bluuebunny/crossref_metadata_2025 huggingface dataset:
Multiple Arithmetic Operations in a Single Neuron: The Recruitment of Adaptation Processes in the Cricket Auditory Pathway Depends on Sensory Context
Authors: Hildebrandt K. Jannis , Benda Jan , Hennig R. Matthias
Published: October 2011

Sensory pathways process behaviorally relevant signals in various contexts and therefore have to adapt to differing background conditions. Depending on changes in signal statistics, this adjustment might be a combination of two fundamental computational operations: subtractive adaptation shifting a neuron's threshold and divisive gain control scaling its sensitivity. The cricket auditory system has to deal with highly stereotyped conspecific songs at low carrier frequencies, and likely much more variable predator signals at high frequencies. We proposed that due to the differences between the two signal classes, the operation that is implemented by adaptation depends on the carrier frequency. We aimed to identify the biophysical basis underlying the basic computational operations of subtraction and division.

We performedin vivointracellular and extracellular recordings in a first-order auditory interneuron (AN2) that is active in both mate recognition and predator avoidance. We demonstrated subtractive shifts at the carrier frequency of conspecific songs and division at the predator-like carrier frequency. Combined application of current injection and acoustic stimuli for each cell allowed us to demonstrate the subtractive effect of cell-intrinsic adaptation currents. Pharmacological manipulation enabled us to demonstrate that presynaptic inhibition is most likely the source of divisive gain control.

We showed that adjustment to the sensory context can depend on the class of signals that are relevant to the animal. We further revealed that presynaptic inhibition is a simple mechanism for divisive operations. Unlike other proposed mechanisms, it is widely available in the sensory periphery of both vertebrates and invertebrates.
GABAergic Precursor Transplantation into the Prefrontal Cortex Prevents Phencyclidine-Induced Cognitive Deficits
Authors: Tanaka Daisuke H. , Toriumi Kazuya , Kubo Ken-ichiro , Nabeshima Toshitaka , Nakajima Kazunori
Published: October 2011

Phencyclidine (PCP) is a noncompetitive NMDA receptor antagonist, and it induces schizophreniform cognitive deficits in healthy humans and similar cognitive deficits in rodents. Although the PCP-induced cognitive deficits appear to be accompanied and possibly caused by dysfunction of GABAergic inhibitory interneurons in the prefrontal cortex (PFC), the potential benefit(s) of GABAergic interneuron manipulations on PCP-induced cognitive deficits remains unexplored. In this study we show that when embryonic medial ganglionic eminence (MGE) cells, many of which differentiate into cortical GABAergic interneuronsin situ, were grafted into the medial PFC (mPFC) of neonatal mice, they differentiated into a specific class of GABAergic interneurons and became functionally integrated into the host neuronal circuitry in adults. Prior MGE cell transplantation into the mPFC significantly prevented the induction of cognitive and sensory-motor gating deficits by PCP. The preventive effects were not reproduced by either transplantation of cortical projection neuron precursors into the mPFC or transplantation of MGE cells into the occipital cortex. The preventive effects of MGE cell transplantation into the mPFC were accompanied by activation of callosal projection neurons in the mPFC. These findings suggest that increasing GABAergic interneuron precursors in the PFC may contribute to the development of a cell-based approach as a novel means of modulating the PFC neuronal circuitry and preventing schizophreniform cognitive deficits.
Homotypic Regulation of Neuronal Morphology and Connectivity in the Mouse Retina
Authors: Lee Sammy C. S. , Cowgill Erin J. , Al-Nabulsi Ali , Quinn Emma J. , Evans Sylvia M. , Reese Benjamin E.
Published: October 2011

The establishment of neuronal circuitry during development relies upon the action of cell-intrinsic mechanisms that specify neuronal form as well as plastic processes that require the transmission of neural activity between afferents and their targets. Here, we examine the role of interactions between neighboring like-type cells within the mouse retina upon neuronal differentiation and circuit formation. Two different genetically modified mouse models were used to modulate the density of homotypic neighbors, the Type 7 cone bipolar cells, without affecting the density of their afferents, the cone photoreceptors. We demonstrate a corresponding plasticity in dendritic field area when the density of Type 7 cone bipolar cells is elevated or reduced. In accord with this variation in dendritic field area across an invariant population of afferents, individual Type 7 cone bipolar cells are also shown to modulate the number of cone pedicles contacted without varying the number of contacts at each cone pedicle. Analysis of developing Type 7 cone bipolar cells reveals that the dendritic tiling present in maturity is achieved secondarily, after an initial stage of dendritic overlap, when the dendritic terminals are stratified at the level of the cone pedicles but are not localized to them. These results demonstrate a conspicuous developmental plasticity in neural circuit formation independent of neural activity, requiring homotypic interactions between neighboring cells that ultimately regulate connectivity within the retina.
Alterations of Molecular and Behavioral Responses to Cocaine by Selective Inhibition of Elk-1 Phosphorylation
Authors: Besnard Antoine , Bouveyron Nicolas , Kappes Vincent , Pascoli Vincent , Pagès Christiane , Heck Nicolas , Vanhoutte Peter , Caboche Jocelyne
Published: October 2011

