Investigation of acute toxicity and the effect of cadmium chloride (CdCl2 . H2O) metal salt on behavior of the guppy (Poecilia reticulata)

In this study 96-h LC50 value of cadmium chloride (CdCl2 . H2O), a metal salt widely used in industry, was determined for the guppy (Poecilia reticulata, Pallas, 1859). The experiments were planned in four series of a total of 440 guppies employing the static test method of acute toxicity. 10 fish were placed in each replicate of each dose. The experiments were performed as four replicates, and behavioral changes in the guppy were determined for each cadmium chloride metal salt concentration. The data obtained were statistically evaluated by the use of EPA computer program based on Finney's Probit Analysis Method and a 96-h LC50 value for P. reticulata was found to be 30.4 mg/l in a static bioassay test system. This value was estimated to be 30.6 mg/l with Behrens-Karber's method. The two methods were in good agreement. 95% lower and upper confidence limits for the LC50 were 29.3 and 31.7 mg/l, respectively. The water temperature was kept between 21 and 23 degrees C. The behavioral changes observed in fish were, swimming in imbalanced manner, capsizing, attaching to the surface, difficulty in breathing and gathering around the ventilation filter.     

Investigation of acute toxicity of cadmium chloride (CdCl2 . H2O) metal salt and behavioral changes it causes on water frog (Rana ridibunda Pallas, 1771)

The 96-h LC(50) value of cadmium chloride (CdCl(2).H(2)O), a metal salt widely used in industry, was determined in the water frog (Rana ridibunda Pallas, 1771). The experiments were conducted in two series and a total of 140 frogs were used to determine acute toxicity. In addition, behavioral changes in the water frog were determined for each cadmium chloride concentration. Data obtained from the cadmium chloride investigation were evaluated by using the probit analysis statistical method and the 96 h LC(50) value for water frog was estimated to be 51.2 mg/l.     

Polymer Supported Calix[4]Arene Derivatives for the Extraction of Metals and Dichromate Anions

Three newly synthesized polymer supported calix[4]arene ionophores (7–9) were synthesized, and their ion binding properties toward selected alkali (Li⁺, Na⁺, K⁺, Cs⁺) and transition metal (Hg²⁺, Ni²⁺, Cu²⁺, Co²⁺, Cd²⁺, and Pb²⁺) cations were investigated. It has been observed that these ionophores are not selective toward a particular metal cation but show better ion binding property as compared to monomeric calixarene derivatives (2 and 6). Ionophore 6 and its supported polymer were also employed in dichromate anion extraction experiments. The polymeric ionophore (9) was found an effective extractant for dichromate anion even at pH 7.     

Comparative thermodynamic performance analysis of a cascade system for cooling and heating applications

In this study, a comparative thermodynamic performance analysis of cascade system (CCS) for cooling and heating applications is presented and compared for different refrigerant couples. The CCS consists of the low-temperature cycle (LTC) and high-temperature cycle (HTC). The CO₂ was used as working fluid in LTC, whereas the HFE 7000, R134a, R152a, R32, R1234yf, and R365mfc refrigerants were used in HTC. The heating and cooling coefficients of performance (COP_ht, COP_cl) and exergy efficiency of CCS are investigated parametrically according to various factors such as the evaporator, condenser, and reference temperatures. After thermodynamic analyses are completed, the COP_cl of CCS is obtained as 1.802, 1.806, 1.826, 1.769, 1.777, and 1.835 for CO₂-HFE7000, CO₂-R134a, CO₂-R152a, CO₂-R32, CO₂-R1234yf, and CO₂-365mfc refrigerant couples, respectively. Furthermore, the heat exchanger has the highest exergy destruction rate, whereas the expansion valves have the lowest of exergy destruction rate.     

Taxonomy of oxalotrophic <Emphasis Type="Italic">Methylobacterium</Emphasis> strains

Most of the oxalotrophic bacteria are facultative methylotrophs and play important ecological roles in soil fertility and cycling of elements. This study gives a detailed picture of the taxonomy and diversity of these bacteria and provides new information about the taxonomical variability within the genus Methylobacterium. Twelve mesophilic, pink-pigmented, and facultatively methylotrophic oxalate-oxidizing strains were included in this work that had been previously isolated from the soil and some plant tissues by the potassium oxalate enrichment method. The isolates were characterized using biochemical tests, cellular lipid profiles, spectral characteristics of carotenoid pigments, G+C content of the DNA, and 16S rDNA sequencing. The taxonomic similarities among the strains were analyzed using the simple matching (S _SM) and Jaccard (S _J) coefficients, and the UPGMA clustering algorithm. The phylogenetic position of the strains was inferred by the neighbor-joining method on the basis of the 16S rDNA sequences. All isolates were Gram-negative, facultatively methylotrophic, oxidase and catalase positive, and required no growth factors. Based on the results of numerical taxonomy, the strains formed four closely related clusters sharing ≥85% similarity. Analysis of the 16S rDNA sequences demonstrated that oxalotrophic, pink-pigmented, and facultatively methylotrophic strains could be identified as members of the genus Methylobacterium. Except for M. variabile and M. aquaticum, all of the Methylobacterium type strains tested had the ability of oxalate utilization. Our results indicate that the capability of oxalate utilization seems to be an uncommon trait and could be used as a valuable taxonomic criterion for differentiation of Methylobacterium species.     

