Dual-Wavelength Spectral Correction Method for Simultaneous Determination of V(IV) and V(V)

Abstract: Simultaneous determination of V(IV) and V(V) was performed when the calibration matrix was obtained using beta-corrected spectral data. The method is based on the reaction between V(IV) and V(V) and 4-(2-pyridylazo)-resorcinol (PAR) as a ligand at pH 6. Using β-correction technique true absorbance of chelate produced can be calculated because the quantity of absorbance, which has related to the fraction of reagent that reacted with metal ion and has been subtracted when reagent applied as reference by this correction has compensated. The parameters controlling behavior of the system were investigated and optimum conditions selected. Calibration model was constructed based on absorption spectra in the 540-600 nm range for 25 different mixtures of V(IV) and V(V) in the concentration ranges of 0.10-4.00 µgmL −1 of V(IV) and 0.10-5.00 µgmL −1 of V(V). Applying this method to the analysis of mixtures of V(IV) and V(V) in waste water and soil samples with total relative standard error of less than 4.3% validated the proposed method

Introducing a new method of retinoscopy for refraction of infants and young children: The �Mirza� tele lens retinoscopy

Purpose: This study aimed to evaluate the refractive error of the uncooperative infants and children with the new method of retinoscopy called the tele-lens (�Mirza�) retinoscopy. Methods: In the �Mirza� tele-lens retinoscopy, the examiner placed the trial lenses in 1/3 distance between the tested eye person and peephole of the retinoscope (22.2 cm far from the spectacle plane). First, the optical calculations were done to find the correction factors for this new method of retinoscopy. Second, the dry standard and �Mirza� tele-lens retinoscopy were performed in 78 eyes from 39 children aged 7�12 years with good cooperation and next, the procedure was repeated using cyclopentolate drops and then the results of the two methods were compared, and at the end, the dry �Mirza� tele-lens retinoscopy was done in the 60 eyes of 31 uncooperative infants with a mean age of 21.85 ± 8.79 months for evaluating the feasibility of the �Mirza� tele-lens retinoscopy procedure. The intraclass correlation coefficient (ICC) and Bland�Altman plot for assessment of agreement between the findings of two retinoscopic methods in dry and cyclo conditions were used. Results: The comparison between the dry standard and �Mirza� tele-lens retinoscopic results with means of 1.39 ± 1.43 and1.36 ± 1.39, respectively were not statistically significant (p > 0.05). Besides, comparing the mean cycloplegic results of two methods (standard vs. �Mirza� tele-lens), the difference was not statistically significant (2.37 ± 1.44 vs. 2.41 ± 1.37) (p > 0.05). Moreover, Two-way repeated measures ANOVA revealed no significant retinoscopy method � use of drops interaction (P = 0.103) in comparing two methods of the standard and �Mirza� tele-lens retinoscopy. ICC results indicated high agreement between two methods in both dry (ICC = 0.993) and cyclo (ICC = 0.989) conditions. Conclusions: The �Mirza� tele-lens retinoscopy method can be performed with satisfactory results in infants and children who do not cooperate for the standard procedure of measuring the refractive errors. © 2020 Spanish General Council of Optometr

Reduced haemodynamic response in the ageing visual cortex measured by absolute fNIRS

The effect of healthy ageing on visual cortical activation is still to be fully explored. This study aimed to elucidate whether the haemodynamic response (HDR) of the visual cortex altered as a result of ageing. Visually normal (healthy) participants were presented with a simple visual stimulus (reversing checkerboard). Full optometric screening was implemented to identify two age groups: younger adults (n = 12, mean age 21) and older adults (n = 13, mean age 71). Frequency-domain Multi-distance (FD-MD) functional Near-Infrared Spectroscopy (fNIRS) was used to measure absolute changes in oxygenated [HbO] and deoxygenated [HbR] haemoglobin concentrations in the occipital cortices. Utilising a slow event-related design, subjects viewed a full field reversing checkerboard with contrast and check size manipulations (15 and 30 minutes of arc, 50% and 100% contrast). Both groups showed the characteristic response of increased [HbO] and decreased [HbR] during stimulus presentation. However, older adults produced a more varied HDR and often had comparable levels of [HbO] and [HbR] during both stimulus presentation and baseline resting state. Younger adults had significantly greater concentrations of both [HbO] and [HbR] in every investigation regardless of the type of stimulus displayed (p<0.05). The average variance associated with this age-related effect for [HbO] was 88% and [HbR] 91%. Passive viewing of a visual stimulus, without any cognitive input, showed a marked age-related decline in the cortical HDR. Moreover, regardless of stimulus parameters such as check size, the HDR was characterised by age. In concurrence with present neuroimaging literature, we conclude that the visual HDR decreases as healthy ageing proceeds

