mM Of Cl Research Articles

Efficient 1O2 production from H2O2 over lattice distortion controlled spinel ferrites

Iron-based materials are difficult to produce single oxygen (1O2) efficiently from H2O2. Herein, we demonstrate that 1O2 production from H2O2 can be manipulated by regulating the lattice distortion degrees of spinel ferrite through controlling the contents of Co and Ni in Co1−xNixFe2O4. Typically, NiFe2O4, which owns the lowest lattice distortion degree, can produce 1O2 as the dominated reactive oxygen species with·O2- as the intermediate. Due to the production of 1O2, the NiFe2O4/H2O2 system removes bisphenol A (BPA) completely within 180 min but removes only ∼ 4% of benzoic acid. In addition, the system demonstrates significant resistance to water matrix interference, as 50 mM of Cl-, NO3-, H2PO4-, and humic acid inhibited the BPA degradation by only ∼0%, ∼2%, ∼40%, and ∼3%, respectively. Our work may shed light for regulating the formation of 1O2 from H2O2 through the rational design of iron-based catalysts for Fenton-like reactions.

Rapid detection of urine chloride enabled by ion exchange in hydrophilic lead halide perovskite nanocrystals.

The rapid and precise detection of chloride ions in biosystems is of great importance for clinical diagnosis. In this work, hydrophilic CsPbBr3 perovskite nanocrystals (PNCs) with a high photoluminescence (PL) quantum yield (QY) of 59% (0.5 g L-1) are successfully achieved through the passivation of micellar glycyrrhizic acid (GA), which enables good dispersion of PNCs in ethanol. Due to the ionic nature and halogen-dominated band edge, PNCs exhibit fast ion-exchange and halogen-dependent optical properties. As a result, colloidal GA-capped PNC ethanol solution shows a continuous PL shift once aqueous Cl- with different concentrations is added. This fluorescence sensor shows a wide linear detection range (2-200 mM) of Cl-, short response time (∼1 s), and low limit of detection (1.82 mM). Because of the encapsulation of GA, good water and pH stability, and anti-interference performance are observed for the GA-capped PNC-based fluorescence sensor. Our findings provide an insight into the biosensor applications of hydrophilic PNCs.

Isomorphic substitution of goethite by cobalt: Effects on the pathway and performance of peroxymonosulfate activation

Isomorphic substitution of Goethite (α-FeOOH) by metal elements with similar radii can greatly alter its physicochemical properties. Herein, a cobalt-substituted α-FeOOH (FeCox) was synthesized by simple coprecipitation on the atomic scale. The effect on the activation of peroxymonosulfate (PMS) was explored using tetracycline (TC) as a model pollutant. Compared with the α-FeOOH, the performance of FeCo10 on PMS activation was greatly enhanced, and 95.4 % of TC was removed within 10 min. Cobalt substitution significantly decreased the metal ion leaching of the catalyst, and the iron and cobalt leaching of FeCo10 was only 4.023 and 33.614 μg/L. Co substitution altered the activation pathway of α-FeOOH for PMS. Electron paramagnetic resonance (EPR) and quenching experiments indicated that singlet oxygen (1O2) was the dominant reactive oxygen species (ROS) in the reaction system. The activation of PMS was achieved by the process that PMS was first complexed with hydroxyls (–OH) on the surface of FeCo10, after which Fe and Co species in FeCo10 broke the peroxide bond. The reaction system could operate efficiently under different concentrations (2–250 mM) of Cl-, HCO3-, SO42- and NO3-. The excellent catalytic performance of FeCo10 was due to the structural defects caused by the introduction of Co, which significantly increased the –OH sites and electron transmission capacity of the catalyst. This work has proved that isomorphic substitution was an effective strategy for improving the PMS activation performance of α-FeOOH.

