Lead and Helium Isotope Evidence from Oceanic Basalts for a Common Deep Source of Mantle Plumes

Linear arrays in lead isotope space for mid-ocean ridge basalts (MORBs) converge on a single end-member component that has intermediate lead, strontium, and neodymium isotope ratios compared with the total database for oceanic island basalts (OIBs) and MORBs. The MORB data are consistent with the presence of a common mantle source region for OIBs that is sampled by mantle plumes. 3He/4He ratios for MORBs show both positive and negative correlation with the 206Pb/204Pb ratios, depending on the MORB suite. These data suggest that the common mantle source is located in the transition zone region. This region contains recycled, oceanic crustal protoliths that incorporated some continental lead before their subduction during the past 300 to 2000 million years.     

Immunohistochemical Localization of Fibroblast Growth Factor‐2 in the Sheep Ovary and its Effects on Pre‐antral Follicle Apoptosis and Development In Vitro

Studies with sheep are important to improve our knowledge about the factors that control folliculogenesis in mammals and to explore possible physiological differences among species. The aims of this study were to characterize FGF‐2 protein expression in ovine ovaries and to verify the effect of FGF‐2 on the morphology, apoptosis and growth of ovine pre‐antral follicles cultured in vitro. After collection, one fragment of ovarian tissue was fixed for histological analysis and TUNEL analysis (fresh control). The remaining fragments were cultured for 7 days in control medium (α‐MEM⁺) alone or supplemented with FGF‐2 at different concentrations (1, 10, 50, 100 or 200 ng/ml). After culturing, ovarian tissue was destined to histology and TUNEL analysis, and oocyte and follicle diameters were measured. The immunostaining for FGF‐2 was observed in oocytes from primordial, primary and secondary follicles, as well as in granulosa cells of secondary and antral follicles. The percentage of normal follicles was similar among control medium, 1 and 10 ng/ml FGF‐2, and significantly higher than those observed in 50, 100 or 200 ng/ml FGF‐2. A significant increase in follicle diameter was observed when tissues were cultured in 10, 50, 100 or 200 ng/ml FGF‐2 compared with the fresh control and the other treatments. Similar results were observed for oocyte diameter in tissues cultured with 50, 100 or 200 ng/ml FGF‐2 (p < 0.05). However, the percentage of apoptotic cells only decreased (p < 0.05) in ovarian tissues cultured in 1 or 10 ng/ml FGF‐2 compared with the control medium and other FGF‐2 treatments. In conclusion, this study demonstrated the presence of FGF‐2 in ovine ovaries. Furthermore, 10 ng/ml FGF‐2 inhibits apoptosis and promotes ovine follicle growth. As the sheep ovary is more similar to that of humans, the culture system demonstrated in this work seems to be an appropriate tool for studies towards human folliculogenesis.     

Use of protocatechuic acid as the sole antioxidant in the base medium for in vitro culture of ovine isolated secondary follicles

This study evaluated the effect of the protocatechuic acid (PCA) as the sole antioxidant in the base medium for in vitro culture of ovine secondary follicles. Secondary follicles (200‐230 μm) were isolated and cultured in α‐minimal essential medium supplemented with BSA, insulin, glutamine and hypoxanthine (α‐MEM: antioxidant‐free medium) or α‐MEM also added by transferrin, selenium and ascorbic acid (α‐MEM+: with antioxidant) or α‐MEM added by PCA (56.25; 112.5; 225; 450; or 900 μg/ml). Moreover, after culture, oocytes were matured and the chromatin configuration and DNA fragmentation were evaluated. After 12 days, the treatment containing 56.25 μg/ml PCA showed higher percentage of normal follicles than control medium or the other treatments (p < .05), except for 900 μg/ml PCA (p > .05). The antrum formation was significantly higher in treatments containing 56.25, 112.5 or 900 μg/ml PCA, compared to the α‐MEM and similar (p > .05) to the other treatments. The rates of fully grown oocytes (≥110 μm) were similar (p > .05) among all treatments containing PCA and α‐MEM+, and those were superior (p < .05) than α‐MEM, except for 450 μg/ml PCA (p > .05). GSH levels and mitochondrial activity were higher (p < .05) in α‐MEM+ than in α‐MEM and similar (p > .05) to all PCA treatments. The rates of meiotic resumption and DNA fragmentation were similar (p > .05) among α‐MEM+ and 56.25 μg/ml PCA. In conclusion, PCA at 56.25 μg/ml as the sole antioxidant added to the medium for ovine isolated secondary follicle culture maintains follicular survival, GSH and active mitochondria levels, meiotic developmental competence and DNA integrity of cultured oocytes.     

