Sensitivity and quality factor improvement of photonic crystal sensors by geometrical optimization of waveguides and micro-ring resonators combination.

In this work, the process of designing and simulating optical sensors based on photonic crystal (PC) micro-ring resonators (MRRs) has been investigated. According to the PC type, different waveguides and resonators can be designed, and various topologies can be proposed from their combination, for optical sensor applications. Here, the investigated MRR is of the symmetrical micro-hexagonal ring resonator (MHRR) type. Different arrays of MHRR arrangement have been designed to investigate their effects on the output spectrum. The results of the design and simulation of different topologies have been analyzed and compared with other numerical researches. Considering all the necessary aspects of PC optical sensors, a detailed and comprehensive algorithm has been presented for designing these devices and choosing the optimal structure. In a more complementary process, the effects of reflector rods have been investigated, which indicates the existence of similarity and compatibility in the design between the distance of reflector rods and the length of MHRRs to obtain the optimal structure. Finally, the effect of different values of lattice constant and radius of dielectric rods on FWHM, transmission (TR) and resonant wavelength is studied, and the most optimal mode is presented. In order to measure the performance of the proposed optimal sensor, its application for gas detection has been analyzed. TR, FWHM, quality factor (QF), sensitivity (S) and figure of merit (FOM) of the proposed sensor were equal to 96%, 0.31 nm, 2636, 6451 nm/RIU and 2960 RIU-1 respectively. An examination of results from similar research indicates a rational and effective approach for generating diverse topologies, aiming to attain the most optimal configuration for optical sensors employing MRRs. Furthermore, employing a systematic design process based on established principles and the proposed algorithm helps prevent arbitrary parameter variations, facilitating the attainment of desired outcomes in a more streamlined and efficient manner. Given the comprehensive nature of this research, it presents a viable solution for designing optical devices based on MRRs for use in optical integrated circuits (OICs) applications.

Enhancement of Radio-Thermo-Sensitivity of 5-Iodo-2-Deoxyuridine-Loaded Polymeric-Coated Magnetic Nanoparticles Triggers Apoptosis in U87MG Human Glioblastoma Cancer Cell Line.

INTRODUCTION: With an emphasis on the radioresistant nature of glioblastoma cells, the aim of the present study was to evaluate the radio-thermo-sensitizing effects of PCL-PEG-coated Superparamagnetic iron oxide nanoparticles (SPIONs) as a carrier of 5-iodo-2-deoxyuridine (IUdR) in monolayer culture of U87MG human glioma cell line. METHODS: Following monolayer culture of U87MG cells, nanoparticle uptake was assessed using Prussian blue staining and ICP-OES method. The U87MG cells were treated with an appropriate concentration of free IUdR and PCL-PEG-coated SPIONs (MNPs) loaded with IUdR (IUdR/MNPs) for 24 h, subjected to hyperthermia (water bath and alternating magnetic field (AMF)) at 43 °C, and exposed to X-ray (2 Gy, 6 MV). The combined effects of hyperthermia with or without magnetic nanoparticles on radiosensitivity of the U87MG cells were evaluated using colony formation assay (CFA) and Flowcytometry. RESULTS: Prussian blue staining and ICP-OES showed that the nanoparticles were able to enter the cells. The results also indicated that IUdR/MNPs combined with X-ray radiation and hyperthermia significantly decreased the colony formation ability of monolayer cells (1.11, 1.41 fold) and increased the percentage of apoptotic (2.47, 4.1 fold) and necrotic cells (12.28, 29.34 fold), when compared to IUdR combined with X-ray and hyperthermia or IUdR/MNPs + X-ray. MTT results revealed that the presence of IUdR/MNPs significantly increased the toxicity of AMF hyperthermia compared to the water bath method. CONCLUSIONS: Our study showed that SPIONs/PCL-PEG, as a carrier of IUdR, can enhance the cytotoxic effects of radiotherapy and hyperthermia and act as a radio-thermo-sensitizing agent. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s12195-021-00675-y.

