Large Concentration Ratio Research Articles

The synergistic effects of salinity and pressure gradients on sustainable energy conversion in nanofluidics

In recent years, osmotic energy conversion and electrokinetic energy conversion within nanochannels have received widespread attention. In this work, we propose four kinds of energy conversion models in nanochannels, including pressure-driven power generation, salinity-driven power generation, the positive combination of pressure gradient and salinity gradient and the negative combination. The changes in ion transport behavior and energy conversion characteristics are analyzed. The results show that the combination of salinity gradient and pressure gradient is not a simple superposition. Compared to the power of the single drive mode before optimization, the power under positive combination (PC) can reach 1.02 pW, and the power enhancement ratio is as high as 1.6. The negative combination has a certain optimization potential under a large concentration ratio and small pressure gradient condition. The higher the surface charge density, the greater the output power, but the optimization effect worsens. On the contrary, a larger channel length corresponds to a smaller output power, but the optimization effect becomes better. The reasonable choice of surface charge density and channel length needs to be weighed. These studies provide valuable guidance for the design of future nanofluidic energy conversion devices.

Mirrored transformation optics.

A mirrored transformation optics (MTO) approach is presented to overcome the material mismatch in transformation optics. It makes good use of the reflection behavior and introduces a mirrored medium to offset the phase discontinuities. Using this approach, a high-performance planar focusing lens of transmission type is designed, which has a larger concentration ratio than the other focusing lens obtained by the generalized Snell's law. The MTO will not change any functionality of the original lens and has promising potential applications in imaging and light energy harvesting.

Manufacturing of Low-Cost Parabolic Dish Concentrators with Manual Dual-Axis Tracking

The increased rate of energy crises around the world results in expanding the role of Concentrating Solar Power (CSP) technology for different applications, comprising heating process and power generation applications. The Parabolic Dish Concentrator (PDC) with its large concentration ratio and its modular capacity attracts researchers’ efforts. In this research work, we have designed and developed a PDC with back silvered mirrors as reflector material. Then we have sized the following geometric parameters: the dish diameter, the focal length, the aperture area, the rim angle, the geometric concentration ratio, the receiver material, and the receiver diameter. Furthermore, a dual-axis manual tracking system has been built for this PDC. It should be mentioned that the different components of the PDC have been recycled from a scrap yard to develop a low-cost PDC system. Finally, we have investigated the temperature evolution as a function of time at the focus spot. The maximum temperature obtained is 112 °C for the PDC with mirror. The findings of the study reveal the possibility of building a low-cost solar concentrator with good performance and high quality, only by employing recycled materials, and it could be operated in various applications.

Performance analysis of a solar photovoltaic power generation system with spray cooling

An efficient cooling system can effectively reduce the temperature and improve the power generation performance of photovoltaic cells. In this study, spray cooling is applied to the cooling of photovoltaic cells, and the mathematical model of a solar photovoltaic power generation system is established by considering the power consumption of the cooling system. The net output power and electrical efficiency of the system are compared under different cooling modes. The results show that spray cooling has more obvious advantages than water cooling at large concentration ratios and there exists an optimal spray flow rate that can maximize the net electrical efficiency. The optimal flow rate increases as the concentration ratio increases. Furthermore, the temperature of the spray fluid significantly affects the system performance, and a 10 K reduction in spray fluid temperature can improve the net output power by 7.3%. Regarding the environmental factors, the influence of the ambient temperature is evident when the concentration ratio is small; however, the influence of wind speed is more evident when the concentration ratio is large. The results of this study provide new insights that may prove useful for optimizing the design of photovoltaic cooling systems.

Stimulation of Bladder Acupoints by Cloprostenol for Treating Back Soreness in Athletic Horses