Studying native fishes in Hamadan province

Studying native fishes of Hamadan province have been done in 159 stations from 51 important water resources (wetland, reservoir, spring, river and qanat) using with electric tool, cast-net, seine and gill-net gears from July 2010 to Oct. 2011 and the main aims were species identifying and determining their distribution and abundance in the studied area. In the study, 33411 fish specimens are caught in 257 times of sampling and selected randomly about 8500 individual and laboratory works showed the fish belong to 37 species from 7 families. Cyprinidae with 25, Nemacheilidae with 6 and Sisoridae with 2 species had the most diversity and Cobitidae, Poeciliidae, Salmonidae and Mastacembelidae had only a representative. 31 fish species were native or endemic and 6 species were alien. Fish species existed in all rivers of Ghezelozan and Sirvan sub-basins but there were not any fish in 10 rivers of Ghara-Chai sub-basin and in 6 rivers of Gamasiab sub-basin, too. Also, it was observe 1-3 fish species in 15 rivers, 4-6 fish species in 10 rivers, 7-10 fish species in 5 rivers and more than 10 fish species in 4 main water resources and Gamasiab sub-basin with 32 fish species was the most diversified and Ghezelozan sub-basin with 2 fish species was the least diversified. There were any species to 4 (mostly 1 or 2) fish species in studied qanats in Ghara-Chai and Gamasiab rivers sub-basins. 23 fish species existed in a subbasin, 12 species in 2 sub-basin, Capoeta capoeta in 3 sub-basin and Squalius cephalus in all sub-basins of studied area. Alburnoides nicolausi,Capoeta aculeata and Alburnus mossulensis have had the most frequency. Studying fish abundance showed Oxynoemacheilus argyrogramma with 17.8%, Garra rufa with 12.3%, A. mossulensis with 12.1% and C. aculeata with 10.2 % of total number of caught fish specimens are dominant. S. cephalus, Capoeta damascina, C. aculeata, C. trutta, Chondrostoma regium and A. mossulensis have had sport fishing value but Acanthobrama marmid, Oxynoemacheilus kiabii, Oxynoemacheilus kermanshahensis, Turcinoemacheilus kosswigi, Alburnus caeruleus and Mastacembelus mastacembelus have biodiversity value for being endemic or having limited habitats in Iran

Quantitative assessment of biopllution caused by Mnemiopsis leidyi on ecological community structure in the southern part of the Caspian Sea

After the arrival of the invasive spexies (Mnemiopsis leidyi) in the ecosystem of Caspian Sea in 1999, It had notable impacts. In this study, we,re assessing impacts of quantitative M. leidyi as a biopllutant on zooplankton community in the southern part of the Caspian Sea during 2001-2010 period. It becomes clear that Abundance and Distribution Range (ADR) of M.leidyi during 2001-2009 was in class E(occurrence in high numbers in all localities) and in year 2010 was in class D(occurrence in moderate numbers in all localities). from 2001- 2009, ADR in Summer season was in class E, but in summer 2010, relatinve biomass of M.leidyi has decreased and ADR was evaluated as D. During the fall seasons of 2001 -2010, only in fall of 2003 and 2010, the ADR was C(occurrence in low numbers in all localities) and D respectively and in other years, the ADR was in class E. In winter season relative biomass of M.leidyi decreased and only in winter of 2001 relative biomass was high and the highest ADR (class E). In winter 2003 and 2004, ADR was in class D. The biomass of M.leidyi was found to be zero in winter 2008. From winter of 2009-2010,ADR, were assessed B and A respectively. In the spring, ADR was evaluated A and D. Considering the obtained results, the yesr 2001, which the relative niomass was more than 90 percent, could be considered as the expantion phase and the following years (2002-2010) with regard to decrease of relative biomass as the adjustment phase. With regards to the loss of the keystone species (Eurytemora sP.) and some other native species, our evalution showed that the impact of M.leidyi on structure of zooplankton community was assessed as massive (C4).During summer and fall seasons that biomass of M.leidyi was higher than 50%, only A.tonsa exist, but during spring and winter seasons that biomass of M.leidyi was decreased and more species have a chance to exist

