Now showing items 1-20 of 1483

    • Direct Visualization and Identification of Membrane Voltage-Gated Sodium Channels from Human iPSC-Derived Neurons by Multiple Imaging and Light Enhanced Spectroscopy

      Moretti, Manola; Limongi, Tania; Testi, Claudia; Milanetti, Edoardo; De Angelis, Maria Teresa; Parrotta, Elvira I; Scalise, Stefania; Santamaria, Gianluca; Allione, Marco; Lopatin, Sergei; Torre, Bruno; Zhang, Peng; Marini, Monica; Perozziello, Gerardo; Candeloro, Patrizio; Pirri, Candido Fabrizio; Ruocco, Giancarlo; Cuda, Giovanni; Di Fabrizio, Enzo (Small methods, 2022-05-20) [Article]
      In this study, transmission electron microscopy atomic force microscopy, and surface enhanced Raman spectroscopy are combined through a direct imaging approach, to gather structural and chemical information of complex molecular systems such as ion channels in their original plasma membrane. Customized microfabricated sample holder allows to characterize Nav channels embedded in the original plasma membrane extracted from neuronal cells that are derived from healthy human induced pluripotent stem cells. The identification of the channels is accomplished by using two different approaches, one of them widely used in cryo-EM (the particle analysis method) and the other based on a novel Zernike Polynomial expansion of the images bitmap. This approach allows to carry out a whole series of investigations, one complementary to the other, on the same sample, preserving its state as close as possible to the original membrane configuration.
    • Continuous extraction and concentration of secreted metabolites from engineered microbes using membrane technology

      Overmans, Sebastian; Ignacz, Gergo; Beke, Aron K.; Xu, Jiajie; Saikaly, Pascal; Szekely, Gyorgy; Lauersen, Kyle J. (Green Chemistry, Royal Society of Chemistry (RSC), 2022-05-18) [Article]
      Microalgal cultivation in photobioreactors and membrane separations are both considered sustainable processes. Here we explore their synergistic combination to extract and concentrate a heterologous sesquiterpenoid produced by engineered green algal cells. A hydrophobic hollow-fiber membrane contactor was used to allow interaction of culture broth and cells with a dodecane solvent phase to accumulate algal produced patchoulol. Subsequent continuous membrane extraction of patchoulol from dodecane enabled product concentration in a methanol stream as well as dodecane recovery for its reuse. A structure-based prediction using machine learning was used to model a process whereby 100% patchoulol recovery from dodecane could be achieved with solvent-resistant nanofiltration membranes. Solvent consumption, E-factor, and economic sustainability were assessed and compared with existing patchoulol production processes. Our extraction and product purification process offers six- and two-orders of magnitude lower solvent consumption compared to synthetic production and thermal-based separation, respectively. Our proposed methodology is transferable to other microbial systems for the isolation of high-value isoprenoid and hydrocarbon products.
    • Physicochemical Characterization of Two Protic Hydroxyethylammonium Carboxylate Ionic Liquids in Water and Their Mixture

      Augusto, Ferrari Felipe; Francisco, Malaret; Stephen, Eustace; Jason, Hallett; Luuk, van der Wielen; Geert-Jan, Witkamp; Forte, Marcus Bruno Soares (Journal of Chemical & Engineering Data, American Chemical Society (ACS), 2022-05-16) [Article]
      A systematic study on the physicochemical properties of two protic ionic liquids (ILs) {2-hydroxyethylammonium acetate ([Mea][Ac]) and 2-hydroxyethylammonium hexanoate ([Mea][Hex])} and their mixtures with water was performed. The density and viscosity were assessed across the entire range of aqueous dilutions between 278 and 393 K. The conductivities, water activities, and surface tension of the binary systems in water were also assessed, and the influence of anions was evaluated. Differential scanning calorimetry (DSC), Fourier transform infrared (FTIR), and 1H and 13C nuclear magnetic resonance (NMR) techniques were used to study the systems at different IL compositions. The excess molar volumes (VE) and thermal expansion coefficients were calculated, with negative values for VE across the entire concentration range. Density data were fitted to a polynomial for density prediction, function of temperature, and concentration, with the average deviation percentage not exceeding 0.63%. The viscosities of the binary systems were studied considering six different models and were better predicted by the model of Herráez et al. at IL concentrations higher than 0.25 mole fraction. The systems containing [Hex]− exhibited higher water activities and lower conductivity and surface tension. All studied systems exhibited a glass transition event, which varied according to the IL composition. The FTIR and NMR analysis confirmed the distinct molecular arrangement of [Mea][Ac] and [Mea][Hex] systems.
    • High-rate microbial electrosynthesis using a zero-gap flow cell and vapor-fed anode design

