bluuebunny/crossref_metadata_2025_split huggingface dataset:
Pesticides in mountain yellow-legged frogs (Rana muscosa) from the Sierra Nevada Mountains of California, USA
Authors: Fellers Gary M. , McConnell Laura L. , Pratt David , Datta Seema 
Published: November 2004

Abstract
In 1997, pesticide concentrations were measured in mountain yellow-legged frogs (Rana muscosa) from two areas in the Sierra Nevada Mountains of California, USA. One area (Sixty Lakes Basin, Kings Canyon National Park) had large, apparently healthy populations of frogs. A second area (Tablelands, Sequoia National Park) once had large populations, but the species had been extirpated from this area by the early 1980s. The Tablelands is exposed directly to prevailing winds from agricultural regions to the west. When an experimental reintroduction of R. muscosa in 1994 to 1995 was deemed unsuccessful in 1997, the last 20 (reintroduced) frogs that could be found were collected from the Tablelands, and pesticide concentrations in both frog tissue and the water were measured at both the Tablelands and at reference sites at Sixty Lakes. In frog tissues, dichlorodiphenyldichloroethylene (DDE) concentration was one to two orders of magnitude higher than the other organochlorines (46 ± 20 ng/g wet wt at Tablelands and 17 ± 8 Sixty Lakes). Both γ-chlordane and trans-nonachlor were found in significantly greater concentrations in Tablelands frog tissues compared with Sixty Lakes. Organophosphate insecticides, chlorpyrifos, and diazinon were observed primarily in surface water with higher concentrations at the Tablelands sites. No contaminants were significantly higher in our Sixty Lakes samples.
Barramundi as an indicator species for environmental monitoring in north Queensland, Australia: Laboratory versus field studies
Authors: Codi Susan , Humphrey Craig , Klumpp David , Delean Steven 
Published: November 2004

Abstract
The dose-response relationship for hepatic 7-ethoxyresorufin-O-deethylase (EROD) induction in barramundi (Lates calcarifer) was examined under controlled laboratory conditions for 15 d using farm-reared barramundi. These results were compared with EROD activity measured in barramundi collected from two rivers catchments (impacted and nonimpacted) in northern Queensland, Australia. Barramundi were dosed by intraperitoneal injection with a known cytochrome P4501A (CYP1A) inducer, β-naphthoflavone (β-NF), at 5, 10, and 50 mg kg−1 using two controls: A vehicle control (corn-oil injected) and an experimental control (no injection). The EROD induction occurred within 4 h in the 5, 10, and 50 mg β-NF kg−1 exposures, reaching mean maximum activities of 88.6 (±51.9), 85.5 (±91.7), and 149.1 (±106.4) pmol min−1 mg protein−1, respectively. Mean EROD activities remained low in the corn-oil controls (2.1 ± 1.8 pmol min−1 mg protein−1) and experimental controls (5.3 ± 4.4 pmol min−1 mg protein−1) throughout the study. Barramundi demonstrated a rapid response curve, which was dose dependent (50 &gt; 10 &gt; 5 mg β-NF kg−1) and decreased progressively over time from induction. Measurement of total cytochrome P450 content (nmol mg protein−1) was not dose dependent. The EROD activities from field-collected barramundi from the Johnstone River (impacted) and Olive River (nonimpacted) suggest exposure to low-level contaminants in the Johnstone River fish only. With more controlled laboratory and field studies, barramundi have the potential to become a major indicator species in assessing exposure to environmental contaminants in coastal areas throughout northern Queensland, Australia.
Occurrence and fate of pharmaceuticals and alkylphenol ethoxylate metabolites in an effluent-dominated river and wetland
Authors: Gross Birgit , Montgomery-Brown John , Naumann Anneke , Reinhard Martin 
Published: November 2004