Effect of Potential and Chlorides on Photoelectrochemical Removal of Diethyl Phthalate from Water

Removal of persistent pollutants from water by photoelectrocatalysis has emerged as a promising powerful process. Applied potential plays a key role in the photocatalytic activity of the semi-conductor as well as the possible presence of chloride ions in the solution. This work aims to investigate these effects on the photoelectrocatalytic oxidation of diethyl phthalate (DEP) by using TiO2 nanotubular anodes under solar light irradiation. PEC tests were performed at constant potentials under different concentration of NaCl. The process is able to remove DEP following a pseudo-first order kinetics: values of kapp of 1.25 × 10−3 min−1 and 1.56 × 10−4 min−1 have been obtained at applied potentials of 1.8 and 0.2 V, respectively. Results showed that, depending on the applied potential, the presence of chloride ions in the solution affects the degradation rate resulting in a negative effect: the presence of 500 mM of Cl− reduces the value of kapp by 50 and 80% at 0.2 and 1.8 V respectively.

The Coupling Use of Weak Magnetic Field and Fe0/H2O2 Process for Bisphenol a Abatement: Influence of Reaction Conditions and Mechanisms

The coupling use of the heterogeneous Fenton-like process (zero-valent iron (Fe0)/H2O2) and weak magnetic field (MWF) for bisphenol A (BPA) abatement was systematically investigated in this study. Though both the Fe0/H2O2 and WMF-Fe0/H2O2 processes are sensitive to pH, WMF remarkably enhanced BPA removal under the pH range of 3.0–6.0 by 0.5–9.5 times. The characterization of Fe0 confirmed the role of WMF in promoting the corrosion of Fe0. Radicals, rather than Fe intermediates, were responsible for BPA degradation. Due to the presence of Cl– as the background ions and its reactivity towards HO•, reactive chlorine species (RCS, i.e., Cl• and Cl2•−) were produced and considerably contributed to BPA degradation. In addition, ~37% and 54% of degraded BPA was ascribed to RCS in the presence of 2 and 100 mM of Cl−, respectively. However, 1.9 mg/L of ClO3− was detected in the presence of 2 mM of Cl− in the WMF- Fe0/H2O2 process. HCO3− could diminish ClO3− generation significantly through transforming RCS. The concentration of ClO3− decreased by 74% and 82% with dosing 1 and 10 mM HCO3−, respectively. The results of this study suggest that the WMF-Fe0/H2O2 process is a promising approach for BPA removal.

Degradation of benzothiazole pollutant by sulfate radical-based advanced oxidation process

ABSTRACT Benzothiazole (BTH) is an aromatic heterocyclic compound with wide industrial applications. In view of its toxicity and wide environmental presence, previous efforts have been made to decompose BTH via different degradation pathways. However, due to its recalcitrant nature, conventional biological treatment methods cannot completely degrade BTH in the wastewater. In this study, sulfate radical-based advanced oxidation process (AOP) technique has been adopted to degrade BTH in aqueous phase. Persulfate (PS) was employed as radical promotor to generate sulfate radical via heat activation. Degradation of BTH by thermally activated persulfate via AOP has been experimentally evaluated in a systematic manner. Laboratory efforts have been made to examine the impact of a number of physiochemical parameters including the type of oxidants, reaction temperature, initial concentrations of PS and BTH, solution pH, and the presence of anionic species. It shows that a higher BTH degradation rate can be achieved by lowering BTH initial concentration or increasing PS concentration. Increasing solution pH or the presence of 10 mM of Cl−, Br−, , or species can decrease BTH degradation rate. Furthermore, the primary radical(s) responsible for BTH degradation have been identified as sulfate radical at an acidic aqueous condition, and hydroxyl radical and sulfate radical combined at a basic condition. This study provides the necessary theoretical and technical foundations for BTH degradation via sulfate radical-based AOP technique. The conclusions from this study can substantially promote the field application of AOP, especially sulfate radical-based AOP technique, for BTH degradation in wastewater treatment process.

Functions of MnOx in NaCl Aqueous Solution for Artificial Photosynthesis.

SummaryPhotoelectrochemical water splitting has been intensively investigated as artificial photosynthesis technology to convert solar energy into chemical energy. The use of seawater and salted water has advantages for minimum environmental burden; however, the oxidation of Cl− ion to hypochlorous acid (HClO), which has toxicity and heavy corrosiveness, should occur at the anode, along with the oxygen evolution. Here, O2 and HClO production in aqueous solution containing Cl− on photoanodes modified with various metal oxides was investigated. The modification of MnOx resulted in the promotion of the O2 evolution reaction (OER) specifically without HClO production over a wide range of conditions. The results will contribute not only to the practical application of artificial photosynthesis using salted water but also to the elucidation of substantial function of manganese as the element for OER center in natural photosynthesis.