      Baek, Gahyun; Rossi, Ruggero; Saikaly, Pascal; Logan, Bruce (Water Research, Elsevier BV, 2022-05-13) [Article]
      Microbial electrosynthesis (MES) cells use renewable energy to convert carbon dioxide into valuable chemical products such as methane and acetate, but chemical production rates are low and pH changes can adversely impact biocathodes. To overcome these limitations, an MES reactor was designed with a zero-gap electrode configuration with a cation exchange membrane (CEM) to achieve a low internal resistance, and a vapor-fed electrode to minimize pH changes. Liquid catholyte was pumped through a carbon felt cathode inoculated with anaerobic digester sludge, with humidified N2 gas flowing over the abiotic anode (Ti or C with a Pt catalyst) to drive water splitting. The ohmic resistance was 2.4 ± 0.5 mΩ m2, substantially lower than previous bioelectrochemical systems (20–25 mΩ•m2), and the catholyte pH remained near-neutral (6.6–7.2). The MES produced a high methane production rate of 2.9 ± 1.2 L/L-d (748 mmol/m2-d, 17.4 A/m2; Ti/Pt anode) at a relatively low applied voltage of 3.1 V. In addition, acetate was produced at a rate of 940 ± 250 mmol/m2-d with 180 ± 30 mmol/m2-d for propionate. The biocathode microbial community was dominated by the methanogens of the genus Methanobrevibacter, and the acetogen of the genus Clostridium sensu stricto 1. These results demonstrate the utility of this zero-gap cell and vapor-fed anode design for increasing rates of methane and chemical productions in MES.
    • CNT/polyimide fiber-based 3D photothermal aerogel for high-efficiency and long-lasting seawater desalination

      Ren, Yafeng; Lian, Ruhe; Liu, Zongxu; Zhang, Guoxian; Wang, Wenbin; Ding, Dongliang; Tian, Miao; Zhang, Qiuyu (Desalination, Elsevier BV, 2022-05-12) [Article]
      Solar steam regeneration is considered an efficient way to desalinate seawater and alleviate the global shortage of freshwater resources. However, the poor mechanical properties, low evaporation rates, and short service life of the currently reported materials can not meet the requirement of actual applications. Here, a composite aerogel with high porosity up to 97.8% was developed by physically cross-linking the electrospinning PI fibers as the backbone and carbon nanotubes as the photothermal component. This composite aerogel composite reached the maximum temperature within 20 s and showed a stable evaporation rate of 2.08 kg m−2 h−1 under 1 sun irradiation (1 kW m−2). In simulated seawater distillation experiments, the material achieved 99% removal efficiency for various concentrations of NaCl solution. The aerogel consisting of polyimide backbone exhibited excellent UV resistance, showing an insignificant change in morphology and evaporation rate under continuous irradiation for 1 h at 40 mW cm−2 under 365 nm UV light. This study provides a reliable solution for developing high-performance solar evaporators with high porosity and endurance.
    • Effects of temperature and humidity ratio on the performance of desiccant dehumidification system under low-temperature regeneration

