Clean water and sanitation for the world population is one of the most important challenges established by the Sustainable Development Goals of the United Nations since worldwide, one in three people ...do not have access to safe drinking water. Groundwater, one of the main sources of fresh water, has been considerably damaged by human activities. Nevertheless, while numerous plants are globally aimed at removing pollutants from surface waters, a much scarcer number of facilities have focused on groundwater remediation. Nowadays, there is increasing concern about the presence of nitrates (NO3−) in groundwaters as a consequence of the intensive use of fertilizers and other anthropogenic sources, such as sewage or industrial wastewater discharge. In this context, the selection and development of highly effective and low-cost solutions for the sustainable management of groundwater resources need to be addressed. Thus, this work collects data from the literature regarding the presence of nitrates in groundwater, and, simultaneously, it reviews the main alternatives available to remove NO3− from groundwater sources. A total of 292 sites have been analyzed categorized by continents, carefully discussing the possible origins of nitrate pollution. In addition, a discussion is carried out of the different technologies currently employed to treat groundwater, highlighting the progress made and the main challenges to be overcome. Finally, the review gathers the data available in the literature for nitrate treatment plants at full-scale.
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•272 regions worldwide are analyzed to a rigorous diagnosis of nitrate pollution.•Groundwater bodies can be contaminated by NO3− (>50 ppm) along with other pollutants.•Agriculture, industry, sewage, septic tanks & landfills are the main pollution sources.•The catalytic reduction has high nitrate conversion (98–100%) and no waste generation.•Nowadays, the number of groundwater treatment plants is still very limited.
The present study aims to assess the proton conductivities of the most investigated proton exchange membranes (PEMs) used in PEM fuel cells (PEMFCs). Specifically, PEMs are analyzed for their use in ...anhydrous fuel cells and proton conductivity upper bounds were provided for them. Considering the direct relationship between proton conductivity and temperature, an upper bound is presented. Based on the obtained upper bounds, suitable membranes for high-temperature performance are determined, and the average range of proton conductivity for each polymer group is discussed. By comparing the available proton conductivity data with upper bound, it was demonstrated that some of poly (ionic liquid)s have provided the highest proton conductivities, however aromatic polymers such as polybenzimidazole (PBI) are found more suitable choices for application at anhydrous conditions and high temperatures. The proton conductivity upper bound for anhydrous PEMs demonstrates the availability of promising polymer options for the deployment of anhydrous fuel cells.
•The proton conductivity of the most investigated PEMs used in anhydrous fuel cells was investigated.•The proton conductivity upper bound for anhydrous PEMs was presented.•Nafion, polybenzimidazole and polyetheretherketone are the most investigated polymers for anhydrous fuel cells.
Proton exchange membranes remain a crucial material and a key challenge to fuel cell science and technology. In this work, new Nafion membranes are prepared by a casting method using aryl- or ...azaheteroaromatic bisphosphonate compounds as dopants. The incorporation of the dopant, considered at 1 wt% loading after previous selection, produces enhanced proton conductivity properties in the new membranes, at different temperature and relative humidity conditions, in comparison with values obtained with commercial Nafion. Water uptake and ionic exchange capacity (IEC) are also assessed due to their associated impact on transport properties, resulting in superior values than Nafion when tested in the same experimental conditions. These improvements by doped membranes prompted the evaluation of their potential application in fuel cells, at different temperatures. The new membranes, in membrane-electrode assemblies (MEAs), show an increased fuel cell maximum power output with temperature until 60 °C or 70 °C, followed by a decrease above these temperatures, a Nafion-like behaviour when measured in the same conditions. The membrane doped with 1,4-phenylenebis(hydroxymethanetriyl)tetrakis(phosphonic acid) (BP2) presents better results than Nafion N-115 membrane at all studied temperatures, with a maximum power output performance of ∼383 mW cm−2 at 70 °C. Open circuit potentials of the fuel cell were always higher than values obtained for Nafion MEAs in all studied conditions, indicating the possibility of advantageous restrain to gas crossover in the new doped membranes.
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•Nafion membranes doped with aryl and azaheteroaromatic bisphosphonates were prepared.•Doped membranes showed higher water uptake and ionic exchange capacity than Nafion.•New membranes had higher proton conductivity than Nafion at the same conditions.•Fuel cell performance was evaluated from 30 °C to 120 °C.•Nafion/BP2-1.0 showed higher power density than Nafion at all studied temperatures.