Abstract
The occurrence of pharmaceuticals, nonylphenol ethoxylate metabolites, and other wastewater-derived contaminants in surface waters is a potential environmental concern, especially since the discovery of contaminants with endocrine-disrupting properties. The present study investigated the discharge of emerging contaminants into the Santa Ana River (CA, USA) and their attenuation during river transport and passage through a constructed wetland. Contaminants studied included pharmaceuticals (gemfibrozil, ibuprofen, naproxen, ketoprofen, and carbamazepine) and their metabolites, hormones, the metabolites of alkylphenol polyethoxylates (APEMs), N-butyl benzenesulfonamide (NBBS), and chlorinated tris-propylphosphates (TCPPs). The APEMs included alkylphenols (APs), short-chain AP polyethoxylates (APEOs), AP polyethoxycarboxylates (APECs), and carboxylated APECs (CAPECs). In wastewater treatment plant effluent, APECs and CAPECs represented the dominant APEM fraction (1.8–18.7 μg/L), whereas APEOs and APs contributed only small amounts to the overall APEM concentrations (0.10–0.92 and ≤0.1 μg/L, respectively) except where the effluent was infiltrated into soil (5.2 μg/L). In effluents, ibuprofen and its metabolites, TCPPs, and NBBS were detected regularly (&lt;0.5 μg/L), and the other pharmaceuticals were detected occasionally. Transport in the Santa Ana River for 11 km resulted in the significant attenuation of all contaminants, from 67% for gemfibrozil to 100% for others. Wetland treatment (residence time, 2–4 d) resulted in partial removal of ibuprofen, gemfibrozil, and TCPPs and transformed APEOs to APECs.
Toxicity of glyphosate-based pesticides to four North American frog species
Authors: Howe Christina M. , Berrill Michael , Pauli Bruce D. , Helbing Caren C. , Werry Kate , Veldhoen Nik 
Published: November 2004

Abstract
Gyphosate-basedherbicides are among the most widely used pesticides in the world. We compared the acute toxicity of the glyphosate end-use formulation Roundup Original® to four North American amphibian species (Rana clamitans, R. pipiens, R. sylvatica, and Bufo americanus) and the toxicity of glyphosate technical, the polyethoxylated tallowamine surfactant (POEA) commonly used in glyphosate-based herbicides, and five newer glyphosate formulations to R. clamitans. For R. clamitans, acute toxicity values in order of decreasing toxicity were POEA &gt; Roundup Original &gt; Roundup Transorb® &gt; Glyfos AU®; no significant acute toxicity was observed with glyphosate technical material or the glyphosate formulations Roundup Biactive®, Touchdown®, or Glyfos BIO®. Comparisons between the four amphibian species showed that the toxicity of Roundup Original varied with species and developmental stage. Rana pipiens tadpoles chronically exposed to environmentally relevant concentrations of POEA or glyphosate formulations containing POEA showed decreased snout-vent length at metamorphosis and increased time to metamorphosis, tail damage, and gonadal abnormalities. These effects may be caused, in some part, by disruption of hormone signaling, because thyroid hormone receptor β mRNA transcript levels were elevated by exposure to formulations containing glyphosate and POEA. Taken together, the data suggest that surfactant composition must be considered in the evaluation of toxicity of glyphosate-based herbicides.
Enzymatic and estrogenic responses in fish exposed to organic pollutants in the New York-New Jersey (USA) Harbor Complex
Authors: Mcardle Margaret E. , Mcelroy Anne E. , Elskus Adria A. 
Published: November 2004

