bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of 4-nonylphenol and 4-tert-octylphenol on sex differentiation and vitellogenin induction in medaka (Oryzias latipes)
Authors: Seki Masanori , Yokota Hirofumi , Maeda Masanobu , Tadokoro Hiroshi , Kobayashi Kunio
Published: March 2010

Medaka (Oryzias latipes) were continuously exposed to various concentrations of two alkylphenols, 4-nonylphenol (NP) and 4-tert-octylphenol (OP), from fertilized eggs to 60 d posthatch. The effects on sexual differentiation and hepatic vitellogenin (VTG) induction in medaka were assessed to elucidate the lowest-observed-effect concentrations (LOECs) of NP and OP for these events during early life stages. The LOECs of NP and OP for these events were 11.6 and 11.4 μg/L, respectively. These results suggest that NP and OP may have adverse effects at similar concentrations during early life stage in medaka. Additionally, we investigated whether the abnormal sex differentiation induced by these alkylphenols would be permanent or reversible once the medaka were returned to clean water. The appearance of the secondary sex characteristics reverted from female to male when fish were returned to clean water. However, gonadal histology showed that intersex gonads still existed, even after the fish were transferred to clean water for two months. These results suggest that the induced feminization of secondary sex characteristics in medaka exposed to alkylphenols during the stage of sexual differentiation may not always be permanent, but the gonadal alteration (testisova) may continue much longer.
Modification of the equilibrium partitioning approach for volatile organic compounds in sediment
Authors: Fuchsman Phyllis C.
Published: March 2010

Although weakly hydrophobic chemicals such as volatile organic compounds (VOCs) tend not to persist in sediments, they may nevertheless be present in some sediments because of recent or ongoing releases. Standard methods are not available for assessing risks to benthic invertebrates due to VOCs in sediment. More strongly hydrophobic organic chemicals are frequently assessed by using the equilibrium partitioning (EqP) approach, which predicts the bioavailable fraction of chemical (the concentration dissolved in pore water) from the sediment-sorbed fraction, assuming that partitioning is at equilibrium. As typically applied, the EqP approach is ineffective for assessing VOCs in sediment, because the standard EqP equation fails to account for the contribution of dissolved chemical to the total chemical concentration in sediment. For chemicals with low organic carbon-water partition coefficients (KOCs), this results in nonsensical sediment-quality benchmarks that are more conservative (i.e., lower) than benchmarks calculated by assuming 100% bioavailability. A modified EqP equation is presented that accounts for the dissolved fraction of total chemical concentrations in sediment. Results of the standard and modified EqP equations converge with increasing KOC and are essentially identical at log KOC values exceeding approximately 3.5.
Mercury effects on predator avoidance behavior of a forage fish, golden shiner (Notemigonus crysoleucas)
Authors: Webber Hannah M. , Haines Terry A.
Published: March 2010

Mercury contamination of fish is widespread in North America and has resulted in the establishment of fish consumption advisories to protect human health. However, the effects of mercury exposure to fish have seldom been investigated. We examined the effects of dietary mercury exposure at environmental levels in a common forage species, golden shiner (Notemigonus crysoleucas). Fish were fed either an unaltered diet (12 ng/g wet wt methylmercury [MeHg] as Hg), a low-Hg diet (455 ng/g Hg), or a high-Hg diet (959 ng/g Hg). After 90 d mean fish whole-body total Hg concentrations were 41, 230, and 518 ng/g wet wt, respectively, which were within the range of concentrations found in this species in northern U.S. lakes. There were no mortalities or differences in growth rate among groups. Groups of fish from each treatment were exposed to a model avian predator and their behavioral response videotaped for analysis. Brain acetylcholinesterase (AChE) activity was determined in fish after behavioral testing. Fish fed the high-Hg diet had significantly greater shoal vertical dispersal following predator exposure, took longer to return to pre-exposure activity level, and had greater shoal area after return to pre-exposure activity than did the other treatments, all of which would increase vulnerability of the fish to predation. There were no differences in brain AChE among treatments. We conclude that mercury exposure at levels currently occurring in northern United States lakes alters fish predator-avoidance behavior in a manner that may increase vulnerability to predation. This finding has significant implications for food chain transfer of Hg and Hg exposure of fish predators.
Accumulation of 137Cs by larvae of the midge Chironomus riparius from sediment: Effect of potassium
Authors: Bervoets Lieven , De Bruyn Luc , Van Ginneken Luc , Blust Ronny
Published: March 2010

We studied the effect of potassium on the uptake of radiocesium from sediment by larvae of the midge Chironomus riparius. Sediment ingestion rate was determined for one week. After 24 h the gut content remained constant, indicating that equilibrium was reached between sediment ingestion and sediment elimination. These data were used to account for radiocesium present in the gut in subsequent uptake experiments. Reference sediment was equilibrated with solutions containing different concentrations of potassium: 1, 10, 100, and 1,000 μM. Adsorption of 137Cs to the sediment was investigated. Three different radiocesium levels (0.3, 0.6, and 1.2 KBq/ml) were applied at the four different potassium levels. In all cases more than 94% of all radiocesium was adsorbed to the sediment within 48 h. The sediment, equilibrated with the four different potassium levels, was spiked with a constant amount of 296 Bq/ml 137Cs. Accumulation by midge larvae was followed for one week, and subsequently elimination was followed for another week. No significant differences in radiocesium levels in midge larvae among the treatments were found after one week of exposure. However, using a one-compartment accumulation model, a small but significant effect of potassium in water and sediment on the uptake and elimination rate constants (ka and ke) was found. These results indicate that although differences were rather small, radiocesium accumulation decreased with increasing potassium level in the sediment.
Relationships among developmental stage, metamorphic timing, and concentrations of elements in Bullfrogs (Rana catesbeiana)
Authors: Snodgrass Joel W. , Hopkins William A. , Roe John H.
Published: March 2010

