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Complex biological environments and multiple physiological barriers significantly impede efficient accumulation and penetration of nanomaterials within tumor tissue for therapy. In situ energy conv...

Insufficient ion capacity from a room temperature polymer electrolyte is commonly a short slab of the solid-state photoelectrochemical systems, like solid-state dye-sensitized solar cells (S-DSSCs). To overcome this drawback, herein a facile strategy based on the light-induced temperature-rise effect on the electrolyte has been given. By applying a photo-heatable, well-nanostructured polymer electrolyte dyed with azobenzene, it is found that the azobenzene can remarkably increase the ion conductivity of the gel electrolyte, and obtain better light-harvesting efficiency. To explore the mechanism, differential scanning calorimeter and infrared imaging system are used to accurately evaluate the temperature rise of such electrolyte under different preparation or irradiation conditions. It shows that significant photothermal heating effect on the electrolyte can both benefit from the incorporated azobenzene as a “micro solar-heater” and the rich nanostructure of the matrix surface that increases the area of ​​interaction with light. Under standard sunlight, the azobenzene-stained polymer electrolyte can obtain a temperature rise from 1.2 °C (no staining) to 9 °C (dyeing), and the corresponding ionic conductivity increases up to about 40%. Accordingly, the photothermal photo-to-electron conversion efficiency of S-DSSC is significantly improved by ∼50%.

Tin perovskite solar cells (TPSCs) are promising for lead-free perovskite solar cells (PSCs) and have led to extensive research; however, the poor crystallinity and chemical stability of tin perovskites are two issues that prevent stable TPSCs. In this study, we outline a new process that addresses these issues by using tin(II) acetate (Sn(Ac)2) in place of the conventional SnF2 precursor additive. Compared with SnF2, Sn(Ac)2 improves the crystallinity and stability of tin perovskite with fewer defects and better charge extraction. Using this process, we developed a device that has a higher external quantum efficiency for charge extraction compared with the control devices and a power conversion efficiency of 9.93%, which maintained more than 90% of its initial efficiency after 1000 h operation at the maximum power point under standard AM 1.5G solar illumination.

Helicobacter pylori infection is a major etiological factor in gastric diseases. However, clinical antibiotic therapy for H. pylori is limited by continuously decreased therapeutic efficacy and side effects to symbiotic bacteria. Herein, we develop an in vivo activatable pH-responsive graphitic nanozyme, PtCo@Graphene (PtCo@G), for selective treatment of H. pylori. Such nanozymes can resist gastric acid corrosion, exhibit oxidase-like activity to stably generate reactive oxygen species only in acidic gastric milieu and demonstrate superior selective bactericidal property. C18-PEGn-Benzeneboronic acid molecules are modified on PtCo@G, improving its targeting capability. Under acidic gastric pH, graphitic nanozymes show notable bactericidal activity toward H. pylori, while no bacterial killing is observed under intestinal conditions. In mouse model, high antibacterial capability toward H. pylori and negligible side effects toward normal tissues and symbiotic bacteria are achieved. Graphitic nanozyme displays the desired enzyme-like activities at corresponding physiological sites and may address critical issues in clinical treatment of H. pylori infections., Helicobacter pylori is a major cause of gastric diseases, but the standard therapy is limited by continuously decreased therapeutic efficacy and side effects to symbiotic bacteria. Here, the authors develop a pH-responsive graphitic nanozyme that is active under low pH gastric conditions, but inactive in intestines, for selective treatment of H. pylori infections.

Tin perovskite solar cells (TPSCs) are the most promising candidates for lead-free perovskite solar cells (PSCs). However, the poor crystallization and chemical stability of Sn perovskites are the two challenging issues for further application of TPSCs. Here, we present a strategy to stabilize CH(NH2)2SnI3 (FASnI3) perovskite enabled by an amine complex, CH3NH3I·3CH3NH2, which can hinder the major degradation issue caused by the oxidation of Sn2+ to Sn4+. The resulting Sn perovskite films exhibit enhanced crystallinity and stability in comparison with those made with conventional inorganic SnF2 additives. Finally, the device achieved a higher external quantum efficiency for charge extraction and a power conversion efficiency (PCE) of 9.53%, which maintained more than 90% of the initial efficiency after 1000 h of light soaking under the standard AM 1.5 G solar illumination.