Effects of the formation of reactive chlorine species on oxidation process using persulfate and nano zero-valent iron

The chloride ion (Cl−) is a matrix ion that plays crucial roles in radical-based oxidation processes used to treat brackish or saline water. Here, the effects of the formation of reactive chlorine species on the performance of and reaction mechanisms involved in persulfate/nano zero-valent iron process were evaluated by investigating the reaction kinetics and performing reactive species scavenging tests. The phenol oxidation rate increased markedly in the early reaction stage in the presence of 25–200 mM of Cl−. This was because excess sulfate radicals (SO4−) reacted with Cl− to produce short-lived reactive chlorine species such as Cl and Cl2− rather than being scavenged by Fe2+ or other SO4−. The reactive chlorine species caused OH to form through radical propagation reactions. The total numbers of reactive species involved in phenol oxidation were higher at brackish to weakly saline Cl− concentrations than at lower and higher Cl− concentrations. At high Cl− concentrations (>400 mM), the phenol oxidation rate decreased because most of the SO4− reacted with Cl− to give large amounts of weaker oxidants such as Cl2− and HOCl. Acceleration of Fe corrosion by Cl− negligibly affected the persulfate/nano zero-valent iron oxidation process.

Morphometric Relationships of the Global Invader Callinectes sapidus Rathbun, 1896 (Decapoda, Brachyura, Portunidae) from Papapouli Lagoon, NW Aegean Sea, Greece. with Notes on Its Ecological Preferences

Callinectes sapidus is native to the Atlantic coasts of the Americas. In the Mediterranean, it appeared around 1949 and though that it is established in East Mediterranean waters, relevant studies are limited. The aim of the present study is to report quantitative and qualitative data on the blue crab’s biology and ecology in its non-native range, that are indispensable for management purposes. Papapouli Lagoon is in Thermaikos Gulf and is ecologically impacted by the blue crabs. Fyke nets with a 20 mm mesh opening were soaked for 12 to 14 h during each survey. Abiotic environmental parameters were obtained. The length–weight relationships were expressed by the equation W = aLb. The species’ ecological preferences at Papapouli Lagoon were assessed with PERMANOVA analysis, using the abiotic parameters as factors. Student’s t-tests were used to assess the differences between sexes. The sex ratio of the blue crab’s population was assessed by a Chi-square (χ2) analysis. The sex ratio was found to be 1.28:1, in favour of males. The most dominant group size of male blue crabs was the 61–70 mm of CL and 130–139 mm of CW. Also, the dominant size group of female blue crabs was 60–69 mm of CL and 120–129 mm CW. The maximum abundance of blue crabs was recorded at a salinity range from 24‰ to 25‰ and the water temperature range was from 26 to 28 °C.

Degradation of benzotriazole by sulfate radical-based advanced oxidation process

ABSTRACT Benzotriazole (BTA) is a recalcitrant contaminant that is widely distributed in aquatic environments. This study explored the effectiveness of sulfate radical-based advanced oxidation process in degrading BTA (SR-AOP). The sulfate radical was generated by heat activation of persulfate (PS). Our results show alkaline pH promoted the BTA degradation. The solution pH also affected the speciation of total radicals. Sulfate radical () predominated at acidic pH while hydroxyl radical (HO•) predominated at basic pH. High temperature, high PS concentration and low BTA concentration promoted the BTA degradation. Influence of water matrix constituents on the reaction kinetics was assessed. We found that ≤10 mM of Cl− promoted the reaction, but 100 mM Cl− inhibited it. was similar to Cl−. Br− and inhibited the reaction while did not affect the reaction. of ≤10 mM did not affect the reaction, but 100 mM of inhibited it. Eleven degradation intermediates were identified using ultra-high solution Orbitrap mass spectrometry. Based on the intermediates identified, possible reaction pathways were proposed. Overall, SR-AOP can effectively mineralize BTA, but water matrix constituents greatly influenced the reaction kinetics and thus should be carefully considered for its practical application. Abbreviations: BTA, benzotriazole; PS, persulfate; PMS, peroxymonosulfate; SPC, sodium percarbonate; AOP, advanced oxidation process; PS-AOP, persulfate-based advanced oxidation process; SR-AOP, sulfate radical-based advanced oxidation process; TAP, thermally activated persulfate; TOC, total organic carbon; TBA, tert-butyl alcohol

