bluuebunny/crossref_metadata_2025 huggingface dataset:
Enhanced Nicotinic Receptor Function and Drug Abuse Vulnerability
Authors: Fagen Zara M. , Mitchum Robert , Vezina Paul , McGehee Daniel S.
Published: August 2007

In animals and humans, vulnerability to drug abuse varies among individuals. Animals that display high activity levels in a novel environment are more likely to self-administer psychostimulant drugs, including nicotine, cocaine, amphetamine, and morphine. Recent reports from behavioral studies indicate that nicotinic acetylcholine receptor (nAChR) activity contributes to the rewarding effects of several different addictive drugs. Thus, we hypothesized that differences in nAChR activity may contribute to the predisposition to drug self-administration. After screening of adult rats (>60 d postnatal) for the behavioral response to a novel environment, electrophysiological measures of nAChR function were conducted in brain slices that included the mesoaccumbens dopamine neurons of the ventral tegmental area (VTA). We found a positive correlation between the response to novelty and nAChR function in each assay conducted, including nAChR modulation of glutamatergic and GABAergic synaptic inputs to VTA dopamine neurons, as well as somatic nAChR responses of VTA neurons. The response to novelty and sensitivity to addictive drugs are positively correlated with the hormonal response to stress. Consistent with this observation, we found enhanced nAChR responsesin vitroafter a 48 h corticosterone treatment andin vivoafter 48 h of repeated stress. Each of these effects was inhibited by RU486 (11β-[p-(dimethylamino)phenyl]-17β-hydroxy-17-(1-propynyl)estra-4,9-dien-3-one) pretreatment, suggesting a steroid hormone receptor-dependent process. These findings suggest that differences in nAChR function within the mesoaccumbens dopamine system may contribute to individual differences in drug abuse vulnerability and that these are likely attributable to differences in stress hormone levels.
Modulation of Thalamic Nociceptive Processing after Spinal Cord Injury through Remote Activation of Thalamic Microglia by Cysteine–Cysteine Chemokine Ligand 21
Authors: Zhao Peng , Waxman Stephen G. , Hains Bryan C.
Published: August 2007

Spinal cord injury (SCI) results in the generation and amplification of pain caused in part by injury-induced changes in neuronal excitability at multiple levels along the sensory neuraxis. We have previously shown that activated microglia, through an ERK (extracellular signal-regulated kinase)-regulated PGE2(prostaglandin E2) signaling mechanism, maintain neuronal hyperexcitability in the lumbar dorsal horn. Here, we examined whether microglial cells in the thalamus contribute to the modulation of chronic pain after SCI, and whether microglial activation is governed by spinally mediated increases in the microglial activator cysteine–cysteine chemokine ligand 21 (CCL21). We report that CCL21 is upregulated in dorsal horn neurons, that tissue levels are increased in the dorsal horn and ventral posterolateral (VPL) nucleus of the thalamus 4 weeks after SCI, and that the increase can be differentially reduced by spinal blockade at T1 or L1. In intact animals, electrical stimulation of the spinothalamic tract induces increases in thalamic CCL21 levels. Recombinant CCL21 injected into the VPL of intact animals transiently activates microglia and induces pain-related behaviors, effects that could be blocked with minocycline. After SCI, intra-VPL antibody-mediated neutralization of CCL21 decreases microglial activation and evoked hyperexcitability of VPL neurons, and restores nociceptive thresholds to near-normal levels. These data identify a novel pathway by which SCI triggers upregulation of the neuroimmune modulator CCL21 in the thalamus, which induces microglial activation in association with pain phenomena.
Relationship Between White Matter Apparent Diffusion Coefficients in Preterm Infants at Term-Equivalent Age and Developmental Outcome at 2 Years
Authors: Krishnan Michelle L. , Dyet Leigh E. , Boardman James P. , Kapellou Olga , Allsop Joanna M. , Cowan Frances , Edwards A. David , Rutherford Mary A. , Counsell Serena J.
Published: August 2007

OBJECTIVE. The aim of this study was to develop a simple reproducible method for the measurement of apparent diffusion coefficient values in the white matter of preterm infants using diffusion-weighted imaging to test the hypothesis that elevated mean apparent diffusion coefficient values are associated with lower developmental quotient scores at 2 years’ corrected age.

METHODS. We obtained diffusion-weighted imaging in 38 preterm infants at term-equivalent age who had no evidence of overt cerebral pathology on conventional MRI. Mean apparent diffusion coefficient values at the level of the centrum semiovale were determined. The children were assessed using a standardized neurologic examination, and the Griffiths Mental Development Scales were administered to obtain a developmental quotient at 2 years’ corrected age. The relationship between mean apparent diffusion coefficient values and developmental quotient was examined. Clinical data relating to postnatal sepsis, antenatal steroid exposure, supplemental oxygen, gender, patent ductus arteriosus, and inotrope requirement were collected, and the mean apparent diffusion coefficient values for each group were compared.

RESULTS. The mean (±SD) apparent diffusion coefficient value in the white matter was 1.385 ± 0.07 × 10−3 mm2/second, and the mean developmental quotient was 108.9 ± 11.5. None of the children had a significant neurologic problem. There was a significant negative correlation between mean apparent diffusion coefficient and developmental quotient.