Leukemia is a cancer of the early-forming cells. Over the past decade, leukemia racial/ethnic disparities have been documented in the United States of America (USA). Although the Puerto Rican ...population in the USA represents the second-largest Hispanic population in the nation, most of the existing studies do not include Puerto Rico. We compared the incidence and mortality rates for leukemia and its subtypes in Puerto Rico and four racial/ethnic groups in the USA.
We used data from the Puerto Rico Central Cancer Registry and the Surveillance, Epidemiology, and End Results Program (2015-2019). The racial/ethnic groups studied were non-Hispanic whites (NHW), non-Hispanic blacks (NHB), Hispanics (USH), and Asian/Pacific Islanders (NHAPI) living in the USA and the Puerto Rico population. We calculated the incidence and mortality rates. The relative risk of developing or dying due to leukemia was also calculated.
Compared with Puerto Rico, NHW standardized incidence rate (SIR) = 1.47; 95%CI = 1.40-1.53; standardized mortality rates (SMR) = 1.55; 95%CI = 1.45-1.65) and NHB (SIR = 1.09; 95%CI = 1.04-1.15; SMR = 1.27; 95%CI = 1.19-1.35) had higher incidence and mortality rates; but lower than the NHAPI (SIR = 0.78; 95%CI = 0.74-0.82; SMR = 0.83; 95%CI = 0.77-0.89); and similar to USH. However, we found differences among leukemia subtypes. For example, NHAPI and USH had lower risk of developing chronic leukemias than Puerto Rico. We found a lower risk to develop acute lymphocytic leukemia in NHB than in Puerto Rico.
Our study provides a better understanding of leukemia's racial/ethnic disparities and fills a knowledge gap by examining the incidence and mortality rates in Puerto Rico. Future studies are needed to better understand the factors influencing the differences found in the incidence and mortality of leukemia among different racial/ethnic groups.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Despite the great prospects of reverse electrodialysis (RED), which directly transforms salinity gradient energy into electricity, new efforts focusing on its optimization are still required before ...large-scale implementation. RED performance is determined by numerous variables including (i) membrane properties, (ii) compartment and spacer design, (iii) stream concentrations defining salinity gradient, (iv) flow velocity and fluidodynamics. Among them, low salinity stream (LC) concentration and feed flow rates are key operation variables with great impact on power output; thus, this work approaches their parametric analysis through modeling tools. Initially, as novel study, LC salinity influence was deeply analyzed by quantifying its relative contribution to the overall internal resistance while determining the rest of all ohmic and non-ohmic components. Seawater was selected as high concentrated solution (HC), 0.55 M NaCl, due to its global availability for RED exploitation. LC and Reynolds number analysis are needed to select suitable water sources and devise new strategies to adapt RED performance. LC salinity of 0.02 M NaCl and ReHC = 3.4 and ReLC = 7 allowed to reach the highest net power density. A previously developed mathematical model was used, with simulated results validated in a laboratory-scale plant, offering valuable input for future decision-making in RED operation and upscaling.
•Parametric analysis of low salinity stream concentration on RED power performance•Quantification of internal resistance components as a function of LC salinity•Influence of Reynolds number in RED stack compartments on gross and net power•New insights for optimal RED operation and upscaling•LC of 0.02 M NaCl with ReHC = 3.4 and ReLC = 7 offered optimal net power density.
ABSTRACT
Fungi are a highly diverse group of heterotrophic eukaryotes characterized by the absence of phagotrophy and the presence of a chitinous cell wall. While unicellular fungi are far from rare, ...part of the evolutionary success of the group resides in their ability to grow indefinitely as a cylindrical multinucleated cell (hypha). Armed with these morphological traits and with an extremely high metabolical diversity, fungi have conquered numerous ecological niches and have shaped a whole world of interactions with other living organisms. Herein we survey the main evolutionary and ecological processes that have guided fungal diversity. We will first review the ecology and evolution of the zoosporic lineages and the process of terrestrialization, as one of the major evolutionary transitions in this kingdom. Several plausible scenarios have been proposed for fungal terrestralization and we here propose a new scenario, which considers icy environments as a transitory niche between water and emerged land. We then focus on exploring the main ecological relationships of Fungi with other organisms (other fungi, protozoans, animals and plants), as well as the origin of adaptations to certain specialized ecological niches within the group (lichens, black fungi and yeasts). Throughout this review we use an evolutionary and comparative‐genomics perspective to understand fungal ecological diversity. Finally, we highlight the importance of genome‐enabled inferences to envision plausible narratives and scenarios for important transitions.
