Determinantal point processes on spheres: multivariate linear statistics

In this paper, we will derive the first and 2nd order Wiener chaos decomposition for the multivariate linear statistics of the determinantal point processes associated with the spectral projection kernels on the unit spheres $S^d$. We will first get a graphical representation for the cumulants of multivariate linear statistics for any determinantal point process. The main results then follow from the very precise estimates and identities regarding the spectral projection kernels and the symmetry of the spheres

Recent progress towards in-situ biogas upgrading technologies

Biogas is mainly produced from the anaerobic fermentation of biomass, containing methane with an extensive range between about 50% and 70%. Higher methane content biogas has higher energy and heat value, which needs biogas upgrading. There are mainly two types of biogas upgrading technologies (ex-situ and in-situ). This manuscript presents a review of technologies on in-situ biogas upgrading. These technologies comprise H2 addition technology (e.g., continuous stirring tank reactor (CSTR), hollow fiber membrane (HFM), nano-bubble (NB) technology, upflow anaerobic sludge blanket (UASB)), high-pressure anaerobic digestion (HPAD), bioelectrochemical system (BES), and additives (e.g., ash, biochar, and iron powder). The results confirm the excellence of H2-addition technology, with the highest average CH4 content obtained (HFM: 92.5%) and one of the few full-scale cases reported (Danish GasMix ejector system: 1110 m3). Meanwhile, newly pop-up technology such as HPAD delivers appropriate CH4 content (an average of 87%) and is close to the full-scale application (https://bareau.nl/en/for-professionals/). More importantly, the combo between HPAD and H2-addition technology is prominent as the former improves the low gas-to-liquid obstacle confronted by the latter. Additionally, recently emerging BES can't stand out yet because of limited efficiency on CH4 content or constraint full-scale application behaviors (disability to operate at high current density). However, its combination with H2-addition technology to form the Power to Gas (PtG) concept is promising, and its commercial application is available (http://www.electrochaea.com/). Hydrogenotrophic methanogens are imperative players in all reviewed technologies for the generation of upgraded CH4

Research Progress in Anaerobic Digestion of High Moisture

High moisture organic waste constitutes a large fraction of municipal solid waste and caused a nuisance. Anaerobic digestion of this high degradable fraction has been developed during the past 20 years. Parameters such as characteristic of substrates, temperature, organic loading rate and hydraulic retention time were studied. The most important conversion of intermediate of volatile fatty acid was observed as a indicator of digestion efficiency. One stage and two stage system are based on the stage separated into acidogenic phase and methnogenis phase. Two stage digestion of this kind of wastes were proved a better efficiency than single stage digestion. Batch system and continuous system are conducted in single stage and two-stage system. One stage system are split between wet system(Total solid less than 15%) and dry system( total solid higher than 15%) according to the characteristics of feedstock. Two-stage solid bed system are observed more and more popular in the digestion of solid state VFW and food waste experimental studies, however the large majority of industrial application use single stage systems. Two stage digestion of HMOW will be applied to industrial scale due to its larger resistance to high loading rate, high and stable gas production

Microbiological and Technological Insights on Anaerobic Digestion of Animal Manure: A Review

Anaerobic digestion of animal manure results in the production of renewable energy (biogas) and nutrient-rich biofertilizer. A further benefit of the technology is decreased greenhouse gas emissions that otherwise occur during manure storage. Since animal manure makes anaerobic digestion cost-efficient and further advance the technology for higher methane yields, it is of utmost importance to find strategies to improve bottlenecks such as the degradation of lignocellulose, e.g., in cattle manure, or to circumvent microbial inhibition by ammonia caused by the degradation of nitrogen compounds in, e.g., chicken, duck, or swine manure. This review summarizes the characteristics of different animal manures and provides insight into the underlying microbial mechanisms causing challenging problems with the anaerobic digestion process. A particular focus is put upon the retention time and organic loading rate in high-ammonia processes, which should be designed and optimized to support the microorganisms that tolerate high ammonia conditions, such as the syntrophic acetate oxidizing bacteria and the hydrogenotrophic methanogens. Furthermore, operating managements used to stabilize and increase the methane yield of animal manure, including supporting materials, the addition of trace elements, or the incorporation of ammonia removal technologies, are summarized. The review is finalized with a discussion of the research needed to outline conceivable operational methods for the anaerobic digestion process of animal manure to circumvent process instability and improve the process performance

