In recent years, forward osmosis (FO) hybrid membrane systems have been investigated as an alternative to conventional high-pressure membrane processes (i.e. reverse osmosis (RO)) for seawater ...desalination and wastewater treatment and recovery. Nevertheless, their economic advantage in comparison to conventional processes for seawater desalination and municipal wastewater treatment has not been clearly addressed. This work presents a detailed economic analysis on capital and operational expenses (CAPEX and OPEX) for: i) a hybrid forward osmosis – low-pressure reverse osmosis (FO-LPRO) process, ii) a conventional seawater reverse osmosis (SWRO) desalination process, and iii) a membrane bioreactor – reverse osmosis – advanced oxidation process (MBR-RO-AOP) for wastewater treatment and reuse. The most important variables affecting economic feasibility are obtained through a sensitivity analysis of a hybrid FO-LPRO system. The main parameters taken into account for the life cycle costs are the water quality characteristics (similar feed water and similar water produced), production capacity of 100,000 m3 d−1 of potable water, energy consumption, materials, maintenance, operation, RO and FO module costs, and chemicals. Compared to SWRO, the FO-LPRO systems have a 21% higher CAPEX and a 56% lower OPEX due to savings in energy consumption and fouling control. In terms of the total water cost per cubic meter of water produced, the hybrid FO-LPRO desalination system has a 16% cost reduction compared to the benchmark for desalination, mainly SWRO. Compared to the MBR-RO-AOP, the FO-LPRO systems have a 7% lower CAPEX and 9% higher OPEX, resulting in no significant cost reduction per m3 produced by FO-LPRO. Hybrid FO-LPRO membrane systems are shown to have an economic advantage compared to current available technology for desalination, and comparable costs with a wastewater treatment and recovery system. Based on development on FO membrane modules, packing density, and water permeability, the total water cost could be further reduced.
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•Economic analysis of forward osmosis – low pressure reverse osmosis (FO-LPRO) system.•FO-LPRO system has lower costs for producing water compared to SWRO desalination.•FO-LPRO system has a comparable cost to wastewater treatment and recovery system.•Most critical aspect in economic feasibility of FO-LPRO systems is FO module cost.
This review focuses on the present status of forward osmosis (FO) niches in two main areas: seawater desalination and wastewater reuse. Specific applications for desalination and impaired-quality ...water treatment and reuse are described, as well as the benefits, advantages, challenges, costs and knowledge gaps on FO hybrid systems are discussed. FO can play a role as a bridge to integrate upstream and downstream water treatment processes, to reduce the energy consumption of the entire desalination or water recovery and reuse processes, thus achieving a sustainable solution for the water-energy nexus. FO hybrid membrane systems showed to have advantages over traditional membrane process like high pressure reverse osmosis and nanofiltration for desalination and wastewater treatment: (i) chemical storage and feed water systems may be reduced for capital, operational and maintenance cost, (ii) water quality is improved, (iii) reduced process piping costs, (iv) more flexible treatment units, and (v) higher overall sustainability of the desalination and wastewater treatment process. Nevertheless, major challenges make FO systems not yet a commercially viable technology, the most critical being the development of a high flux membrane, capable of maintaining an elevated salt rejection and a reduced internal concentration polarization effect, and the availability of appropriate draw solutions (cost effective and non-toxic), which can be recirculated via an efficient recovery process. This review article highlights the features of hybrid FO systems and specifically provides the state-of-the-art applications in the water industry in a novel classification and based on the latest developments toward scaling up these systems.
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•Hybrid FO systems state-of-the-art applications in water industry.•Desalination and impaired-quality water treatment and reuse applications.•Assessment of energy, economics and major challenges of FO systems.•Novel classification for FO processes in water industry.
Summary
Background
Plasma and other body fluids contain membranous extracellular vesicles (EVs), which are considered to derive from activated or apoptotic cells. EVs participate in physiological and ...pathological processes and have potential applications in diagnostics or therapeutics. Knowledge on EVs is, however, limited, mainly due to their sub‐micrometer size and to intrinsic limitations in methods applied for their characterization.