Abstract
This study examines biochemical and hormonal responses in resident and migratory fish from the New York-New Jersey (USA) Harbor Complex (NY-NJHC) and those treated with sediment-associated organic contaminants. Following laboratory exposures to organic extracts of NY-NJHC sediments (injection), livers from adult male mummichogs, Fundulus heteroclitus, were analyzed for vitellogenin (VTG), cytochrome P4501A (CYP1A), CYP3A, and estradiol 2-hydroxylase (E2OHase) and ethoxyresorufin-O-deethylase (EROD) activities. Levels of CYP1A (311–391% of control) and EROD (267–361% of control) were elevated in mummichogs exposed to high doses of sediment extracts, while VTG, CYP3A, and E2OHase were unaffected. In field studies, reproductively mature male mummichogs collected from a highly contaminated area, Newark Bay (NJ, USA), did not have detectable levels of VTG but did exhibit elevated levels of CYP1A and EROD. Vitellogenin was also not detected in juvenile striped bass (Morone saxatilis) collected from the main stem of the lower Hudson River (NY, USA). Similar to results in the sediment extract- treated fish, CYP3A and E2OHase were unaltered in Newark Bay F. heteroclitus. The lack of response of CYP3A and E2OHase activities to contaminant mixtures, either environment or sediment derived, suggests that compounds in these mixtures either do not alter these enzymes, produce antagonistic effects in mixtures, are present at ineffective concentrations, or are regulated in a species-specific manner.
Health symptoms and exposure to organophosphate pesticides in farmworkers
Authors: Strong Larkin L. , Thompson Beti , Coronado Gloria D. , Griffith William C. , Vigoren Eric M. , Islas Ilda 
Published: November 2004

AbstractBackgroundFew studies have examined the relationship between reported health symptoms and exposure to organophosphate (OP) pesticides.MethodsFisher's exact test was used to assess the relationship between self‐reported health symptoms and indicators of exposure to OP pesticides in 211 farmworkers in Eastern Washington.ResultsThe health symptoms most commonly reported included headaches (50%), burning eyes (39%), pain in muscles, joints, or bones (35%), a rash or itchy skin (25%), and blurred vision (23%). Exposure to pesticides was prevalent. The proportion of detectable samples of various pesticide residues in house and vehicle dust was weakly associated with reporting certain health symptoms, particularly burning eyes and shortness of breath. No significant associations were found between reporting health symptoms and the proportion of detectable urinary pesticide metabolites.ConclusionsCertain self‐reported health symptoms in farmworkers may be associated with indicators of exposure to pesticides. Longitudinal studies with more precise health symptom data are needed to explore this relationship further. Am. J. Ind. Med. 46:599–606, 2004. © 2004 Wiley‐Liss, Inc.
Analysis of UBV photometry in selected area 133
Authors: Karataş Y. , Bilir S. , Karaali S. , Ak S. G. 
Published: November 2004

AbstractWe interpret the de‐reddened UBV data for the field SA 133 to deduce the stellar density and metallicity distribution functions. The logarithmic local space density for giants, D*(0) = 6.40, and the agreement of the luminosity function for dwarfs and sub‐giants with the one of Hipparcos confirms the empirical method used for their separation. The metallicity distribution for dwarfs gives a narrow peak at [Fe/H] = +0.13 dex, due to apparently bright limiting magnitude, Vo = 16.5, whereas late‐type giants extending up to z ∼ 4.5 kpc from the galactic plane have a multimodal distribution. The metallicity distribution for giants gives a steep gradient d[Fe/H]/dz = –0.75 dex kpc–1 for thin disk and thick disk whereas a smaller value for the halo, i.e. d[Fe/H]/dz = –0.45 dex kpc–1. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
On the class of Oe stars'
Authors: Negueruela I. , Steele I. A. , Bernabeu G. 
Published: November 2004

AbstractWe present high‐quality spectra of the majority of stars that have been classified as Oe and find that their published spectral types are generally too early, most likely due to infilling of He I lines. As a matter of fact, all stars classified as Oe actually fall inside the range O9–B0 with the important exception of HD 155806 (O7.5 III) and perhaps HD 39680 (difficult to classify, but likely O8.5V). Observations of a sample of objects with published spectral types in the O9–B0 range previously classified as peculiar or emission‐line stars fail to reveal any new Oe star with spectral type earlier than O9.5. Most objects classified as peculiar in “classical” literature show signs of binarity in our spectra, but no spectral anomalies. We conclude that there is likely a real decline in the fraction of Be stars for spectral types earlier than B0, not due to observational bias. The few Oe stars with spectral types earlier than O9.5 deserve detailed investigation in order to provide constraints on the physical reasons of the Be phenomenon. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Recombinational DNA repair: the ignored repair systems
Authors: Smith Kendric C. 
Published: November 2004

