Underestimated Methane Emissions from Solid Waste Disposal Sites Reveal Missed Greenhouse Gas Mitigation Opportunities

1.Introduction Cities are responsible for approximately 70%of all anthropogenic greenhouse gas(GHG)emissions and about 60%of all anthropogenic methane(CH4)emissions[1,2].Solid waste disposal sites(including landfills and dumpsites),which are prevalent in global cities,emit CH4 generated from the anaerobic biodegradation of municipal solid waste(MSW).Notably,the proportions of CH4 emissions from disposal sites surpass 50%of the total CH4 emissions in some megalopolises[3].CH4 has a high global warming potential(GWP),being 28 times stronger than carbon dioxide(CO_(2))over a 100-year period and 80 times stronger over a 20-year period[4].Understanding and mitigating CH4 emissions from solid waste disposal sites is particularly pertinent and pressing,considering that the latest Synthesis Report from the Intergovernmental Panel on Climate Change(IPCC)emphasizes that the current pace of mitigation and adaptation policies and measures falls short of restraining global temperature rise to under 1.5℃ within the 21st century[4].More than 150 countries signed the Global Methane Pledge at the United Nations Climate Change Conference in Glasgow(COP26),which aims to reduce global annual CH4 emissions by 30%by 2030,compared with emissions in 2020[5].

PERIODIC POINTS AND NORMALITY CONCERNING MEROMORPHIC FUNCTIONS WITH MULTIPLICITY

In this article,two results concerning the periodic points and normality of meromorphic functions are obtained:(i)the exact lower bound for the numbers of periodic points of rational functions with multiple fixed points and zeros is proven by let ting R(z)be a nonpolynomial rational function,and if all zeros and poles of R(z)—z are multiple,then Rk(z)has at least k+1 fixed points in the complex plane for each integer k≥2;(ii)a complete solution to the problem of normality of meromorphic functions with periodic points is given by let ting F be a family of meromorphic functions in a domain D,and let ting k≥2 be a positive integer.If,for each f∈F,all zeros and poles of f(z)-z are multiple,and its iteration fk has at most k distinct fixed points in D,then F is normal in D.Examples show that all of the conditions are the best possible.

Tracing Sources of Geochemical Anomalies in a Deeply Buried Volcanic-Related Hydrothermal Uranium Deposit:the Daguanchang Deposit,Northern Hebei Province,North China Craton

Radon(Rn)and helium(He)gases from uranium decay form distinct anomalies related to buried uranium deposits.In order to trace the geochemical anomalous sources from the volcanic-related uranium deposits in deeply buried areas,systematical Rn contents and He isotope ratios were analyzed from the Daguanchang uranium deposit.The soil gas Rn concentrations above the deep uranium are ten times higher than those in barren areas,indicating that instantaneous Rn content measurements can be used to detect deeply buried uranium.The helium isotope ratios(^(3)He/^(4)He)of the unmineralized samples from the mineralized drill hole(ZK1)are relatively lower and uniform compared to those of the samples from no-mineral drill hole(ZK2).However,the Th and U contents of the drill core samples from ZK1 are slightly lower than those of the samples from ZK2,indicating that the lower 3He/4He ratios in ZK1 are most likely due to the addition of 4He from underlying uranium intervals.The differences in the instantaneous Rn contents are consistent with the variations in the He isotope ratios of the drill core samples.These results demonstrate that soil gas Rn and ^(3)He/^(4)He ratios are useful tracers and can indicate the existence of deeply buried volcanic-related hydrothermal uranium ores.

Time-dependent metabolomics uncover dynamic metabolic adaptions in MCF-7 cells exposed to bisphenol A

The biochemical consequences induced by xenobiotic stress are featured in dose-response and timeresolved landscapes.Understanding the dynamic process of cellular adaptations is crucial in conducting the risk assessment for chemical exposure.As one of the most phenotype-related omics,metabolome in response to environmental stress can vary from seconds to days.Up to now,very few dynamic metabolomics studies have been conducted to provide time-dependent mechanistic interpretations in understanding xenobiotics-induced cellular adaptations.This study aims to explore the time-resolved metabolite dysregulation manner and dynamically perturbed biological functions in MCF-7 cells exposed to bisphenol A(BPA),a well-known endocrine-disrupting chemical.By sampling at 11 time points from several minutes to hours,thirty seven significantly dysregulated metabolites were identified,ranging from amino acids,fatty acids,carboxylic acids and nucleoside phosphate compounds.The metabolites in different pathways basically showed distinct time-resolved changing patterns,while those within the common class or same pathways showed similar and synchronized dysregulation behaviors.The pathway enrichment analysis suggested that purine metabolism,pyrimidine metabolism,aminoacyl-tRNA biosynthesis as well as glutamine/glutamate(GABA)metabolism pathways were heavily disturbed.As exposure event continued,MCF-7 cells went through multiple sequential metabolic adaptations from cell proliferation to energy metabolism,which indicated an enhancing cellular requirement for elevated energy homeostasis,oxidative stress response and ER-αmediated cell growth.We further focused on the time-dependent metabolite dysregulation behavior in purine and pyrimidine metabolism,and identified the impaired glycolysis and oxidative phosphorylation by redox imbalance.Lastly,we established a restricted cubic splinebased model to fit and predict metabolite’s full range dysregulation cartography,with metabolite’sensitivity comparisons retrieved and novel biomarkers suggested.Overall,the results indicated that 8 h BPA exposure leaded to global dynamic metabolome adaptions including amino acid,nucleoside and sugar metabolism disorders,and the dysregulated metabolites with interfered pathways at different stages are of significant temporal distinctions.