Intracerebroventricular injection of propranolol blocked analgesic and neuroprotective effects of resveratrol following L5 spinal nerve ligation in rat.

OBJECTIVES: Resveratrol as a natural polyphenolic agent can alleviate neuropathic pain symptoms. The mechanism of analgesic activity of resveratrol is far from clear. The current study examine whether analgesic activity of resveratrol is mediated by its neuroprotective and anti-oxidant activity in the neuropathic pain. We further examine whether analgesic activity of resveratrol is mediated by ß-adrenoceptors in the brain. METHODS: Neuropathic pain induced by L5 spinal nerve ligation (SNL). Male Wistar rats assigned into sham, SNL, SNL + resveratrol (40 µg/5 µL), and SNL + resveratrol + propranolol (a non-selective ß-adrenoceptor antagonist, 30 µg/5 µL) groups. Drugs injected intracerebroventricular (ICV) at day SNL surgery and daily for 6 days following SNL. Thermal allodynia and anxiety examined on days of -1, 2, 4, and 6 following SNL. Electrophysiological study performed on day 6 following SNL for evaluation of resveratrol effects on sciatic nerve conduction velocity (NCV). The activity of catalase (Cat) and superoxide dismutase (SOD) enzymes in the brain assessed on days 6 following SNL. RESULTS: Resveratrol significantly decreased thermal allodynia (and not anxiety) in all experimental days. Additionally, resveratrol significantly increased NCV, and also normalized the disrupted Cat and SOD activities following neuropathic pain. Furthermore, propranolol significantly blocked the analgesic and neuroprotective effects of resveratrol. CONCLUSIONS: It is suggested that the analgesic effects of resveratrol is mediated by its neuroprotective and antioxidant activities in the neuropathic rats. Furthermore, propranolol blocked the analgesic and neuroprotective effects of resveratrol.

Parasitic causes of meat and organs in cattle at four slaughterhouses in Sistan-Baluchestan Province, Southeastern Iran between 2008 and 2016.

This 8-year (from 2008 to 2016) retrospective study calculated the percentage of carcass and organ (lung and liver) condemnations and estimated the direct financial costs at four slaughterhouses in Sistan-Baluchestan Province, Southeastern Iran. Each carcass and organ (lung and liver) was thoroughly examined through inspection, palpation and incision following the standard protocol. Identification of the parasites was performed macroscopically. The total direct economic loss due to meat's condemnation was estimated by adding weights of each organ or carcass part and multiplying individual organ totals by their 2016 market unit price. A total of 857,039 cattle were slaughtered during this period, 64,497 livers (7.5%), 31,401 lungs (3.6%) and the carcasses of 1,171 cattle (0.1%) were condemned due to lesions caused by parasites. The main parasitic lesions in the condemned livers were attributed to Echinococcus granulosus (4.2%), Fasciola spp. (3.1%) and Dicrocoelium dendriticum (0.1%). All the condemned lungs were due to E. granulosus (3.6%). Taenia saginata cysticerci were detected in 0.1% of inspected animals. Liver condemnation due to cystic echinococcosis was the highest in fall (4.7%, p < 0.001); while lung condemnation was the highest during spring (3.98%, p < 0.001). Liver condemnation due to Fasciola spp. was the lowest in winter (2.99%, p < 0.001). Carcass condemnation as a result of cysticercosis was the highest in summer (p < 0.001). Considering the 2016 market prices, condemnations due to the studied parasites caused direct costs estimated U.S. $ 3,191,879. To the best of our knowledge, this is the first report estimating the monetary losses due to parasitic infections in the slaughterhouses of this province. Due to the high financial impact of the studied parasites, a control programme should be implemented to decrease this impact.

Integration of synthetic aperture radar and optical satellite data for corn biomass estimation.