AbstractThe recent finding of a role for the recA gene in DNA replication restart does not negate previous data showing the existence of recA‐dependent recombinational DNA repair, which occurs when there are two DNA duplexes present, as in the case for recA‐dependent excision repair, for postreplication repair (i.e., the repair of DNA daughter‐strand gaps), and for the repair of DNA double‐strand breaks. Recombinational DNA repair is critical for the survival of damaged cells. BioEssays 26:1322–1326, 2004. © 2004 Wiley Periodicals, Inc.
PolyADP‐ribose polymerase‐1 (PARP‐1) and the evolution of learning and memory
Authors: Sung Ying‐Ju , Ambron Richard T. 
Published: November 2004

AbstractPARP‐1 is a multifunctional enzyme that can modulate gene expression. Cohen‐Armon et al.1 found that a homologue of PARP‐1 is activated in the Aplysia nervous system as the animal responds to an aversive stimulus, which leads to sensitization, and during a more complex form of learning that involves feeding behavior. Significantly, inhibiting PARP‐1 activation blocked the learning. Several key pathways in Aplysia neurons are activated both during learning and after injury, suggesting that mechanisms of learning evolved from primitive responses to injury. Since PARP‐1 is evolutionarily conserved as a responder to various forms of stress, the finding that PARP‐1 is activated during learning supports this idea. BioEssays 26:1268–1271, 2004. © 2004 Wiley Periodicals, Inc.
Effect of feed and bleed rate on hybridoma cells in an acoustic perfusion bioreactor: Part I. Cell density, viability, and cell‐cycle distribution
Authors: Dalm Marcella C.F. , Cuijten Suzanne M.R. , van Grunsven Wout M.J. , Tramper Johannes , Martens Dirk E. 
Published: November 2004

AbstractFor the development of optimal perfusion processes the effect of the feed and bleed rate on cell growth in a perfusion bioreactor was studied. The viable‐cell density, viability, growth, death, and lysis rate and cell‐cycle distribution of a hybridoma cell line producing an IgG1 were studied over a range of specific feed and bleed rates. It was found that the feed and bleed rates applied in the different cultures could be divided into two regions based on the viable‐cell density and cell‐cycle distribution. The cultures in the first region, low feed rates (0.5 and 1.0 d−1) combined with low bleed rates (0.05 and 0.10 d−1), were nutrient‐limited, as an increase in the feed rate resulted in an increase in the viable‐cell density. The cultures in the second region, high feed and bleed rates, were nonnutrient‐limited. In this region the viable‐cell density decreased more or less linearly with an increase in the bleed rate and was independent of the feed rate. This suggests that the cells were limited by a cell‐related factor. Comparison of Trypan‐blue dye‐exclusion measurements and lactate‐dehydrogenase activity measurements revealed that cell lysis was not negligible in this bioreactor set‐up. Therefore, lactate‐dehydrogenase activity measurements were essential to measure the death rate accurately. The specific growth rate was nearly constant for all tested conditions. The viability increased with an increase of the bleed rate and was independent of the feed rate. Furthermore, the specific productivity of monoclonal antibody was constant under all tested conditions. For the optimal design of a perfusion process it should first be established whether viability is an important parameter. If not, a bleed rate as low as possible should be chosen. If low viabilities are to be avoided, the bleed rate chosen should be higher, with the value depending on the desired viability. Next, the feed rate should be set at such a rate that the cells are just in the nonnutrient‐limited region. © 2004 Wiley Periodicals, Inc.
Ferrocenyl‐Modified DNA: Synthesis, Characterization and Integration with Semiconductor Electrodes
Authors: Pike Andrew R. , Ryder Lyndsey C. , Horrocks Benjamin R. , Clegg William , Connolly Bernard A. , Houlton Andrew 
Published: November 2004