Twenty-five Thoroughbred jumper geldings suffered back soreness with poor performance, and 5 control horses were assessed by archived computer data, clinical examination, and laboratory analyses of complete blood picture, serum enzymes, and cortisol level, before and after cloprostenol-pharmacopuncture. The 25 diseased horses before therapy showed significant increases in aspartate aminotransferase and creatine phosphokinase with clinical pains scored mild in 15 horses, moderate in 9 horses, and severe in one horse, without changes in the hormonal and hematological data. After therapy, they responded by an increase of heart rate (57.8 ± 4.3 bpm), body temperature (38.5 ± 0.7°C), respiration rate (28.3 ± 2.1 bpm), and capillary refilling time (CRT) (1.0 ± 0.0). On the 2nd day, a significant decrease in the mean levels of aspartate aminotransferase and creatine phosphokinase (P = 0.001) was detected, while on the 4th day, they mimed the level of the 5 controls, and on the 6th day, they showed a significant decrease (P = 0.002). The serum cortisol level showed a significant increase on the 6th day of treatment (P = 0.013). The blood picture showed significant increases in red blood cells, mean corpuscular volume, platelets, white blood cells, hemoglobin, mean corpuscular hemoglobin, mean corpuscular hemoglobin concentration, mean platelet volume, platelet distribution width, lymphocytes, plateletcrit, and large platelet concentration ratio (P < 0.05) and nonsignificant changes in hematocrit, granulocytes, and midocytes. The improved blood parameters, enzymes, hormones, and performance progress after cloprostenol-pharmacopuncture proved its effectiveness in treating back soreness in athletic horses.

SYNTHESIS, CHARACTERIZATION, AND IN VIVO IMMUNOMODULATION OF CCR2 AND VASCULAR ENDOTHELIAL GROWTH FACTOR ANTAGONISTS-LOADED PEGYLATED NANOPARTICLES

Objective: Chemokine (C-C motif) ligand 2 (CCL2), a candidate of cytokines, orchestrates immune cell recruitment to inflamed organs. CCL2 has been shown to have direct angiogenic effects, so providing an anti-angiogenic agent, Avastin (AV), to be combined with the CCR2 antagonist (concentration ratio [CR]) plays an essential role in the hemostatic strategy for immunomodulation. Lack of targetability and the adverse effects of chemical treatments are the main obstacles led scientists to develop novel strategies using nano-delivery approaches such as pegylated nanoparticles (NPs) which exhibits reduced drug clearance rates. The rationale of the current study is to test the in vivo immunomodulatory effects of AV and/or CR in their NPs or free counterparts.Methods: These NPs were synthesized and characterized using different physicochemical techniques. Males Wistar rats (n=114) were used and divided into 7 groups treated with vehicle, AV, AVNP, CCR2 antagonist (CR), CCR2 antagonist NPs (CRNP), AV-CCR2 antagonist (AVCR), and AV-CCR2 antagonist NPs (AVCRNP). Groups were subdivided into three subgroups according to the administrated dose. Blood was taken from rats for differential leukocyte and platelet profile measurements. Sera were collected to test vascular endothelial growth factor (VEGF) levels. Autopsy samples from liver were taken for histopathological investigation.Results: The morphology of the NPs was spherical and had sizes ranging from 89.89 nm to 146 nm. Monocytes and lymphocytes accumulated in the blood circulation and VEGF levels were inhibited after AV and CR administrations. In addition, large platelets concentration ratio was elevated in the blood circulation.Conclusion: We concluded that AV ad CR therapeutic regimens have an immunomodulatory role through induction of monocyte-platelet aggregation and inhibition of VEGF.

SYNTHESIS, CHARACTERIZATION, AND IN VIVO IMMUNOMODULATION OF CCR2 AND VASCULAR ENDOTHELIAL GROWTH FACTOR ANTAGONISTS-LOADED PEGYLATED NANOPARTICLES

Objective: Chemokine (C-C motif) ligand 2 (CCL2), a candidate of cytokines, orchestrates immune cell recruitment to inflamed organs. CCL2 has been shown to have direct angiogenic effects, so providing an anti-angiogenic agent, Avastin (AV), to be combined with the CCR2 antagonist (concentration ratio [CR]) plays an essential role in the hemostatic strategy for immunomodulation. Lack of targetability and the adverse effects of chemical treatments are the main obstacles led scientists to develop novel strategies using nano-delivery approaches such as pegylated nanoparticles (NPs) which exhibits reduced drug clearance rates. The rationale of the current study is to test the in vivo immunomodulatory effects of AV and/or CR in their NPs or free counterparts.Methods: These NPs were synthesized and characterized using different physicochemical techniques. Males Wistar rats (n=114) were used and divided into 7 groups treated with vehicle, AV, AVNP, CCR2 antagonist (CR), CCR2 antagonist NPs (CRNP), AV-CCR2 antagonist (AVCR), and AV-CCR2 antagonist NPs (AVCRNP). Groups were subdivided into three subgroups according to the administrated dose. Blood was taken from rats for differential leukocyte and platelet profile measurements. Sera were collected to test vascular endothelial growth factor (VEGF) levels. Autopsy samples from liver were taken for histopathological investigation.Results: The morphology of the NPs was spherical and had sizes ranging from 89.89 nm to 146 nm. Monocytes and lymphocytes accumulated in the blood circulation and VEGF levels were inhibited after AV and CR administrations. In addition, large platelets concentration ratio was elevated in the blood circulation.Conclusion: We concluded that AV ad CR therapeutic regimens have an immunomodulatory role through induction of monocyte-platelet aggregation and inhibition of VEGF.