Efforts to use satellites to monitor the condition and productivity of crops, although extensive, can be challenging to operationalize at field scales in part due to low frequency revisit of higher resolution space-based sensors, in the context of an actively growing crop canopy. The presence of clouds and cloud shadows further impedes the exploitation of high resolution optical sensors for operational monitoring of crop development. The objective of this research was to present an option to facilitate greater temporal observing opportunities to monitor the accumulation of corn biomass, by integrating biomass products from Synthetic Aperture Radar (SAR) and optical satellite sensors. To accomplish this integration, a transfer function was developed using a Neural Network algorithm to relate estimated corn biomass from SAR to that estimated from optical data. With this approach, end users can exploit biomass products to monitor corn development, regardless of the source of satellite data.•The Water Cloud Model (WCM) was calibrated or parametrized for horizontal transmit and horizontal received (HH) and horizontal transmit and vertical received (HV) C-band SAR backscatter using a least square algorithm.•Biomass and volumetric soil moisture were estimated from dual-polarized RADARSAT-2 images without any ancillary input data.•A feed forward backpropagation Neural Network algorithm was trained as a transfer function between the biomass estimates from RADARSAT-2 and the biomass estimates from RapidEye.

Mechanistic investigation of ciprofloxacin recovery by magnetite-imprinted chitosan nanocomposite: Isotherm, kinetic, thermodynamic and reusability studies.

Recovery of antibiotics from water and wastewaters has recently gained a great deal of attention due to their serious health and environmental problems. In this work, a magnetite imprinted chitosan polymer nanocomposites (Fe-CS NCs) were synthesized and applied for the adsorptive removal of ciprofloxacin (CIFO) as a model fluoroquinolone antibiotics. The composition and surface morphology of Fe-CS NCs were studied by SEM, BET, XRD, TEM, FTIR and zeta potential meter. Modelling and optimization of adsorption process were studied using response surface methodology (RSM). The reliability of the RSM models was tested by fitting the data. A comparative analysis of the results derived from the models demonstrated that the second-order model was the best. From the contour plotting results, at pH < pHiep low adsorption rate was observed due to protonation of the chitosan NH2 groups, whereas the adsorption rate was significantly enhanced and achieved to a maximum level at pH 6 due to the electrostatic interactions and hydrophobic interactions. Under optimum conditions, maximum removal efficiency and maximum adsorption capacity were obtained 68% and 142 mg/g, respectively. Well regenerability of Fe-CS together with its high capacity of fluoroquinolone antibiotics removal provide a promisable strategy to remediation of wastewaters.

The comparison of selenium and lead accumulation between contaminated muddy and sandy sediments from four estuaries along the Persian Gulf: effect of grain size.

Persian Gulf is one of the most important water sources in the economically developed south part of Iran, and metal pollution is a major concern for the Gulf. The bioavailability and distribution of selenium (Se) and lead (Pb) between muddy and sandy sediments from four estuaries along the Persian Gulf were analyzed. The geoaccumulation index and enrichment factor for metals and correlation between particles size with metals concentration were studied. The average concentration of metals in sediment was ranged 0.08-1.14 µg/g for Se and 0.32-4.37 µg/g for Pb in all estuaries, with the highest concentrations in Musa estuary. The results showed there was positive correlation between particles size of sediment with metals concentration. The highest of metal concentration was absorbed in silt (< 63 µm) sediment, followed by extremely fine sand (63-125 µm), fine sand (125-250 µm), medium sand (250-500 µm) and coarse sand (500-1000 µm), respectively. The organic matter and carbonate in the muddy sediment are higher than sandy sediment, and they had high specific storage capacity for accumulation of heavy metals. The result of Pearson correlation (r) for organic matter and metal was 0.78 for Se and 0.67 for Pb, and for carbonates and metal was 0.54 for Se and 0.61 for Pb. The values of EF in all estuaries show that the enrichment of sediment by heavy metals was by anthropogenic activities such as discharge of petrochemical and oil industrial. Geoaccumulation index indicates that the sediment in the Ahmadi and Ghanam estuaries was unpolluted to moderately polluted, while in the Arvand river is moderately to strongly polluted, and in the Musa estuary is extremely polluted.