      Yu, Hao; Seo, Sang won; Mikšík, František; Thu, Kyaw; Miyazaki, Takahiko; Ng, Kim Choon (Journal of Thermal Analysis and Calorimetry, Springer Science and Business Media LLC, 2022-05-06) [Article]
      The desiccant dehumidification system can separate the latent heat and sensible heat in the air-conditioning system and achieve energy savings by removing latent heat. Industrial waste heat and renewable energy could be utilized in desiccant dehumidification systems, where the desorption process can be performed below 70 °C. The vapor pressure and temperature of the regenerating air dictate the desorption process corresponding to the isotherm properties. This study has focused on the effects of various temperatures and humidity ratios of regeneration air on the performance of a desiccant dehumidifier using a polymer as an adsorbent. Experiments were performed using the regeneration air with the humidity ratios of 0.005 kg kg−1, 0.010 kg kg−1, 0.015 kg kg−1, and 0.020 kg kg−1, while the air temperatures were varied from 40 °C to 70 °C. The evaluation of this study employs the adsorption/desorption amount, average moisture removal capacity, and latent energy ratio (LER) of the regeneration process as key performance indexes. At the regeneration temperature of 68 °C, the peak desorption amount at the humidity ratio of 0.005 kg kg−1 and 0.010 kg kg−1 both reached 0.011 kg kg−1. The results indicated that the higher desorption temperature led to a higher desorption amount. Besides, with the increased desorption temperature, the average moisture removal capacity increases. In contrast, the high humidity ratio of regeneration air resulted in a weak dehumidification ability. Lower regeneration temperature was difficult to apply to regenerate the polymer-based desiccant under a high-humidity-ratio atmosphere. To attain a high LER, a lower humidity ratio of dry air and regeneration temperature was preferred. The regeneration air with a humidity ratio of 0.020 kg kg−1 is not suitable to apply in the dehumidification system in the temperature range of 40–70 °C.
    • A sacrificial protective layer as fouling control strategy for nanofiltration in water treatment

      Li, Sihang; Meng, Huanna; Wang, Haihua; Vrouwenvelder, Johannes S.; Li, Zhenyu (Water Research, Elsevier BV, 2022-05-06) [Article]
      High-performance nanofiltration (NF) membrane with super antifouling capability as well as reusability is highly desired in water treatment. A new antifouling strategy by a coating-decoating-recoating cycle was investigated for effective removal of fouling and restoring the original membrane performance. The functional membrane surface was fabricated by in-situ coating a ‘green’ and biodegradable carboxymethyl chitosan (CMCS) layer as physical barrier. The CMCS layer can be decoated and re-coated by simple procedures. Results showed that (i) the CMCS layer enhanced surface hydrophilicity, surface smoothness and fouling resistance of NF membrane, (ii) both the unfouled and fouled CMCS layer were easily decoated by the strong acid solution, (iii) the CMCS layer was easily re-coated by facile recoating and (iv) the water flux recovery ratio of membrane with coating layer was maintained more than 88.8% during fouling testing by natural organic matter (NOM) after four sequential cycles of coating, decoating and recoating process. The re-coated membrane exhibited stable, improved membrane operational and antifouling performance. The coating-decoating-recoating approach is proven to be low-cost and eco-friendly strategy for NOM fouling control on NF membrane in water treatment applications.
    • Monitoring coastal water flow dynamics using sub-daily high-resolution SkySat satellite and UAV-based imagery

      Johansen, Kasper; Dunne, Aislinn; Tu, Yu-Hsuan; Jones, Burton; McCabe, Matthew (Water Research, Elsevier BV, 2022-05-05) [Article]
      Sub-daily tracking of dynamic features and events using high spatial resolution satellite imagery has only recently become possible, with advanced observational capabilities now available through tasking of satellite constellations. Here, we provide a first of its kind demonstration of using sub-daily 0.50 m resolution SkySat imagery to track coastal water flows, combining these data with object-based detection and a machine-learning approach to map the extent and concentration of two dye plumes. Coincident high-frequency unmanned aerial vehicle (UAV) imagery was also employed for quantitative modeling of dye concentration and evaluation of the sub-daily satellite-based dye tracking. Our results show that sub-daily SkySat imagery can track dye plume extent with low omission (8.73–16.05%) and commission errors (0.32–2.77%) and model dye concentration (coefficient of determination = 0.73; root mean square error = 28.68 ppb) with the assistance of high-frequency UAV data. The results also demonstrate the capabilities of using UAV imagery for scaling between field data and satellite imagery for tracking coastal water flow dynamics. This research has implications for monitoring of water flows and nutrient or pollution exchange, and it also demonstrates the capabilities of higher temporal resolution satellite data for delivering further insights into dynamic processes of coastal systems.
    • In situ conductive spacers for early pore wetting detection in membrane distillation

