019 (COVID-19) pandemic has caused an unprecedented crisis, which has been exacerbated because specific drugs and treatments have not yet been developed. In the post-pandemic era, humans and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) will remain in equilibrium for a long time. Therefore, we still need to be vigilant against mutated SARS-CoV-2 variants and other emerging human viruses. Plant-derived products are increasingly important in the fight against the pandemic, but a comprehensive review is lacking. This review describes plant-based strategies centered on key biological processes, such as SARS-CoV-2 transmission, entry, replication, and immune interference. We highlight the mechanisms and effects of these plant-derived products and their feasibility and limitations for the treatment and prevention of COVID-19. The development of emerging technologies is driving plants to become production platforms for various antiviral products, improving their medicinal potential. We believe that plant-based strategies will be an important part of the solutions for future pandemics.

A New Target of Electroacupuncture Pretreatment Mediated Sympathetic Nervous to Improve MIRI: Glutamatergic Neurons in Fastigial Nucleus of the Cerebellum.

Ischemic heart disease is a fatal cardiovascular disease that irreversibly impairs the function of the heart, followed by reperfusion leading to a further increase in infarct size. Clinically, we call it myocardial ischemia-reperfusion injury (MIRI). A growing number of clinical observations and experimental studies have found electroacupuncture (EA) to be effective in alleviating MIRI. This study attempts to investigate whether glutamatergic neurons in fastigial nucleus (FN) of the cerebellum are involved in EA pretreatment to alleviate MIRI via sympathetic nerves, and the potential mechanisms of EA pretreatment process. A MIRI model was established by ligating the coronary artery of the left anterior descending branch of the heart for 30 minutes, followed by 2 hours of reperfusion. Multichannel physiological recordings, electrocardiogram, cardiac ultrasound, chemical genetics, enzyme-linked immunosorbent assay and immunofluorescence staining methods were combined to demonstrate that EA pretreatment inhibited neuronal firing and c-Fos expression in FN of the cerebellum and reduced cardiac sympathetic firing. Meanwhile, EA pretreatment significantly reduced cardiac ejection fraction (EF), shortening fraction (SF), percentage infarct area, decreased myocardial norepinephrine (NE), creatine kinase isoenzyme MB (CK-MB) concentrations, and improved MIRI-induced myocardial tissue morphology. The results were similar to the inhibition of glutamatergic neurons in FN. However, the activation of glutamatergic neurons in FN diminished the aforementioned effects of EA pretreatment. This study revealed that glutamatergic neurons in FN of the cerebellum is involved in EA pretreatment mediated sympathetic nervous and may be a potential mediator for improving MIRI.

[Study on the influence of Barbecure combined with Epley on residual dizziness of horizontal canal benign paroxysmal positional vertigo by SRM-vertigo diagnosis system].

Objective:To investigate the influence of Barbecure combined with Epley on residual dizziness of horizontal canal benign paroxysmal positional vertigo（HC-BPPV） by SRM-vertigo diagnosis system. Methods:A total of 406 patients diagnosed with HC-BPPV from Nov 2021 to Nov 2022 were enrolled by rapid axial roll test and Dix-Hallpike in the department of Otorhinolaryngology Head and Neck Surgery, the First Affiliated Hospital of Xi'an Jiaotong University. The patients were divided into two groups by hospital card numbers, in which the numbers that were odd were considered as group A, and the numbers that were even were considered as group B. The group A underwent two circles of Barbecure repositioning procedure by SRM-vertigo diagnosis system, while the group B underwent two circles Barbecure combined with Epley repositioning procedure by SRM-vertigo diagnosis system. The treatment was stopped on the next day when two groups of patients were cured, and those who were not cured will continue treatment with the same method. Results:The cure rate of group A was 83.41%, and the cure rate of group B was 80.51%, the difference between the two groups was not-statistically significant difference（P>0.05）. The rate of residual dizziness of group A was 23.30%, the rate of residual dizziness of group B was 11.46%, the difference between the two groups was statistically significant（P<0.05）. Conclusion:The Barbecure combined with Epley otoliths repositioning maneuver by SRM-vertigo diagnosis system can significantly reduce the rate of residual dizziness after the treatment of HC-BPPV, and improve the quality of life of patients.

Climate change impacts of conventional sewage sludge treatment and disposal.