Oligomers from the Synthetic Polymers:Another Potential Iceberg of New Pollutants

Pollution generated by synthetic polymers,particularly plastics,has become a significant global environmental problem.However,when compared to polymer-derived products like microplastics,oligomers have not received the attention they deserve.Oligomers are by-products of polymer production and intermediates of degradation.Despite the industrial advancements leading to an exponential increase in the production of new polymers,a majority of oligomers have remained inadequately researched.While the exposure and toxic effects of polylactic acid oligomers have been documented,the structures and fundamental properties of oligomers derived from most polymers are still poorly understood.This knowledge gap presents challenges in establishing effective analytical methods.Considering the potential of oligomers to act as new pollutants,it is imperative to investigate their environmental behavior,as well as their absorption,distribution,metabolism,excretion,and toxicity(ADMET)properties.This perspective highlights the research gap concerning oligomers.

Association between Metal(loid)Exposure and Risk of Polycystic Ovary Syndrome Mediated by Anti-Müllerian Hormone among Women Undergoing In Vitro Fertilization and Embryo Transfer

Objective To investigate the relationship and potential pathways between metal(loid)exposure and the risk of polycystic ovary syndrome(PCOS)in women of childbearing age.Methods This case-control study included 200 patients with PCOS(cases)and 896 non-PCOS controls with the age of 25-37 years.The concentrations of 29 metal(loid)s in the follicular fluid(FF)and clinical indicators in the serum were measured in all participants.Logistic regression analysis and mediation analysis were conducted to evaluate the associations between metal(loid)exposure and PCOS risk and investigate the possible roles of clinical indicators,respectively.Results Logistic regression analysis revealed an association between high copper levels in FF and increased PCOS risk(highest vs.lowest quartile:adjusted odds ratio=2.94,95%confidence interval:1.83-4.72).A high luteinizing hormone/follicle-stimulating hormone ratio and elevated levels of testosterone and anti-Müllerian hormone(AMH)were strongly associated with increased PCOS risk induced by high copper exposure.The mediation analysis indicated a mediating effect of AMH in the association between copper exposure and PCOS risk.Conclusion Copper may affect PCOS risk through the hypothalamic-pituitary-ovarian axis,mediated by AMH.Copper exposure and internal AMH levels are important indicators for early warning of PCOS development.

Emerging organic contaminants of liquid crystal monomers:Environmental occurrence,recycling and removal technologies,toxicities and health risks

Liquid crystal monomers(LCMs)are a family of synthetic organic chemicals applied in the liquid crystal displays(LCDs)of various electric and electronic products(e-products).Due to their unique properties(i.e.,persistence,bioaccumulative potential,and toxicity)and widespread environmental distributions,LCMs have attracted increasing attention across the world.Recent studies have focused on the source,distribution,fate,and toxicity of LCMs;however,a comprehensive review is scarce.Herein,we highlighted the persistence and bioaccumulation potential of LCMs by reviewing their physical–chemical properties.The naming rules were suggested to standardize the abbreviations regarding LCMs.The sources and occurrences of LCMs in different environmental compartments,including dust,sediment,soil,leachate,air and particulate,human serum,and biota samples,were reviewed.It is concluded that the LCMs in the environment mainly originate from the usage and disassembly of eproducts with LCDs.Moreover,the review of the potential recycling and removal technologies regarding LCMs from waste LCD panels suggests that a combination of natural attenuation and physic-chemical remediation should be developed for LCMs remediations in the future.By reviewing the health risks and toxicity of LCMs,it is found that a large gap exists in their toxicity and risk to organisms.The fate and toxicity investigation of LCMs,and further investigations on the effects on the human exposure risks of LCMs to residents,especially to occupational workers,should be considered in the future.

Meromorphic Function Sharing Sets with Its Difference Operator or Shifts

Let f be a nonconstant meromorphic function, c ∈ C, and let ■be a meromorphic function. If f(z) and P(z, f(z)) share the sets {a(z),-a(z)},{0} CM almost and share {∞} IM almost, where P(z, f(z)) is defined as(1.1), then f(z) ≡±P(z, f(z)) or f(z)P(z, f(z)) ≡±a^2(z). This extends the results due to Chen and Chen(2013), Liu(2009) and Yi(1987).

Periodic points and normal families concerning multiplicity

In 1992,Yang Lo posed the following problem:let F be a family of entire functions,let D be a domain in C,and let k 2 be a positive integer.If,for every f∈F,both f and its iteration f^khave no fixed points in D,is F normal in D?This problem was solved by Ess′en and Wu in 1998,and then solved for meromorphic functions by Chang and Fang in 2005.In this paper,we study the problem in which f and f^(k ) have fixed points.We give positive answers for holomorphic and meromorphic functions.(I)Let F be a family of holomorphic functions in a domain D and let k 2 be a positive integer.If,for each f∈F,all zeros of f(z)-z are multiple and f^khas at most k distinct fixed points in D,then F is normal in D.Examples show that the conditions"all zeros of f(z)-z are multiple"and"f^k having at most k distinct fixed points in D"are the best possible.(II)Let F be a family of meromorphic functions in a domain D,and let k 2 and l be two positive integers satisfying l 4 for k=2 and l 3 for k 3.If,for each f∈F,all zeros of f(z)-z have a multiplicity at least l and f^khas at most one fixed point in D,then F is normal in D.Examples show that the conditions"l 3for k 3"and"f^k having at most one fixed point in D"are the best possible.