Bacterial biofilm infection is perplexing people’s life. Systemic administration of antibiotics usually causes adverse effects and bacterial resistance. How to make antibacterial agents quickly penetrate and eradicate the biofilm without adverse effects is an urgent problem. Here, polyamine-functionalized carbon quantum dots (CQDs), abbreviated as CQD600, CQD1w and CQD2.5w, are synthesized by a simple hydrothermal treatment of citric acid and branched polyethyleneimine (bPEI) with different molecular weight (MW). It is found that the antibacterial activity is promoted with high MW of bPEI, which is due to the protonated amines on the surface of the CQDs. Moreover, in terms of eradicating mature Staphylococcus aureus biofilm, CQD2.5w possesses significantly higher activity than CQD600 and CQD1w because of stronger electrostatic interactions and longer surface coronas. Additionally, the cytotoxicity test exhibits the L929 cells can keep at high survival rates even treated with 500 µg mL−1 CQDs for 3 days. In this study, the surface chemistry related to antibacterial activity and low cytotoxicity give the chance in designing and developing better CQDs for biofilm infection.

Summary Operational stability of efficient opto-electronic conversion is crucial for the success in large-scale application of perovskites devices. Owing to the intrinsically weak structure of perovskites, iodide represents the most volatile constituents, and its diffusion can induce irreversible degradation that continues to present a great challenge to realize stable perovskite devices. Here, we introduce a low-temperature processing strategy to increase the operational stability of high-efficiency perovskite solar modules by engineering low-dimensional diffusion barriers, reducing the unwanted interfacial diffusion of ions by 103–107 times in magnitude. We finally achieved stable and efficient perovskite solar modules with an area of 36 cm2 retaining over 95% of their initial efficiency of over 15% after 1,000 h of heating at 85°C, and 91% after light soaking in AM 1.5 G solar light for 1,000 h, respectively. Our findings provide an effective strategy to realize operationally stable and efficient perovskite solar cell modules.

Lithium–sulfur (Li–S) batteries have attracted tremendous attention as the next generation of lithium batteries. In the battery construction, a nanopore separator can improve the performance of the Li–S battery by working as a nanofiltration film, inhibiting the migration of soluble polysulfide ions between the electrodes. Herein, a new strategy to synthesize a nanopore separator of poly(propylene glycol)-co-pentaerythritol triacrylate (PPG-co-PETA) particles to suppress polysulfide shuttling has been proposed. The PPG-co-PETA cross-linked particles were easily obtained by a facile approach of UV-induced monomer polymerization while implementing molecular cross-linking for nanopore control. The characteristic nanopore size of the PPG-co-PETA separator ranged from ∼1.24 nm to ∼1.86 nm upon changing the type of photo-initiator and content of cross-linking agent. The results showed that the optimized separator for a Li–S battery could possess an electrolyte uptake of 350% with excellent thermal, mechanical and electrochemical properties. Notably, the Li–S battery using such a new type of nanopore separator exhibits superior retention discharge capacity (>200 cycles). It is believed that the nanopore separator of cross-linked PPG-co-PETA is a potential alternative to the commercial Celgard separator for effectively blocking polysulfide shuttling in Li–S batteries.

Diverting food waste (FW) into the sulfate-laden sewer may pose a significant influence on the production of methane and sulfide in sewers. Identifying microbial electron utilization is essential to understanding the interaction of sulfidogenesis and methanogenesis in depth. Here, we reported sulfide and methane production from the sewer bioreactors receiving sulfate-laden wastewater (160 mg S/L), with and without FW addition. Long-term monitoring showed that the addition of FW (1 g/L) could boost both sulfide (by 39%) and methane (by 44%) production. As for the electrons used for sulfidogenesis and methanogenesis, about 98% flowed to sulfidogenesis. Cryosection-fluorescence in situ hybridization showed that high sulfate content suppressed the accumulation of methanogens in biofilm outer layer, whereas methanogens in the inner layer were enriched with FW addition. Moreover, the FW addition fostered the diversity of the fermentative bacteria and changed the type of methanogens in biofilms, and up-regulated the key enzymes expressions for sulfidogenesis and methanogenesis. A model-based investigation suggests that increased FW-to-sewage ratios would exert a significant impact on methane production than on sulfide production. The microbial electron flows were highly dependent on sulfate concentration and FW-to-sewage ratios. The findings of this study suggest that sulfate and substrate levels play a key role in microbial electron utilization for sulfide and methane production, and diverting FW into the sulfate-laden sewer may exert negative impacts on sewer management and the environment.