Assessment of imidacloprid toxicity on reproductive organ system of adult male rats

In the current study it was aimed to investigate the toxicity of low doses of imidacloprid (IMI) on the reproductive organ systems of adult male rats. The treatment groups received 0.5 (IMI-0.5), 2 (IMI-2) or 8 mg IMI/kg body weight by oral gavage (IMI-8) for three months. The deterioration in sperm motility in IMI-8 group and epidydimal sperm concentration in IMI-2 and IMI-8 groups and abnormality in sperm morphology in IMI-8 were significant. The levels of testosterone (T) and GSH decreased significantly in group IMI-8 compared to the control group. Upon treatment with IMI, apoptotic index increased significantly only in germ cells of the seminiferous tubules of IMI-8 group when compared to control. Fragmentation was striking in the seminal DNA from the IMI-8 group, but it was much less obvious in the IMI-2 one. IMI exposure resulted in elevation of all fatty acids analyzed, but the increases were significant only in stearic, oleic, linoleic and arachidonic acids. The ratios of 20:4/20:3 and 20:4/18:2 were decreased and 16:1n-9/16:0 ratio was increased. In conclusion, the present animal experiments revealed that the treatment with IMI at NOAEL dose-levels caused deterioration in sperm parameters, decreased T level, increased apoptosis of germ cells, seminal DNA fragmentation, the depletion of antioxidants and change in disturbance of fatty acid composition. All these changes indicate the suppression of testicular function.     

A dendroecological study on Pinus nigra Arn. at different altitudes of northern slopes of Kazdaglari, Turkey

This study was carried out to investigate the relationship between tree ring widths of Pinus nigra in Kazdaglari having humid and very humid climatic conditions. Sixty two trees were cut from 24 sampled points from different altitudes in Kazdaglari to measure treering widths. To determine the responses to the climate, correlation coefficients between treering widths and climatic data were calculated during biological years from October of the previous year to September of the current year In lower altitudes, where climate type is humid, spring and summer precipitation affect the growth of tree rings, but they are not statistically limiting factors. In higher altitudes, this effect is weaker. As a result, we can conclude that the negative effects of the drought are still not clear on the Pinus nigra trees under humid and very humid climatic conditions and at the northern slopes in submediterranean mountainous regions in Turkey.     

Synthesis and Extraction Study of Calix[4]arene Dinitrile Derivatives Incorporated in a Polymeric Backbone with Bisphenol-A

Two new copolymers containing pendant calix[4]arene units with nitrile functionalities at their lower rim have been synthesized via nucleophilic substitution reactions involving 5,11,17,23-tetra-tert-butyl-25,27-bis(cyanomethoxy)-26,28-dihydroxy-calix[4]arene (3) or 25,27-bis(cyanometh oxy)-26,28-dihydroxy-calix[4]arene (4) with 1,5-dibromopentane and bisphenol-A. The phase transfer studies were performed by using liquid–liquid extraction procedures. It has been deduced from the observations that both copolymers show a good phase transfer affinity toward selected alkali, alkaline earth, and transition metal cations, unlike their precursor (3).     

Computational fluid dynamics assessment of damaging wind loads on the One Indiana Square tower

In this paper, we simulated damaging wind loads on the One Indiana Square tower in Indianapolis due to the storm of April 2nd 2006. We followed recommended practice guidelines for this urban wind modeling. First, a test case, Aerodynamics of Commonwealth Advisory Aeronautical Council (CAARC) building were modeled and simulated to compare with a publicly available experiment and other computational studies. Based on the modeling parameters in the CAARC study, then, as a clean building configuration, we modeled the One Indiana tower alone without surrounding buildings. Finally, the flow field around the tower including nearby downtown buildings were simulated. We used the Fluent flow analysis software tools. The domain was meshed using unstructured grids, the first boundary layer grid element being 10 cm (4 in.) and 15 cm (6 in.) in height from the tower and the ground for the CAARC building and the One Indiana tower, respectively. Two different wind directions of 260 \(^\circ \) and 280 \(^\circ \) at 137 km/h (85 mph) speed were considered to estimate wind loads on the One Indiana tower façades. Simulated pressure distributions on the tower and flow patterns over the downtown buildings were discussed to draw conclusions about the mechanism of extreme wind load that caused the damage. The simulations revealed that suction forces are almost twice higher hence more damaging at the corners of the west façades than straight wind. It was also seen in the simulation results that upstream building topology, specifically Chase, One America, and some low-rise towers, augmented the actual wind load unfavorably on the One Indiana Square tower. Although this study presents a specific case, the applicability of its findings are of more general interest. Similar wind events are common especially during storm seasons both in urban and suburban areas. In similar incidents, one can follow the same procedure to analyze their problems as certain modeling guidelines were followed in this study.