Diffusion of multiple electrolytes cannot be treated independently: model predictions with experimental validation.

We study the diffusion of multiple electrolytes in a one-dimensional pore. We model the scenario where an electrolyte is in contact with a reservoir of another electrolyte, such that the cation of the two electrolytes is common. The model reveals that several factors influence the ion concentration profiles: (i) relative diffusivities of the ions, (ii) ratio of the electrolyte concentrations in the pore and the reservoir, and (iii) the valence of the ions. We demonstrate that it is crucial to consider the interaction between ion fluxes as treating the electrolytes independently, as is sometimes proposed, does not completely capture the dynamics of ion transport. We validate our numerical predictions by conducting experiments with sodium fluorescein salt in the pore and sodium chloride/sodium sulphate/sodium hydroxide in the reservoir. Our visualization and results demonstrate that ion diffusivities and concentrations in the reservoir can influence the diffusion rates of fluorescein, which underscores that ion fluxes are coupled and that multiple electrolytes cannot be treated independently. These results should be useful to the wide range of situations where concentration variations are imposed on systems with an existing background electrolyte.

Computational Model of Calcium Signaling in Cardiac Atrial Cells at the Submicron Scale.

In cardiac cells, calcium is the mediator of excitation-contraction coupling. Dysfunctions in calcium handling have been identified as the origin of some cardiac arrhythmias. In the particular case of atrial myocytes, recent available experimental data has found links between these dysfunctions and structural changes in the calcium handling machinery (ryanodine cluster size and distribution, t-tubular network, etc). To address this issue, we have developed a computational model of an atrial myocyte that takes into account the detailed intracellular structure. The homogenized macroscopic behavior is described with a two-concentration field model, using effective diffusion coefficients of calcium in the sarcoplasmic reticulum (SR) and in the cytoplasm. The model reproduces the right calcium transients and dependence with pacing frequency. Under basal conditions, the calcium rise is mostly restricted to the periphery of the cell, with a large concentration ratio between the periphery and the interior. We have then studied the dependence of the speed of the calcium wave on cytosolic and SR diffusion coefficients, finding an almost linear relation with the former, in agreement with a diffusive and fire mechanism of propagation, and little dependence on the latter. Finally, we have studied the effect of a change in RyR cluster microstructure. We find that, under resting conditions, the spark frequency decreases slightly with RyR cluster spatial dispersion, but markedly increases when the RyRs are distributed in clusters of larger size, stressing the importance of RyR cluster organization to understand atrial arrhythmias, as recent experimental results suggest (Macquaide et al., 2015).

Temperature regulated reverse electrodialysis in charged nanopores

Nanofluidic reverse electrodialysis (RED) is a promising way to utilize the vastly existed salinity gradient energy. In this paper, impacts of temperature gradient across the nanopore on the ion transportation and power generation performance are systematically investigated, and a theoretical description has been derived to illustrate the energy conversion efficiency under asymmetric temperatures. Results reveal that under isothermal reservoirs, the maximum power increases with increasing temperatures, while the corresponding efficiency presents no obvious difference due to synchronous enhancement of the cation and anion diffusive coefficients. For salt solutions under asymmetric temperatures, at small concentration ratios, the larger average temperature, the larger maximum power output due to augmented enhanced ion transportation. A negative temperature gradient contributes to the maximum power efficiency while the positive one decreases the maximum power efficiency. At large concentration ratios, the nanofluidic RED system exhibits different behaviours. A negative temperature gradient contributes to the maximum power and the corresponding efficiency while the positive one decreases the maximum power and the corresponding efficiency. The results in this paper may offer desirable guidance for improving nanofluidic RED performance.