The Preventive Role of Low-Dose Intravenous Ketamine on Postoperative Shivering in Children: A Placebo Randomized Controlled Trial.

BACKGROUND: Postoperative shivering is a major problem in children undergoing general anesthesia. OBJECTIVES: The aim of the present study was to investigate the role of low-dose intravenous ketamine for prevention of shivering after induction of general anesthesia in children who had undergone tonsillectomy. PATIENTS AND METHODS: This was a randomized, double-blinded, placebo-controlled trial including 80 children, of American society of anesthesiologists (ASA) physical status I or II, scheduled for tonsillectomy under general anesthesia who were randomly assigned to an intravenous ketamine (0.5 mg/kg, n = 40; group K) group or matched dose placebo (n = 40; group N) group. Surgical and demographic data, unexpected side effects, and the occurrence of shivering for each child were assessed by a blinded observer at the following time points: T0, in the recovery room; T10, at 10 minutes; T20, at 20 minutes; T30, and at 30 minutes. RESULTS: With regards to the demographic and surgical data, no significant differences between the two study groups were observed (P ≥ 0.05). Shivering intensity in children who had received ketamine was significantly lower than children who had not received ketamine, at T0, T10, T20, and T30 after arrival (P < 0.05). There were no significant differences in hallucination, nausea, vomiting, hemodynamic dysfunction, blurred vision, and seizure in the K group compared with the N group (P ≥ 0.05). CONCLUSIONS: Administration of intravenous ketamine at a dosage of 0.5 mg/kg immediately after anesthesia induction had a preventive effect on shivering intensity without hemodynamic alterations in children undergoing general anesthesia for tonsillectomy.

Detection of blaKPC and blaGES Carbapenemase Genes in Klebsiella pneumoniae Isolated from Hospitalized Patients in Kashan, Iran.

INTRODUCTION: Klebsiella pneumoniae carbapenemase (KPC)-producing bacteria are among the highly antimicrobial resistant gram negative bacteria and infections due to them are an increasingly major health problem worldwide. METHODS: In this study we have detected the blaKPC and blaGES carbapenemase genes in Klebsiella pneumoniae isolated from hospitalized patients in Kashan, Iran. In a cross-sectional study, a total of 181 K. pneumoniae isolates were recovered from clinical specimens during November 2013 to October 2014. RESULT: Antimicrobial susceptibility profiles were determined using disk diffusion method according to the European Committee on Antimicrobial Susceptibility Testing (EUCAST) and CLSI guidelines. Carbapenem-resistant K. pneumoniae isolates were identified. PCR method and sequencing were used for detection of blaKPC and blaGES carbapenemase genes. Of the 181 K. pneumoniae isolates, 35 (19.3%) were found to be resistant to imipenem and 150 (82.9%) were identified as MDR strains. Among carbapenems, the most resistant rate 39 (21.5%) was seen against ertapenem using disk diffusion method. Of K. pneumoniae isolates 21 (11.6%) and 42 (23.2%) carried blaKPC and blaGES genes, respectively and 19(10.5%) carried both genes simultaneously. CONCLUSION: The data of current study revealed that the frequency of resistance to carbapenems and production of carbapenemase enzymes especially GES type was high among clinical isolates of K pneumoniae in Kashan, Iran.

An urban approach to planetary boundaries.

The achievement of global sustainable development goals subject to planetary boundaries will mostly be determined by cities as they drive cultures, economies, material use, and waste generation. Locally relevant, applied and quantitative methodologies are critical to capture the complexity of urban infrastructure systems, global inter-connections, and to monitor local and global progress toward sustainability. An urban monitoring (and communications) tool is presented here illustrating that a city-based approach to sustainable development is possible. Following efforts to define and quantify safe planetary boundaries in areas such as climate change, biosphere integrity, and freshwater use, this paper modifies the methodology to propose boundaries from a city's perspective. Socio-economic boundaries, or targets, largely derived from the Sustainable Development Goals are added to bio-physical boundaries. Issues such as data availability, city priorities, and ease of implementation are considered. The framework is trialed for Toronto, Shanghai, Sao Paulo, Mumbai, and Dakar, as well as aggregated for the world's larger cities. The methodology provides an important tool for cities to play a more fulsome and active role in global sustainable development.