Revealing the link between evolution of electron transfer capacity of humic acid and key enzyme activities during anaerobic digestion

Humic acid (HA) is an important active compound formed during anaerobic digestion process, with a complex structure and dynamic electron transfer capacity (ETC). However, the mechanisms by which these macromolecular organic compounds dynamically interact with the microbial anaerobic digestion process at different operating temperatures are still unclear. In this study, the link between the evolution of the ETC of HAs and the microbial community under mesophilic and thermophilic conditions was investigated. The results showed an increasing trend in the ETC of HAs in both mesophilic (671–1479 μmol gHA−1) and thermophilic (774–1506 μmol gHA−1) anaerobic digestion (AD) until day 25. The ETC was positively correlated with the bacterial community of hydrolytic and acidogenic phases, but negatively correlated with the archaeal community of the methanogenic phase. Furthermore, the relationship between ETC and key enzyme activity was explored using a co-occurrence network analysis. HAs revealed a high potential to promote key enzyme activities during hydrolysis (amylase and protease) and acidification (acetate kinase, butyrate kinase, and phosphotransacetylase) while inhibiting the key enzyme activity in the methanogenic phase during the anaerobic digestion process. Moreover, HAs formed under thermophilic conditions had a greater influence on key enzyme activities than those formed under mesophilic conditions. This study advances our understanding of the mechanisms underlying the influence of HAs on anaerobic digestion performance

Dynamic evolution of humic acids during anaerobic digestion: exploring an effective auxiliary agent for heavy metal remediation

Information on the dynamic evolution of humic acid (HA) from anaerobic digestate and the potential of HA serving as an effective agent for remedying heavy metals is rather scarce. This study monitored the evolution of the structure and functional groups and metal-binding abilities of HA during chicken manure and corn stover anaerobic digestion (AD) processes. Higher increases in aromatic (41-66%) and oxygen-containing functional groups (37-45%) were observed in HA from the AD of corn stover, resulting in higher metal-binding abilities for Cu(II), Co(II), and Ni(II) than those of chicken manure AD. Moreover, HA extracted from fast (before day 12 for chicken manure and day 16 for corn stover), and slow (day 40) methane production stages performed different complexation capacities for the heavy metals. These results reveal the mechanisms of HA and heavy metal interactions, and confirm the potential of HA extracted from AD process for the remediation of heavy metals

Transduction of Adeno-Associated Virus Vectors Targeting Hair Cells and Supporting Cells in the Neonatal Mouse Cochlea

Adeno-associated virus (AAV) is the preferred vector for gene therapy of hereditary deafness, and different viral serotypes, promoters and transduction pathways can influence the targeting of AAV to different types of cells and the expression levels of numerous exogenous genes. To determine the transduction and expression patterns of AAV with different serotypes or promoters in hair cells and supporting cells in the neonatal mouse cochlea, we examined the expression of enhanced green fluorescent protein (eGFP) for five different types of AAV vectors [serotypes 2, 9, and Anc80L65 with promoter cytomegalovirus (CMV)-beta-Globin and serotypes 2 and 9 with promoter chicken beta-actin (CBA)] in in vitro cochlear explant cultures and we tested the transduction of AAV2/2-CBA, AAV2/9-CBA, and AAV2/Anc80L65-CMV by in vivo microinjection into the scala media of the cochlea. We found that each AAV vector had its own transduction and expression characteristics in hair cells and supporting cells in different regions of the cochlea. There was a tonotopic gradient for the in vitro transduction of AAV2/2-CBA, AAV2/9-CBA, AAV2/2-CMV, and AAV2/9-CMV in outer hair cells (OHCs), with more OHCs expressing eGFP at the base of the cochlea than at the apex. AAV2/2-CBA in vitro and AAV2/Anc80L65-CMV in vivo induced more supporting cells expressing eGFP at the apex than in the base. We found that AAV vectors with different promoters had different expression efficacies in hair cells and supporting cells of the auditory epithelium. The CMV-beta-Globin promoter could drive the expression of the delivered construct more efficiently in hair cells, while the CBA promoter was more efficient in supporting cells. The in vitro and in vivo experiments both demonstrated that AAV2/Anc80L65-CMV was a very promising vector for gene therapy of deafness because of its high transduction rates in hair cells. These results might be useful for selecting the appropriate vectors for gene delivery into different types of inner ear cells and thus improving the effectiveness of gene therapy