AbstractThe ferrocenyl‐nucleoside, 5‐ethynylferrocenyl‐2′‐deoxycytidine (1) has been prepared by Pd‐catalyzed cross‐coupling between ethynylferrocene and 5‐iodo‐2′‐deoxycytidine and incorporated into oligonucleotides by using automated solid‐phase synthesis at both silica supports (CPG) and modified single‐crystal silicon electrodes. Analysis of DNA oligonucleotides prepared and cleaved from conventional solid supports confirms that the ferrocenyl‐nucleoside remains intact during synthesis and deprotection and that the resulting strands may be oxidised and reduced in a chemically reversible manner. Melting curve data show that the ferrocenyl‐modified oligonucleotides form duplex structures with native complementary strands. The redox potential of fully solvated ferrocenyl 12‐mers, 350 mV versus SCE, was shifted by +40 mV to a more positive potential upon treatment with the complement contrary to the anticipated negative shift based on a simple electrostatic basis. Automated solid‐phase methods were also used to synthesise 12‐mer ferrocenyl‐containing oligonucleotides directly at chemically modified silicon <111> electrodes. Hybridisation to the surface‐bound ferrocenyl‐DNA caused a shift in the reduction potential of +34 mV to more positive values, indicating that, even when a ferrocenyl nucleoside is contained in a film, the increased density of anions from the phosphate backbone of the complement is still dominated by other factors, for example, the hydrophobic environment of the ferrocene moiety in the duplex or changes in the ferrocene–phosphate distances. The reduction potential is shifted >100 mV after hybridisation when the aqueous electrolyte is replaced by THF/LiClO4, a solvent of much lower dielectric constant; this is consistent with an explanation based on conformation‐induced changes in ferrocene–phosphate distances.
Car–Parrinello Molecular Dynamics Study of the Initial Dinitrogen Reduction Step in Sellmann‐Type Nitrogenase Model Complexes
Authors: Kirchner Barbara , Reiher Markus , Hille Andreas , Hutter Jürg , Hess Bernd A. 
Published: November 2004

AbstractWe have studied reduction reactions for nitrogen fixation at Sellmann‐type model complexes with Car–Parrinello simulation techniques. These dinuclear complexes are especially designed to emulate the so‐called open‐side FeMoco model. The main result of this work shows that in order to obtain the reduced species several side reactions have to be suppressed. These involve partial dissociation of the chelate ligands and hydrogen atom transfer to the metal center. Working at low temperature turns out to be one necessary pre‐requisite in carrying out successful events. The successful events cannot be described by simple reaction coordinates. Complicated processes are involved during the initiation of the reaction. Our theoretical study emphasizes two experimental strategies which are likely to inhibit the side reactions. Clamping of the two metal fragments by a chelating phosphane ligand should prevent dissociation of the complex. Furthermore, introduction of tert‐butyl substituents could improve the solubility and should thus allow usage of a wider range of (mild) acids, reductants, and reaction conditions.
Six‐ and Eightfold Palladium‐Catalyzed Cross‐Coupling Reactions of Hexa‐ and Octabromoarenes
Authors: Stulgies Baldur , Prinz Peter , Magull Jörg , Rauch Karsten , Meindl Kathrin , Rühl Stephan , de Meijere Armin 
Published: November 2004