Activation of the extracellular signal-regulated kinase (ERK) signaling pathway in the striatum is crucial for molecular adaptations and long-term behavioral alterations induced by cocaine. In response to cocaine, ERK controls the phosphorylation levels of both mitogen and stress-activated protein kinase 1 (MSK-1), a nuclear kinase involved in histone H3 (Ser10) and cAMP response element binding protein phosphorylation, and Elk-1, a transcription factor involved in serum response element (SRE)-driven gene regulations. We recently characterized the phenotype ofmsk-1knock-out mice in response to cocaine. Herein, we wanted to address the role of Elk-1 phosphorylation in cocaine-induced molecular, morphological, and behavioral responses. We used a cell-penetrating peptide, named TAT–DEF–Elk-1 (TDE), which corresponds to the DEF docking domain of Elk-1 toward ERK and inhibits Elk-1 phosphorylation induced by ERKs without modifying ERK or MSK-1in vitro. The peptide was injectedin vivobefore cocaine administration in mice. Immunocytochemical, molecular, morphological, and behavioral studies were performed. The TDE inhibited Elk-1 and H3 (Ser10) phosphorylation induced by cocaine, sparing ERK and MSK-1 activation. Consequently, TDE altered cocaine-induced regulation of genes bearing SRE site(s) in their promoters, including c-fos,zif268, ΔFosB, andarc/arg3.1(activity-regulated cytoskeleton-associated protein). In a chronic cocaine administration paradigm, TDE reversed cocaine-induced increase in dendritic spine density. Finally, the TDE delayed the establishment of cocaine-induced psychomotor sensitization and conditioned-place preference. We conclude that Elk-1 phosphorylation downstream from ERK is a key molecular event involved in long-term neuronal and behavioral adaptations to cocaine.
Intraamygdala Infusion of Fibroblast Growth Factor 2 Enhances Extinction and Reduces Renewal and Reinstatement in Adult Rats
Authors: Graham Bronwyn M. , Richardson Rick
Published: October 2011

Systemic fibroblast growth factor 2 (FGF2) has been shown to enhance extinction of conditioned fear and attenuate subsequent relapse in developing rats. However, it is not clear whether FGF2 has the same effect in adult rats, and furthermore, the neuroanatomical locus of the effect of FGF2 on extinction is unknown. These experiments examined the effect of 200 ng of FGF2, infused bilaterally into the basolateral complex of the amygdala (BLA), on the extinction of conditioned fear in adult rats. Experiment 1 confirmed that intra-BLA FGF2 significantly enhances extinction recall in adult rats, and extinction training is necessary for this effect to occur (FGF2 did not reduce conditioned freezing in the absence of extinction training). In Experiments 2 and 3, vehicle-treated rats were given four times the amount of extinction training as FGF2-treated rats to equate the strength of extinction between groups. In Experiment 2, rats were tested in both the extinction training context and the conditioning context to examine the effect of FGF2 on renewal of fear. In Experiment 3, the FGF2-treated rats and one-half of the vehicle-treated rats received a single unsignaled shock before test to examine the effect of FGF2 on reinstatement of fear. In both procedures, FGF2 administered immediately after extinction training significantly reduced relapse at test. These results support a growing body of evidence that FGF2 may be a potentially useful pharmacological adjunct to exposure-based therapies for anxiety disorders.
Altered Neocortical Rhythmic Activity States inFmr1KO Mice Are Due to Enhanced mGluR5 Signaling and Involve Changes in Excitatory Circuitry
Authors: Hays Seth A. , Huber Kimberly M. , Gibson Jay R.
Published: October 2011

Despite the pronounced neurological deficits associated with mental retardation and autism, the degree to which neocortical circuit function is altered remains unknown. Here, we study changes in neocortical network function in the form of persistent activity states in the mouse model of fragile X syndrome—theFmr1knock-out (KO). Persistent activity states, or UP states, in the neocortex underlie the slow oscillation which occurs predominantly during slow-wave sleep, but may also play a role during awake states. We show that spontaneously occurring UP states in the primary somatosensory cortex are 38–67% longer inFmr1KO slices.In vivo, UP states reoccur with a clear rhythmic component consistent with that of the slow oscillation and are similarly longer in theFmr1KO. Changes in neocortical excitatory circuitry likely play the major role in this alteration as supported by three findings: (1) longer UP states occur in slices of isolated neocortex, (2) pharmacologically isolated excitatory circuits inFmr1KO neocortical slices display prolonged bursting states, and (3) selective deletion ofFmr1in cortical excitatory neurons is sufficient to cause prolonged UP states whereas deletion in inhibitory neurons has no effect. Excess signaling mediated by the group 1 glutamate metabotropic receptor, mGluR5, contributes to the longer UP states. Genetic reduction or pharmacological blockade of mGluR5 rescues the prolonged UP state phenotype. Our results reveal an alteration in network function in a mouse model of intellectual disability and autism which may impact both slow-wave sleep and information processing during waking states.
Annexin A2 Promotes Glioma Cell Invasion and Tumor Progression
Authors: Zhai Haiyan , Acharya Suchitra , Gravanis Iordanis , Mehmood Saira , Seidman Roberta J. , Shroyer Kenneth R. , Hajjar Katherine A. , Tsirka Stella E.
Published: October 2011