      Alpatova, Alla; Qamar, Adnan; Alhaddad, Mohammed; Kerdi, Sarah; Soo Son, Hyuk; Amin, Najat A.; Ghaffour, NorEddine (Separation and Purification Technology, Elsevier BV, 2022-04-30) [Article]
      Membrane distillation (MD) suffers from pore wetting which deteriorates membrane separation properties and causes water protrusion to permeate side. The early detection of pore wetting is a challenge which needs to be addressed to achieve stable MD performance. In this study, electrically-conductive Pt-coated spacers placed inside the feed and coolant channels with a dual purpose of maximizing permeate flux and instantaneous wetting detection once first membrane pores are compromised are proposed. Upon wetting, permeate salt concentration increases thereby initiating redox reactions at two spacer electrodes under the applied electrical potential. As a result, electrical current is produced and measured. The competence of the proposed wetting detection method was explored in MD process in the presence of organic substances with high wetting propensity. An increase in generated electrical current upon wetting development and substantial signal amplification with the voltage increase was demonstrated. The new wetting detection method achieved a faster response comparing to conventional conductivity measurements. Moreover, this method allows to define the wetting onset which can serve as an indication of early membrane impairment. Different spacer geometries and observed no adverse effect of spacer coating on MD performance were further compared. Experimental and numerical simulations accentuated an importance of spacer design by providing specific permeate flux gain for a 1-helical spacer comparing to a spacer with a smooth cylindrical filament. This effect became more evident at higher feed water temperature, condition that favors greater temperature polarization.
    • Adsorption heat transformer cycle using multiple adsorbent plus water pairs for waste heat upgrade

      Saren, Sagar; Mitra, Sourav; Miyazaki, Takahiko; Ng, Kim Choon; Thu, Kyaw (JOURNAL OF THERMAL ANALYSIS AND CALORIMETRY, 2022-04-28) [Article]
      Adsorption heat transformers (AHTs) are considered as promising systems for upgrading waste heat to a higher temperature. The cycle operates among three temperature reservoirs: (i) heat sink at the low temperature (TL), (ii) heat source at the medium temperature (TM), and (iii) heat supply at the high temperature (TH). In the present study, the performance the AHT cycle was analyzed for possible applications in the waste heat upgrade and thermal desalination. An equilibrium model was developed using adsorption characteristics and isotherm data. Five types of commercially available silica gels and three types of zeolites were investigated as adsorbents. Nonlinear optimization technique was utilized for the determination of the intermediate pressure and uptake for preheating and precooling phase of the AHT cycle. The performance parameters in terms of useful heat ratio and condensation heat ratio were determined and compared for the reservoir temperatures at 30 °C (TL)—60 °C (TM)—80 °C (TH). Parametric evaluation of the performance parameters was carried out based on the variation in gross temperature lift, as well as the heat exchanger mass ratio. It was found out that reduction in the gross temperature lift had a positive impact on the useful heat ratio and a negative influence on the condensation heat ratio of the AHT cycle. Significant variations in the maximum adsorption capacity and slope of the isosteric heat of adsorption across various adsorption pairs containing zeolites were observed. As a result, AQSOA-Z01 zeolite exhibited the highest heat exchange values of the AHT cycle in the range of ~ 320–370 kJ per kg of adsorbent. On the contrary, type AQSOA-Z02 zeolite displayed the lowest corresponding values in the range of ~ 60–90 kJ kg-1 of adsorbent. On the other hand, variation across the different silica gel adsorbents was comparatively smaller because of similar isotherm and isosteric heat of adsorption characteristics. This study will assist the research on the theoretical development of the AHT cycle via material selection and system design optimization.
    • Carbon Nitride Thin Film-Sensitized Graphene Field-Effect Transistor: A Visible-Blind Ultraviolet Photodetector