AbstractPalladium‐catalyzed sixfold coupling of hexabromobenzene (20) with a variety of alkenylboronates and alkenylstannanes provided hexaalkenylbenzenes 1 in up to 73 % and 16 to 41 % yields, respectively. In some cases pentaalkenylbenzenes 21 were isolated as the main products (up to 75 %). Some functionally substituted hexaalkenylbenzene derivatives containing oxygen or sulfur atoms in each of their six arms have also been prepared (16 to 24 % yield). The sixfold coupling of the less sterically encumbered 2,3,6,7,10,11‐hexabromotriphenylene (24) gave the desired hexakis(3,3‐dimethyl‐1‐butenyl)triphenylene (25) in 93 % yield. The first successful cross‐coupling reaction of octabromonaphthalene (26) gave octakis‐(3,3‐dimethyl‐1‐butenyl)naphthalene (27) in 21 % yield. Crystal structure analyses disclose that, depending on the nature of the substituents, the six arms are positioned either all on the same side of the central benzene ring as in 1 a and 1 i, making them nicely cup‐shaped molecules, or alternatingly above and below the central plane as in 1 h and 23. In 27, the four arms at C‐1,4,6,7 are down, while the others are up, or vice versa. Upon catalytic hydrogenation, 1 a yielded 89 % of hexakis(tert‐butylethyl)benzene (23). Some efficient accesses to alkynes with sterically demanding substituents are also described. Elimination of phosphoric acid from the enol phosphate derived from the corresponding methyl ketones gave 1‐ethynyladamantane (3 b, 62 % yield), 1‐ethynyl‐1‐methylcyclohexane (3 c, 85 %) and 3,3‐dimethylpentyne (3 e, 65 %). 1‐(Trimethylsilyl)ethynylcyclopropane (7) was used to prepare 1‐ethynyl‐1‐methylcyclopropane (3 d) (two steps, 64 % overall yield). The functionally substituted alkynes 3 f–h were synthesized in multistep sequences starting from the propargyl chloride 11, which was prepared in high yields from the dimethylpropargyl alcohol 10 (94 %). The alkenylstannanes 19 were prepared by hydrostannation of the corresponding alkynes in moderate to high yields (42–97 %), and the alkenylboronates 2 and 4 by hydroboration with catecholborane (27–96 % yield) or pinacolborane (26–69 % yield).
Altering Hydrogen Storage Properties by Hydride Destabilization Through Alloy Formation: LiH and MgH2 Destabilized with Si.
Authors: Vajo John J. , Mertens Florian , Ahn Channing C. , Bowman Robert C. Jr. , Fultz Brent 
Published: November 2004

AbstractFor Abstract see ChemInform Abstract in Full Text.
Unsymmetrical Diaryl Sulfones and Aryl Vinyl Sulfones Through Palladium‐Catalyzed Coupling of Aryl and Vinyl Halides or Triflates with Sulfinic Acid Salts.
Authors: Cacchi Sandro , Fabrizi Giancarlo , Goggiamani Antonella , Parisi Luca M. , Bernini Roberta 
Published: November 2004

AbstractFor Abstract see ChemInform Abstract in Full Text.
Synthesis of Some New Fluorine Containing 1,3,4‐Oxadiazole Derivatives as Potential Antibacterial and Anticancer Agents.
Authors: Bhat K. Subrahmanya , Karthikeyan M. S. , Holla B. Shivarama , Shetty N. Suchetha 
Published: November 2004

AbstractFor Abstract see ChemInform Abstract in Full Text.
Synthesis and Photochromic Properties of Methoxy Substituted 2,2‐Diaryl‐2H‐naphtho[1,2‐b]pyrans.
Authors: Gabbutt Christopher D. , Hepworth John D. , Heron B. Mark , Thomas David A. , Kilner Colin , Partington Steven M. 
Published: November 2004

AbstractFor Abstract see ChemInform Abstract in Full Text.
Synthesis of 3,5‐Difunctionalized 1‐Methyl‐1H‐pyrazolo [3,4‐b]Pyridines Involving Palladium‐Mediated Coupling Reactions.
Authors: Lavecchia G. , Berteina‐Raboin S. , Guillaumet G. 
Published: November 2004

AbstractFor Abstract see ChemInform Abstract in Full Text.
1,2,4‐Triazines in Organic Synthesis. Part 25. Synthesis of Functionalized 1H‐Pyrazolo[4,3‐e][1,2,4]triazines and Their Fused Derivatives via ipso‐Substitution of Methylsulfonyl Group with O‐, N‐, S‐ and C‐Nucleophiles.
Authors: Mojzych Mariusz , Rykowski Andrzej 
Published: November 2004

AbstractFor Abstract see ChemInform Abstract in Full Text.