Improving the concentration ratio of parabolic troughs using a second-stage flat mirror

Increasing the concentration ratio of parabolic troughs is one of the challenges to make this technology economically competitive against fossil fuels. Parabolic troughs with large concentration ratios face several problems such as difficulty capturing all the solar direct radiation and structural issues associated with thermal expansions and wind resistance amongst others. For larger mirrors it may be necessary to use a bigger absorber in order to capture all the radiation, thus increasing the thermal losses. A second stage reflector helps to increase the concentration ratio without increasing the primary mirror size. In this work, a theoretical analysis of a parabolic trough with a secondary flat reflector is developed and ray tracing is conducted in order to validate the equations obtained. A flat reflector will have a minimal economic impact in the cost of a parabolic trough and it allows larger concentration ratios for identical primary mirror areas compared to a standard parabolic trough. Increases of concentration ratio up to 80% are observed when a secondary flat reflector is inserted in a commercial system, while the shadow area introduced in the primary mirror is usually less than 15% of the primary mirror area. The increase in pumping power is offset by the increase in system efficiency.

A zero-liquid-discharge scheme for vanadium extraction process by electrodialysis-based technology

The sharp increase of demand for vanadium makes the treatment of the wastewater generated from its extraction process become an urgent problem. In this study, a hybrid process coupling the electrodialysis with the cooling crystallization is put forward for upgrading the conventional vanadium extraction process to zero discharge. Accordingly, the objective of this work lies in evaluating the feasibility of the proposed scheme on the basis of a systematic study on the influences of membrane types and operating parameters on the electrodilysis performance. The results indicate that the relative importance of osmosis and electro-osmosis to overall water transport is closely related to the applied current density. The increase in the applied current density and the decrease in the mole ratio of water and salt flux will contribute to the concentration degree. Moreover, it is worth noting that a relatively large concentration ratio can result in the remarkable decrease of current efficiency and increase of energy consumption. In general, the reclamation scheme can easily achieve the recovered water with relatively low salt content and the highly concentrated Na2SO4 solution (e.g., 300g/L) for producing high-purity sodium sulphate crystals.

Pepper mild mottle virus as an indicator and a tracer of fecal pollution in water environments: Comparative evaluation with wastewater-tracer pharmaceuticals in Hanoi, Vietnam

We analyzed pepper mild mottle virus (PMMoV) in 36 samples taken from surface water, wastewater, groundwater, tap water and bottled water in Hanoi, Vietnam. We then compared the occurrence and fates of PMMoV with pharmaceuticals and personal care products (PPCPs), which are known wastewater tracers. PMMoV was detected in 94% of the surface water samples (ponds, water from irrigated farmlands and rivers) and in all the wastewater samples. The PMMoV concentration ranged from 5.5×106–7.2×106copies/L in wastewater treatment plant (WWTP) influents, 6.5×105–8.5×105copies/L in WWTP effluents and 1.0×104–1.8×106copies/L in surface water. Among the sixty PPCPs analyzed, caffeine and carbamazepine had high detection rates in surface water (100% and 88%, respectively). In surface water, the concentration ratio of PMMoV to caffeine remained unchanged than that in WWTP influents, suggesting that the persistence of PMMoV in surface water was comparable to that of caffeine. The persistence and the large concentration ratio of PMMoV in WWTP influents to the method detection limit would account for its ubiquitous detection in surface water. In comparison, human enteric viruses (HEV) were less frequently detected (18–59%) than PMMoV in surface water, probably because of their faster decay. Together with the reported high human feces-specificity, our results suggested that PMMoV is useful as a sensitive fecal indicator for evaluating the potential occurrence of pathogenic viruses in surface water. Moreover, PMMoV can be useful as a moderately conservative fecal tracer for specifically tracking fecal pollution of surface water. PMMoV was detected in 38% of the groundwater samples at low concentrations (up to 19copies/L). PMMoV was not detected in the tap water and bottled water samples. In groundwater, tap water and bottled water samples, the occurrence of PPCPs and HEV disagreed with that of PMMoV, suggesting that PMMoV is not suitable as an indicator or a tracer in those waters.