Gliomas are highly invasive, lethal brain tumors. Tumor-associated proteases play an important role in glioma progression. Annexin A2 is overexpressed in many cancers and correlates with increased plasmin activity on the tumor cell surface, which mediates degradation of extracellular matrix and promotes neoangiogenesis to facilitate tumor growth. In this study, we used two glioma cell lines, mouse GL261–EGFP and rat C6/LacZ, as well as stable clones transfected with an annexin A2 knockdown construct. We find that the annexin A2 knockdown decreased glioma cell migrationin vitroand decreased membrane-bound plasmin activity.In vivo, we injected the glioma cells into the rodent brain and followed glioma progression. Knockdown of annexin A2 in glioma cells decreased tumor size and slowed tumor progression, as evidenced by decreased invasion, angiogenesis, and proliferation, as well as increased apoptosis in the tumor tissue of the annexin A2 knockdown group. Moreover, we report that the levels of expression of annexin A2 in human glioma samples correlate with their degree of malignancy. Together, our findings demonstrate that inhibition of annexin A2 expression in glioma cells could become a new target for glioma therapy.
AlkIs a Transcriptional Target of LMO4 and ERα That Promotes Cocaine Sensitization and Reward
Authors: Lasek Amy W. , Gesch Julie , Giorgetti Francesco , Kharazia Viktor , Heberlein Ulrike
Published: October 2011

Previously, we showed that the mouse LIM-domain only 4 (Lmo4) gene, which encodes a protein containing two zinc-finger LIM domains that interact with various DNA-binding transcription factors, attenuates behavioral sensitivity to repeated cocaine administration. Here we show that transcription of anaplastic lymphoma kinase (Alk) is repressed by LMO4 in the striatum and thatAlkpromotes the development of cocaine sensitization and conditioned place preference, a measure of cocaine reward. Since LMO4 is known to interact with estrogen receptor α (ERα) at the promoters of target genes, we investigated whetherAlkexpression might be controlled by a similar mechanism. We found that LMO4 and ERα are associated with theAlkpromoter by chromatin immunoprecipitation and thatAlkis an estrogen-responsive gene in the striatum. Moreover, we show that ERα knock-out mice exhibit enhanced cocaine sensitization and conditioned place preference and an increase inAlkexpression in the nucleus accumbens. These data define a novel regulatory network involved in behavioral responses to cocaine. Interestingly, sex differences in several behavioral responses to cocaine in humans and rodents have been described, and estrogen is thought to mediate some of these differences. Our data suggest that estrogen regulation ofAlkmay be one mechanism responsible for sexually dimorphic responses to cocaine.
Circuitry Underlying Spectrotemporal Integration in the Auditory Midbrain
Authors: Yavuzoglu Asuman , Schofield Brett R. , Wenstrup Jeffrey J.
Published: October 2011

Combination sensitivity in central auditory neurons is a form of spectrotemporal integration in which excitatory responses to sounds at one frequency are facilitated by sounds within a distinctly different frequency band. Combination-sensitive neurons respond selectively to acoustic elements of sonar echoes or social vocalizations. In mustached bats, this response property originates in high-frequency representations of the inferior colliculus (IC) and depends on low and high frequency-tuned glycinergic inputs. To identify the source of these inputs, we combined glycine immunohistochemistry with retrograde tract tracing. Tracers were deposited at high-frequency (>56 kHz), combination-sensitive recording sites in IC. Most glycine-immunopositive, retrogradely labeled cells were in ipsilateral ventral and intermediate nuclei of the lateral lemniscus (VNLL and INLL), with some double labeling in ipsilateral lateral and medial superior olivary nuclei (LSO and MSO). Generally, double-labeled cells were in expected high-frequency tonotopic areas, but some VNLL and INLL labeling appeared to be in low-frequency representations. To test whether these nuclei provide low frequency-tuned input to the high-frequency IC, we combined retrograde tracing from IC combination-sensitive sites with anterograde tracing from low frequency-tuned sites in the anteroventral cochlear nucleus (AVCN). Only VNLL and INLL contained retrogradely labeled cells near (≤50 μm) anterogradely labeled boutons. These cells likely receive excitatory low-frequency input from AVCN. Results suggest that combination-sensitive facilitation arises through convergence of high-frequency glycinergic inputs from VNLL, INLL, or MSO and low-frequency glycinergic inputs from VNLL or INLL. This work establishes an anatomical basis for spectrotemporal integration in the auditory midbrain and a functional role for monaural nuclei of the lateral lemniscus.
Distinct Roles of Three Frontal Cortical Areas in Reward-Guided Behavior
Authors: Noonan M. P. , Mars R. B. , Rushworth M. F. S.
Published: October 2011

Functional magnetic resonance imaging was used to measure activity in three frontal cortical areas, the lateral orbitofrontal cortex (lOFC), medial orbitofrontal cortex (mOFC)/ventromedial frontal cortex (vmPFC), and anterior cingulate cortex (ACC), when expectations about type of reward, and not just reward presence or absence, could be learned. Two groups of human subjects learned 12 stimulus–response pairings. In one group (Consistent), correct performances of a given pairing were always reinforced with a specific reward outcome, whereas in the other group (Inconsistent), correct performances were reinforced with randomly selected rewards. The mOFC/vmPFC and lOFC were not distinguished by simple differences in relative preference for positive and negative outcomes. Instead lOFC activity reflected updating of reward-related associations specific to reward type; lOFC was active whenever informative outcomes allowed updating of reward-related associations, regardless of whether the outcomes were positive or negative, and the effects were greater when consistent stimulus-outcome and response-outcome mappings were present. A psychophysiological interaction analysis demonstrated changed coupling between lOFC and brain areas for visual object representation, such as perirhinal cortex, and reward-guided learning, such as the amygdala, ventral striatum, and habenula/mediodorsal thalamus. In contrast, mOFC/vmPFC activity reflected expected values of outcomes and occurrence of positive outcomes, regardless of consistency of outcome mappings. The third frontal cortical region, the ACC, reflected the use of reward type information to guide response selection. ACC activity reflected the probability of selecting the correct response, was greater when consistent outcome mappings were present, and was related to individual differences in propensity to select the correct response.
Prevalence of Dental Anomalies in Patients with Nonsyndromic Cleft Lip and/or Palate in a Brazilian Population
Authors: Paranaiba Lívia Máris Ribeiro , Coletta Ricardo D. , Swerts Mário Sérgio Oliveira , Quintino Rafaela Pacífico , De Barros Letízia Monteiro , Martelli-Júnior Hercílio
Published: October 2011