CONCLUSION. These findings suggest that higher white matter apparent diffusion coefficient values at term-equivalent age in preterm infants without overt lesions are associated with poorer developmental performance in later childhood. Consequently, apparent diffusion coefficient values at term may be of prognostic value for neurodevelopmental outcome in infants who are born preterm and who have no other imaging indicators of abnormality.
Immunotherapy of Familial Hemophagocytic Lymphohistiocytosis With Antithymocyte Globulins: A Single-Center Retrospective Report of 38 Patients
Authors: Mahlaoui Nizar , Ouachée-Chardin Marie , de Saint Basile Geneviève , Neven Bénédicte , Picard Capucine , Blanche Stéphane , Fischer Alain
Published: August 2007

OBJECTIVES. Familial hemophagocytic lymphohistiocytosis is a genetically determined condition that is characterized by unremitting CD8 T lymphocyte and macrophage activation and leads to death in the absence of therapy. On the basis of the immunologic pathophysiology of familial hemophagocytic lymphohistiocytosis, we propose a therapy with a combination of antithymocyte globulins with corticosteroids, cyclosporin A, and intrathecal injections of methotrexate.

METHODS. We retrospectively analyzed the outcome of antithymocyte globulin–based therapy that was performed in 38 consecutive patients who had familial hemophagocytic lymphohistiocytosis and were treated in a single center between 1991 and 2005. Overall, they received 45 courses of antithymocyte globulin (5–10 mg/kg per day for 5 days).

RESULTS. This regimen was associated with infections after 10 of 45 courses of antithymocyte globulin. There were 6 events after 11 antithymocyte globulin courses given as second-line therapy against 4 after 34 antithymocyte globulin courses in patients who were treated primarily with antithymocyte globulin. Antithymocyte globulin administration led to rapid and complete response of familial hemophagocytic lymphohistiocytosis in 73% of cases, partial response in 24%, and no response only once. When hematopoietic stem cell transplantation was performed early after complete or partial response induction, it led to a high rate of cure, in 16 of 19 cases. Overall survival was 21 of 38 with 4 toxic deaths.

CONCLUSION. Antithymocyte globulin based immunotherapy of familial hemophagocytic lymphohistiocytosis is efficient and carries an acceptable toxicity when used as a first treatment of familial hemophagocytic lymphohistiocytosis.
Astaxanthin-Supplemented Diets Do Not Improve Adult Survival of Coho Salmon
Authors: Tipping Jack M
Published: August 2007

Astaxanthin, a natural carotenoid pigment from primary producers in the salmonid food chain, may be an important contributor to the natural salmonid coloration that enhances predation avoidance. In an attempt to improve survival to maturity in hatchery-reared coho salmon Oncorhynchus kisutch, I administered an astaxanthin-supplemented diet to three replicate groups of fish (1 group/year) for 3–4 months before release. Control fish were fed the same diet but without astaxanthin. Both groups of fish were coded-wire-tagged before release. Differences in external hue coloration of treated and control fish were noted at release. Although mean adult survival of astaxanthin-fed fish was 14% lower than control fish survival, the difference was not significant. Supplementation of feed with astaxanthin did not yield a survival benefit for coho salmon.
Electrofishing Effort Required to Estimate Biotic Condition in Southern Idaho Rivers
Authors: Maret Terry R. , Ott Douglas S. , Herlihy Alan T.
Published: August 2007

An important issue surrounding biomonitoring in large rivers is the minimum sampling effort required to collect an adequate number of fish for accurate and precise determinations of biotic condition. During the summer of 2002, we sampled 15 randomly selected large-river sites in southern Idaho to evaluate the effects of sampling effort on an index of biotic integrity (IBI). Boat electrofishing was used to collect sample populations of fish in river reaches representing 40 and 100 times the mean channel width (MCW; wetted channel) at base flow. Minimum sampling effort was assessed by comparing the relation between reach length sampled and change in IBI score. Thirty-two species of fish in the families Catostomidae, Centrarchidae, Cottidae, Cyprinidae, Ictaluridae, Percidae, and Salmonidae were collected. Of these, 12 alien species were collected at 80% (12 of 15) of the sample sites; alien species represented about 38% of all species (N = 32) collected during the study. A total of 60% (9 of 15) of the sample sites had poor IBI scores. A minimum reach length of about 36 times MCW was determined to be sufficient for collecting an adequate number of fish for estimating biotic condition based on an IBI score. For most sites, this equates to collecting 275 fish at a site. Results may be applicable to other semiarid, fifth-order through seventh-order rivers sampled during summer low-flow conditions.
Noninvasive Tracking of Cardiac Embryonic Stem Cells In Vivo Using Magnetic Resonance Imaging Techniques
Authors: Ebert Steven N. , Taylor David G. , Nguyen Ha-Long , Kodack David P. , Beyers Ronald J. , Xu Yaqin , Yang Zequan , French Brent A.
Published: August 2007