      Palanisamy, Tamilarasan; Mitra, Somak; Batra, Nitinkumar; Smajic, Jasmin; Emwas, Abdul-Hamid; Roqan, Iman S.; Da Costa, Pedro M. F. J. (Advanced Materials Interfaces, Wiley, 2022-04-27) [Article]
      Ultraviolet (UV) photodetectors often suffer from the lack of spectral selectivity due to strong interference from visible light. In this study, the exceptional electrical properties of graphene and the unique optical properties of carbon nitride thin films (CNTFs) are used to design visible-blind UV photodetectors. First, polycrystalline CNTFs with different thicknesses (12–94 nm) are produced by thermal vapor condensation. Compared to the bulk carbon nitride powder, these films have a considerable sp2 nitrogen deficiency, which is thickness dependent. In addition to showing a wider bandgap than the bulk counterpart, their optical absorption profile (in the ultraviolet–visible range) is unique. Critically, the absorbance falls sharply above 400 nm, making the CNTFs suitable for ultraviolet photodetection. As a result, graphene field-effect transistors (GFETs) sensitized with CNTFs show 103 A W−1 responsivity to UV radiation, a stark contrast to the negligible value obtained in the visible spectrum. The effect of film thickness on the photoresponse is determined, with the thinner CNTF leading to much better device performance. The CNTF/GFET photodetectors are also characterized by their fast response and recovery times, 0.5 and 2.0 s, respectively. These findings pave a simple route for the development of sensitive, visible-blind UV photodetectors.
    • Control strategies against algal fouling in membrane processes applied for microalgae biomass harvesting

      Malaguti, Marco; Novoa, Andres F.; Ricceri, Francesco; Giagnorio, Mattia; Vrouwenvelder, Johannes S.; Tiraferri, Alberto; Fortunato, Luca (Journal of Water Process Engineering, Elsevier BV, 2022-04-22) [Article]
      Microalgae biomass is increasingly applied in a variety of high-end applications, such as biofuel production, CO2 fixation, food, and cosmetics. As the demand for microalgae increases, improvements in biomass harvesting techniques are required since dewatering represents a significant fraction of the total algae production cost. While membrane technology is growing as a means to achieve effective biomass harvesting, fouling from microalgae suspensions is a major drawback, since these streams are rich in organic compounds, nutrients, and biological materials. The aim of this paper is to present the state-of-the-art of the control strategies to manage algal fouling. The control strategies are divided into: (i) mitigation strategies, including pre-treatment options, modified membrane surfaces, and hydrodynamic approaches; and (ii) adaptation strategies, which include physical, mechanical, and chemical cleaning. Fouling mitigation strategies are implemented in membrane separation processes seeking to maintain high productivity without compromising biomass quality, while minimizing the energy cost related to fouling control. Adaptation techniques include optimization of the cleaning time and effective removal of the irreversible foulants. Further, minimization in the use of chemicals and of the backflush permeate must be achieved to ensure an efficient performance in chemical cleaning and backwash approaches, respectively. Finally, the article discusses future research perspectives in membrane-based microalgae harvesting with a focus on zero liquid discharge and effective fouling control strategies within the water-energy nexus.
    • Why did only one genus of insects, Halobates, take to the high seas?

      Cheng, Lanna; Mishra, Himanshu (PLOS Biology, Public Library of Science (PLoS), 2022-04-13) [Article]
      Oceans cover more than 70% of the Earth’s surface and house a dizzying array of organisms. Mammals, birds, and all manner of fish can be commonly sighted at sea, but insects, the world’s most common animals, seem to be completely absent. Appearances can deceive, however, as 5 species of the ocean skater Halobates live exclusively at the ocean surface. Discovered 200 years ago, these peppercorn-sized insects remain rather mysterious. How do they cope with life at the ocean surface, and why are they the only genus of insects to have taken to the high seas?
    • Solar thermal energy conversion and utilization—New research horizon

      Wang, Peng; Zhu, Jia (EcoMat, Wiley, 2022-04-12) [Article]
    • Innovative Solid Desiccant Dehumidification Using Distributed Microwaves

      Ybyraiymkul, Doskhan; Chen, Qian; Burhan, Muhammad; Shahzad, Muhammad Wakil; Akhtar, Faheem; Kumja, M; AlRowais, Raid; Ng, Kim Choon (SSRN Preprint Server, 2022-04-06) [Preprint]
      Dehumidification is one of the key challenges facing the air conditioning (AC) industry in the treatment of moist air. Over many decades, the dual role of heat exchangers of AC chillers for the sensible and latent cooling of space has hindered the thermal-lift reduction in the refrigeration cycle, due to the requirements of water vapor removal at dew-point and heat rejection to the ambient air. These practical constraints of AC chillers have resulted in the leveling of energy efficiency of mechanical vapor compressors (MVC) for many decades. One promising approach to energy efficiency improvement is the decoupling of dehumidification from sensible processes so that innovative but separate processes can be applied. In this paper, an advanced microwave dehumidification method is investigated in the laboratory, where the microwave (2.45 GHz) energy can be irradiated onto the dipole structure of water vapor molecules, desorbing rapidly from the pores of adsorbent. Results show a significant improvement in performance for microwave dehumidification, up to 4-fold, as compared to data available in the literature.
    • Direct imaging of polymer filaments pulled from rebounding drops