Objective

Many studies have demonstrated a high frequency of dental anomalies in patients with cleft lip and/or palate. Because dental anomalies may complicate dental treatment, we investigated the prevalence of dental anomalies in a group of Brazilian patients with nonsyndromic cleft lip and/or palate.

Design, Participants, Setting

Retrospective analysis was performed using clinical records of 296 patients aged between 12 and 30 years with repaired nonsyndromic cleft lip and/or palate without history of tooth extraction and orthodontic treatment. Associations between oral clefts and presence of dental anomalies outside the cleft area were investigated.

Results

Dental anomalies were identified in 39.9% of the nonsyndromic cleft lip and/or palate patients, and tooth agenesis (47.5%), impacted tooth (13.1%), and microdontia (12.7%) were the most common anomalies. Cleft lip patients were less affected by dental anomalies compared with cleft palate or cleft lip and palate patients ( p = .057). Specifically, patients with unilateral cleft lip and palate were significantly more affected by dental anomalies than those with bilateral cleft lip and palate ( p = .00002), and individuals with unilateral complete cleft lip and palate ( p = .002) and complete cleft palate ( p = .01) were significantly more affected by tooth agenesis than other cleft types. Agenesis of the premolars ( p = .043) and maxillary lateral incisors ( p = .03) were significantly more frequent in patients with unilateral complete cleft lip and palate.

Conclusions

The present study revealed a high frequency of dental anomalies in nonsyndromic cleft lip and/or palate patients and further demonstrated that patients with unilateral cleft lip and palate were frequently more affected by dental anomalies than those with bilateral cleft lip and palate. Moreover, our results demonstrate that dental anomalies should be considered during dental treatment planning for individuals affected by nonsyndromic cleft lip and/or palate.
13Carbon Isotope Discrimination in Roots and Shoots of Major Weed Species of Southern U.S. Rice Fields and Its Potential Use for Analysis of Rice–Weed Root Interactions
Authors: Gealy David R. , Gealy Glenn S.
Published: October 2011

Assessing belowground plant interference in rice has been difficult in the past because intertwined weed and crop roots cannot be readily separated. A 13C discrimination method has been developed to assess distribution of intermixed roots of barnyardgrass and rice in field soils, but the suitability of this approach for other rice weeds is not known. 13C depletion levels in roots and leaves of rice were compared with those of 10 troublesome weed species grown in monoculture in the greenhouse or field. Included were C4 tropical grasses: barnyardgrass, bearded sprangletop, Amazon sprangletop, broadleaf signalgrass, fall panicum, and large crabgrass; C4 sedge, yellow nutsedge; and C3 species: red rice, gooseweed, and redstem. Rice root δ13C levels averaged ∼ −28‰, indicating that these roots are highly 13C-depleted. Root δ13C levels ranged from −12‰ to −17‰ among the tropical grasses, and were −10‰ in yellow nutsedge, indicating that these species were less 13C depleted than rice, and were C4 plants suitable for 13C discrimination studies with rice. Among the C4 species, bearded sprangletop and yellow nutsedge were most and least 13C depleted, respectively. δ13C levels in shoot and root tissue of pot-grown plants averaged 6% greater for C4 plants and 9% greater for rice in the field than in the greenhouse. In pots, shoots of rice typically were slightly more 13C depleted than roots. A reverse trend was seen in most C4 species, particularly for broadleaf signalgrass and plants sampled from field plots. Corrections derived from inputs including the total mass, carbon mass, carbon fraction, and δ13C levels of roots and soil increased greatly the accuracy of root mass estimates and increased slightly the accuracy of root δ13C estimates (∼ 0.6 to 0.9%) in samples containing soil. Similar corrective equations were derived for mixtures of rice and C4 weed roots and soil, and are proposed as a labor-saving option in 13C discrimination root studies.
Salinity Tolerance of Foxtail Barley (Hordeum jubatum) and Desirable Pasture Grasses
Authors: Israelsen Karl R. , Ransom Corey V. , Waldron Blair L.
Published: October 2011