Population structure of Macrobrachium amazonicum (Heller, 1862) (Decapoda: Palaemonidae) in Miranda Hydroelectric Plant Reservoir, Araguari river, Minas Gerais, Brazil

Abstract Aim The present study aimed to analyze a M. amazonicum population structure in a reservoir of the “Triângulo Mineiro”, Brazil. Methods Monthly surveys were carried out from April/2012 to May/2013 at the Miranda Hydroelectric Plant Reservoir located in Araguari river, state of Minas Gerais. A sampling section of 100 m long, 5 m wide and depth not exceeding 1 m was defined on the banks of the reservoir. Sampling consisted on two persons quickly passing a 2 mm sieves in partially submerged marginal vegetation, for one hour. The sampled specimens were identified, sexed and measured. Results A total of 2,584 specimens were analyzed, of which 64.62% were females (3.93% ovigerous, 5.94% non-ovigerous and 54.75% juveniles), 29.16% males (21.41% adults and 7.76% juveniles) and 6.22% juveniles of undetermined sex. The sex ratio (1:2.21) indicated a clear deviation for females, for the whole sampling period, monthly and for each size class. Males had an average carapace length (CL = 4.50 ± 0.71 mm) significantly lower than females (CL = 4.64 ± 1.47 mm) and the size frequency distribution revealed a unimodal pattern, with peaks occurring in 4.0 - 4.9 mm size class for males and in 3.0 - 3.9 mm size class for females. The relation between total and carapace length was significant, indicating a negative allometric growth. No males’ morphotypes were found. The population presented a continuous reproduction with a gradual increase between April and June/2012. Female sexual maturity was determined for 6.3 mm of CL, while for males was estimated for 4.0 mm. Conclusion The Miranda reservoir population had a body size variation similar to the continental populations of Pantanal. The sexual dimorphism observed may be related to the absence of male morphotypes and to the “pure search” reproduction strategy. The deviated sex ratio for females may increase the chance of fertilization and the reproductive success. The presence of juveniles and ovigerous females throughout the year indicates a continuous reproduction pattern of the population.

Modelling study on the effects of chloride on the degradation of bezafibrate and carbamazepine in sulfate radical-based advanced oxidation processes: Conversion of reactive radicals

The degradation rates of pharmaceuticals contaminants (such as bezafibrate and carbamazepine) in the UV/S2O82− process at different Cl− concentrations (0.01, 0.1, 1.0, 10, and 100 mM) and pH values (3, 5, 7, 9 and 11) were investigated in this study. The degradation rate of bezafibrate showed an upward trend before the critical point (Cl− = 1.0 mM), the maximum enhancement was 51%, then the degradation rate decreased. The degradation rate of carbamazepine increased continuously, and the maximum enhancement was 66% when the Cl− concentration was 100 mM. The degradation rate of bezafibrate showed the maximum value at pH = 7 while the most rapid degradation rate of carbamazepine was observed at pH = 3. To explain these interesting results, a kinetic model was used to investigate the conversion of reactive radicals (such as SO4−, OH, Cl, and Cl2−) at different Cl− concentrations and pH values. Simulation results showed that low concentrations (<1.0 mM) of Cl− transformed SO4− into OH and Cl. With the further increased concentration of Cl− from 1.0 mM to 100 mM, OH and Cl can be converted into Cl2−. Furthermore, Cl2− was the dominant reactive species when pH < 7, whereas OH dominated when pH > 7. Few organic chlorinated products were observed in the UV/S2O82−/Cl− process, indicating that the reactions between bezafibrate/carbamazepine and the reactive chlorine radicals Cl/Cl2− occurred mainly through electron transfer and H-extraction, whereas the substitution reaction leading to the formation of organic chlorinated products was not dominated. This study positively demonstrated the absence of chlorinated product formation during SR-AOPs application.