Preliminary Experimental Comparison of the Performance of a Novel Lens-Walled Compound Parabolic Concentrator (CPC) with the Conventional Mirror and Solid CPCs

A conventional mirror compound parabolic concentrator (CPC) is limited by its half acceptance angle when pursuing a large geometrical concentration ratio with no tracking. A solid CPC, which is made from solid dielectric materials without notches, can achieve a larger half acceptance angle compared with the conventional mirror CPC of the same geometrical concentration ratio, which is attributed to the optical refraction caused by the dielectric material. However, solid CPCs are heavier and costlier. This paper presents a preliminary experiment on a novel lens-walled CPC. An experimental comparison of the conventional mirror and solid CPCs and the lens-walled CPC with the same geometrical concentration ratios of 2.5 is given for different incidence angles. Here the conventional mirror CPC chose the evaporated aluminium coating as the reflection layer, for short conventional CPC. Transparent acrylic was chosen as both the dielectric material and lens material. The three CPCs were all attached to a PV cell. Through the output characteristics of the cell, the optical performances of these CPCs can be obtained. The results showed that when the incidence angle was smaller than 35°, the optical efficiency of the lens-walled CPC remained above 46.7% and was more stable against incidence angle changes compared with the conventional CPC. It also weighed and cost less than the solid CPC. Thus, lens-walled CPC adequately combines the advantages of conventional and solid CPCs, and has great potential for use in large-scale practical applications.

Photodissociation and photoionization of 2,5-dihydroxybenzoic acid at 193 and 355 nm

Photodissociation and photoionization of 2,5-dihydroxybenzoic acid (25DHBA), at 193 and 355 nm were investigated separately in a molecular beam using multimass ion imaging techniques. Two channels competed after excitation by one 193 nm photon. One channel is dissociation from the repulsive excited state along O-H bond distance, resulting in H atom elimination from meta-OH functional group. The other channel is internal conversion to the ground state, followed by H(2)O elimination. Some of the fragments further proceeded to secondary dissociation. On the other hand, absorption of one 355 nm photon gave rise to H(2)O elimination channel on the ground state. Absorption of more than one 355 nm photon resulted in the three-body dissociation which also occurs on the ground state. Dissociation on the excited state does not play a role at 355 nm. The large concentration ratio (2×10(5)), between neutral fragments and cations produced from 355 nm multiphoton excitation indicates that internal conversion followed by dissociation, is the major channel for 355 nm multiphoton excitation. Multiphoton ionization is a minor channel. Multiphoton ionization of 25DHBA clusters only produces 25DHBA cations. Neither anion nor protonated 25DHBA cation were observed. It is very different from the ions produced from solid matrix-assisted laser desorption/ionization (MALDI), experiments. This suggests that protonated 25DHBA and negatively charged 25DHBA generated in MALDI experiments does not simply result from the ionization following proton transfer reactions or charge transfer reactions of the clusters in the gas phase.

On the non-linear instability of fiber suspensions in a Poiseuille flow

The non-linear instability characteristics of fiber suspensions in a plane Poiseuille flow are investigated. The evolution equation of the perturbation amplitude analogous to Landau equation is formulated and solved numerically for different fiber parameters. It is found that the equilibrium amplitude decreases with the increase of the fiber aspect ratio and volume fraction, i.e. the addition of the fibers reduces the amplitude of the perturbation, and leads to the reduction of the flow instability. This phenomenon becomes significant for large volume concentration and aspect ratio. The mechanism of the reduction of the flow instability is also analyzed by taking into account of the modification of the mean flow and the energy transfer from the mean flow to the perturbation flow.

Particulate Polycyclic Aromatic Hydrocarbons and Their Nitrated Derivatives in Three Cities in Liaoning Province, China

Airborne particulates were collected in nine size fractions by using Andersen low-volume air samplers in the cities of Shenyang, Fushun, and Tieling, Liaoning Province, in northeast China, during the period from July 2001 through December 2003. Nine polycyclic aromatic hydrocarbons (PAHs) and seven nitropolycyclic aromatic hydrocarbons (NPAHs) in the airborne particulates were determined. The mean concentrations of the sums of the nine PAHs and seven NPAHs were highest in Fushun, which is an industrial city, and lowest in Shenyang, which is a commercial city, although the consumption of petroleum and coal were largest in Shenyang. The nine fractions were grouped into three groups: > 7 μ m, 2.1–7 μ m and < 2.1 μ m. In each city, more than 50% of the total PAHs and total NPAHs were found in the fine particulate fraction (< 2.1 μ m). In each city, all PAHs and all NPAHs were clearly higher in winter than in summer. The concentration ratio of 1-nitropyrene to pyrene, which is a suitable indicator to identify diesel engine and coal combustion as proposed by our previous study, showed that the major contributors of PAHs and NPAHs in the airborne particulates were coal-combustion systems both in summer and winter in Fushun and Tieling. In Shenyang, atmospheric PAHs and NPAHs also seemed to be affected by coal combustion systems in winter, whereas gasoline engine vehicles seemed to be a major contributor in summer by the larger concentration ratio of 1-nitropyrene to pyrene. Cluster analysis and other diagnostic ratios such as benz[a]anthracene to chrysene, benzo[ghi]perylene to benzo[a]pyrene supported these results.