Greenhouse studies were conducted to determine the relative salinity tolerance of foxtail barley and seven desirable pasture grasses. Grass species were reed canarygrass, timothy, altai wildrye, tall fescue, tall wheatgrass, orchardgrass, creeping meadow foxtail, and foxtail barley. Grasses were exposed to increasing electrical conductivity levels of NaCl and CaCl2 salt solution over time. Grass species were compared using a cumulative value of salt exposure (ECdays), which was calculated to account for the electrical conductivity (EC) and the time a plant was exposed at that level of conductivity. Salinity tolerance varied among grass species. Increasing EC significantly reduced plant biomass of all species. All grass species experienced a 50% biomass reduction (GR50) between 271 and 512 ECdays in 2008 and between 297 and 575 ECdays in 2009. Foxtail barley was among the most salt tolerant (GR50 = 512 and 525 ECdays), requiring the highest salt exposure in 2008 and the second-highest exposure in 2009 to reduce biomass 50%. Grass mortality increased with increasing EC levels. Reed canarygrass and timothy were most susceptible to increasing salinity, with 50% mortality (LD50) of both grass species occurring between 983 and 1,186 ECdays. Moderate salinity tolerance was exhibited by orchardgrass, which required 1,977 and 1,844 ECdays; creeping foxtail, which required 1,998 and 2,431 ECdays; and tall fescue, which required 2,501 and > 2,840 ECdays to LD50 in 2008 and 2009, respectively. Foxtail barley, altai wildrye, and tall wheatgrass were most tolerant of salinity and persisted with little mortality occurring at 3,033 and 2,840 ECdays in 2008 and 2009, respectively. All grass species with higher growth rates than foxtail barley and altai wildrye were more susceptible to salinity, with the exception of tall wheatgrass. Growth rates of foxtail barley and altai wildrye were less than they were for other grasses, suggesting that slower growth rates may aid in salinity tolerance.
Seed Biology and Ecology of Natalgrass (Melinis repens)
Authors: Stokes Courtney A. , MacDonald Gregory E. , Adams Carrie Reinhardt , Langeland Kenneth A. , Miller Deborah L.
Published: October 2011

Natalgrass is an invasive species that has become increasingly problematic in natural areas in Florida and other subtropical and tropical regions around the world. Natalgrass is a prolific seed producer, but little information is available regarding its seed biology and ecology. Research was conducted to determine levels of seed dormancy and to examine the effects of light, temperature, pH, water stress, and depth of burial on natalgrass seed germination. In addition, seed persistence under field conditions was examined both on the soil surface and while buried. Seeds appeared to undergo afterripening. Seed germination was not light dependent and occurred from 15 to 35 C, with optimum germination occurring at 20 to 35 C. Germination occurred at pH levels of 6 and 8 and was affected by water stress; no germination was observed at osmotic potentials less than −0.2 MPa. Seeds emerged from depths of at least 5 cm. Under field conditions, germination was reduced after burial; however, burial lengths of 3 to 15 mo did not result in differences in germination levels. Seedling numbers from seed deposits on the soil surface were greatly reduced after 1 mo, and no seedling emergence was observed after 4 mo.
Nonlinear Regression Analysis of Herbicide Absorption Studies
Authors: Kniss Andrew R. , Vassios Joseph D. , Nissen Scott J. , Ritz Christian
Published: October 2011

Although foliar herbicide absorption has been studied intensively, there is currently no standardized method for data analysis when evaluating herbicide absorption over time. Most peer-reviewed journals require the treatment structure of data be incorporated in the analysis; however, many herbicide absorption studies published in the past 5 yr do not account for the time structure of the experiment. Herbicide absorption studies have been presented in a variety of ways, making it difficult to compare results among studies. The objective of this article is to propose possible nonlinear models to analyze herbicide absorption data and to provide a stepwise framework so that researchers may standardize the analysis method in this important research area. Asymptotic regression and rectangular hyperbolic models with similar parameterizations are proposed, so that the maximum herbicide absorption and absorption rate may be adequately modeled and statistically compared among treatments. Adoption of these models for herbicide absorption analysis over time will provide a standardized method making comparison of results within and among studies more practical.
Ecosystem services, targets, and indicators for the conservation and sustainable use of biodiversity
Authors: Perrings Charles , Naeem Shahid , Ahrestani Farshid S , Bunker Daniel E , Burkill Peter , Canziani Graciela , Elmqvist Thomas , Fuhrman Jed A , Jaksic Fabian M , Kawabata Zen'ichiro , Kinzig Ann , Mace Georgina M , Mooney Harold , Prieur-Richard Anne-Hélène , Tschirhart John , Weisser Wolfgang
Published: October 2011

After the collective failure to achieve the Convention on Biological Diversity's (CBD's) 2010 target to substantially reduce biodiversity losses, the CBD adopted a plan composed of five strategic goals and 20 “SMART” (Specific, Measurable, Ambitious, Realistic, and Time‐bound) targets, to be achieved by 2020. Here, an interdisciplinary group of scientists from DIVERSITAS – an international program that focuses on biodiversity science – evaluates these targets and considers the implications of an ecosystem‐services‐based approach for their implementation. We describe the functional differences between the targets corresponding to distinct strategic goals and identify the interdependency between targets. We then discuss the implications for supporting research and target indicators, and make several specific suggestions for target implementation.
Evaluation of biofilm performance as a protective barrier against biocorrosion using an enzyme electrode
Authors: Soleimani S. , Ormeci B. , Isgor O. B. , Papavinasam S.
Published: October 2011

Sulfide is known to be an important factor in microbiologically influenced corrosion (MIC) of metals and concrete deterioration in wastewater treatment structures and sewer pipelines. A sulfide biosensor was used to determine the effectiveness of Escherichia coli DH5α biofilm as a protective barrier against MIC. The biofilm was shown to be effective in protecting surfaces from sulfide and helping to reduce MIC using amperometric measurements. The results also indicated that the growth conditions of E. coli DH5α may have an impact on the performance of the biofilm as a sulfide barrier. The simple method provided in this work enables the comparison of several microbial biofilms and selection of the ones with potential to prevent MIC in a relatively short time.
Characteristic of algogenic organic matter and its effect on UF membrane fouling
Authors: Li T. , Dong B. Z. , Liu Z. , Chu W. H.
Published: October 2011