Conversion of food and beverage (F&B) waste into high fructose syrup (HFS) was proposed in this study. Hydrolysate obtained from saccharification of mixed F&B waste is rich in glucose (260.3 ± 7.8 g L−1) and fructose (54.1 ± 1.6 g L−1) but also contains trace preservatives, caffeine, colourants, ions and soluble proteins. Over 99% of these impurities were removed by adsorption and ion exchange chromatography, followed by enzymatic isomerisation where glucose was converted to reach 50% of fructose content. Pilot scale downstream processing was successfully conducted with more than 89% of sugars recovered from the hydrolysate. Mass balance analysis indicated an overall conversion yield of 0.08 kg HFS per kg of mixed F&B waste and meanwhile the HFS also conforms to industrial standards. This proposed process is believed to promote the development of a circular economy by recycling F&B waste as a renewable resource for HFS production.

Recently, the integration of sulfur-driven denitrification and anammox process has been extensively studied as a promising alternative nitrogen removal technology. Most of these studies investigated the process feasibility and monitored the community dynamics. However, an in-depth understanding of this new sulfur-nitrogen cycle bioprocess based on mathematical modeling and elucidation of complex interactions among different microorganisms has not yet been achieved. To fill this gap, we developed a kinetic model (with 7 bioprocesses, 12 variables, and 19 parameters) to assess the sulfur(thiosulfate)-driven denitrification and anammox (TDDA) process in a single reactor. The parameters used in this process were separately estimated by fitting the data obtained from the experiments. Then, the model was further validated under different conditions, and the results demonstrated that the developed model could describe the dynamic behaviors of nitrogen and sulfur conversions in the TDDA system. The newly developed branched thiosulfate oxidation model was also verified by conducting a metagenomics analysis. Using the developed model, we i) examined the interactions between sulfur-oxidizing bacteria and anammox bacteria at steady-state conditions with varying substrates to demonstrate the reliability of TDDA, and ii) evaluated the feasibility and operation of the TDDA process in terms of practical implementation. Our results will benefit further exploration of the significance of this novel S-N cycle bioprocess and guide its future applications.

Waste valorisation practices have attracted a significant amount of attention in recent years with the aim at managing waste in the most sustainable way. Most of the studies focused on converting solid waste feedstock for value-added chemicals and fuels production. However, less effort has been devoted on liquid waste such as beverage waste which is a significant sewage stream in urban area. In this study, a bioconversion process was developed to produce low-cost fructose syrup using beverages waste as feedstock. The process composed of enzymatic hydrolysis, activated carbon treatment, ion exchange chromatography and ligand exchange chromatography. Beverages waste collected from local supermarket was treated by commercial pectinase and sucrase. Optimisation study on enzyme activities indicated that both enzymes were most active at 50 °C and pH of 4.0–4.5. Hydrolysate containing 36.0 g/L glucose and 45.0 g/L fructose was then de-colourised in the activated carbon treatment. Also, more than 98% ions were removed after the cation and anion exchange chromatography. Lastly, high fructose syrup was produced by ligand exchange chromatography at a fructose separation efficiency of 74.9%. A total of 47.5% sugars in the hydrolysate were recovered as high fructose syrup, while the remaining sugars were in the glucose-rich stream. The proposed method would be a green and sustainable process for nutrient recovery in beverage waste valorisation. Future study should focus on increasing fructose separation efficiency by using simulated moving bed system and the enhancement of fructose production yield by isomerisation of glucose-rich stream.

Bacterial infection is one of the most formidable problems in wound healing, which inflicts severe pain on patients while causing wound ulceration. Here, we prepared an injectable self-healing carbon dot hydrogel with outstanding antibacterial activity only using e-poly(L-lysine) carbon dot (PL-CD) and oxidized dextran (ODA). The particle size of PL-CD prepared by pyrolysis of poly-l-lysine was about 3 nm. Moreover, PL-CD with abundant -NH2 on its surface could not only act as nodes to connect ODA through Schiff base to construct PL-CD@ODA hydrogel network, but also offer excellent antibacterial properties. As the contacting and releasing antibacterial action of the PL-CD@ODA hydrogel, nearly 100 % of the 107 CFU/mL of S. aureus was killed after 10 min of contacting. In addition, PL-CD@ODA hydrogel showed flexible injectability and extremely strong self-healing properties after being severely damaged. When 1000 % shear stress applied to the hydrogel, complete healing could be achieved within a few seconds.