      Yang, Zi Qiang; Zhang, Peng; Shi, Meng; Julaih, Ali Al; Mishra, Himanshu; Fabrizio, Enzo Di; Thoroddsen, Sigurdur T (arXiv, 2022-04-04) [Preprint]
      Polymer filaments form the foundation of biology from cell scaffolding to DNA. Their study and fabrication play an important role in a wide range of processes from tissue engineering to molecular machines. We present a simple method to deposit stretched polymer fibers between micro-pillars. This occurs when a polymeric drop impacts on and rebounds from an inclined superhydrophobic substrate. It wets the top of the pillars and pulls out liquid filaments which are stretched and can attach to adjacent pillars leaving minuscule threads, with the solvent evaporating to leave the exposed polymers. We use high-speed video at the microscale to characterize the most robust filament-forming configurations, by varying the impact velocity, substrate structure and inclination angle, as well as the PEO-polymer concentration. Impacts onto plant leaves or randomized nano-structured surface leads to the formation of a branched structure, through filament mergers at the free surface of the drop. SEM shows the deposition of filament bundles which are thinner than those formed by evaporation or rolling drops. Raman spectroscopy identifies mode B stretched DNA filaments from aqueous-solution droplets.
    • Long-Term Fouling Control Strategies in Gravity-Driven Membrane Bioreactors (Gd-Mbrs): Impact on Process Performance and Membrane Fouling Properties

      Ranieri, Luigi; Vrouwenvelder, Johannes S.; Fortunato, Luca (SSRN Electronic Journal, Elsevier BV, 2022-04-01) [Preprint]
      This study aims to assess the effects of periodic physical cleanings operations in Gravity-Driven Membrane Bioreactor (GD-MBR) treating primary wastewater. The impact of each cleaning strategy on the reactor performance (permeate flux and water quality), biomass morphology, and fouling composition were evaluated. The application of air scouring coupled with intermittent filtration resulted in the highest permeate flux (4 LMH) compared to only intermittent filtration (i.e., relaxation) (1 LMH) and air scouring under continuous filtration (2.5 LMH). Air scouring coupled with relaxation led to a thin (~50 µm) but with more porous fouling layer and low hydraulic resistance, presenting the lowest concentration of extracellular polymeric substance (EPS) in the biomass. Air scouring under continuous filtration led to a thin (~50 µm), dense, compact, and less porous fouling layer with the highest specific hydraulic resistance. The employment of only relaxation led to the highest fouling deposition (~280 µm) on the membrane surface. The highest TN removal (~62%) was achieved in the reactor with only relaxation (no aeration) due to the anoxic condition in the filtration tank, while the highest COD removal (~ 60%) was achieved with air scouring under continuous filtration due to the longer aeration time and the denser fouling layer. The presented results highlighted the versatility of the GD-MBR, where the choice of the appropriate operation relies on the eventual discharge or reuse of the treated effluent.
    • High-Frequency Variability of Bacterioplankton in Response to Environmental Drivers in Red Sea Coastal Waters