We collected bullfrog (Rana catesbeiana) larvae from a coal combustion waste settling basin to investigate the effects of developmental stage and timing of metamorphosis on concentrations of a series of trace elements in bullfrog tissues. Bullfrogs at four stages of development (from no hind limbs to recently metamorphosed juveniles) and bullfrogs that metamorphosed in the fall or overwintered in the contaminated basin and metamorphosed in the spring were analyzed for whole-body concentrations of Al, V, Cr, Ni, Cu, As, Pb, Cd, Zn, Ag, Sr, and Se. After the effects of dry mass were removed, tissue concentrations of six elements (Al, V, Cr, Ni, Cu, As, and Pb) decreased from the late larval stage through metamorphosis. Decreases in concentrations through metamorphosis ranged from 40% for Cu to 97% for Al. Tissue concentrations of these elements were also similar or higher in spring; Al and Cr concentrations were 34 and 90% higher in the spring, respectively, whereas As, Ni, Cu, and Pb concentrations were <10% higher. Concentrations of Cd, Se, and Ag varied among seasons but not among stages; Cd and Ag concentrations were 40 and 62% lower, respectively, and Se concentrations were 21% higher in spring. Concentrations of Zn varied only among stages; concentrations decreased gradually through late larval stage and then increased through metamorphosis. Concentrations of Sr varied among stages, but this variation was dependent on the season. Concentrations of Sr were higher in larval stages during the spring, but because concentrations of Sr increased 122% through metamorphosis in the fall and only 22% in the spring, concentrations were higher in fall metamorphos when compared with spring metamorphs. Our results indicate that metamorphosis and season of metamorphosis affects trace element concentrations in bullfrogs and may have important implications for the health of juveniles and the transfer of pollutants from the aquatic to the terrestrial environment.
Exposure and effects of chemical contaminants on tree swallows nesting along the Housatonic River, Berkshire County, Massachusetts, USA, 1998–2000
Authors: Custer Christine M. , Custer Thomas W. , Dummer Paul M. , Munney Kenneth L.
Published: March 2010

Hatching success of tree swallows (Tachycineta bicolor) was assessed for three years in relation to chemical contamination along the Housatonic River, Berkshire County (MA, USA), in 1998, 1999, and 2000. Nest boxes were erected at five sites along the Housatonic River and its tributaries and at one reference location. Concentrations of total polychlorinated biphenyls (PCBs) were some of the highest ever reported in bird eggs. Mean concentrations at sites along the Housatonic River ranged between 32 and 101 μg/g wet weight. A significant negative relationship was observed between concentrations of total PCBs in clutches and hatching success. A significant negative relationship was also observed between hatching success and the sum of the total dioxins and furans and the associated toxic equivalents (TEQs) for dioxins and furans. In a combined model with PCB TEQs and dioxin/furan TEQs, PCB TEQs were not significantly correlated to hatching success, whereas dioxin/furan TEQs were. Contamination of tree swallows was from local food sources. Accumulation rates of total PCBs in 12-d-old nestlings averaged between 34 and 76 μg/d at the sites along the main stem of the Housatonic River compared to <1 μg/d at the reference location.
Naturally produced halogenated dimethyl bipyrroles bind to the aryl hydrocarbon receptor and induce cytochrome P4501A and porphyrin accumulation in chicken embryo hepatocytes
Authors: Tittlemier Sheryl A. , Kennedy Sean W. , Hahn Mark E. , Reddy Christopher M. , Norstrom Ross J.
Published: March 2010

Halogenated dimethyl bipyrroles (HDBPs) recently have been identified as a group of environmentally persistent naturally produced bioaccumulative organohalogens. The ability of these compounds to activate the aryl hydrocarbon receptor (AhR) signaling pathway in vitro was examined. Induction of cytochrome P4501A (CYP1A), measured as ethoxyresorufin-O-deethylase (EROD) activity, and porphyrin accumulation were monitored after exposure of chick embryo hepatocytes to three individual HDBP congeners and two HDBP mixtures. All HDBP congeners and mixtures tested caused induction of EROD activity. Induction equivalency factors, calculated as the ratio of the effective concentration of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) to induce 10 and 50% of the maximal EROD induction to that of the HDBP congener or mixture ranged from 0.0004 to 0.05. Halogenated dimethyl bipyrroles also caused porphyrin accumulation, which increased with exposure time of the hepatocytes and molar bromine content of the HDBP congener or mixture. Heptacarboxylporphyrin III and corproporphyrinogen III were the most abundant porphyrins observed after an exposure period of 48 h. The individual HDBP congeners and mixtures also inhibited binding of [3H]TCDD to chicken and mouse AhR. Binding of [3H]TCDD to chicken AhR was inhibited approximately 20% by tetra- to hexabrominated congeners at concentrations of 20 to 40 μM; binding to mouse AhR was inhibited 40 to 50% by tri- and tetrabrominated dimethyl bipyrroles (DBPs) at 10 μM. The relative affinity of the hexabrominated DBP congener (vs TCDD) for binding to chicken AhR was estimated to be 0.000017. The results of this work illustrate that HDBPs act as agonist ligands for the AhR in the same manner as many anthropogenic organohalogens.
Minisatellite DNA mutation rate in dandelions increases with leaf-tissue concentrations of Cr, Fe, Mn, and Ni
Authors: Rogstad Steven H. , Keane Brian , Collier Matthew H.
Published: March 2010