Natural Fe-bearing manganese ore facilitating bioelectro-activation of peroxymonosulfate for bisphenol A oxidation

The natural Fe-bearing manganese ore (FMO) and bioelectricity supplied by a single-chamber microbial fuel cell (MFC) were employed to construct the peroxymonosulfate (PMS) activation system (FMO/MFC/PMS) for the degradation of bisphenol A (BPA). The FMO was characterized by X-ray fluorescence (XRF), X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, Brunauer-Emmett-Teller (BET), field-emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM). The results show that ε-MnO2 and α-Fe2O3 were the active components of the natural FMO and they could greatly facilitate the bioelectro-activation of PMS for the oxidation of BPA. When FMO dosage, PMS concentration and current density were set as 0.5 g L−1, 10 mM and 100 mA m−2, respectively, 97.8% of BPA degradation could be achieved at natural pH of BPA solution after 80 min reaction and about 80% of TOC could be removed when the reaction time was prolonged to 120 min. Based on the electron paramagnetic resonance result, scavenging tests, fluorescence spectra experiment and X-ray photoelectron spectroscopy analysis, both radical oxidation (sulfate and hydroxyl radical) and non-radical reactions (such as singlet oxygen and direct electron transfer) were considered to be responsible for BPA removal. The FMO exhibited good stability and could be recycled at least 3 runs without any additional special treatment. 10 mM of Cl− and HCO3− could suppress the degradation of BPA while 10 mM of NO3− showed negligible effects on BPA removal. The FMO/MFC/PMS process could be applied in natural water without the decrease of BPA removal.

Effects of Salt Stress on Photosynthetic Pigments and Activity of Ribulose-1,5-bisphosphate Carboxylase/Oxygenase in Kalidium foliatum

The effects of NaCl and Na2SO4 on photosynthetic pigments, malondialdehyde (MDA), Rubisco activity and superoxide dismutase (SOD) activity were investigated in Kalidium foliatum (Pall.) Moq., which is distributed in the saline soil of Hetao irrigation area in Inner Mongolia China. The K. foliatum plants were treated with NaCl (0, 100, 250, 400 and 500 mM), Na2SO4 (0, 100, 250, 400 and 500 mM) and NaCl + Na2SO4 (1: 1, v/v) (0, 100, 250, 400 and 500 mM of Na+ concentration, 0, 50, 125, 200 and 250 mM of Cl– and SO 4 2– concentration) for 10 days. Content of chlorophylls and carotenoids were significantly higher than control at increasing NaCl and Na2SO4 concentration, in contrast, were significantly reduced by higher concentration of NaCl + Na2SO4. Rubisco activity reduced steadily at 100 and 250 mM NaCl, while increased at 400 and 500 mM NaCl. Rubisco activity was significantly higher than control at 100 mM Na2SO4, and was no more change under NaCl + Na2SO4 treatment. The SOD activity increased with increasing NaCl and Na2SO4, and increased at moderate NaCl + Na2SO4 treatment. MDA content was lower than control at 250 mM salt concentration. On the basis of the data obtained, K. foliatum showed resistance to salt such as Na+, Cl–and SO 4 2– , Rubisco activity in K. foliatum might be more sensitive to salt.

Impacts of inorganic anions and natural organic matter on thermally activated persulfate oxidation of BTEX in water

The present study investigated the impacts of water matrix constituents (CO32−, HCO3−, Cl−, Br−, PO43−, HPO42−, H2PO4−, NO3−, SO42− and natural organic matters (NOM) on the oxidation of a mixture of benzene, toluene, ethylbenzene, and xylenes (BTEX) by thermally activated persulfate (PS). In the absence of matrix constituents, the BTEX oxidation rates decreased in the following order: xylenes > toluene ≈ ethylbenzene > benzene. HCO3−/CO32− and NOM inhibited the BTEX oxidation and the inhibiting effects became more pronounced as the HCO3−/CO32−/NOM concentration increased. SO42−, NO3−, PO43− and H2PO4− did not affect the BTEX oxidation while HPO42− slightly inhibited the reaction. The impacts of Cl− and Br− were complex. Cl− inhibited the benzene oxidation while 100 mM and 500 mM of Cl− promoted the oxidation of m-xylene and p-xylene. Br− completely suppressed the benzene oxidation while 500 mM of Br− strongly promoted the oxidation of xylenes. Detailed explanations on the influence of each matrix constituent were discussed. In addition, various halogenated degradation byproducts were detected in the treatments containing Cl− and Br−. Overall, this study indicates that some matrix constituents such as NOM, HCO3−, CO32−, H2PO4−, Cl− and Br− may reduce the BTEX removal efficiency of sulfate radical-based advanced oxidation process (SR-AOP) and the presence of Cl− and Br− may even lead to the formation of toxic halogenated byproducts.