Despite rapid advances in the stem cell field, the ability to identify and track transplanted or migrating stem cells in vivo is limited. To overcome this limitation, we used magnetic resonance imaging (MRI) to detect and follow transplanted stem cells over a period of 28 days in mice using an established myocardial infarction model. Pluripotent mouse embryonic stem (mES) cells were expanded and induced to differentiate into beating cardiomyocytes in vitro. The cardiac-differentiated mES cells were then loaded with superparamagnetic fluorescent microspheres (1.63 μm in diameter) and transplanted into ischemic myocardium immediately following ligation and subsequent reperfusion of the left anterior descending coronary artery. To identify the transplanted stem cells in vivo, MRI was performed using a Varian Inova 4.7 Tesla scanner. Our results show that (a) the cardiac-differentiated mES were effectively loaded with superparamagnetic microspheres in vitro, (b) the microsphere-loaded mES cells continued to beat in culture prior to transplantation, (c) the transplanted mES cells were readily detected in the heart in vivo using noninvasive MRI techniques, (d) the transplanted stem cells were detected in ischemic myocardium for the entire 28-day duration of the study as confirmed by MRI and post-mortem histological analyses, and (e) concurrent functional MRI indicated typical loss of cardiac function, although significant amelioration of remodeling was noted after 28 days in hearts that received transplanted stem cells. These results demonstrate that it is feasible to simultaneously track transplanted stem cells and monitor cardiac function in vivo over an extended period using noninvasive MRI techniques.

Disclosure of potential conflicts of interest is found at the end of this article.
Differential resistance to copper and mine drainage inDaphnia longispina: Relationship with allozyme genotypes
Authors: Martins Nelson , Lopes Isabel , Harper Ruth Maureen , Ross Philippe , Ribeiro Rui
Published: August 2007

Differential resistance to metal pollution in Daphnia longispina populations was reported in previous studies. In this work, we tried to determine if variation in polymorphic enzymes, often referred as being under metal selection, were related with differences in resistance to acute single- and mixed-metal exposure. Allozyme genotype of 20 putatively polymorphic enzymes, 48-h median lethal concentration (LC50) for copper, and median lethal time (LT50) for a 3% dilution of acid mine drainage (AMD) were determined for 24 lineages of D. longispina. The copper LC50s ranged from 29.3 to 226 μg/L, and the AMD LT50s ranged from 48 min to 25 h and 29 min, with a strong correlation between both end points. Five distinct multilocus genotypes were identified based on polymorphisms in glucose-6-phosphate isomerase, lactate dehydrogenase, malate dehydrogenase, nicotinamide adenine dinucleotide phosphate (NADP+), phosphoglucomutase, and peroxidase. No differences were found in average genotype sensitivity for both toxicity end points or in genotype frequencies between the resistant- and sensitive-lineage groups. The results obtained indicate that allozyme genotype is not associated with increased resistance to acute metal stress in D. longispina.
Tamoxifen protects against 17α-ethynylestradiol-induced liver damage and the development of urogenital papillae in the rainbow darter (Etheostoma caeruleum)
Authors: Elias Eric Edward , Kalombo Eddie , Mercurio Steven Don
Published: August 2007

Juvenile rainbow darters (Etheostoma caeruleum) were exposed to nominal concentrations of 20 to 1,000 ng/L of 17α-ethynylestradiol (EE2) at 120 d posthatch and in a subsequent experiment to 200 ng/L of EE2 with 2.0 to 20,000 ng/L of tamoxifen (TMX) at 150 d posthatch to determine the threshold of estrogen-induced morphological and histological changes in a sexually dimorphic benthic fish species ecologically relevant to southern Minnesota (USA). 17α-Ethynylestradiol induced female-associated urogenital papillae in males at 200 ng/L, enlargement and development of fibrosis in male testes, enlargement of ovary and oocyte size in females, and large fatty inclusions in the liver of both sexes. Exposure to 1,000 ng/L of EE2 caused gross hypertrophy of the liver and kidneys and high mortalities, predominantly in male fish. A low incidence of ovotestes found in all treatment groups was unaffected by EE2, which may be unusual to this species or a response to unknown water contaminants present during the hatching or early development of the darters. Gonadosomatic index was not altered for either sex by any treatment. A TMX level equal to or less than that of EE2 decreased fat accumulation in the liver in both sexes, and a TMX level greater than that of EE2 appeared to prevent urogenital papilla in males. Tamoxifen did not significantly alter fibrosis caused by EE2 in testes. It appears that the presence of TMX in the environment can mask many signs of estrogen exposure, including secondary sexual characteristics, hypertrophy of ovaries and testes, and fatty infiltration of organs. Ovotestes did not prove to be a good indicator of estrogen exposure at this late stage of juvenile darter development.
In situ and laboratory bioassays withChironomus ripariuslarvae to assess toxicity of metal contamination in rivers: The relative toxic effect of sediment versus water contamination
Authors: Faria Mafalda S. , Lopes Ricardo J. , Nogueira António J.A. , Soares Amadeu M.V.M.
Published: August 2007

We used bioassays employing head capsule width and body length increase of Chironomus riparius larvae as end points to evaluate metal contamination in streams. Bioassays were performed in situ near an abandoned Portuguese goldmine in the spring of 2003 and 2004. Bioassays also were performed under laboratory conditions with water and sediment collected from each stream to verify if laboratory bioassays could detect in situ toxicity and to evaluate the relative contribution of sediment and water to overall toxicity. We used field sediments with control water and control sediments with field water to discriminate between metal contamination in water and sediment. Field water with dry and sieved, organic matter–free, and nontreated sediments was used to determine the toxicity of heavy metals that enter the organism through ingested material. In both in situ and laboratory bioassays, body length increase was significantly inhibited by metal contamination, whereas head capsule width was not affected. Body length increase was more affected by contaminated sediment compared to contaminated water. The lowest-effect level of heavy metals was observed in the dry and sieved sediment that prevented ingestion of sediment particles by larvae. These results suggest that body length increase of C. riparius larvae can be used to indicate the impact of metal contamination in rivers. Chironomus riparius larvae are more affected by heavy metals that enter the organism through ingested sediment than by heavy metals dissolved in the water column. Nevertheless, several factors, such as the particle size and organic matter of sediment, must be taken into account.
Competitive binding comparison of endocrine-disrupting compounds to recombinant androgen receptor from fathead minnow, rainbow trout, and human
Authors: Wilson Vickie S. , Cardon Mary C. , Gray L. Earl , Hartig Phillip C.
Published: August 2007