Objectives
Our aim was to provide a comprehensive description of EVs from plasma of healthy subjects.
Methods
Cryo‐transmission electron microscopy combined with receptor‐specific gold labeling was used to reveal the morphology, size and phenotype of EVs. An original approach based on sedimentation on electron microscopy grids was developed for enumerating EVs. A correlation was performed between conventional flow cytometry and electron microscopy results.
Results
We show that platelet‐free plasma samples contain spherical EVs, 30 nm to 1 μm in diameter, tubular EVs, 1–5 μm long, and membrane fragments, 1–8 μm large. We show that only a minority of EVs expose the procoagulant lipid phosphatidylserine, in contrast to the classical theory of EV formation. In addition, the concentrations of the main EV sub‐populations are determined after sedimentation on EM grids. Finally, we show that conventional flow cytometry, the main method of EV characterization, detects only about 1% of them.
Conclusion
This study brings novel insights on EVs from normal plasma and provides a reference for further studies of EVs in disease situations.
Summary
Background
Plasma contains cell‐derived extracellular vesicles (EVs), which participate in physiopathological processes and have potential applications as disease biomarker. However, the ...enumeration of EVs faces major problems, due to their sub‐micrometer size and to intrinsic limitations in methods of characterization, mainly flow cytometry (FCM).
Objectives
Our objective is to enumerate EVs in plasma, by taking as the prototype the population of phosphatidylserine (PS)‐exposing EVs, which constitute one of the major EV populations and are responsible for thrombotic disorders.
Methods
The concentration of PS‐exposing EVs in platelet‐free plasma (PFP) of healthy subjects was measured by FCM using either light scattering or fluorescence as the trigger and fluorescent Annexin‐5 (Anx5) as the specific label. In addition, PS‐exposing EVs were enumerated by electron microscopy (EM) after labeling with Anx5 gold nanoparticles and sedimentation on EM grids.
Results
We show that about 50× more Anx5‐positive EVs are detected by FCM when detection is triggered on fluorescence as compared with light scattering. By fluorescence triggering, concentrations of 22 000–30 000 Anx5‐positive EVs per μL PFP were determined, using two different flow cytometers. The limit of detection of the fluorescence triggering method was estimated at about 1000–2500 Anx5 molecules. Results from EM suggest that EVs down to 100–150 nm diameter are detected by fluorescence triggering.
Conclusion
This study presents a simple method for enumerating EVs. We believe that this method is applicable in a general context and will improve our understanding of the roles of EVs in pathophysiological situations, which will open avenues for the development of EV‐based diagnosis assays.
Microbial stress priming: a meta‐analysis Andrade‐Linares, Diana R; Lehmann, Anika; Rillig, Matthias C
Environmental microbiology,
April 2016, Letnik:
18, Številka:
4
Journal Article
Recenzirano
Microbes have to cope with complex and dynamic environments, making it likely that anticipatory responses provide fitness benefits. Mild, previous stressors can prepare microbes (stress priming) to ...further and potentially damaging stressors (triggering). We here quantitatively summarize the findings from over 250 trials of 34 studies including bacteria and fungi, demonstrating that priming to stress has a beneficial impact on microbial survival. In fact, survival of primed microbes was about 10‐fold higher compared with that in non‐primed microbes. Categorical moderators related to microbial taxonomy and the kind of stress applied as priming or as triggering revealed significant differences of priming effect size among 14 different microbial species, 6 stress categories and stressor combination. We found that priming by osmotic, physiological and temperature stress had the highest positive effect sizes on microbial response. Cross‐protection was evident for physiological, temperature and pH stresses. Microbes are better prepared against triggering by oxidative, temperature and osmotic stress. Our finding of an overall positive mean effect of priming regardless of the microbial system and particular stressor provides unprecedentedly strong evidence of the broad ecological significance of microbial stress priming. These results further suggest that stress priming may be an important factor in shaping microbial communities.