Life cycle of the freshwater anomuran Aegla schmitti Hobbs, 1978 (Decapoda: Anomura: Aeglidae) from southeastern Brazil

We describe the reproductive cycle, population structure, growth and longevity of Aegla schmitti Hobbs, 1978 from the Betari River, at the Alto Ribeira Tourist State Park (24°31′57″S, 48°42′09″W), on the southern portion of state of Sao Paulo. A total of 1528 specimens (1204 males and 324 females) were sampled from September 2010 to December 2011. Carapace length excluding rostrum (CL) was measured in all individuals, and females were inspected for late developing ovaries or eggs attached to the pleopods. Growth curve equations were CL t = 28 . 358 ( 1 − e − 0 . 058 ( t + 1 . 127 ) ) for males and CL t = 21 . 69 ( 1 − e − 0 . 060 ( t + 1 . 468 ) ) for females. Average longevity was estimated to be 34.03 and 38.40 months for males and females, respectively. Size at the onset of functional maturity of females was estimated as 12.92 mm of CL. Aegla schmitti from the Betari River has two reproductive cycles during the expected lifespan. Each reproductive cycle extends for 9 months and can be subdivided in two sequential periods of similar duration: a first, from April to July, characterized by higher reproductive intensity and including the hatching of most of the juveniles in July, and a second, from August to December, with less intense reproductive activity. We discuss regional variations in water flow velocity as a selective pressure that regulates the timing of juvenile hatching in Aegla schmitti as well as in other aeglid species.

Arsenic Uptake from Arsenic-Contaminated Water Using Hyperaccumulator Pteris vittata L.: Effect of Chloride, Bicarbonate, and Arsenic Species

High As groundwater normally contained high concentrations of Cl - and HCO 3 - . This study examined the effects of Cl-, HCO 3 -, and As species on As uptake by hyperaccumulator Pteris vittata. Plants were exposed hydroponically to 5.0 mg/L As(III) or As(V) in the presence of 0, 0.5, 1, 2, 5, 10, and 20 mM of Cl- or HCO 3 - for 10 days. Addition of high Cl- concentrations (10 mM) slightly inhibited P. vittata growth (biomass), while generally had no significant effect on plant As uptake. High solution pH resulted in reduced plant growth and As uptake, which attributed to the inhibitory effects in HCO 3 - treatments with the high pH of the high HCO 3 - concentration. It was speculated that addition of HCO 3 - (20 mM) would have no significant effect on plant growth and As uptake. The inhibitory effect of HCO 3 - on As translocation was less apparent in the As(III) solutions than the As(V) solutions. For the high As groundwater with As(III) as the predominant species, high pH, instead of high concentrations HCO 3 - and Cl-, was expected to inhibit As uptake. The results suggested that optimum plant growth and maximum As hyperaccumulation could be achieved by adjusting solution pH in the growth media (around 7.2). 2012 Springer Science+Business Media B.V.

Sodium plays a more important role than potassium and chloride in growth of Salicornia europaea

Salicornia europaea is a succulent euhalophyte that belongs to the Chenopodiaceae family. It is found that moderate concentration of NaCl can dramatically stimulate the growth of S. europaea plants. To elucidate the mech- anism underlying the phenomenon, morphological and physiological changes of S. europaea in response to dif- ferent ions, including cations (Na ? ,K ? ,L i ? ,C s ? ) and anions (Cl - ,N O 3 - ,C H 3COO - ) were investigated, and the effects of Na ? ,C l - and K ? on the growth of S. europaea were also studied. Na ? was more effective than K ? and Cl - in stimulating shoot succulence, cell expansion, and stomatal opening. Plants treated with Na ? (including NaCl, Na ? , NaNO3) showed better plant growth, increased pho- tosynthesis and less cell membrane damage than those untreated and treated with 200 mM of Cl - and K ? (including KCl and KNO3). Both SEM-X-Ray microanal- ysis and flame emission results revealed that well devel- oped S. europaea plants had a higher content of sodium but lower potassium and chlorine. It is concluded that sodium plays a more important role in the growth and development of S. europaea than potassium and chloride.