Typically, in vitro hazard assessments for the identification of endocrine-disrupting compounds (EDCs), including those outlined in the Endocrine Disruptor Screening and Testing Advisory Committee (EDSTAC) Tier 1 Screening protocols, utilize mammalian receptors. Evidence, however, exists that fish sex steroid hormone receptors differ from mammalian receptors both structurally and in their binding affinities for some steroids and environmental chemicals. Most of the binding studies to date have been conducted using cytosolic preparations from various tissues. In the present study, we compare competitive binding of a set of compounds to full-length recombinant rainbow trout androgen receptor α (rtAR), fathead minnow androgen receptor (fhAR), and human androgen receptor (hAR), each expressed in COS cells. Saturation binding and subsequent Scatchard analysis using [3H]R1881, a high-affinity synthetic androgen, revealed an equilibrium dissociation constant (Kd) of 0.11 nM for the rtAR, 1.8 nM for the fhAR, and 0.84 nM for the hAR. Compounds, including endogenous and synthetic steroids, known mammalian antiandrogens, and environmental compounds, were tested for competitive binding to each of the three receptors. Overall, agreement existed across receptors as to binding versus nonbinding for all compounds tested in this study. Minor differences, however, were found in the relative order of binding of the compounds to the individual receptors. Studies such as these will facilitate the identification of EDCs that may differentially affect specific species and aid in the development and support of future risk assessment protocols.
Bayesian multimodel inference for dose-response studies
Authors: Link William A. , Albers Peter H.
Published: August 2007

Statistical inference in dose—response studies is model-based: The analyst posits a mathematical model of the relation between exposure and response, estimates parameters of the model, and reports conclusions conditional on the model. Such analyses rarely include any accounting for the uncertainties associated with model selection. The Bayesian inferential system provides a convenient framework for model selection and multimodel inference. In this paper we briefly describe the Bayesian paradigm and Bayesian multimodel inference. We then present a family of models for multinomial dose—response data and apply Bayesian multimodel inferential methods to the analysis of data on the reproductive success of American kestrels (Falco sparveriuss) exposed to various sublethal dietary concentrations of methylmercury.
Recovery of cholinesterase activity in the earthworm Eisenia fetida Savigny following exposure to chlorpyrifos
Authors: Aamodt Solveig , Konestabo Heidi Sjursen , Sverdrup Line Emilie , Gudbrandsen Marius , Reinecke Sophiè A. , Reinecke Adriaan J. , Stenersen Jørgen
Published: August 2007

Organophosphorus (OP) insecticides inhibit cholinesterase activity, an essential process in the nervous system of most animals. Re-establishment of active enzymes is slow and depends on elimination of the insecticide from the body followed by two lengthy processes: Reactivation and/or biosynthesis of new enzymes. Earthworms (Eisenia fetida) were exposed to either clean or chlorpyrifos-containing (240 mg/kg) soil for 48 h. After transfer to clean soil, we monitored two cholinesterases (E1 and E2) and chlorpyrifos content of the earthworms for 12 weeks. After 14 to 21 d of recovery, the exposed and control worms were indistinguishable in terms of appearance and behavior. Chemical analysis showed a rapid elimination of chlorpyrifos from the earthworms, with only minor levels detected after one week. The activities of E1 and E2 were measured spectrophotometrically in whole specimen homogenates using acetylthiocholine as the substrate. Carbaryl, which selectively inhibits E1, was used to discriminate the enzyme activities. Mean ± standard error of mean of E1 and E2 activity in the controls immediately after exposure were 1.57 ± 0.18 nanokatal (nkat)/mg protein (n = 3) and 0.95 ± 0.07 nkat/mg protein, respectively, and 0.48 ± 0.07 nkat/mg and 0.45 ± 0.06 nkat/mg, respectively, in exposed worms. After three weeks, E1 had regained an activity comparable to the controls, whereas E2 remained depressed throughout the 12-week monitoring period. The non- or late recovery of E2 makes this enzyme a potential biomarker candidate for previous OP insecticide exposure in Eisenia fetida, provided the protocol for measurements is improved and standarized.
3-Methyl-4-nitrophenol metabolism by uridine diphosphate glucuronosyltransferase and sulfotransferase in liver microsomes of mice, rats, and Japanese quail (Coturnix japonica)
Authors: Lee Chul-Ho , Kamijima Michihiro , Li ChunMei , Taneda Shinji , Suzuki Akira K. , Nakajima Tamie
Published: August 2007