Local bacterial infection remains an increasingly severe threat to human health worldwide, and infection control is still a challenging task in clinics. Systemic administration of antibiotics usually causes adverse effects and bacterial resistance. Multi-functions hydrogel without drug-resistance is highly desired. Herein, we first synthesize antibacterial carbon quantum dots (CQDAG) with low-drug resistance using gentamicin sulfate and diammonium citrate as precursors. Then carboxymethyl chitosan (CMCS)-mixed CQDAG is reacted with oxidized dextran (ODex) through the Schiff base linkage to yield hydrogel network. Hydrogel decorated with 2 mg/mL CQDAG (CQDAG2-hydrogel) shows multi-functions including inherent self-healing, injectable, stretchable, compressive property, pH-dependent release of CQDAG and especially inhibiting biofilm formation, which are beneficial for treating bacterial infections. Besides, it is important that CQDAG2-hydrogel exhibits good cytocompatibility while sterilizing. In vivo antibacterial and wound healing evaluations demonstrate CQDAG2-hydrogel have the effect of anti-inflammation and promoting wound repair, which is manifested in wound healing rate, granulation tissue thickness and collagen disposition. The result indicates that the CQDAG2-hydrogel is excellent candidate for full-thickness skin wound healing.

Objective: Across Japan, around 2 million people are infected with hepatitis C virus (HCV) with long-term complications such as cirrhosis, hepatocellular carcinoma (HCC) and liver transplant (LT). Current treatment options have several limitations due to side effects, interferon intolerability and ineligibility, long treatment durations and low sustained virological responses (SVR) rates, especially for the most severe patients. Sofosbuvir (SOF) is the first nucleotide analog NS5B polymerase inhibitor with pan-genotypic activity. SOF, administered in combination with ribavirin (RBV) with or without pegylated interferon (PEGIFN) resulted in high SVR rates across genotype (GT) 1–6 patients. It is also the first available regimen for patients that are unsuitable for interferon. This analysis assessed the cost–utility ratio of sofosbuvir in GT2 patients in Japan. Research design and methods: A Markov model followed a cohort of 10,000 GT2 patients until patients reached 100 years of age. Approximately 20% of patients initiated treatment at the cirrhotic stage. Comparators were based on the current recommendations in Japan, including PEGIFN with ribavirin (RBV), telaprevir (TVR) in combination with PEGIFN + RBV and no treatment. Costs and outcomes were discounted at 2%. Results: Sofosbuvir was cost-effective across all the studied indications, especially in patients unsuitable for interferon, with incremental cost–effectiveness ratios (ICERs) lower than JPY 5,000,000. Compared to the other treatments included in the analysis, SOF + RBV resulted in improved clinical outcomes. Results were robust to sensitivity analyses. Conclusion: SOF combined with RBV was shown to be cost-effective in GT2 patients in Japan. Compared to PEGIFN + RBV, TVR + PEGIFN + RBV and no treatment SOF offers a more efficacious, shorter and better tolerated treatment option and extends treatment to reach HCV-infected patients who are ineligible for interferon-based regimens. Although adverse events were not included in the analyses, this would not make any changes to our conclusion.

Our previous study has confirmed the feasibility of using seawater as an economical precipitant for urine phosphorus (P) precipitation. However, we still understand very little about the ureolysis in the Seawater-based Urine Phosphorus Recovery (SUPR) system despite its being a crucial step for urine P recovery. In this study, batch experiments were conducted to investigate the kinetics of microbial ureolysis in the seawater-urine system. Indigenous bacteria from urine and seawater exhibited relatively low ureolytic activity, but they adapted quickly to the urine-seawater mixture during batch cultivation. During cultivation, both the abundance and specific ureolysis rate of the indigenous bacteria were greatly enhanced as confirmed by a biomass-dependent Michaelis-Menten model. The period for fully ureolysis was decreased from 180 h to 2.5 h after four cycles of cultivation. Based on the successful cultivation, a lab-scale SUPR reactor was set up to verify the fast ureolysis and efficient P recovery in the SUPR system. Nearly complete urine P removal was achieved in the reactor in 6 h without adding any chemicals. Terminal Restriction Fragment Length Polymorphism (TRFLP) analysis revealed that the predominant groups of bacteria in the SUPR reactor likely originated from seawater rather than urine. Moreover, batch tests confirmed the high ureolysis rates and high phosphorus removal efficiency induced by cultivated bacteria in the SUPR reactor under seawater-to-urine mixing ratios ranging from 1:1 to 9:1. This study has proved that the enrichment of indigenous bacteria in the SUPR system can lead to sufficient ureolytic activity for phosphate precipitation, thus providing an efficient and economical method for urine P recovery.