Mercury contamination in some marine biota species from Khuzestan shore, Persian Gulf.

In this study, concentrations of mercury (Hg) were analyzed in some marine biota species (fish, shrimp, and crab) from Khuzestan shore, north part of the Persian Gulf. It was also our intention to evaluate potential risks to human health associated with seafood consumption. The results indicated that concentrations of Hg in the fish and crustacean were different among the species and tissues. Liver in fish and hepatopancreas in crustacean exhibited higher Hg concentration than the other tissues. The highest concentration of Hg was detected in Acanthopagrus latus liver (1.37 µg/g), followed by Labeo rohita (0.87 µg/g), Johnius belangerii (0.79 µg/g), and Barbus grypus (0.69 µg/g), respectively. Also the highest Hg concentrations were detected in shrimp species, Penaeus semisulcatus hepatopancreas (0.95 µg/g), followed by blue crab Portunus pelagicus (0.76 µg/g) and Metapenaues affinis (0.64 µg/g), respectively. The comparison indicated that benthic species were more contaminated than were other pelagic species. The results indicated that highest concentrations of Hg between different stations were detected in Musa estuary. The Hg concentration in all species were low than standards, expect in A. latus and P. semisulcatus collected from Musa estuary (S4). The variation in Hg levels among the species is likely to have resulted from metal bioavailability, changes in tissue composition, habitat,s and locations.

Heavy metals (Cd, Co, Cu, Ni, Pb, Fe, and Hg) content in four fish commonly consumed in Iran: risk assessment for the consumers.

In this study, concentrations of Cd, Co, Cu, Ni, Pb, Fe, and Hg were determined in commercially valuable fish from Khuzestan shore, northwest of the Persian Gulf. It was also our intention to evaluate potential risks to human health associated with seafood consumption. The liver and skin showed higher metal concentrations than the muscle. The results showed that heavy metal concentrations in different food habitats increase in the following order: benthic omnivorous fish < zooplanktivore fish < phytoplanktivore fish < piscivore fish. Also, the comparison indicated that benthic species (Euryglossa orientalis, Otolithes ruber) were more contaminated than pelagic species (Liza abu and Psettodes erumei). Therefore, the concentration of heavy metals in edible part of fish species did not exceed the permissible limits proposed by Food and Agriculture Organization (FAO) (1983), WHO (1996), Regional Organization for the Protection of the Marine Environment (ROPME) (1999), and FAD (2001) which are suitable for human consumption, except for Ni and Cd in E. orientalis and Pb in O. ruber.

Bioaccumulation of polychlorinated biphenyl (PCB), polycyclic aromatic hydrocarbon (PAH), mercury, methyl mercury, and arsenic in blue crab Portunus segnis from Persian Gulf.

Bioaccumulation of polychlorinated biphenyl (PCB), polycyclic aromatic hydrocarbon (PAH), mercury (Hg), methyl mercury (MMHg), and arsenic (As) in the hepatopancreas and muscle of blue swimming crab Portunus segnis from Bushehr shore, north Part of Persian Gulf, were investigated. In addition, the relationships between crab size (carapace width) and PCBs, PAH, Hg, MMHg, and As levels in tissues were investigated by linear regression analysis. There were significant correlation between pollutants levels and crab size which were positive. The pollutants' concentrations were highest in hepatopancreas whereas lowest in the muscle of all crab species. The mean concentrations were 0.51 ng g(-1)PCB 16, 0.64 ng g(-1) PCB 99, 1.2 µg g(-1) Hg, 0.81 µg g(-1) MMHg, and 0.14 µg g(-1) As. Also, mean concentrations of different PAHs were 0.31 ng g(-1) Acenaphthylene, 0.51 ng g(-1) Acenaphthene, and 0.71 ng g(-1) Anthracene. Comparison between male and female indicated that the average PCBs, PAH, Hg, MMHg, and As concentrations in tissues of male crab were found to be significantly higher than those found in the female crab.