Almost all the dehydrated cassava puree is pregelatinized cassava starch (PCS). Its potential application in food would add variety. But food characteristics vary depending on the raw materials used. ...We examined how the structure of snacks changed when PCS was used instead of flour in terms of porosity, instrumental textural parameters, and acoustic parameters and compare them to commercial crackers. The volume of air was unaffected by the substitution. However, substitution did reduce thickness and alter the number, size, and wall firmness of pores, as well as their distribution and shape, which raise the values of firmness, fracturability, hardness, and fragility, though not linearly. The partial substitutions and the control did not exhibit any appreciable differences in the acoustic parameters. The total replacement sample was noisier and maintained a wide variety of sounds. The PCS vitreous state is primarily responsible for structure changes, but other elements, such as processing conditions, contribute to differences in comparison to the commercial samples. The porosity of commercial samples was lower than that of the elaborated samples. Texturally, it led to lower fracturability and greater fragility (less mm until fracture and fewer force peaks). The elaborated samples were all louder than the commercials. Although sensory analysis is required to classify a food as crunchy, the physicochemical changes caused by the substitution and their impact on the structure's behavior were established. Each textural parameter cannot determine whether the food is crunchy, crispy, or friable on its own; an analysis that incorporates all the characteristics is required. Supplement Material. PRACTICAL APPLICATION: This study demonstrates that pregelatinized cassava flour can be used to partially or completely replace wheat flour in baked snacks. Although textural differences were noted, these alterations were acceptable for products with a similar market niche. These findings might be used in the food business, notably by companies aiming to offer baked snack choices that are not made with standard wheat flour.
Forward osmosis (FO) indirect desalination systems integrate wastewater recovery with seawater desalination. Niche applications for FO systems have been reported recently, due to the demonstrated ...advantages compared to conventional high-pressure membrane processes such as nanofiltration (NF) and reverse osmosis (RO). Among them, wastewater recovery has been identified to be particularly suitable for practical applications. However, biofouling in FO membranes has rarely been studied in applications involving wastewater effluents. Feed spacers separating the membrane sheets in cross-flow systems play an important role in biofilm formation. The objective of this study was to determine the influence of feed spacer thickness (28, 31 and 46 mil) on biofouling development and membrane performance in a FO system, using identical cross-flow cells in parallel studies. Flux development, biomass accumulation, fouling localization and composition were determined and analyzed. For all spacer thicknesses, operated at the same feed flow and the same run time, the same amount of biomass was found, while the flux reduction decreased with thicker spacers. These observations are in good agreement with biofouling studies for RO systems, considering the key differences between FO and RO. Our findings contradict previous cross-flow studies on particulate/colloidal fouling, where higher cross-flow velocities improved system performance. Thicker spacers reduced the impact of biofouling on FO membrane flux.
Background and aim The root endophytic fungus Piriformospora indica increases plant resistance and tolerance to stress and promotes plant growth, but its ability to support plant nutrition is still ...controversially discussed. Irrespective of a potential nutrient transport towards the plant, the fungus might release P from sources unavailable for plant usage by transformation to available forms. Methods To test this hypothesis, sterile solid and liquid in vitro cultures of P. indica supplied with different organic and inorganic P sources were established. Cultures were investigated for growth, solubilised P, enzyme activities, RNA accumulation of the four genes encoding phosphate transporters and the two genes for acid phosphatases and phytases respectively found in P. indica genome, and for pH values in the media. Results P. indica growth was higher in the presence of inorganic P than in organic P sources. Significant amounts of P were solubilised by P. indica from Ca₃(PO₄)₂ and rock phosphate. However, no relevant intra-or extracellular enzymatic activity was detected despite RNA accumulation of related genes. In general, the genes were all repressed by higher amounts of inorganic P and were expressed the most when the fungus received phytate. We observed a decrease in medium pH in the presence of P. indica irrespective of the P source. Conclusions P. indica is able to solubilise phosphate from inorganic, but not from organic P sources. This P solubilisation is not due to enzymatic activities but rather to the lowering of the medium pH.