A new deposition method for solar-panel polycrystalline perovskite thin films enables the production of large-area uniform films and avoids the need for common solvents or vacuum. Hybrid inorganic–organic perovskites are the most likely materials to replace silicon as absorber layers for solar cells, but issues with stability and scaling-up thin films mean that large-scale production is not yet possible. Liyuan Han and colleagues have developed a new deposition method for polycrystalline thin films that does not rely on spin- or drip-coating precursors in solvent or on vacuum deposition, and is therefore more amenable to larger-area films than are previous techniques. The procedure uses gaseous precursors and application of pressure, and has enabled a device with an area of 36 square centimetres to be certified at 12.1 per cent power conversion efficiency. Recent advances in the use of organic–inorganic hybrid perovskites for optoelectronics have been rapid, with reported power conversion efficiencies of up to 22 per cent for perovskite solar cells1,2,3,4,5,6,7,8,9. Improvements in stability have also enabled testing over a timescale of thousands of hours10,11,12,13,14. However, large-scale deployment of such cells will also require the ability to produce large-area, uniformly high-quality perovskite films. A key challenge is to overcome the substantial reduction in power conversion efficiency when a small device is scaled up: a reduction from over 20 per cent to about 10 per cent is found15,16,17,18,19,20,21 when a common aperture area of about 0.1 square centimetres is increased to more than 25 square centimetres. Here we report a new deposition route for methyl ammonium lead halide perovskite films that does not rely on use of a common solvent1,2,4,5,6,7,8,9,10,11,12,13,14,15 or vacuum3: rather, it relies on the rapid conversion of amine complex precursors to perovskite films, followed by a pressure application step. The deposited perovskite films were free of pin-holes and highly uniform. Importantly, the new deposition approach can be performed in air at low temperatures, facilitating fabrication of large-area perovskite devices. We reached a certified power conversion efficiency of 12.1 per cent with an aperture area of 36.1 square centimetres for a mesoporous TiO2-based perovskite solar module architecture.

Objective: Hepatitis C is the result of a ribonucleic acid (RNA) virus (hepatitis C virus; HCV). The Japan Society of Hepatology (JSH) estimated that 1.5–2 million people in Japan carry HCV. Six major HCV genotypes (GT) and a large number of subtypes have been described in the literature. In Japan, around 70% to 80% of people are infected with HCV genotype 1b. The progress of the disease primarily affects the liver and may lead to liver cirrhosis, hepatocellular carcinoma (HCC) and death. Sofosbuvir (SOF) is a nucleotide analogue NS5B inhibitor and ledipasvir (LDV) is an inhibitor of the HCV NS5A protein. They are combined in a single tablet regimen for the treatment of GT1 patients and resulted in sustained virological response (SVR) above 94% in large phase III trials. This analysis assesses the cost–utility of LDV/SOF in GT1 patients in Japan. Research design and methods: A cohort of 10,000 patients was followed through a Markov model until they reached 100 years of age. GT1 treatment-naïve and experienced, non-cirrhotic and cirrhotic patients were studied separately. LDV/SOF was compared to several treatment regimens containing pegylated interferon (PEGIFN), telaprevir (TVR), simeprevir (SMV), daclatasvir (DCV), asunaprevir (ASV) and ribavirin (RBV). Discount rates of 2% were applied to costs and outcomes according to the Japanese guidelines. Results: LDV/SOF was cost-effective against most comparators with incremental cost-effectiveness ratios (ICERs) below JPY 5,000,000. By applying a societal perspective, LDV/SOF was the dominant treatment strategy in all cases. Moreover, LDV/SOF reduced the number of cases of advanced liver disease. These results were robust to sensitivity analyses. Conclusions: LDV/SOF was cost-effective compared to most of the currently recommended treatments. Furthermore, LDV/SOF extends treatments to HCV-infected patients who are ineligible for interferon and RBV-based regimens. LDV/SOF thus has the potential to help reduce the burden of HCV in Japan.

A plasma assisted reactive pulsed laser deposition process was demonstrated for low-temperature deposition of thin hafnia (HfO 2 ) and zirconia (ZrO 2 ) films from metallic hafnium or zirconium with assistance of an oxygen plasma generated by electron cyclotron resonance microwave discharge. The structure and the interface of the deposited films on silicon were characterized by means of Fourier transform infrared spectroscopy, which reveals the monoclinic phases of HfO 2 and ZrO 2 in the films with no interfacial SiO x layer between the oxide film and the Si substrate. The optical properties of the deposited films were investigated by measuring the refractive indexes and extinction coefficients with the aid of spectroscopic ellipsometry technique. The films deposited on fused silica plates show excellent transparency from the ultraviolet to near infrared with sharp ultraviolet absorption edges corresponding to direct band gap.