Sewage sludge (SS) management remains a challenge across the world. We quantified the potential climate change impacts of eight conventional technology configurations (TCs) for SS treatment and disposal by considering four different energy exchanges and using a life cycle assessment (LCA) model that employed uncertainty distributions for 104 model parameters. All TCs showed large climate change loads and savings (net values ranging from 123 to 1148 kg CO2-eq/t TS) when the energy exchange was with a fossil-based energy system, whereas loads and savings were approximately three times lower when the energy exchange was with a renewable energy system. Uncertainty associated with the climate change results was more than 100% with fossil-energy exchange and low TS content of SS but was lower for renewable energy. Landfilling had the greatest climate change impact, while thermal drying with incineration had the highest probability of providing better climate change performance than other TCs. The global sensitivity analysis identified nine critical technological parameters. Many of them can be easily measured for relevant SS and technology levels to improve specific estimates of climate change impact. When all scenarios were optimized to the 20% best cases, thermal drying with incineration outperformed the other TCs. This paper contributes to better quantifying the climate change impacts of different technologies used for sludge treatment given changing energy systems and identifies crucial parameters for further technological development.

Mini-review of inventory data for the dewatering and drying of sewage sludge.

Technological comparison and system modelling of sewage sludge treatment are important in terms of sustainable development and climate change mitigation. Dewatering and drying are important processes for reducing volume for transportation and often a requirement for further sludge treatment. Inventory data on mass transfers and material and energy consumptions are therefore crucial in improving and understanding sludge management systems. Reviewing the scientific literature (2003-2021) revealed 55 and 21 datasets on dewatering and drying of sewage sludge, respectively. The scarcity of data did not allow for identifying detailed relationships between inputs and outputs for the technologies, but the reviewed data can serve as the first port of call when planning sludge management. The average total solid (TS) content obtained was statistically different for mechanical dewatering (MDW), deep dewatering, bio-drying (BDR) and thermal drying (TDR). Loss of volatile solids (VS) during dewatering is barely described, but a substantial VS loss was observed for TDR (8%) and BDR (27%). The use of chemical agents in MDW showed typical values of 5-15 g kg-1 TS. The use of energy is low for MDW (average of 0.12 and 0.26 kWh kg-1 TS for raw and digested sludges, respectively) but substantially higher for TDR (average of 3.8 kWh kg-1 TS). The justified inventory data for sludge dewatering and drying provide essential support to system modelling and technological comparison in future studies, but additional data from full-scale plants on energy consumption and the composition of removed water are strongly requested to improve the inventory.

Review of inventory data for the biological treatment of sewage sludge.

The biological treatment of municipal sewage sludge, including anaerobic digestion and composting, was reviewed with the purpose of establishing inventory data to address all the inputs and outputs related to sludge treatment. We identified 193 scientific papers, resulting in 64 datasets on anaerobic digestion and 35 datasets on composting. For anaerobic digestion, biogas production varied significantly (up to a factor of four) depending on the sludge. A useful correlation was identified between the amount of methane produced and the degradation of volatile solids. According to statistical tests, no significant differences were found in biogas production for mesophilic and thermophilic digesters. In addition, methane content varied significantly, and very few data were available for digestate composition or for energy consumption and recovery. For composting, accurate estimates relating to the degradation of sewage sludge could not be made, since organic bulking materials were part of the final composted product. Data on emissions to air are currently scarce, which points to the need for more published information. The inventory data evaluated herein are useful in the feasibility assessment of the biological treatment of sewage sludge, for comparing technologies, for example in LCA studies and as a basis for evaluating the performance of a specific biological sludge treatment plant. However, a great deal of the reviewed data originated from laboratory and pilot-scale studies, and so there is a need for more complete datasets on the performance of full-scale technologies, in order to establish full inventories and identify differences in technologies and operational conditions.

Mini-review of sewage sludge parameters related to system modelling.

System modelling of sewage sludge (SS) treatment attracts a growing interest for better comparison and optimisation of technologies. However, SS parameters need to be generalised to be used in holistic assessments, since scattered data may inhibit the development and interpretation of system models. A review of the literature on SS parameters relevant to modelling SS treatment systems revealed 208 datasets published in 162 publicly available scientific papers. We treated thickened and dewatered sludge in the same data analysis, but in some cases, this was an incorrect assumption. The compositional data showed significant variations, but most of the data subscribed to a lognormal distribution, albeit with varying levels of significance. On average, the thickened sludge contained 3.3 ± 1.7% total solid (TS), and the dewatered sludge contained 21.0 ± 6.7% TS. For the combined data, the average Ash content was 32.4 ± 11.8% of TS. Other characteristic parameters were the lower heating value (LHV) of 22.1 ± 2.1 MJ kg-1 volatile solid (VS) and the biochemical methane potential (BMP) of 0.25 ± 0.11 m3 CH4 kg-1 VS. Fertiliser-related elements were on average 53.3 ± 9.3% C in VS, 6.8 ± 2.2% N in VS, 6.7 ± 2.4% P in Ash and 1.7 ± 1.3% K in Ash. The data reviewed herein provide a good basis for assessing the generality of individual SS data and for selecting key parameters for modelling SS treatment systems. However, the review reveals a need for the better characterisation of SS in the future.