We have examined whether mutation rates at minisatellite DNA loci in dandelions (Taraxacum officinale Weber, sensu lato; Asteraceae) increase with increasing exposure to metal pollution. From 16 sites (Colorado to Pennsylvania, USA) covering a range of airborne particulate-matter exposures, soil metal concentrations, and leaf-tissue metal concentrations, we grew an average of 7.9 offspring from each of 10 parent plants, and we analyzed the parent-offspring transmission of 82,715 minisatellite DNA markers to 1,258 offspring for rates of mutation. The mean number of markers examined per individual (using six minisatellite probes) was 65.8. Detection of mutations is facilitated by agamospermous reproduction (clonal seed production) in dandelions. Across sites, the average single-event, parent-offspring marker transmission mutation rate was 0.0067, ranging from 0.002 to 0.015 (a 7.5-fold difference). No significant correlation was detected between site single-event mutation rates and either airborne particulate-matter or soil concentrations for any of the metals. However, across sites, mutation rates were significantly (p < 0.05) and positively correlated to increasing leaf-tissue concentrations of Cr, Fe, Mn, and Ni (Cd, Cu, Pb, and Zn exhibited no correlation). Multiple-regression analyses suggest that a model including three metals—in order of importance: Cr (p = 0.002), Fe (p = 0.02), and Ni (p = 0.005); overall, p = 0.001—may improve the ability to predict mutation rate relative to leaf metal concentrations in dandelions. Mutations at minisatellite DNA loci in sexually apomictic organisms may thus provide convenient biomarkers by which to assess the mutagen stressor risk in environments.
Assessing the source of mercury in foliar tissue of quaking aspen
Authors: Frescholtz Toby F. , Gustin Mae S. , Schorran David E. , Fernandez George C. J.
Published: March 2010

Foliar accumulation of mercury has been demonstrated to occur as plants leaf out, yet the primary source of this mercury is not known. Using closed-system growth chambers, uptake of mercury by quaking aspen (Populus tremuloides) foliage was measured over time as a function of soil mercury concentrations (0.01, 6.2, and 25.6 μg/g) and atmospheric mercury exposure concentrations (1.4, 14.9, and 68.5 ng/m3). Foliar mercury concentrations increased as a function of time for all exposures. Twice during the experiment, leaf washes were analyzed for mercury to assess surface deposition, and little mercury was removed (0.02-0.04 ng/m2), suggesting that direct deposition to the leaf surface was not significant during this experiment. At the end of the four-month experiment, whole-plant mercury concentrations were determined. It was found that whereas mercury in the atmosphere primarily influenced foliar uptake, root concentrations were related to the soil mercury concentration. The implication of this study is that litterfall may serve as a pathway for new, atmospherically derived mercury to be deposited to forest soils. This has significant implications for watershed management of ecosystems where mercury is of concern.
Assessing relationships between chemical exposure, parasite infection, fish health, and fish ecological status: A case study using chub (Leuciscus cephalus) in the Bílina River, Czech Republic
Authors: Wenger Michael , Ondračková Markéta , Machala Miroslav , Neča Jiří , Hyršl Pavel , Šimková Andrea , Jurajda Pavel , von der Ohe Peter , Segner Helmut
Published: March 2010

Multiple stressor scenarios, as they are relevant in many watersheds, call for approaches extending beyond conventional chemical-focused approaches. The present study, investigated the fish population, represented by chub (Leuciscus cephalus), in the Bílina River (Czech Republic), which is impacted by various pollution sources and might pose a risk on the fish population. To confirm or reject this hypothesis it was examined whether there exists an association between abundance of chub and exposure to toxic chemicals as well as natural stressors, represented by parasites, and whether health-related suborganismal traits, namely, organ indices, tissue histopathology, and immune parameters, would help in revealing relationships between stressor impact and population status. Toxic pressure was assessed by the toxic unit approach, which gives an integrative estimate of toxic effect concentrations and by measuring the biomarkers cytochrome P4501A and vitellogenin, which indicate exposure to bioavailable arylhydrocarbon- or estrogen receptor ligands. Parasite pressure was estimated by determining abundance and species composition of ecto- and endoparasites of chub. Chub abundance was high upstream in the Bílina, low to zero in the middle stretches, and increased again downstream. Toxic pressure increased in the downstream direction, while parasite intensity decreased in this direction. Health status of chub did not differ clearly between up-, middle-, and downstream sites. Thus, it appears that neither toxic pressure nor parasite pressure nor their combination translates into a change of chub health status. By using varied assessment tools, this study provides evidence against a presumed causative role of toxicants impairing the fish ecological status of the Bílina River. Environ. Toxicol. Chem. 2010;29:453–466. © 2009 SETAC
Bioavailability assessment of a contaminated field sediment from Patrick Bayou, Texas, USA: Toxicity identification evaluation and equilibrium partitioning
Authors: Perron Monique M. , Burgess Robert M. , Ho Kay T. , Pelletier Marguerite C. , Cantwell Mark G. , Shine James P.
Published: March 2010