Background Plasminogen activator inhibitor-1 (PAI-1) is reported to be expressed in many cancer cell types and regarded as one of the most informative biochemical markers for poor prognosis. However, no previous study has evaluated whether PAI-1 could serve as a target in antitumor and antimetastasis therapies of colorectal cancer (CRC). Methods The plasma level of PAI-1 in CRC patients was detected and its correlation with the clinicopathologic features was evaluated. PAI-1 protein expression was assessed by Western blot assay and immunohistochemistry. The biologic consequences of PAI-1 silencing in colon cancer cell lines and CRC bearing nude mice were also investigated. Results Plasma PAI-1 level was higher in CRC patients with liver metastasis and correlated with liver metastasis, tumor size, differentiation, serosa infiltration, Duke’s stage, and lymphatic metastasis. PAI-1 protein expression in the CRC tissue of patients with liver metastasis was significantly greater than that in those without liver metastasis. In addition, the abilities of proliferation, invasion, and migration of CRC cells transfected with lentivirus expressing PAI-1 small interfering RNA were reduced significantly. Nude mice inoculated with PAI-1 knockdown cells also had fewer metastatic nodules in the liver and smaller tumor volumes. Conclusion Plasma PAI-1 level was increased in CRC patients with liver metastasis, and PAI-1 silencing may significantly compromise the malignant behaviors of CRC cells in vitro and in vivo. These findings may provide evidence for PAI-1 targeted therapy of CRC.

Freshwater toilet flushing consumes 20–35% of typical household water demand. Seawater toilet flushing, as practised by Hong Kong since 1958, provides an alternative water source. To maximise the benefits of this unique dual water supply, urine separation could be combined to allow low-cost struvite production and subsequent urine nitrification – in-sewer denitrification. This paper reports on a laboratory-scale study of seawater urine phosphate recovery (SUPR) and seawater–urine nitrification. A laboratory-scale SUPR reactor was run under three phases with hydraulic retention time between 1.5 and 6 h, achieving 91–96% phosphorus recovery. A urine nitrification sequencing batch reactor (UNSBR) was also run for a period of over 650 days, averaging 90% ammonia removal and loading of up to 750 mg-N/L.d. Careful control of the SUPR phosphate removal was found necessary for operation of the downstream UNSBR, and system integration considerations are discussed.

Phosphorus (P) is a crucial and non-renewable resource, while it is excessively discharged via sewage, significant amounts originating from human urine. Recovery of P from source-separated urine presents an opportunity not only to recover this precious resource but also to improve downstream sewage treatment works. This paper proposes a simple and economic method to recover urine derived P by using seawater as a low-cost precipitant to form struvite, as Hong Kong has practised seawater toilet flushing as an alternative water resource since 1958. Chemical reactions, process conditions and precipitate composition for P precipitation in urine have been investigated to develop this new urine P recovery approach. This study concluded that ureolysis extent in a urine-seawater mixture determines the reaction pH that in turn influences the P recovery efficiency significantly; 98% of urine P can precipitate with seawater within 10 min when 40–75% of the urea in urine is ureolysed; the urine to seawater ratio alters the composition of the precipitates. The P content in the precipitates was found to be more than 9% when the urine fraction was 40% or higher. Magnesium ammonium phosphate (MAP) was confirmed to be the predominant component of the precipitates.

A thermoacoustic engine operating below 10 Hz, with gas and liquid as the working fluids, is experimentally studied in this paper. The emphasis of measurement and analysis focuses on the impact of liquid column mass, mean operating pressure, gas working fluids, and liquid working fluids on the resonant frequency and the pressure amplitude. Experimental results demonstrate that a remarkable drop of resonant frequency and an increase of pressure amplitude can be realized by introducing a liquid column into a thermoacoustic engine with mere gas working fluid. A larger liquid column mass or a higher mean operating pressure can lead to a higher pressure amplitude. Compared with nitrogen, carbon dioxide and helium, argon seems to be advantageous for achieving a larger pressure amplitude at the same heating power, whereas the carbon dioxide-water system gets the lowest resonant frequency. As to the liquid working fluid, a small viscosity is preferable for elevating the pressure amplitude.