      Ansari, Mohd Ikram; Calleja, Maria Li; Silva, Luis; Viegas, Miguel; Ngugi, David; Huete-Stauffer, Tamara; Moran, Xose Anxelu G. (Frontiers in microbiology, Frontiers Media SA, 2022-03-31) [Article]
      Autotrophic and heterotrophic bacterioplankton are essential to the biogeochemistry of tropical ecosystems. However, the processes that govern their dynamics are not well known. We provide here a high-frequency assessment of bacterial community dynamics and concurrent environmental factors in Red Sea coastal waters. Weekly sampling of surface samples during a full annual cycle at an enclosed station revealed high variability in ecological conditions, which reflected in changes of major bacterioplankton communities. Temperature varied between 23 and 34°C during the sampling period. Autotrophic (Synechococcus, 1.7–16.2 × 104 cells mL−1) and heterotrophic bacteria (1.6–4.3 × 105 cells mL−1) showed two maxima in abundance in spring and summer, while minima were found in winter and autumn. Heterotrophic cells with high nucleic acid content (HNA) peaked in July, but their contribution to the total cell counts (35–60%) did not show a clear seasonal pattern. Actively respiring cells (CTC+) contributed between 4 and 51% of the total number of heterotrophic bacteria, while live cells (with intact membrane) consistently accounted for over 90%. Sequenced 16S rRNA amplicons revealed a predominance of Proteobacteria in summer and autumn (>40%) and a smaller contribution in winter (21–24%), with members of the Alphaproteobacteria class dominating throughout the year. The contribution of the Flavobacteriaceae family was highest in winter (21%), while the Rhodobacteraceae contribution was lowest (6%). Temperature, chlorophyll-a, and dissolved organic carbon concentration were the environmental variables with the greatest effects on bacterial abundance and diversity patterns
    • CubeSat constellations provide enhanced crop phenology and digital agricultural insights using daily leaf area index retrievals

      Johansen, Kasper; Ziliani, Matteo G.; Houborg, Rasmus; Franz, Trenton E.; McCabe, Matthew (Springer Science and Business Media LLC, 2022-03-28) [Article]
      Satellite remote sensing has great potential to deliver on the promise of a data-driven agricultural revolution, with emerging space-based platforms providing spatiotemporal insights into precision-level attributes such as crop water use, vegetation health and condition and crop response to management practices. Using a harmonized collection of high-resolution Planet CubeSat, Sentinel-2, Landsat-8 and additional coarser resolution imagery from MODIS and VIIRS, we exploit a multi-satellite data fusion and machine learning approach to deliver a radiometrically calibrated and gap-filled time-series of daily leaf area index (LAI) at an unprecedented spatial resolution of 3 m. The insights available from such high-resolution CubeSat-based LAI data are demonstrated through tracking the growth cycle of a maize crop and identifying observable within-field spatial and temporal variations across key phenological stages. Daily LAI retrievals peaked at the tasseling stage, demonstrating their value for fertilizer and irrigation scheduling. An evaluation of satellite-based retrievals against field-measured LAI data collected from both rain-fed and irrigated fields shows high correlation and captures the spatiotemporal development of intra- and inter-field variations. Novel agricultural insights related to individual vegetative and reproductive growth stages were obtained, showcasing the capacity for new high-resolution CubeSat platforms to deliver actionable intelligence for precision agricultural and related applications.
    • Influence of biofilm thickness on the removal of thirteen different organic micropollutants via a Membrane Aerated Biofilm Reactor (MABR)

      Sanchez Huerta, Claudia; Fortunato, Luca; Leiknes, TorOve; Hong, Pei-Ying (Journal of Hazardous Materials, Elsevier BV, 2022-03-26) [Article]
      The presence of organic micropollutants (OMPs) in natural water bodies has become an emerging concern due to their fast dissemination into natural water sources, high persistence, ubiquitous nature, and detrimental impact on the environment and human health. This study evaluated the Membrane Aerated Biofilm Reactor (MABR) efficiency in the removal of 13 OMPs commonly reported in water. Results demonstrated that OMPs removal is dependent on biofilm thickness and bacterial cell density, microbial community composition and physicochemical properties of OMPs. Effective removals of ammonium and organic carbon (COD, >50%), acetaminophen (70%) and triclosan (99%) were obtained even at early stages of biofilm development (thickness < 0.33 mm, 2.9 ×105 cell mL−1). An increase in biofilm thickness and cell density (1.02 mm, 2.2 ×106 cell mL−1) enhanced the system performance. MABR achieved over 90% removal of nonpolar, hydrophobic and hydrophilic OMPs and 22–69% removal of negatively charged and acidic OMPs. Relative abundances of Zoogloea, Aquabacterium, Leucobacter, Runella, and Paludilbaculum bacteria correlated with the removal of certain OMPs. In addition, MABR achieved up to 96% nitrification and 80% overall COD removal by the end of the experiment. The findings from this study demonstrated MABRs to be a feasible option to treat municipal wastewater polluted by OMPs.