Contaminated sediments are commonly found in urbanized harbors. At sufficiently high contaminant levels, sediments can cause toxicity to aquatic organisms and impair benthic communities. As a result, remediation is necessary and diagnosing the cause of sediment toxicity becomes imperative. In the present study, six sediments from a highly industrialized area in Patrick Bayou (TX, USA) were subjected to initial toxicity testing with the mysid, Americamysis bahia, and the amphipod, Ampelisca abdita. All sediments were toxic to the amphipods, while sites PB4A, PB6A, and PB9 were the only sites toxic to mysids. Due to its toxicity to both test organisms, site PB6A was chosen for a marine whole sediment phase I toxicity identification evaluation (TIE). Results of the TIE found toxicity to amphipods was primarily due to nonionic organic contaminants (NOCs), rather than cationic metals or ammonia. Causes of mysid toxicity in the TIE were less clear. An assessment of metal bioavailability using equilibrium partitioning (EqP) approaches supported the results of the TIE that cationic metals were not responsible for observed toxicity in PB6A for either organism. Toxic units (TU) calculated on measured concentrations of NOCs in the sediment yielded a total TU of 1.25, indicating these contaminants are contributing to the observed sediment toxicity. Using a combination of these TIE and EqP assessment tools, this investigation was capable of identifying NOCs as the likely class of contaminants causing acute toxicity to amphipods exposed to Patrick Bayou sediment. The cause of mysid toxicity was not definitively determined, but unmeasured NOCs are suspected. Environ. Toxicol. Chem. 2010;29:742–750. © 2009 SETAC
The role of indirect photolysis in limiting the persistence of crop protection products in surface waters
Authors: Wallace Derek F. , Hand Laurence H. , Oliver Robin G.
Published: March 2010

The photodegradation of six crop protection products (CPPs) was studied in 16 natural waters collected from across the midwest of the United States under simulated sunlight to determine the significance of indirect photolysis. The rate of degradation of five of the CPPs was faster in irradiated natural waters than in buffer systems, with the effect particularly significant with the relatively photostable compounds propiconazole and prometryn. Degradation rates were correlated with the concentration of one or more photosensitizers, or ratios thereof, by means of a Pearson's correlation and linear regression analysis. It was found that the photodegradation of chlorotoluron, pinoxaden, propiconazole and prometryn were linked to the concentration of nitrate, pointing to a significant role of hydroxyl radical (.OH) as a reactive intermediate. Increased concentrations of dissolved organic carbon (DOC) and bicarbonate relative to nitrate were found to decrease the rate of degradation of these compounds, consistent with a quenching role. Chlorothalonil appeared to be rapidly degraded by means of the carbonate radical (.CO 3−), whereas the photodegradation of emamectin was particularly complex. Overall, indirect photolysis significantly enhanced the rate of CPP degradation and fate models based on these experiments appear to offer more realism than those that only take into account direct photolysis. Environ. Toxicol. Chem. 2010;29:575–581. © 2009 SETAC
Effects of sublethal concentrations of bifenthrin and deltamethrin on fecundity, growth, and development of the honeybee Apis mellifera ligustica
Authors: Dai Ping-Li , Wang Qiang , Sun Ji-Hu , Liu Feng , Wang Xing , Wu Yan-Yan , Zhou Ting
Published: March 2010

Bifenthrin and deltamethrin have been widely used as pesticides in agriculture and forestry and are becoming an increasing risk to honeybees. The honeybee, Apis mellifera ligustica, is widely recognized as a beneficial insect of agronomic, ecological, and scientific importance. It is important to understand what effects these chemicals have on bees. Effects of two pesticides at sublethal concentrations on fecundity, growth, and development of honeybees were examined with the feeding method for a three-year period (2006–2008). It was shown that both bifenthrin and deltamethrin significantly reduced bee fecundity, decreased the rate at which bees develop to adulthood, and increased their immature periods. The toxicity of bifenthrin and deltamethrin on workers of Apis mellifera ligustica was also assessed, and the results from the present study showed that the median lethal effects of bifenthrin and deltamethrin were 16.7 and 62.8 mg/L, respectively. Environ. Toxicol. Chem. 2010;29:644–649. © 2009 SETAC
Protein-based electrochemical biosensor for detection of silver(I) ions
Authors: Krizkova Sona , Huska Dalibor , Beklova Miroslava , Hubalek Jaromir , Adam Vojtech , Trnkova Libuse , Kizek Rene
Published: March 2010

Silver(I) ions are extremely toxic to aquatic animals. Hence, monitoring of these ions in the environment is needed. The aim of the present study was to suggest a simple biosensor for silver(I) ions detection. The suggested biosensor is based on the modification of a hanging mercury drop electrode (HMDE) by the heavy metal binding protein metallothionein (MT) for silver(I) ions detection. Metallothionein accumulated for 120 s onto the HMDE surface. After rinsing the electrode, the biosensor (MT modified HMDE) was prepared prior to detection of silver(I) ions. The biosensor was immersed in a solution containing silver(I) ions. These ions were bound to the MT structure. Furthermore, the electrode was rinsed and transferred to a pure supporting electrolyte solution, in which no interference was present. Under these experimental conditions, other signals relating to heavy metals naturally occurring in MT were not detected. This phenomenon confirms the strong affinity of silver(I) ions for MT. The suggested biosensor responded well to higher silver(I) ion concentrations. The relative standard deviation for measurements of concentrations higher than 50 µM was approximately 2% (n = 8). In the case of concentrations lower than 10 µM, the relative standard deviation increased to 10% (n = 8). The detection limit (3 signal/noise) for silver(I) ions was estimated as 500 nM. Environ. Toxicol. Chem. 2010;29:492–496. © 2009 SETAC
Multicentre phase II study of CyclOBEAP plus rituximab in patients with diffuse large B‐cell lymphoma
Authors: Niitsu Nozomi , Kohri Mika , Hagiwara Yuki , Tanae Ken , Takahashi Naoki , Bessho Masami , Okamoto Masataka
Published: March 2010