Echocardiographic Assessment of Pulmonary Arteries Pulsatility Index in Fontan Circulation.

BACKGROUND: Late complications after Fontan procedure may be due to the absence of pump and pulsatile pulmonary blood flow in this type of palliation. Our aim was to quantify the degree of pulsation by echocardiographic method in patients with extracardiac total cavopulmonary connection (ECTCPC) in comparison with biventricular circulation and few cases of pulsatile Fontan. METHODS: In a case series study, pulsatility index (PI) derived by echocardiographic method were compared between 20 patients with ECTCPC, 6 patients with pulsatile Fontan and 18 normal individual aged 4 to 20 years old. All patients were in New York Heart Association class of I and there was no report of complication. RESULTS: In patients with ECTCPC pulmonary artery branches Doppler flow study showed lower peak and mean velocities compared to the pulsatile Fontan and normal groups. ECTCPC patients had PI of 0.59 ± 0.14 and 0.59 ± 0.09 for right and left pulmonary arteries (RPA and LPA) respectively. PI was higher in patients with preserved antegrade flow (RPA PI = 0.94 ± 0.26, LPA PI = 0.98 ± 0.27) and in normal individuals (RPA PI = 1.59 ± 0.12, LPA PI = 1.64 ± 0.17) for both branches (p = 0.000). CONCLUSION: Using a Doppler derived index for pulsatility, patients with ECTCPC had the least pulsation. The pulmonary artery flow pattern in patients with preserved antegrade flow showed higher pulsatility indices in both branches. Normal individuals had the greatest pulsatility index.

Mercury distribution in contaminated surface sediments from four estuaries, Khuzestan shore, north part of Persian Gulf.

The distribution of mercury in surface sediment from four estuaries along the Khuzestan shore, north part of Persian Gulf, was measured. The concentration of mercury varied among sampling stations (p < 0.05). The concentrations of mercury in all estuaries were from 0.01 to 2.16 µg g(-1). Relatively high mercury concentrations were observed in sediments from Musa estuary. The percentage of mercury associated with different fractions in the sediment from all stations were in the order of residual (70.4 %) > organic matter (16.6 %) > easily and exchangeable (2.2 %) > acid reduction (0.8 %). I geo values calculated for mercury (1.5) showed higher values in Musa estuary than in the other stations. The bioavailability of mercury in sediments could be controlled by physicochemical factors such as pH, oxidation and reduction potential, organic carbon content and cation exchange capacity.

Mercury accumulation in selected tissues of shrimp Penaeus merguiensis from Musa estuary, Persian Gulf: variations related to sex, size, and season.

The levels of mercury in tissues of Penaeus merguiensis from Musa estuary, northwest of the Persian Gulf, were investigated. This study assessed the relationship between mercury levels in hepatopancrea, gill, and muscle with sex, size, and season. The order of mercury concentrations in tissues of the shrimp P. merguiensis was as follows: hepatopancreas > gill > muscle. There was a positive correlation between mercury concentrations in shrimp species with sex and size of its food items. We expected to see higher mercury levels in tissues of female species because they are larger and can eat larger food items. Also, there was a positive correlation between mercury concentrations in shrimp species with its food source. Therefore, female species feed more on shrimp and plant and are contaminated with high levels of mercury. There was significant difference (p < 0.05) in mercury levels between different seasons; higher mercury levels were found in July (summer season).

The effect of size and sex on PCB and PAH concentrations in crab Portunus pelagicus.