3-Methyl-4-nitrophenol (PNMC) is a component of diesel exhaust particles and one of the major breakdown products of the insecticide fenitrothion. This chemical has a high potential for reproductive toxicity in Japanese quail (Coturnix japonica) and rats. Because PNMC inhaled by the body is metabolized by uridine diphosphate glucuronosyltransferase (UGT) and sulfo-transferase, we investigated these enzyme activities in the hepatic microsomes and cytosols of quail (as a model of wild birds) and compared these activities with those of rats and mice as models of ecological and human risk assessment. The maximum velocity of the UGT for PNMC in quail was 12.7 nmol/min/mg, which was one third and one fourth those of rats and mice, respectively. The Michaelis–Menten constant of UGT for PNMC in quail was 0.29 mM, which was 1.3- and 1.8-fold higher than that in mice and rats, respectively, but not significantly different. In accordance with these results, UGT activities for PNMC were lowest in quail, with those in mice and rats being 4.4- and 2.7-fold higher, respectively. Sulfotransferase activity for PNMC was considerably less than that of UGT in all animals, including quail; no significant differences in the activities were found among mice, rats, and quail. These results suggest that glucuronidation may be involved primarily in PNMC elimination from wild birds as well as mammals and that the UGT activity in quail is less than that in the rodents.
Acute toxicity of sodium nitrate, potassium nitrate, and potassium chloride and their effects on the hemolymph composition and gill structure of early juvenile blue swimmer crabs (Portunus pelagicus Linnaeus, 1758) (decapoda, brachyura, portunidae)
Authors: Romano Nicholas , Zeng Chaoshu
Published: August 2007

Various nutrients, including K+ and NO−3, are increasingly being discharged into aquatic systems via anthropogenic sources, which may impact marine organisms. The present study was conducted on blue swimmer crab (Portunus pelagicus) early juveniles to determine the acute toxicity of NaNO3, KNO3, and KCl; if a toxicity interaction exists between K+ and NO−3; the hemolymph Na+, K+, and Ca2+ changes; and the gill histopathological alterations following exposure to elevated NaNO3, KNO3, and KCl levels. A total of 20 replicate crabs were exposed to each of the five NaNO3, KNO3, and KCl concentrations for 96 h. After 96 h, the surviving crabs were sampled for hemolymph Na+, K+, and Ca2+ levels and fixed for histological examination of the anterior gills. The 96-h median lethal concentration of NaNO3-N, KNO3-N, KNO3-K, and KCl-K was 3,452, 112, 312, and 356 mg/L, respectively, for early P. pelagicus juveniles. The toxicity of NaNO3-N was significantly less (p < 0.01) than that of KNO3-N. Furthermore, at the same K+ levels, KNO3-K was significantly (p < 0.05) more toxic than KCl-K, indicating a toxicity interaction between K+ and NO−3. Following exposure to elevated KNO3 and KCl levels, the crabs had significantly higher (p < 0.01) hemolymph K+ levels compared to the control. Conversely, following exposure to elevated NaNO3 concentrations, the crabs had significantly higher (p < 0.01) hemolymph Na+ levels but significantly lower (p < 0.01) hemolymph K+ levels. Despite the markedly different hemolymph ionic changes following NaNO3 and KNO3/KCl exposure, the histopathological changes to the anterior gill lamellae of the crabs appeared to be similar, including lamellae swelling, epithelial thickening, pillar cell disruption, necrosis, and distortion.
Hood Infiltrometer—A New Type of Tension Infiltrometer
Authors: Schwärzel Kai , Punzel Jürgen
Published: August 2007

Disk infiltrometers are widely used to determine saturated and near‐saturated soil hydraulic conductivity. Previous studies have recommended applying a high‐permeability material to the undisturbed soil surface to establish a complete hydraulic bond between the disk and the infiltration surface. Other studies have shown that the use of the contact material affects the infiltration, and hence also the determination of saturated and near‐saturated conductivity. In this study, we tested a new type of infiltrometer (that we call a hood infiltrometer), which might overcome these problems. Instead of requiring a disk and contact material, it places a water‐filled hood, open side down, onto the soil surface. In this study, repeated hood and disk infiltrometer field tests in conjunction with time‐domain reflectometry (TDR) measurements were performed at the same location to compare the performance of the two types of infiltrometer. Furthermore, we extracted undisturbed soil cores to measure the hydraulic functions in the lab. The measured hood and disk data were analyzed using Wooding's solution and by numerical parameter optimization technique using uni‐ and bimodal hydraulic functions. Running the disk infiltrometer with a contact layer provided saturated hydraulic conductivities that were 10 times smaller than corresponding values measured by the hood infiltrometer. We attributed these differences to smearing, sealing, and clogging of pores, which led to additional flow impedances in the soil surface layer. We were able to show, however, that the combined use of hood and disk infiltrometers in conjunction with TDR enabled hydraulic characterization of the soil from saturation to dry conditions.
Magnetic Enhancement and Iron Oxides in the Upper Luochuan Loess–Paleosol Sequence, Chinese Loess Plateau
Authors: Torrent José , Liu Qingsong , Bloemendal Jan , Barrón Vidal
Published: August 2007