Algogenic organic matter (AOM) was extracted from blue-green algae (cyanobacteria) and its characteristic was determined by various methods including high-pressure size-exclusion chromatography (HP-SEC), hydrophobic and hydrophilic fractionation, molecular weight (MW) fractionation and fluorescence excitation emission matrix (EEM). The results revealed that AOM was hydrophilic fractionation predominantly, accounting for 78%. The specific ultraviolet absorbance of AOM was 1.1 L/(mg m) only. The analysis for MW distribution demonstrated that organic matter greater than 30,000 MW accounted for over 40% and was composed of mostly neutral hydrophilic compound. EEM analyses revealed that protein-like and humic-substances existed in AOM. A test for membrane filtration exhibited that AOM could make ultrafiltration membrane substantial flux decline, which can be attributed to membrane pore clog caused by neutral hydrophilic compound with larger MW.
Multiple responses analysis and modeling of Fenton process for treatment of high strength landfill leachate
Authors: Mohajeri Soraya , Aziz Hamidi Abdul , Zahed Mohammed Ali , Mohajeri Leila , Bashir Mohammed J. K. , Aziz Shuokr Qarani , Adlan Mohd Nordin , Isa Mohamed Hasnain
Published: October 2011

Landfill leachate is one of the most recalcitrant wastes for biotreatment and can be considered a potential source of contamination to surface and groundwater ecosystems. In the present study, Fenton oxidation was employed for degradation of stabilized landfill leachate. Response surface methodology was applied to analyze, model and optimize the process parameters, i.e. pH and reaction time as well as the initial concentrations of hydrogen peroxide and ferrous ion. Analysis of variance showed that good coefficients of determination were obtained (R2 > 0.99), thus ensuring satisfactory agreement of the second-order regression model with the experimental data. The results indicated that, pH and its quadratic effects were the main factors influencing Fenton oxidation. Furthermore, antagonistic effects between pH and other variables were observed. The optimum H2O2 concentration, Fe(II) concentration, pH and reaction time were 0.033 mol/L, 0.011 mol/L, 3 and 145 min, respectively, with 58.3% COD, 79.0% color and 82.1% iron removals.
Analyses of calcium carbonate scale deposition on four RO membranes under a seawater desalination condition
Authors: Kang Nam Wook , Lee Seockheon , Kim Dooil , Hong Seungkwan , Kweon Ji Hyang
Published: October 2011

Inorganic fouling is one of the critical operational issues in reverse osmosis membrane. Few researches investigated effects of membrane surface characteristics on inorganic fouling and on anti-scaling techniques although the fouling occurs on the membrane surface. The objective of this paper was to examine whether different characteristics of deposition of calcium carbonate solids would occur on four membranes having distinctive surface properties. A lab-scale cell reactor with a crossflow velocity was installed and two coupons were used for one type of membranes. Two feed waters were examined: concentrated synthetic seawater simulating a 30% recovery and a concentrate from a seawater RO plant in operation at Changwon, Korea. The amounts of solid deposition on the attached membranes were increased in all four membranes but the degree of deposition on each membrane was different. Various types of calcium carbonate solids were clearly detected by both XRD and SEM analyses. In general, a membrane with greater roughness and negative surface charge appeared to form more scales. This implied that membrane surface characteristics such as roughness and surface charge affected inorganic fouling, presumably by providing favourable sites for precipitation and enhancing attraction of species to the membrane surface.
Biodegradation of estrogen conjugates by bacteria isolated from river sediments
Authors: Duong C. N. , Lee J. H. , Lim B. J. , Kim S. D.
Published: October 2011

The objective of this study was to investigate the ability of E. coli in river sediments to degrade estrogen conjugates. Biodegradation experiments on glucuronide estrogens (E1-GLU, E2-GLU and E3-GLU) using E. coli, non-E. coli bacteria as well as sediment crude extracts were carried out in batch mode. A pure identified E. coli strain (KCTC 2571) was used for comparison of enzyme activity. The results showed that the degradation rate of estrogen conjugates by KCTC 2571 and E. coli isolated from sediments followed a similar trend. Fecal bacteria showed a high ability to deconjugate glucuronided estrogens. Approximately 50% of glucuronide moieties were cleaved within 4 h of contact time in experiments using pure E. coli. The degradation rate was slower in experiments using crude extracts of sediments, and conjugated estrogens were not completely degraded even after 12 h of reaction. These results provide a clear understanding of the fate and behavior of estrogen by bacteria in the environment.
Anaerobic treatment of a medium strength industrial wastewater at low-temperature and short hydraulic retention time: a pilot-scale experience
Authors: Esparza Soto M. , Solís Morelos C. , Hernández Torres J. J.
Published: October 2011

The aim of this work was to evaluate the performance of a pilot-scale upflow anaerobic sludge blanket (UASB) reactor during the treatment of cereal-processing industry wastewater under low-temperature conditions (17 °C) for more than 300 days. The applied organic loading rate (OLRappl) was gradually increased from 4 to 6 and 8 kg CODsol/m3d by increasing the influent soluble chemical oxygen demand (CODsol), while keeping the hydraulic retention time constant (5.2 h). The removal efficiency was high (82 to 92%) and slightly decreased after increasing the influent CODsol and the OLRappl. The highest removed organic loading rate (OLRrem) was reached when the UASB reactor was operated at 8 kg CODsol/m3d and it was two times higher than that obtained for an OLRappl of 4 kg CODsol/m3d. Some disturbances were observed during the experimentation. The formation of biogas pockets in the sludge bed significantly complicated the biogas production quantification, but did not affect the reactor performance. The volatile fatty acids in the effluent were low, but increased as the OLRappl increased, which caused an increment of the effluent CODsol. Anaerobic treatment at low temperature was a good option for the biological pre-treatment of cereal processing industry wastewater.
Evaluating Henry's law constant of N-Nitrosodimethylamine (NDMA)
Authors: Haruta Shinsuke , Jiao Wentao , Chen Weiping , Chang Andrew C. , Gan Jay
Published: October 2011