Prevalence of low automated platelet counts in cats: comparison with prevalence of thrombocytopenia based on blood smear estimation

Abstract: True thrombocytopenia is uncommon in cats; however, low platelet counts frequently are found using automated cell counters. Although this discrepancy is a well known problem, the prevalence of low automated platelet counts in feline blood samples has not been documented. We retrospectively compared the prevalence of low automated platelet counts with low blood smear-estimated platelet counts in feline blood samples. Results of blood sample analysis from 359 cats during a 1-year period at the University of Glasgow Veterinary Haematology Laboratory were examined. Smear estimates of platelet number were done in those cases in which records did not indicate adequate platelet numbers. Platelet counts obtained with an impedance counter (Minos Vet, Abx Hematologie) were <200×10⁹ cells/L in 256 samples (71%) and <50×10⁹ cells/L in 43 samples (12%). However, based on estimation of platelet numbers from blood smears, only 11 samples (3.1%) had platelet counts of <200×10⁹ cells/L and 9 samples (2.5%) had counts of <50×10⁹ cells/L. Four cats with thrombocytopenia estimated by blood smear evaluation had clinical signs of a bleeding disorder. Disorders associated with thrombocytopenia included neoplasia, cytotoxic chemotherapy, and infectious diseases. There was no evidence that delay due to mailing of samples was associated with lower automated platelet counts than would have been obtained on the day of sampling. The high prevalence of apparent thrombocytopenia in automated platelet counts was attributed to a combination of platelet aggregation and the impedance method of cell differentiation by size. Vigilance and careful examination of blood smears is required to identify the few cats with true thrombocytopenia.     

Trends in polymer development

Polymer science and technology has flourished as polymers with many new compositions have been, synthesized. The range of properties attainable has been continually extended, providing materials with higher strength, better reinforcing capabilities, and greater resistance to extreme thermal and corrosive environments. Examples of evolutionary developments in the polyamides, the fluorocarbon resins, and the aromatic engineering plastics are used to illustrate the trends. It is expected that this process will continue in order to meet changing needs and that emphasis will be put on selective polymer design for specific applications.     

Identification of New Drinking Water Disinfection by - Products from Ozone, Chlorine Dioxide, Chloramine, and Chlorine

Many drinking water treatment plants are currently using alternative disinfectants to treat drinking water, with ozone, chlorine dioxide, and chloramine being the most popular. However, compared to chlorine, which has been much more widely studied, there is little information about the disinfection by-products (DBPs) that these alternative disinfectants produce. Thus, it is not known if the DBPs from alternative disinfectants are safer or more hazardous than those formed by chlorine. To answer this question, we have set out to comprehensively identify DBPs formed by these alternative disinfectants, as well as by chlorine. The results presented here represent a compilation of the last 8 years of our research in identifying new DBPs from ozone, chlorine dioxide, chloramine, and chlorine. We also include results from recent studies of Israel drinking water disinfected with both chlorine dioxide and chloramine. Over 200 DBPs were identified, many of which have never been reported. In comparing by-products formed by the different disinfectants, ozone, chlorine dioxide, and chloramine formed fewer halogenated DBPs than chlorine.     

The status of marine biodiversity in the Eastern Central Atlantic (West and Central Africa)

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Chlorpyrifos transformation by aqueous chlorine in the presence of bromide and natural organic matter

The aqueous chlorination of chlorpyrifos (CP) was investigated in the presence of bromide and natural organic matter (NOM), which were identified as naturally occurring aqueous constituents that could affect CP transformation rates to the toxic product chlorpyrifos oxon (CPO). Bromide can be oxidized by chlorine to form hypobromous acid (HOBr), which was found to oxidize CP at a rate that was 3 orders of magnitude faster than was the case with chlorine: k HOBr,CP=1.14 (+/-0.21)x10(9) M(-1) h(-1) and k HOCl,CP=1.72x10(6) M(-1) h(-1), respectively. Similar to previous findings with the hypochlorite ion, hypobromite (OBr-) was found to accelerate the hydrolysis of CP and CPO: kOBr,CP=965 (+/-110) M(-1) h(-1) and kOBr,CPO=1390 (+/-160) M(-1) h(-1), respectively. Treated water from the Athens-Clarke County (ACC) water treatment plant in Athens, GA, was used in some of the experiments as a NOM source. A mechanistic model was used to adequately predict the loss of CP as well as the formation of CPO and the hydrolysis product 3,5,6-trichloro-2-pyridinol (TCP) in the presence of the ACC water.