Variations in the low‐field magnetic susceptibility of the wind‐blown Chinese Loess Plateau (CLP) loess–paleosol sequences reflect changes in the global paleoclimate on different time scales. Magnetic enhancement in paleosols has been ascribed to the neoformation of fine‐grained maghemite; however, little is known about the pathway through which this mineral was formed in the CLP paleosols, its relationships with the other pedogenic Fe oxides (viz. hematite and goethite), and the pedoclimatic significance of such relationships. In this work, we characterized various magnetic, chemical, and mineralogical properties of the loess–paleosol units at depths from about 23 to 55 m in the Upper Luochuan section, central CLP. The concentration of pedogenic hematite (ΔHm) and the frequency‐dependent magnetic susceptibility (χFD), which is used as a proxy for the concentration of fine‐grained pedogenic maghemite, were found to be linearly correlated (R2 = 0.825, P < 0.001). This supports the idea that these two minerals were formed concomitantly during pedogenesis, which is consistent with the results of previous in vitro experiments showing that the ferrihydrite → maghemite → hematite transformation takes place under aerobic conditions. By contrast, the concentration of pedogenic goethite (ΔGt) was only weakly correlated with either χFD or ΔHm, which suggests that goethite formed through an alternative pathway. The paleosols above 40 m (S4, S5, corresponding to marine isotope stages 9 and 11, respectively) exhibit a higher degree of weathering and higher ΔHm/(ΔHm + ΔGt) ratio than those below such a depth (S6–S8). This was ascribed to differences in paleoclimatic conditions, which are moister and warmer in the former paleosols than in the latter, rather than to differences in pedogenesis duration.
Water governance, resilience and global environmental change – a reassessment of integrated water resources management (IWRM)
Authors: Galaz V.
Published: August 2007

Integrated Water Resource Management (IWRM) is gaining increased acceptance among water policy makers and researchers as a way to create more effective governance institutions, leading towards integrated water development solutions for poverty alleviation, while addressing social, economic and environmental aspects of water challenges. However, global environmental change poses fundamental challenges to water policy makers as it implies vast scientific, and hence, policy uncertainty; its implications for international water governance initiatives remain unspecified, effectively hindering dialogue on how current IWRM initiatives should be modified. This paper addresses the lag between our growing understanding of resilient interconnected freshwater resources (and their governance) and the reforms being promoted by policy makers. In particular, there is a need to rethink some of IWRM's key components to better tackle the challenges posed by the complex behaviour of interconnected social-ecological systems and global environmental change.
Flood risk mapping at European scale
Authors: Barredo J.I. , de Roo A. , Lavalle C.
Published: August 2007

The aim of this article is to illustrate a framework for flood risk mapping at pan-European scale produced by the Weather-Driven Natural Hazards (WDNH) action of the EC-JRC-IES. Early results are presented in the form of flood risk index maps. We assess several flood risk factors that contribute to the occurrence of flood disasters. Among the causal factors of a flood disaster one is triggering a natural event in the form of extreme precipitation and consequently extreme river discharge and extreme flood water levels. The threatening natural event represents the hazard component in our assessment. Furthermore exposure and vulnerability are anthropogenic factors that contribute also to flood risk. In the proposed approach, flood risk is considered on the light of exposure, vulnerability and hazard. We use a methodology with a marked territorial approach for the assessment of the flood risk. Hence, based on mathematical calculations, risk is the product of hazard, exposure and vulnerability. Improvements on datasets availability and spatial scale are foreseen in the next phases of this study. This study is also a contribution to the discussion about the need for communication tools between the natural hazard scientific community and the political and decision making players in this field.
Climate change and the EU Water Framework Directive: how to deal with indirect effects of changes in hydrology on water quality and ecology?
Authors: ter Heerdt G.N.J. , Schep S.A. , Janse J.H. , Ouboter M.
Published: August 2007

In order to set ecological goals and determine measures for the European Water Framework Directive, the effects of climate change on lake ecosystems should be estimated. It is thought that the complexity of lake ecosystems makes this effect inherently unpredictable. However, models that deal with this complexity are available and well calibrated and tested. In this study we use the ecosystem model PCLake to demonstrate how climate change might affect the ecological status of a shallow peaty lake in 2050.

With the model PCLake, combined with a long-term water and nutrient balance, it is possible to describe adequately the present status of the lake. Simulations of future scenarios with increasing precipitation, evaporation and temperature, showed that climate change will lead to higher nutrient loadings. At the same time, it will lead to lower critical loadings. Together this might cause the lake to shift easier from a clear water to a turbid state. The amount of algae, expressed as the concentration Chl-a, will increase, as a consequence turbidity will increase. The outcome of this study; increasing stability of the turbid state of the lake, and thus the need for more drastic measures, is consistent with some earlier studies.
Tensions in water management: Dutch tradition and European policy
Authors: Ravesteijn W. , Kroesen O.
Published: August 2007

Present-day worldwide water problems require new management tools and sustainable system innovations. At Delft University of Technology research is being carried out into water resources and management development aimed at forming such tools and innovations, focused on Integrated River Basin Management (IRBM). One of the case-studies deals with Dutch water management and technology in the context of European IRBM in the form of the 2000 Water Frame Directive. The Netherlands experience many water problems and European IRBM could bring help by offering a framework for both international cooperation and technological innovations. To work as an adequate management tool European IRBM should be tailored to the Dutch water tradition, which recently culminated in Integrated Water Management. Both approaches are in some respects contradicting. Europe pursues, for example, centralized control; while the Dutch have their strongly water boards based decentralized administration. The tensions between both approaches require mutual adaptation, for which the concept of subsidiarity might offer points of departure. This paper describes the first results of the case-research into Dutch water management and technology in the context of Europe as well as the backgrounds and the set-up of the research as a whole.
Instrumentation Network Design for Solids Processes
Authors: Pogodda Matthias , Willms Eike , Gruhn Guenter , Werther Joachim
Published: August 2007