The survey on aquaculture capacity of Ghar-Khatlo dam reservoir in Zanjan province

Qhar-khetlu dam reservoir is in the central part of Ijrud city of Zanjan province with a reservoir volume of 500000 and a water volume of 900000 cubic meters, covering an area of 6 hectares and containing 3500 hectares of the watershed in order to control seasonal floods, drinking water in the village, strengthening the aquifers of the area and As a water supply in the dry seasons, 120 hectares of agricultural land was planted for irrigation.Study of this water source with the aim of measuring biological and non-biological factors, determination of aquaculture production and Fish release capacity and fishing capacity for optimal use of fishery management in Zanjan province was done in 2006.The results of hydrochemical analysis of the water of Qharkhetlu dam reservoir showed that the minimum and maximum temperature of water ranged from 4.5 to 26 ° C, the pH of the water was 4.7 to 8.8, the dissolved oxygen was 7.7 to 12.2 mg, the total water hardness fluctuation was 154 194 mg/L and electrical conductivity of 272 to 390 micrometers per square centimeter, the water transparency was 25 to 380 centimeters.In this study, six phytoplankton classes with 31 genera and 3 classes of zooplankton with 14 genera were obtained. The abundance of phytoplanktons was counted from 150,000 to 206,000 per liter, and the average chlorophyll a, 1.10 micrograms, was estimated. The frequency of zooplanktons were 32 to 132 per liter, as well as the mean of 544 per square meter of macrobenthos.By comparing of the physical, chemical and biological factors and also the results of previous studies of this water source, the conditions for the introduction of warm water and cold water fishes including silver carp, big head carp, rainbow trout out and native fishes including species of Barbus and Capoeta genera are suitable. Estimation of Qhar-khetlu dam reservoir production is 80 kg/ha and its production capacity is 484 kg per year

Survey of diversity, distribution, abundance and biomass of macrobenthic fauna in the southern Caspian Sea

The Sampling of macrobenthic communities in southeastern Caspian Sea, Iranian coast, were investigated seasonally from April to March 2012. Sampling was carried out at 8 transect as named Astara, Badar Anzali, Sefied rood, Tonekaboon, Nooshahr, Babolsar, Amirabad, Gomishan.In each transect were choice 8 stations at 5m, 10m, 20m, 50m, 100m depths respectively. Samples were taken in triplet with a 0.1m^² van Veen grab.Totally 28 macrofaunal species belonging to 10 families were identified as gamaridae (9species), corophidae (3species),psudocumidae(8 species), amphartidae (2species), balanidae, chironomidae, cardidae scorbicolaridae, nereidae, sponoidae, each one species. Polychaetes were dominated, representing 72.5% of the whole fauna while while (equal 62.4% of total abundance and 5/1%biomass) were belong to Streblospio spp. from Spionidae family. Cerastoderma lamarcki belong to bivavia consist of 2/3% total macobethos abundance and 73% biomass. Total abundance of macrobenthos of middle area were higher than east and west area in southern Caspian Sea. Average benthic population density (no/m^2) with (SE) was 4581(444 ). The benthic biomass (mg/m^2) with an overall mean of 12. 125(02). Spatial and temporal variations of benthos. In the present study showed, maximum abundance Macrobenthos 17855(5543) no/m^2) were recorded in 20 meter depths at Nooshahr trancect , while minimum 841(109 )in 10 meter depths at Amirabad trancect p<0.05. Maximum biomass 135.10(126) g/m^2 were obtained at 10m depths in Astara minimum 0.51(0.4) ) g/m^2 at 5m depths in Nooshahr transect . maximum were obtained in winter and minimum in summer Number of species varied 3 to 18 , Generally, minimum species diversity were obtained at 20 m depth in Tonekabon transects and the maximum value was observed at 100 m depth of sefeidrood variations physicochemical factors were between salinity 12.5to12.9ppt ,temperature 8-19˚c and PH 8.1 dissolve oxygen 69-101mg/li. Total secondary production calculated, according ,104/996g AFDW/m^2/yr.Maximum were recorded in 10meter depth (30/381AFDW/m^2/yr) and minimum at 50 meter depth(11/007g AFDW/m^2/yr) respectively. Average total organic matter were 3/18 percent in sample periods. Percent of total organic matter (TOM) were low in 5 and 10 m depths and increased toward offshore depths. TOM percent was 1/67(0.11 ) at 5 m depth and increased to 4/38(0.13 )in 100 m depth. Average total silt &clay were 68/63(2.97) percent in sample periods. Positive significant relation was between silt &clay and total organic matter. Macrobenthos community reduce in high silt clay and high sandy contents. Due to increase of streptolosbio.spp, monitoring program for understanding effect of this organism on ecosystem and on fish feeding is necessary