The R‐CHOP regimen has been found to improve the outcome of diffuse large B‐cell lymphoma (DLBCL). However, it does not provide a satisfactory treatment outcome in the high‐risk group. We previously administered the CyclOBEAP regimen to patients with DLBCL, and reported its safety and efficacy. The R‐CyclOBEAP regimen was administered over a total period of 12 weeks, and rituximab 375 mg/m2was given every 2 weeks. There were 101 eligible patients. CR was achieved in 96 patients (95%). The 5‐year overall survival (OS) rate was 85% and progression‐free survival (PFS) rate was 76%. When the patients were divided according to the IPI, the 5‐year OS and PFS rates did not significantly differ among the risk groups. The 5‐year PFS of the germinal centre B‐cell group was 80% and that of the non‐GCB group was 74% (NS). Univariate analysis showed that the presence of B symptoms, extranodal lesions ≧2, and sIL‐2R were significant poor prognostic factors. Grade 4 neutropenia was observed in 91 patients and thrombocytopenia in 9 patients. The addition of rituximab to CyclOBEAP therapy may enhance the effect of CyclOBEAP therapy for DLBCL. Copyright © 2010 John Wiley & Sons, Ltd.
Estimating historic lake stages from one‐time snapshot, the Shuttle Radar Topography Mission of 2000
Authors: Bhang Kon Joon , Schwartz Frank W. , Park Seok‐Soon
Published: March 2010

Lake studies play an important role in water management, ecology and other environmental issues. Monitoring lake stages is typically the first step on the lake studies. However, for the Prairie Pothole Region (PPR) of North America with millions of small lakes and potholes, onsite measurements for lake stages are almost impossible with the conventional gage stations due to the limited accessibility to lakes and the requirement of economical and human resources. To overcome this limitation, we employed the remote‐sensing approach to extract lake stages in PPR for bulk processing. To estimate lake stages, several image‐processing techniques were used with the Shuttle Radar Topography Mission (SRTM) data in January, 2000, a one‐time snapshot useful in historic lake level reconstruction. In this research, image processing techniques, for example, averaging, Fast Fourier Transform (FFT), Lee‐Sigma filtering were applied and masking with Canny Edge Detector (CED) and semi‐automated contouring were developed for lake stage estimation. In terms of simplicity, averaging might be useful if 1·5 m of the local bias for the study area in stage estimates. However, the FFT and Lee‐Sigma methods were slightly better than averaging. Masking with CED and semi‐automated contouring provided outstanding accuracy in the estimation. The masking and contouring methods provided ± 0·5 m of stage differences for relatively large lakes greater than 10 km2 when compared with stage reading in spite of their calculation complexities and was shown as the best approaches among implemented methods in this study. Copyright © 2010 John Wiley & Sons, Ltd.
Water percolation process studies in a Mediterranean karst area
Authors: Lange J. , Arbel Y. , Grodek T. , Greenbaum N.
Published: March 2010

To investigate processes of water percolation, the drip response of stalactites in a karstic cave below a 143 m2 sprinkling plot was measured. The experiment was conducted in Mount Carmel, Israel, at the end of the dry season and intended to simulate a series of two high‐intensity storms on dry and wet soils. In addition to hydrometric measurements (soil moisture, surface runoff, stalactite dripping rates), two types of tracers (electrical conductivity and bromide) were used to study recharge processes, water origin and mixing inside a 28‐m vadose zone. Results suggested that slow, continuous percolation through the rock matrix is of minor importance and that percolating water follows a complicated pattern including vertical and horizontal flow directions. While bromide tracing allowed identification of quick direct flow paths at all drips with maximum flow velocities of 4·3 m/h, mixing analysis suggested that major water fractions were mobilized by piston flow, pushing out water stored in the unsaturated zone above the cave. Under dry preconditions, 80 mm of artificial rainfall applied in less than 7 h was not enough to initiate significant downward water percolation. Most water was required to fill uppermost soil and rock storages. Under wet preconditions during the second day sprinkling, higher water contents in soils and karst cavities facilitated piston flow effects and a more intense response of the cave drips. Results indicate that in Mediterranean karst regions, filling of the unsaturated zone, including soil and rock storages, is an important precondition for the onset of significant water percolation and recharge. This results in a higher seasonal threshold for water percolation than for the generation of surface runoff. Copyright © 2010 John Wiley & Sons, Ltd.
Neurochemical profile of the mouse hypothalamus using in vivo1H MRS at 14.1T
Authors: Lei Hongxia , Poitry‐Yamate Carol , Preitner Frédéric , Thorens Bernard , Gruetter Rolf
Published: March 2010