Proper plant control and operation has to be based on measurements of process data at different locations within the process. The design of the instrumentation network is therefore an important step in the design phase of a given process. An advanced instrumentation network design should not only allow process control on a minimum data basis but should enable the plant operator to gain more insights into the functionality and capabilities of his process. For this purpose in-process balancing based on a suitably configured instrumentation network is necessary. To make full use of the measurements the data has to be processed by data reconciliation methods. In the present work an earlier approach by Chmielewski et al. (2002) has been applied to solids processes. This paper shows how the selected approach can be adopted to the measurement and processing of distributed variables, e.g. particle size and densities. An optimal instrumentation with regard to investment cost can be found that ensures that all necessary data for the reconciliation problem can be collected. The application to solids processes is illustrated with the examples of a simple screening-crushing process and a hydrocyclone cascade.
Maxillary and Mandibular Dentoalveolar Heights of French-Canadians 10 to 15 Years of Age
Authors: Buschang Peter H. , Carrillo Roberto , Liu Sean S. , Demirjian Arto
Published: August 2007

Objective: To establish reference data for anterior and posterior dentoalveolar heights of growing French-Canadians with untreated normal occlusions and malocclusions.

Materials and Methods: The mixed longitudinal sample includes 227 French-Canadians, 119 male and 108 female, with cephalograms taken annually between 10–15 years of age. Maxillary and mandibular dentoalveolar heights were measured as the perpendicular distances of the incisor tips and first molar mesial cusp tips to the palatal (ANS-PNS) and mandibular (Go-Me) planes.

Results: Male dentoalveolar heights were significantly (P < .05) greater than female heights at all ages. Dentoalveolar heights at 15 years of age were significantly larger (P < .05) than at 10 years of age, with differences ranging from 2.1–4.2 mm in male subjects and from 2.1–3.8 mm in female subjects. The greatest difference in dentoalveolar heights between the 10- and 15-year-old age groups was for the maxillary first molar; the maxillary central incisor height showed the smallest age effects. The coefficients of variation were greater for the maxillary than the mandibular dentoalveolar heights. Correlations of dentoalveolar heights within jaws ranged from 0.53 to 0.82; correlations between jaws ranged from 0.30 to 0.44. The mandibular heights showed the strongest associations.

Conclusions: French-Canadian adolescents require age- and sex-specific reference data for dentoalveolar heights.
Influence of Surface Characteristics on Survival Rates of Mini-Implants
Authors: Chaddad Karim , Ferreira AndréF. H. , Geurs Nico , Reddy Michael S.
Published: August 2007

Objective: To compare the clinical performance and the survival rate of two mini-implant systems with different surface characteristics under immediate orthodontic loading.

Materials and Methods: Seventeen machined titanium (MT) mini-implants and 15 sandblasted, large grit, acid-etched (SLA) mini-implants were placed in 10 patients. The mini-implants were immediately loaded and the patients seen at 7, 14, 30, 60, and 150 days. Clinical parameters such as anatomical location, character of the soft tissue at the screw head emergence, type of mini-implant system, diameter, and length were analyzed. In addition, the insertion torque recorded at the time of insertion was also assessed. Survival rate and clinical parameters were evaluated by the chi-square exact tests using the SAS version 9.1.

Results: The overall survival rate was 87.5%. Over the four failing mini-implants, three were MT and one SLA resulting in an individual survival rate of 82.4% and 93.4%, respectively. In the failure group, all the fixtures had their screw emergence at the oral mucosa and recorded a torque range of less than 15 Ncm. The insertion torque statistically influenced the survival rate of the mini-implants (P < .05). Surface treatment, anatomical location, as well as soft tissue emergence were not statistically significant.

Conclusion: Surface characteristics did not appear to influence survival rates of immediately loaded mini-implants.
Automatic Cephalometric Analysis
Authors: Leonardi Rosalia , Giordano Daniela , Maiorana Francesco , Spampinato Concetto
Published: August 2007

Objective: To describe the techniques used for automatic landmarking of cephalograms, highlighting the strengths and weaknesses of each one and reviewing the percentage of success in locating each cephalometric point.

Materials and Methods: The literature survey was performed by searching the Medline, the Institute of Electrical and Electronics Engineers, and the ISI Web of Science Citation Index databases. The survey covered the period from January 1966 to August 2006. Abstracts that appeared to fulfill the initial selection criteria were selected by consensus. The original articles were then retrieved. Their references were also hand-searched for possible missing articles. The search strategy resulted in 118 articles of which eight met the inclusion criteria. Many articles were rejected for different reasons; among these, the most frequent was that results of accuracy for automatic landmark recognition were presented as a percentage of success.

Results: A marked difference in results was found between the included studies consisting of heterogeneity in the performance of techniques to detect the same landmark. All in all, hybrid approaches detected cephalometric points with a higher accuracy in contrast to the results for the same points obtained by the model-based, image filtering plus knowledge-based landmark search and “soft-computing” approaches.