Polychlorinated biphenyl and polycyclic aromatic hydrocarbon concentrations in the hepatopancreas of blue swimming crab (Portunus pelagicus) from the north Persian Gulf were measured. In addition, the relationships between crab size (carapace width) and polychlorinated biphenyl (PCB) and polycyclic aromatic hydrocarbon (PAH) levels in hepatopancreas were investigated by linear regression analysis. Among the PCBs, congeners 110 and 153 were the most frequent and abundant. The results showed that, except in a few cases, significant relationships between PCB and PAH levels and crab size were positive. Comparison between male and female indicated that the average PCB16, 44, 153, and acenaphthylene, acenaphthene, and anthracene concentrations in hepatopancreas of male crab were found to be significantly higher than those found in the female crab.

Bioaccumulation of trace mercury in trophic levels of benthic, benthopelagic, pelagic fish species, and sea birds from Arvand River, Iran.

In this study, concentration of mercury was determined in the trophic levels of benthic, benthopelagic, pelagic fish species, and river birds from Arvand River, located in the Khuzestan province in the lowlands of southwestern Iran at the head of the Persian Gulf. The order of mercury concentrations in tissues of the fish species was as follows: liver>gill>muscle and in tissues of the kingfisher species was as follows: feather>liver>kidney>muscle. Therefore, liver in fish and feather in kingfisher exhibited higher mercury concentration than the other tissues. There was a positive correlation between mercury concentrations in fish and kingfisher species with size of its food items. We expected to see higher mercury levels in tissues of female species because they are larger and can eat larger food items. The results of this study show that the highest mean mercury level were found in the kingfisher (Anas crecca), followed by benthic (Epinephelus diacanthus), benthopelagic (Chanos chanos), and pelagic fish (Strongylura strongylura). Mean value of mercury in fish species, S. strongylura were (0.61 µg g(-1) dry weight), C. chanos (0.45 µg g(-1) dry weight), E. diacanthus (0.87 µg g(-1) dry weight), and in kingfisher species A. crecca was (2.64 µg g(-1) dry weight). Significant correlation between mercury concentration in fish and kingfisher may be related to high variability of mercury in the fish.

The effect of primary producers of experimental aquatic food chains on mercury and PCB153 biomagnification.

The biomagnification of mercury and PCB153 was studied in experimental aquatic food chains involving three species of phytoplankton, one species of zooplankton and one species of fish. The phytoplankton species Ceratium furca, Ceratium tripos and Chaetoceros brevis were exposed to 0, 0.2, 0.5, 1.0 and 2.0 mg/l of Hg and 0, 0.5 and 2.0 mg/kg of PCB 153. Subsequently, each species was fed to the zooplankton Daphnia hyaline, which was then used as food for the fish Liza abu. The results indicated biomagnification of Hg and PCB153 in all three chains. Highest concentration of mercury was found in C. brevis and the highest concentration of PCB153 was observed in C. tripos. Accordingly, highest concentration of Hg and PCB 153 was found in D. hyaline and in the liver of L. abu belonging to food chains started from Chaetoceros brevis and Ceratium tripos respectively.

Distribution of metals in the tissues of benthic, Euryglossa orientalis and Cynoglossus arel., and bentho-pelagic, Johnius belangerii., fish from three estuaries, Persian Gulf.

Concentrations of Cd, Co, Cu, Ni, Pb, Fe and Zn were determined in the muscle, liver and gills of three commercial benthic and pelagic fish species (Johnius belangerii, Euryglossa orientalis and Cynoglossus arel) from three estuaries in the northwest Persian Gulf. Metals levels varied significantly depending on the tissues, species and locations. Generally, the results showed that liver accumulate higher concentrations of the metals in comparison to muscle and gills, except in few cases. Among the species, E. orientalis showed the highest levels of Co, Cu, Ni and Fe, while the highest concentrations of Pb and Zn were observed in C. arel. J. belangerii accumulated the highest level of Pb element.