The hypothalamus plays an essential role in the central nervous system of mammals by among others regulating glucose homeostasis, food intake, temperature, and to some extent blood pressure. Assessments of hypothalamic metabolism using, e.g. 1H MRS in mouse models can provide important insights into its function. To date, direct in vivo 1H MRS measurements of hypothalamus have not been reported. Here, we report that in vivo single voxel measurements of mouse hypothalamus are feasible using 1H MRS at 14.1T. Localized 1H MR spectra from hypothalamus were obtained unilaterally (2–2.2 µL, VOI) and bilaterally (4–4.4 µL) with a quality comparable to that of hippocampus (3–3.5 µL). Using LCModel, a neurochemical profile consisting of 21 metabolites was quantified for both hypothalamus and hippocampus with most of the Cramér‐Rao lower bounds within 20%. Relative to the hippocampus, the hypothalamus was characterized by high γ‐aminobutryric acid and myo‐inositol, and low taurine concentrations. When studying transgenic mice with no glucose transporter isoform 8 expressed, small metabolic changes were observed, yet glucose homeostasis was well maintained. We conclude that a specific neurochemical profile of mouse hypothalamus can be measured by 1H MRS which will allow identifying and following metabolic alterations longitudinally in the hypothalamus of genetic modified models. Copyright © 2010 John Wiley & Sons, Ltd.
A new model for the origin of kinetic hydrogen isotope effects
Authors: Klinman Judith P.
Published: March 2010

Measurements of kinetic hydrogen isotope effects in enzymatic CH bond cleavage reactions have generated a body of data that is inconsistent with either a semi‐classical formalism for the origin of the isotope effects or a semi‐classical formalism together with a modest degree of hydrogen tunneling. A model that treats the movement of hydrogen as a wave, and whose behavior is dictated by the heavy atom environment, is presented and discussed. A list of unanswered questions and challenges is given at the end of this paper. Copyright © 2010 John Wiley & Sons, Ltd.
Development of a handheld sensor system system for the online measurement of hydrogen peroxide in aseptic filling systems
Authors: Reisert Steffen , Henkel Hartmut , Schneider Andreas , Schäfer Daniel , Friedrich Peter , Berger Jörg , Schöning Michael J.
Published: March 2010

A handheld sensor system for the online measurement of hydrogen peroxide (H2O2) in aseptic sterilisation processes has been developed. It is based on a calorimetric‐type gas sensor that consists of a differential set‐up of two temperature sensors, of which one is catalytically activated and the second one is passivated and used as reference. The sensor principle relies in detecting a rise in temperature on the active sensor due to the exothermic reaction of H2O2 on the catalytic surface. To characterise the sensor system towards H2O2 sensitivity and other influencing factors, measurements have been carried out both at an experimental set‐up and a manufacturer's sterilisation machine. Physical sensor characterisation was done by means of the optical microscopy.
Development of an electrolyte–insulator–semiconductor (EIS) based capacitive heavy metal sensor for the detection of Pb2+ and Cd2+ ions
Authors: Spelthahn Heiko , Schaffrath Sophie , Coppe Thomas , Rufi Frederic , Schöning Michael J.
Published: March 2010

Chalcogenide glass materials as membranes for potentiometric sensors for chemical analysis in solutions have been studied since more than 20 years. In this work, an electrolyte–insulator–semiconductor structure was combined with chalcogenide glass membranes prepared by means of the pulsed laser deposition technique. Depending on the membrane composition a selectivity to different ions (Cd2+ and Pb2+) is achieved. The different sensor membranes have been physically characterised using microscopy, ellipsometry, profilometry, atomic force microscopy (AFM), scanning electron microscopy (SEM) and Rutherford backscattering spectrometry (RBS). The electrochemical behaviour has been investigated via capacitance/voltage (C/V) and constant capacitance (ConCap) measurements and results in a Cd2+ sensitivity of 23.1 ± 0.6 mV per decade in a linear range from 7 × 10−6 to 10−2 mol/l and 24.4 ± 0.5 mV per decade in a linear range from 5 × 10−6 to 10−2 mol/l for Pb2+, respectively.
Tree colonization trends on a sediment bar after a major flood
Authors: Asaeda T. , Gomes P. I. A. , Sakamoto K. , Rashid Md. H.
Published: March 2010

Tree mortality and regeneration in riparian areas are greatly influenced by flooding. The elevational distribution ofSalixspp. andRobinia pseudoacaciawere investigated by observing densities and standing conditions before and after a major flood on a sediment bar in the middle reaches of the Arakawa River in Kumagaya, Japan. The subsequent tree recruitment was also examined.R. pseudoacaciawas easily washed away with the eroded sediment, whereasSalixspp. was found to be more tolerant. Both species were able to survive even after collapsing, provided that their roots were fully or partially embedded in the sediment. Re‐shooting of collapsed trees, rather than emergence from saplings (either by seeds or vegetative fragments), was observed to be the major method of recruitment after the flood. Therefore, tree density before the flood was unchanged, unless the trees were subject to washing away.Salixspp. recruitment was mainly observed in low‐lying areas andR. pseudoacaciain elevated areas. Recruitment from saplings was species‐specific.Salixspp. at high elevations originated mainly from shoot fragments as they need high levels of moisture for seed germination and at higher elevations, sediment moisture content is very low.R. pseudoacacia, on other hand, originated mainly from roots and seeds. At a given elevation, past recruitment patterns indicated that the annual recruitment of trees increased with tree density up to a particular threshold of recruitment density. Further increases in tree density beyond that optimum value resulted in a decline in recruitment. Furthermore, threshold density was observed to increase along with elevation forR. pseudoacaciawhile declining withSalixspp. Copyright © 2010 John Wiley & Sons, Ltd.
Microchemical characterisation of carbon–metal interface in Ti6Al4VSiCf composites
Authors: Kaciulis S. , Mezzi A. , Donnini R. , Deodati P. , Montanari R. , Ucciardello N. , Amati M. , Kazemian‐Abyaneh M. , Testani C.
Published: March 2010

The composite of Ti6Al4V alloy, reinforced by unidirectional SiC fibres coated with graphite, has been investigated through a new fabrication process, roll diffusion bonding (RDB), developed at the CSM laboratories. Microchemical characteristics of the interface between carbon (coating of SiC fibres) and metal (Ti6Al4V) have been investigated by means of XPS, multipoint AES and photoemission spectromicroscopy (Electron Spectroscopy for Chemical Analysis (ESCA) microscopy beamline at the ELETTRA synchrotron light source). The results obtained revealed that the composition of the fibre–metal interface is similar to that of the composites produced by conventional method of hot isostatic pressing (HIP).