Conclusions: The systems described in the literature are not accurate enough to allow their use for clinical purposes. Errors in landmark detection were greater than those expected with manual tracing and, therefore, the scientific evidence supporting the use of automatic landmarking is low.
Rabies surveillance in the United States during 2006
Authors: Blanton Jesse D. , Hanlon Cathleen A. , Rupprecht Charles E.
Published: August 2007

Summary—During 2006, 49 states and Puerto Rico reported 6,940 cases of rabies in animals and 3 cases in humans to the CDC, representing an 8.2% increase from the 6,417 cases in animals and 1 case in a human reported in 2005. Approximately 92% of the cases were in wildlife, and 8% were in domestic animals. Relative contributions by the major animal groups were as follows: 2,615 raccoons (37.7%), 1,692 bats (24.4%), 1,494 skunks (21.5%), 427 foxes (6.2%), 318 cats (4.6%), 82 cattle (1.2%), and 79 dogs (1.1%). Compared with numbers of reported cases in 2005, cases in 2006 increased among all groups except cattle. Increases in numbers of rabid raccoons during 2006 were reported by 11 of the 20 eastern states where raccoon rabies was enzootic, and reported cases increased by 3.2% overall, compared with 2005.

On a national level, the number of rabies cases in skunks during 2006 increased by 6.1% from the number reported in 2005. Once again, Texas reported the greatest number (n = 351) of rabid skunks and the greatest overall state total of animal rabies cases (889). No cases of rabies associated with the dog/coyote rabies virus variant were reported. The last identified case of this canine rabies virus variant was identified in March 2004, along the US/Mexi-co border. With 2006 marking the second year of no apparent transmission of the dog/coyote variant, these findings from surveillance data support the contention that the canine rabies virus variant is no longer in circulation in the United States. Total number of cases of rabies reported nationally in foxes increased 13.6%, compared with 2005. Increases in the number of reported rabid foxes were attributable to greater numbers of foxes reported with the Arctic fox rabies virus variant in Alaska, the Texas gray fox rabies virus variant in Texas, and the raccoon rabies virus variant in Virginia. The 1,692 cases of rabies reported in bats represented a 14.5% increase, compared with numbers reported in 2005, making bats the second most reported rabid animal behind raccoons. Cases of rabies in cats, dogs, horses and mules, and sheep and goats increased 18.2%, 3.9%, 12.8%, and 22.2%, respectively, whereas cases reported in cattle decreased 11.8%. In Puerto Rico, reported cases of rabies in mongooses increased 9.2%, and rabies in domestic animals, presumably attributable to spillover infection from mongooses, increased 20%.

Three cases of human rabies were reported from Texas, Indiana, and California during 2006. The cases in Indiana and Texas were attributed to bat rabies virus variants, whereas the case in California was attributed to an exposure to a dog in the Philippines.
Longer you play, the more hostile you feel: examination of first person shooter video games and aggression during video game play
Authors: Barlett Christopher P. , Harris Richard J. , Baldassaro Ross
Published: August 2007

This study investigated the effects of video game play on aggression. Using the General Aggression Model, as applied to video games by Anderson and Bushman, [2002] this study measured physiological arousal, state hostility, and how aggressively participants would respond to three hypothetical scenarios. In addition, this study measured each of these variables multiple times to gauge how aggression would change with increased video game play. Results showed a significant increase from baseline in hostility and aggression (based on two of the three story stems), which is consistent with the General Aggression Model. This study adds to the existing literature on video games and aggression by showing that increased play of a violent first person shooter video game can significantly increase aggression from baseline. Aggr. Behav. 33:486–497, 2007. © 2007 Wiley‐Liss, Inc.
Distributed rereading can hurt the spacing effect in text memory
Authors: Verkoeijen Peter P. J. L. , Rikers Remy M. J. P. , Özsoy Binnur
Published: August 2007

The spacing effect refers to the commonly observed phenomenon that memory for spaced repetitions is better than for massed repetitions. In the present study, we examined this effect in students' memory for a lengthy expository text. Participants read the text twice, either in immediate succession (massed repetition), with a 4‐day interstudy interval (spaced short), or with a 3.5‐weeks interstudy interval (spaced long). Two days after the second study trial, all participants were tested. The results demonstrated that students in the spaced‐short condition remembered more of the content than those in the massed condition. By contrast, students in the spaced‐long condition remembered as much as students in the massed condition. These results were interpreted in terms of a theoretical framework, which combines mechanisms of encoding variability and study‐phase retrieval to account for the spacing effect. Copyright © 2007 John Wiley & Sons, Ltd.
Mathematics‐aided quantitative analysis of diffusion characteristics of pHEMA sponge hydrogels
Authors: Lou X. , Wang S. , Tan S. Y.
Published: August 2007

This study reports the current progress in quantitative analysis of the release characteristics of pHEMA spongy hydrogels using prednisolone 21‐hemisuccinate sodium salt as a model drug. Extraction of effective diffusion coefficients of the drug from various pHEMA matrices was made using a novel mathematical model that handles both boundary layer and initial burst effects. Drug loading level and entrapment efficiency were also determined. The computed diffusion coefficients and the drug loading capacity in relation to the device porous structure and drug concentration of the loading solution, as well as the size of device are discussed. Mathematical modelling proves to be a powerful tool not only for establishing and interpreting structure and performance relationships but also for handling experimental ambiguity. Copyright © 2007 Curtin University of Technology and John Wiley & Sons, Ltd.