N-Nitrosodimethylamine (NDMA), a potential carcinogen, may contaminate the groundwater when the reclaimed wastewater is used for irrigation and groundwater recharge. Henry's law constant is a critical parameter to assess the fate and transport of reclaimed wastewater-borne NDMA in the soil profile. We conducted a laboratory experiment in which the change of NDMA concentration in water exposed to the atmosphere was measured with respect to time and, based on the data, obtained the dimensionless Henry's law constant (KH′) of NDMA, at 1.0 × 10−4. The KH′ suggests that NDMA has a relatively high potential to volatilize in the field where NDMA-containing wastewater is used for irrigation and the volatilization loss may be a significant pathway of NDMA transport. The experiment was based on the two boundary-layer approach of mass transfer at the atmosphere-water interface. It is an expedient method to delineate KH′ for volatile or semi-volatile compounds present in water at low concentrations.
Alternate anoxic/aerobic operation for nitrogen removal in a membrane bioreactor for municipal wastewater treatment
Authors: Guglielmi G. , Andreottola G.
Published: October 2011

A large pilot-scale membrane bioreactor (MBR) with a conventional denitrification/nitrification scheme for municipal wastewater treatment has been run for one year under two different aeration strategies in the oxidation/nitrification compartment. During the first five months air supply was provided according to the dissolved-oxygen set-point and the system run as a conventional pre-denitrification MBR; then, an intermittent aeration strategy based on effluent ammonia nitrogen was adopted in the aerobic compartment in order to assess the impact on process performances in terms of N and P removal, energy consumption and sludge reduction. The experimental inferences show a significant improvement of the effluent quality as COD and total nitrogen, both due to a better utilization of the denitrification potential which is a function of the available electron donor (biodegradable COD) and electron acceptor (nitric nitrogen); particularly, nitrogen removal increased from 67% to 75%. At the same time, a more effective biological phosphorus removal was observed as a consequence of better selection of denitrifying phosphorus accumulating organisms (dPAO). The longer duration of anoxic phases also reflected in a lower excess sludge production (12% decrease) compared with the standard pre-denitrification operation and in a decrease of energy consumption for oxygen supply (about 50%).
Quasi-Static Axial Crushing Behavior of Honeycomb-Filled Thin-Walled Aluminum Tubes
Authors: Aktay Levent , Çakıroğlu Cem , Güden Mustafa
Published: October 2011

The experimental and numerical quasi-static crushing behaviors of Nomex™ honeycomb-filled thin-walled Al
tubes were investigated. The honeycomb filler was modeled using a unit cell model. The numerical model and
experimental results have shown that, 6.4 mm and 4.8 mm cell size honeycomb filling had no effect on the deformation
mode (diamond); however 3.2 mm cell size honeycomb filling changed the deformation mode to mixed/concertina.
Honeycomb filling was also shown to increase the specific energy absorption of filled tubes over that of Al tube. The
specific energy absorption of honeycomb filling was further compared with those of tube wall thickening and Al closedcell
foam filling.
Pressure Effect on Hydrodynamics of a High Pressure X-ray Transparent Polyethylene Fluidized Bed
Authors: Orta Ana , Wu Bangyou , Ghods Mahfam , Guerrero Adriana , Bellehumeur Celine , Kantzas Apostolos
Published: October 2011

Hydrodynamics of a polyethylene fluidized bed were studied at different operating pressures (191-2908 kPa) and constant temperature of 30°C. Minimum fluidization velocity (Umf) decreased with increasing of operating pressures. Measured Umf agree well with calculated Umf as derived from the standard deviation of pressure fluctuations using Puncochar’s Method (1985). As expected, with the increase of superficial velocity, amplitude and standard deviation of pressure fluctuation series also increase, which is indication of more vigorous bubbling behavior inside the bed. Power spectral density of pressure fluctuation series indicates similar frequency distribution of the bubbling behavior at different superficial velocities. The dominant frequency from the power spectral was found to be around 1 Hz. Bubble diameter and bubble velocity were estimated from X-ray fluoroscopy images. Bubble diameter and bubble velocity increase with increasing bed height and superficial gas velocity due to bubble coalescence and more gas flowing upwards. At the same fluidization number, the average bubble size slightly decreases with increasing pressure at all bed heights because there is less gas flowing and the bubbles coalesce less rapidly. The bubble velocity is observed to have a small decrease from 191 kPa up to 2200 kPa, and then a substantial increase due to the fact that at higher pressure, the solid circulation increases at the bed.
Catalytic Activity of Sulfated Iron-Tin Mixed Oxide for Esterification of Free Fatty Acids in Crude Palm Oil: Effects of Iron Precursor, Calcination Temperature and Sulfate Concentration
Authors: Nuithitikul Kamchai , Prasitturattanachai Worawoot , Limtrakul Jumras
Published: October 2011