Mutual separation of two monovalent metal ions by multistage electrodialysis

A multistage electrodialyzer having an enriching section and a stripping one has been developed to separate monovalent cation species in the aqueous solution. A feed solution containing LiCl and KCl is supplied to the middle stage of the dialyzer, and a solution of HCl is supplied to the cathode stage. Stages from cathode to feed are the enriching section and those from feed to anode are stripping section. Aqueous solution flows from the cathode stage toward the anode stage as a reflux flow. The ratio K + / Li + in the enriching product increased with the increase in reflux flow rate and decreased with the increase in current density, while the ratio Li + / K + in the stripping product increased with the current density and decreased with the reflux flow rate. Simulation by a stage to stage calculation was carried out by use of the operating equation based on mass balance and the relation of permselectivities alternatively. The calculated results were in good agreement with the experimental ones, and indicated that a large yield of product as well as a large concentration ratio can be achieved by increasing stage number.

Determining the Optical Properties of PETAL, the 400m2 Parabolic Dish at Sede Boqer

PETAL (Parabolic Energy Transformation and Astrophysics Laboratory) is a large multipurpose dish-shaped concentrator, located at Sede Boqer. Its 2-axis tracking paraboloidal surface, with aperture area in excess of 400m2, is constructed from 216 adjustable mirror panels. The very large aperture and high concentration ratio of PETAL render the direct characterization of its optical performance a nontrivial task. We have applied a variety of methods in order to assess PETAL’s optical quality. These include imaging the full moon and Jupiter at night, and analysis of the 3-D caustic image produced by the scattering of focused sunlight off particles in the air. The main results of these studies, together with the preliminary results of measurements on 36 individual panels, are presented here. Among the three measurements that look at objects of the same angular size (i.e. the sun and moon), the average image size (i.e. radius of circle containing 90% of the intensity) is 0.247±0.012m, demonstrating a 5% spread about the mean for three different methods. This result is in agreement with 0.22 m for the Jupiter image. Successful application of these methods for characterization of PETAL proves their applicability to more commonly used solar dishes of smaller sizes but with similar or better concentration ratios.

Effects of three PBDEs on development, reproduction and population growth rate of the harpacticoid copepod Nitocra spinipes

The current knowledge concerning effects of polybrominated diphenyl ethers (PBDEs) on aquatic organisms is very limited. A full life-cycle (⩽26 days exposure) ecotoxicity test with the particle-feeding copepod Nitocra spinipes was therefore used to study effects of BDE-47, -99 and -100 on larval development rate (LDR) and population growth rate ( r m). LDR significantly decreased in copepods exposed for 6 days to nominal concentrations ⩾0.013 mg/l BDE-47 and ⩾0.03 mg/l BDE-99. Large concentration ratios (⩽338) between adult acute and juvenile subchronic endpoints were observed. Exposure over the full life cycle (⩽26 days) showed that r m in general was a less sensitive endpoint than LDR. Still, the r m in copepods exposed to 0.04 mg/l BDE-47 was significantly reduced compared to the controls (*** P<0.001). Partitioning experiments with 14C-BDE-47 and 14C-BDE-99 in the test system showed that the major fractions (∼50–80%) were associated to particulate material. Our findings indicate that development and reproduction in N. spinipes are sensitive to the tested PBDEs and that ingestion of particle-adsorbed PBDEs most likely is the predominant route of exposure in N. spinipes. However, to further improve the usefulness of laboratory effect levels of PBDEs and other lipophilic substances for environmental risk assessment, it is important to develop ecotoxicological tools, which can evaluate and rate the toxic contribution from different matrices, such as suspended particles, sediment, food, water etc.