Ammonia, a molecule that is gaining more interest as a fueling vector, has been considered as a candidate to power transport, produce energy, and support heating applications for decades. However, ...the particular characteristics of the molecule always made it a chemical with low, if any, benefit once compared to conventional fossil fuels. Still, the current need to decarbonize our economy makes the search of new methods crucial to use chemicals, such as ammonia, that can be produced and employed without incurring in the emission of carbon oxides. Therefore, current efforts in this field are leading scientists, industries, and governments to seriously invest efforts in the development of holistic solutions capable of making ammonia a viable fuel for the transition toward a clean future. On that basis, this review has approached the subject gathering inputs from scientists actively working on the topic. The review starts from the importance of ammonia as an energy vector, moving through all of the steps in the production, distribution, utilization, safety, legal considerations, and economic aspects of the use of such a molecule to support the future energy mix. Fundamentals of combustion and practical cases for the recovery of energy of ammonia are also addressed, thus providing a complete view of what potentially could become a vector of crucial importance to the mitigation of carbon emissions. Different from other works, this review seeks to provide a holistic perspective of ammonia as a chemical that presents benefits and constraints for storing energy from sustainable sources. State-of-the-art knowledge provided by academics actively engaged with the topic at various fronts also enables a clear vision of the progress in each of the branches of ammonia as an energy carrier. Further, the fundamental boundaries of the use of the molecule are expanded to real technical issues for all potential technologies capable of using it for energy purposes, legal barriers that will be faced to achieve its deployment, safety and environmental considerations that impose a critical aspect for acceptance and wellbeing, and economic implications for the use of ammonia across all aspects approached for the production and implementation of this chemical as a fueling source. Herein, this work sets the principles, research, practicalities, and future views of a transition toward a future where ammonia will be a major energy player.
ABSTRACT
The fungal kingdom comprises a hyperdiverse clade of heterotrophic eukaryotes characterized by the presence of a chitinous cell wall, the loss of phagotrophic capabilities and cell ...organizations that range from completely unicellular monopolar organisms to highly complex syncitial filaments that may form macroscopic structures. Fungi emerged as a ‘Third Kingdom’, embracing organisms that were outside the classical dichotomy of animals versus vegetals. The taxonomy of this group has a turbulent history that is only now starting to be settled with the advent of genomics and phylogenomics. We here review the current status of the phylogeny and taxonomy of fungi, providing an overview of the main defined groups. Based on current knowledge, nine phylum‐level clades can be defined: Opisthosporidia, Chytridiomycota, Neocallimastigomycota, Blastocladiomycota, Zoopagomycota, Mucoromycota, Glomeromycota, Basidiomycota and Ascomycota. For each group, we discuss their main traits and their diversity, focusing on the evolutionary relationships among the main fungal clades. We also explore the diversity and phylogeny of several groups of uncertain affinities and the main phylogenetic and taxonomical controversies and hypotheses in the field.
The exponentially growing contribution of renewable energy sources in the electricity mix requires large systems for energy storage to tackle resources intermittency. In this context, the ...technologies for hydrogen production offer a clean and versatile alternative to boost renewables penetration and energy security. Hydrogen production as a strategy for the decarbonization of the energy sources mix has been investigated since the beginning of the 1990s. The stationary sector, i.e. all parts of the economy excluding the transportation sector, accounts for almost three-quarters of greenhouse gases (GHG) emissions (mass of CO2-eq) in the world associated with power generation. While several publications focus on the hybridization of renewables with traditional energy storage systems or in different pathways of hydrogen use (mainly power-to-gas), this study provides an insightful analysis of the state of art and evolution of renewable hydrogen-based systems (RHS) to power the stationary sector. The analysis started with a thorough review of RHS deployments for power-to-power stationary applications, such as in power generation, industry, residence, commercial building, and critical infrastructure. Then, a detailed evaluation of relevant techno-economic parameters such as levelized cost of energy (LCOE), hydrogen roundtrip efficiency (HRE), loss of power supply probability (LPSP), self-sufficiency ratio (SSR), or renewable fraction (fRES) is provided. Subsequently, lab-scale plants and pilot projects together with current market trends and commercial uptake of RHS and fuel cell systems are examined. Finally, the future techno-economic barriers and challenges for short and medium-term deployment of RHS are identified and discussed.
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•Review of Renewable hydrogen-based systems (RHS) for stationary applications.•Off-grid energy systems optimization based on techno-economic indicators.•Small and large pilot plants to boost RHS deployment in the stationary sector.•Barriers to broader hydrogen market penetration.
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