In the matrix, near to the fibres, the anomalous shape of Al 2p signal indicated the presence of CAl atom pairs which are responsible for the anelastic characteristics of the composite. Copyright © 2010 John Wiley & Sons, Ltd.
Crystallographic aspects of intergranular failure of archaeological silver artefacts
Authors: Lejček Pavel , Gärtnerová Viera , Jäger Aleš , Vaníčková Jaroslava , Děd Jiří , Haloda Jakub
Published: March 2010

Excavated archaeological silver objects often exhibit extended intergranular degradation. This failure is most probably caused by the localised corrosion of highly copper‐segregated grain boundaries in case of a AgCu base alloy during burial for more than 1000 years in graves. Detailed electron backscatter diffraction (EBSD) analysis of individual grain boundaries showed that this corrosion degradation is controlled by the crystallography of the grain boundaries: exclusively, the general grain boundaries are prone to the corrosion while the special ones are not attacked at all. It is also deduced that the orientation of the grain boundary plane plays an important role in the selective corrosion attack. Copyright © 2010 John Wiley & Sons, Ltd.
Effective medium theory for REELS analysis of amorphous carbon films
Authors: Calliari L. , Fanchenko S. , Filippi M.
Published: March 2010

We use effective medium theory (EMT) as a framework to describe reflection electron energy loss spectra (REELS) from polycrystalline graphite and amorphous carbon (a‐C), the latter obtained by ion irradiation of the former. Such materials, isotropic at a macroscopic scale, are anisotropic at the micro‐ or nano‐scale. For them, we prove the value of the concept of effective isotropic energy loss function to describe EELS in the plasmon region. Based on this function, we calculate a differential inverse inelastic mean free path (DIIMFP) which, compared to experimental spectra from pristine and ion‐irradiated polycrystalline graphite, is able to reproduce their main features. Copyright © 2010 John Wiley & Sons, Ltd.
Voltage‐assisted sodium ion incorporation and transport in thin silicon dioxide films
Authors: Krivec S. , Buchmayr M. , Detzel Th. , Nelhiebel M. , Hutter H.
Published: March 2010

Na+ is a well‐known contaminant in metal‐oxide‐semiconductor field effect transistor devices, which may cause severe changes in their input characteristics. This work is addressed to investigate the incorporation and transport behavior of mobile Na+ ions in SiO2, representing a material of major importance in semiconductor technology. We design an appropriate model system, to deliberately incorporate Na+ ions into a thin SiO2 film, which is attached on an n‐doped Si wafer. A spin‐coated thin polymer film, doped with sodium triflate in a low concentration, serves as external Na+ host matrix. The incorporation is assisted by means of an external voltage. Time of flight–secondary ion mass spectrometry is chosen as the tool for determination of Na+ ion location and distribution in SiO2. Measurements show that once Na+ was incorporated, the enormous internal electrical field in the bulk SiO2 causes an immediate drift of these ions toward the SiO2/Si interface, where a pile up of Na+ occurs. The related diffusion part can therefore be neglected. However, this accumulation has a counteracting effect on the electrical field and thus influences the incorporation rate. A comparison between the detected number of Na+ ions from potentiostatic and spectrometric data shows good agreement. Copyright © 2010 John Wiley & Sons, Ltd.
Size shift of XPS lines observed from PbS nanocrystals
Authors: Kovalev Anatoly I. , Wainstein Dmitry L. , Rashkovskiy Alexandr Yu. , Osherov Anna , Golan Yuval
Published: March 2010

Crystals of PbS with different sizes were obtained by chemical deposition from aqueous solution (chemical bath deposition technique) onto undoped Si (100) substrate. The morphology and size of crystals were analyzed by high resolution scanning electron microscopy. The fine structure of Pb 4f and S 2p photoelectron lines was measured by X‐ray photoelectron spectroscopy with monochromatic Al Kα source (hν = 1486.6 eV). The phenomenon of size shift, i.e. growth of binding energies for both donor Pb 4f and acceptor S 2p photoelectron lines with decreasing nanocrystals' size, was found and quantified as a function of nanocrystals' size. The size shift values of the Pb 4f5/2 and 4f7/2 lines were determined for nanocrystals with a size from 20 to 250 nm. The interband and intraband electronic transitions were investigated by high resolution electron energy losses spectroscopy. It was shown that width and spatial anisotropy of the band gap depend on the size of PbS nanocrystals. The dependence of size shift from nanocrystals' size, the nature of this phenomenon, and a role of changes in fine structure of electronic states near the band gap are discussed in the report. Copyright © 2010 John Wiley & Sons, Ltd.
Photoelectric threshold of silicon wafer surfaces implanted with H, Si and Ar ions
Authors: Momose Y. , Kosaka S. , Sakurai T. , Yanagisawa M. , Nakayama K.
Published: March 2010