Pregnancy rates after fixed-time artificial insemination of Brahman heifers treated to synchronize ovulation with low-dose intravaginal progesterone releasing devices, with or without eCG

The objective was to determine whether eCG in an ovulation synchronization protocol with an intravaginal progesterone (P 4)-releasing device (IPRD) containing a low dose of P 4 improves pregnancy rate (PR) to fixed-time AI (FTAI) in Bos indicus heifers. Day 0, 2 y old Brahman heifers were allocated to either eCG+ (n = 159) or eCG- (n = 157) treatment groups. All heifers were weighed, body condition scored (BCS), and ultrasonographically examined to measure uterine horn diameter and presence of a CL. On Day 0, all heifers received a low-dose IPRD (0.78 g P 4) and 1 mg of estradiol benzoate (EB) im. On Day 8, the IPRD was removed, all heifers received 500 μg cloprostenol im, and those in the eCG+ treatment group received 300 IU of eCG im. On Day 9, all heifers received 1 mg EB im. All heifers were FTAI 52 to 56 h after IPRD removal. Ten days after FTAI, heifers were exposed to bulls. Heifers were diagnosed as pregnant to FTAI, natural mating, or not detectably pregnant (NDP) 65 d after FTAI. Treatment with eCG+ as compared to eCG- did not affect PR to FTAI (28.9 vs 30.6%; P = 0.590), natural mating (51.3 vs 47.7%; P = 0.595), or overall (65.4 vs 63.7%; P = 0.872). Mean live weight gain from Days 0 to 65 d post-FTAI was higher in heifers pregnant to FTAI (72.29 ± 4.26 kg; P = 0.033) and overall (66.83 ± 3.65 kg; P = 0.021), compared to heifers that were NDP (60.03 ± 3.16 kg). Uterine diameter group, 9–11, 12–13, and 14–20 mm (26.2, 31.3, and 33.3%; P = 0.256), presence and absence of CL (29.8 vs 29.4%; P = 0.975), AI technicians 1, 2, and 3 (32.6, 28.8, and 22.4%; P = 0.293) and sires A, B, and C (23.9, 36.0 and 27.0%; P = 0.122) had no effect on PR to FTAI, natural mating, or overall. In conclusion, treatment of primarily cycling Brahman heifers with 300 IU eCG in conjunction with a low P 4-dose (0.78 g) IPRD and EB to synchronize ovulation, did not improve PR after FTAI, natural mating, or overall.

Life history of Talorchestia deshayesii (Amphipoda, Talitridae) in the Ionian sandy beach (southern Italy)

The population structure and reproductive biology of Talorchestia deshayesii (Audouin, 1826) on an exposed sandy beach in Taranto (Italy) was examined during one year cycle. Monthly surveys were performed from September 2002 to August 2003. Individuals were subdivided into sex, measured and abundance were calculated for each sampling. Abundance varied during the study period, with a marked decrease in winter. T. deshayesii, was found in a relative narrow zone near the sea in winter and summer while in spring and autumn the animals were widespread along the supralittoral. Reproduction occurred from February to November. The minimum average CL at the moment of recovery ranged from 0.22 to 0.28 mm. The sex ratio was female biased. The females and males became distinguishable at 0.35 mm (corresponding to 4.5 mm of LT). The first time that females were observed ovigerous happened when they reached a size about 0.4 mm of CL. The males of T. deshayesii grew larger than the females. The males reached a maximum CL of 1.05 (corresponding to 13.2 mm of LT), while females reached a CL of 1 mm (corresponding to 12.6 mm of LT). Mean length was the lowest in the summer months. Maximum total length was 10.5 mm and the size at first reproduction for the females was 3.5 mm total length. T. deshayesii produced two generations per year. Fecundity varied from 3 to 20 eggs per female and mean fecundity varied through time.