A comparison of methods to assess the antimicrobial activity of nanoparticle combinations on bacterial cells

Copyright: © 2018 Bankier et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.BACKGROUND: Bacterial cell quantification after exposure to antimicrobial compounds varies widely throughout industry and healthcare. Numerous methods are employed to quantify these antimicrobial effects. With increasing demand for new preventative methods for disease control, we aimed to compare and assess common analytical methods used to determine antimicrobial effects of novel nanoparticle combinations on two different pathogens. METHODS: Plate counts of total viable cells, flow cytometry (LIVE/DEAD BacLight viability assay) and qPCR (viability qPCR) were used to assess the antimicrobial activity of engineered nanoparticle combinations (NPCs) on Gram-positive (Staphylococcus aureus) and Gram-negative (Pseudomonas aeruginosa) bacteria at different concentrations (0.05, 0.10 and 0.25 w/v%). Results were analysed using linear models to assess the effectiveness of different treatments. RESULTS: Strong antimicrobial effects of the three NPCs (AMNP0-2) on both pathogens could be quantified using the plate count method and flow cytometry. The plate count method showed a high log reduction (>8-log) for bacteria exposed to high NPC concentrations. We found similar antimicrobial results using the flow cytometry live/dead assay. Viability qPCR analysis of antimicrobial activity could not be quantified due to interference of NPCs with qPCR amplification. CONCLUSION: Flow cytometry was determined to be the best method to measure antimicrobial activity of the novel NPCs due to high-throughput, rapid and quantifiable results.Peer reviewe

The survey of Khandaghloo dam reservoir of Mahneshan city of Zanjan province

Reservoirs are one of the most constructions for control and water supply for different usage that could have various social an economical effects. The Khandaghloo dam reservoir with area of 100 ha located in Mahneshan city of Zanjan province and related to Parichay river watershed. Khandaghloo reservoir is valuable water body that the aim of its establishment was supply of water for agriculture farms. The reservoir has been studied for responsible and sustainable fisheries exploitation proposes. Results showed that the reservoir categorizes as eutroph to super eutroph based on different indices.Also phosphorous is limiting factor of the water body.Totally 42 genera from 6 phyla including green-blue algae cyanophyta, diatoms (Bacillariophyta), green algae, chlorophyta, euglenophyta, pyrrophyta and xanthophyta has been identified and cyanophyta was the dominant group that comprise 74.3 % of phytoplankton population. The zooplankton of the reservoir comprised 4 phyla and 20 genera. 1 genera of the protozoa and rhizopoda, 1 genra of the ciliophora ,15 genera of rotatoria, 2 genera of cladocera has been identified in zooplankton communities. Tubificidae and chironomidae has been identified in all months of the survey. The mean total length of crayfish was 130.5±20.5 mm ( 636) and mean weight was measured as 69.4±34.1 g with maximum and minimum weight of 1.9 and 207.2 g respectively .Total biomass of crayfish in Khandaghloo reservoir estimated as 3.4 tones with a range of 1.1–5.7 tones. But it is recommended not to harvest for at least two year due to high mortality of the populations.The fishes of the reservoir comprised common carp Chinese carp (silver carp, big head and grass carp) (released), Caspian kutum (accidentally released by fishery sector) and some endemic species as Siamahii. The catch of the reservoir fluctuated between 8 to 26 tones during 2000-2010.The fish production of Khandaghloo reservoir ranged from 167 to 324 kg/ha based on different methods that by consideration of 100 ha area of the reservoir, the total production of fish fluctuated between 16.7 to 32.4 tones. The fingerling restocking of Chinese carp in Khandaghloo reservoir with density of 1500 fingerling/ha recommended as 68% of phytoplanktonivorous fish (silver carp) ,12% zooplanktonivorous fish (big head), 6.6% of Crass carp and 10% of benthophagous fish (common carp)