The effect of ion implantation on the photoemission spectral yield for native oxide‐covered Si(100) wafer surfaces has been studied. Three types of H, Si and Ar atoms were employed for the ion implantation. For one sample the yield curve was measured successively first at 25 °C, next after heating to 340 °C, and subsequently after cooling to 40 °C. All implanted samples showed the photoemission in the spectral yield with a much enhanced intensity compared to a nonimplanted sample, moreover, more strongly at 340 °C than at 25 and 40 °C. The analysis of the yield curve showed two distinct photothresholds of ϕ1 and ϕ2, which can be attributed to the interface states at the SiO2/Si interface and the silicon bulk, respectively, and the creation of a localized emitting center ascribed to E′ center (≡ Si ·). Both thresholds for the implanted samples were reduced about 0.3–0.5 eV compared to those for the nonimplanted sample. The localized center appeared at the photon energy of 5.66 eV (25 and 40 °C) and 5.76 eV (340 °C), and the amount of the centers created at 340 °C was much greater than that at 25 and 40 °C. Interestingly, the amount of the E′ centers at 25 °C for the H implanted sample tended to decrease with an increase in the concentration of implanted H atoms. Copyright © 2010 John Wiley & Sons, Ltd.
Analysis of Fe nanoparticles using XPS measurements under d.c. or pulsed‐voltage bias
Authors: Suzer Sefik , Baer Donald R. , Engelhard Mark H.
Published: March 2010

The impact of solution exposure on the charging properties of oxide coatings on Fe metal‐core oxide–shell nanoparticles has been examined by sample biasing during XPS measurements. The Fe nanoparticles were suspended in relatively unreactive acetone and analyzed after particles containing solutions were deposited on SiO2/Si or Au substrates. The particle and substrate combinations were subjected to ± 10V d.c. or ± 5V a.c., biasing in the form of square wave (SQW) pulses. The samples experienced variable degrees of charging for which low‐energy electrons at ∼1 eV, 20 µA and low‐energy Ar+ ions were used to minimize it. Application of d.c. bias and/or SQW pulses significantly influences the extent of charging, which is utilized to gather additional analytical information about the sample under investigation. This approach allows separation of otherwise overlapping peaks. Accordingly, the O1s peaks of the silicon oxide substrate, the iron oxide nanoparticles, and that of the casting solvent can be separated from each other. Similarly, the C1s peak belonging to the solvent can be separated from that of the adventitious carbon. The charging shifts of the iron nanoparticles are strongly influenced by the solvent to which the particles were exposed. Hence, acetone exhibited the largest shift, water the smallest, and methanol in between. Dynamical measurements performed by application of the voltage stress in the form of SQW pulses provides information about the time constants of the processes involved, which leads us to postulate that these charging properties we probe in these systems stem mainly from ionic movement(s). Copyright © 2010 John Wiley & Sons, Ltd.
Study on surface morphology of nanoscale structure of pure and zinc‐doped tin oxide uniform thin films
Authors: Rozati S. M. , Shadmani E.
Published: March 2010

In this study, we investigated the surface morphology of uniform pure and zinc‐doped tin oxide thin films in detail. Films of undoped and Zn‐doped tin oxide (SnO2: Zn) were prepared on glass substrates at 450 °C by spray pyrolysis technique. Tin chloride dehydrate (SnCl2.2H2O), and zinc acetate (Zn(CH3COO)2.2H2O) and zinc chloride (ZnCl2) were used as sources of tin (Sn) and zinc (Zn), respectively. The variation in the solution concentration of the films was reflected in their morphologies as examined by scanning electron microscopy (SEM) and atomic force microscopy (AFM). Their findings show that the films have nanoscale structure. The surface parameters were calculated for thin films. The root mean square (RMS) roughness obtained for undoped SnO2 thin films reduced with the addition of Zn in the starting solution. A comparison between the doped films with zinc acetate and zinc chloride shows a difference in their roughness. The electrical and optical properties of the films were also measured. Copyright © 2010 John Wiley & Sons, Ltd.
Structure and composition of electrospun titania nanofibres doped with Eu
Authors: Mezzi A. , Kaciulis S. , Cacciotti I. , Bianco A. , Gusmano G. , Lamastra F. R. , Fragalà M. E.
Published: March 2010

Electrospinning technique was used to prepare the nanofibres of pure and Europium (Eu)‐doped titania with Eu content of 3–10%mol. The solution was electrospun in air at room temperature. The obtained fibrous mats were thermally treated at 500 or 1000 °C.

Morphology and phase analyses of the resulting fibrous ceramic mats were carried out by using SEM and X‐ray diffraction (XRD), while the surface chemical composition was investigated by XPS. Annealed mats consisted of randomly oriented fibres with fairly uniform and nanometric diameter, dependent on the doping level. The main titania phase in the samples, heated at 500 °C, was anatase, whereas rutile phase with small traces of Eu2Ti2O7 were identified in the samples calcined at 1000 °C.

From the XPS analysis, it was determined that all the samples were composed of Ti4+ and Eu3+ species. XPS quantification of annealed samples revealed a surface enrichment with Eu. XPS depth profiles demonstrated that the chemical composition of the samples was constant. Moreover, it was observed that the Ti4+ reduction, induced by ion sputtering, decreased in the samples with higher concentration of Eu dopant. Copyright © 2010 John Wiley & Sons, Ltd.