The influence of organic nutrient load on biomass accumulation (biofouling) and pressure drop development in membrane filtration systems was investigated. Nutrient load is the product of nutrient ...concentration and linear flow velocity. Biofouling – excessive growth of microbial biomass in membrane systems – hampers membrane performance.
The influence of biodegradable organic nutrient load on biofouling was investigated at varying (i) crossflow velocity, (ii) nutrient concentration, (iii) shear, and (iv) feed spacer thickness. Experimental studies were performed with membrane fouling simulators (MFSs) containing a reverse osmosis (RO) membrane and a 31 mil thick feed spacer, commonly applied in practice in RO and nanofiltration (NF) spiral-wound membrane modules. Numerical modeling studies were done with identical feed spacer geometry differing in thickness (28, 31 and 34 mil). Additionally, experiments were done applying a forward osmosis (FO) membrane with varying spacer thickness (28, 31 and 34 mil), addressing the permeate flux decline and biofilm development. Assessed were the development of feed channel pressure drop (MFS studies), permeate flux (FO studies) and accumulated biomass amount measured by adenosine triphosphate (ATP) and total organic carbon (TOC).
Our studies showed that the organic nutrient load determined the accumulated amount of biomass. The same amount of accumulated biomass was found at constant nutrient load irrespective of linear flow velocity, shear, and/or feed spacer thickness. The impact of the same amount of accumulated biomass on feed channel pressure drop and permeate flux was influenced by membrane process design and operational conditions. Reducing the nutrient load by pretreatment slowed-down the biofilm formation. The impact of accumulated biomass on membrane performance was reduced by applying a lower crossflow velocity and/or a thicker and/or a modified geometry feed spacer. The results indicate that cleanings can be delayed but are unavoidable.
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•Organic nutrient load determined the biomass accumulation in membrane systems.•The amount of accumulated biomass was independent of applied shear.•Biofilm impact on performance influenced by cross-flow velocity and spacer thickness.•Retarding the rate of biofouling required a lower organic nutrient load.•A thicker spacer reduced the effect of biofouling on membrane performance.
Objectives To assess the knowledge and practice preferences of anaphylaxis in pediatric emergency medicine (PEM) physicians by practice setting, and to identify factors associated with intramuscular ...(IM) epinephrine administration and admission of patients with anaphylaxis. Study design The cohort was a cross-sectional convenience sample; potential participants were recruited using contact information obtained from the American Board of Pediatrics and American Board of Medical Specialties membership databases and were asked to complete a 12 item survey. Board-certified PEM physicians were categorized by practice setting: university hospital, non-university hospital with a residency training program, or community hospital with no residency training program. Management practices based on practice setting are presented as proportions. Multivariate logistic regression identified factors associated with IM epinephrine administration and admission of patients with anaphylaxis for observation. Results Of the 1114 PEM physicians solicited, 620 (56%) completed the survey. The majority (93.5%) correctly identified epinephrine as the treatment of choice for anaphylaxis, yet only 66.9% used the IM route of administration, and only 37.4% admitted affected patients for observation. Factors associated with the use of IM epinephrine included the presence of a residency program at the site of care (OR, 2.28, 95% CI, 1.3-4.04) and higher volume of anaphylaxis cases (OR, 1.21; 95% CI, 1.06-1.38). Increasing anaphylaxis case volume was associated with decreased likelihood of admission of patients with anaphylaxis (OR, 0.81; 95% CI, 0.72-0.92). Conclusion Even though the majority of PEM physicians correctly report using epinephrine in pediatric anaphylaxis, not all use the preferred administration route, and many discharge patients home after an abbreviated period.
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