The activities of sulfated iron-tin mixed oxide catalysts for esterification of free fatty acids in crude palm oil were investigated. The iron-tin mixed oxides were prepared from co-precipitation method when the iron content was fixed at 10 mol%. Types of iron precursor, sulfate concentration and calcination temperature were varied. The optimum study in the esterification reaction variables (stirring speed, reaction time, catalyst loading, methanol/oil molar ratio and reaction temperature) was also conducted with the best sulfated iron-tin mixed oxide catalyst. The findings show that iron sulfate is the best precursor. The activities of sulfated iron-tin mixed oxide catalysts increase with sulfate concentration. The optimum calcination temperature to prepare sulfated iron-tin mixed oxides is 450°C. The addition of iron oxide into sulfated tin oxide improves the stability of the catalyst during the reusability process. Therefore, sulfated iron-tin mixed oxide is a better candidate than sulfated tin oxide for esterification of free fatty acids. For the esterification study, the optimum reaction conditions are: the stirring speed of 250 rpm, the catalyst loading of 4.5 wt% of the oil, the methanol/oil molar ratio of 14.2, the reaction temperature of 80°C and the reaction time of 3 h.
Polyhedral Particles Hopper Flowrate Predictions using Discrete Element Method
Authors: Fraige Feras Y. , Langston Paul A. , Al-Khatib Laila A.
Published: October 2011

Discrete, or Distinct, element modelling, DEM, is used to investigate the effect of particle shape on hopper flowrate. Firstly, simulation results using a model based on spherical particles are validated against solid discharge rates predicted by the modified Beverloo equation. The validated model is then used to investigate the shape effects on discharge rate from a flat bottomed rectangular hopper. Two regular rounded polyhedral particles are studied. The discharge rate varies significantly with particle shape. A reduction on flowrate of up to 49% and 41% is observed for tetrahedral and octahedral particles, respectively. The effects of friction, cohesion, and damping on flowrate are also investigated with DEM.
Mandating Wholesale Provisions with the Retail-minus Regulation in Mobile Telecommunications
Authors: Kang Sawoong
Published: October 2011

We examine a situation where asymmetric MNOs (Mobile Network Operators) are competing a la Cournot and a potential MVNO (Mobile Virtual Network Operator) is attempting to enter the market by purchasing a wholesale service from one of MNOs. We present two scenarios: (1) if the MVNO can choose the wholesale service provider first and a bargaining game is used to determine the wholesale price, the most efficient (largest) MNO is chosen as the wholesale provider; or (2) if the MNOs play an auction game to determine the wholesale provider and the wholesale price at the same time, the outcome depends on the MNOs cost difference. Regarding the cost difference, (a) if the MNOs cost difference is large, the most efficient MNO will become the wholesale provider, and (b) if the cost difference is small, any MNO can become the wholesale provider. In any case, the wholesale price is determined at each providers monopoly level and does not fall to the marginal cost level. Furthermore, we show that if the MVNOs efficiency level is low and/or the MNOs have been colluding to restrict outputs, the MNOs have an incentive to (collectively or individually) refuse to provide wholesale service. This situation calls for a policy of mandating wholesale provisions. Additionally, we show that the retail-minus regulation - the simple form of the ECPR (Efficient Component Pricing Rule) - is more favorable to MNOs compared with the complicated ECPR form and that the retail price is lower under the complicated ECPR form.
Stability-indicating liquid chromatographic method for quantification of new anti-epileptic drug lacosamide in bulk and pharmaceutical formulation
Authors: Chhalotiya Usmangani , Bhatt Kashyap , Shah Dimal , Baldania Sunil , Patel Jigar
Published: October 2011

An isocratic stability indicating reversed-phase liquid chromatographic
determination was developed for the quantitative determination of lacosamide
in the pharmaceutical dosage form. A Hypersil C-18, 4.5?m column with mobile
phase containing acetonitrile-water (20:80, v/v) was used. The flow rate was
1.0 mL min-1 and effluents were monitored at 258 nm. The retention time of
lacosamide was 8.9 min. The method was found to be linear in the
concentration range of 5-100 ?g/ml and the recovery was found to be in the
range of 99.15 - 100.09 %. The limit of detection and limit of
quantification were found to be 2 ?g/ml and 5 ?g/ml, respectively.
Lacosamide stock solutions were subjected to acid and alkali hydrolysis,
chemical oxidation and dry heat degradation. The drug was found to be stable
to the dry heat and acidic condition attempted. The proposed method was
validated and successfully applied to the estimation of lacosamide in tablet
dosage forms.
A personalized multimedia contents recommendation using a psychological model
Authors: Park Won-Ik , Kang Sanggil , Kim Young-Kuk
Published: October 2011

With the development and diffusion of compact and portable mobile devices,
users can use multimedia content such as music and movie on personal mobile
devices, anytime and anywhere. However, even with the rapid development of
mobile device technology, it is still not easy to search multimedia content
or manage large volume of content in a mobile device with limited resources.
To resolve these problems, an approach for recommending content on the
server-side is one of the popular solutions. However, the recommendation in a
server also leads to some problems like the scalability for a lot of users
and the management of personal information. Therefore, this paper defines a
personal content manager which acts between content providers (server) and
mobile devices and proposes a method for recommending multimedia content in
the personal content manager. For the recommendation based on user's personal
characteristic and preference, this paper adopts and applies the DISC model
which is verified in psychology field for classifying user's behavior
pattern. The proposed recommendation method also includes an algorithm for
reflecting dynamic environmental context. Through the implements and
evaluation of a prototype system, this paper shows that the proposed method
has acceptable performance for multimedia content recommendation.