bluuebunny/crossref_metadata_2025 huggingface dataset:
Habitat‐contingent responses to disturbance: impacts of cattle grazing on ant communities vary with habitat complexity
Authors: Arcoverde Gabriela B. , Andersen Alan N. , Leal Inara R. , Setterfield Samantha A.
Published: June 2018

Predicting community responses to disturbance is a major challenge for both ecology and ecosystem management. A particularly challenging issue is that the same type and intensity of disturbance can have different impacts in different habitats. We investigate how habitat contingency influences ant community responses to disturbance in arid Australia, testing the hypothesis that disturbance has a greater impact in more complex habitats. We also assess the effectiveness of a highly simplified ant assessment protocol that considers larger species only. We sampled ants at 46 sites from two habitats (Chandler, low chenopod shrubland; and mulga, low woodland) with contrasting complexity, using distance from water as a surrogate for variation in grazing intensity. We assessed variation in habitat structural variables (basal area of perennial grass, and cover of herbs, litter, and bare ground) and ant communities in relation to habitat and distance from water, first using data from the entire ant community and then for larger ants (>4 mm body length) only. Site species richness was almost twice as high in mulga, the more structurally complex habitat, than in Chandler, and ant communities in mulga showed far more variation in relation to distance from water. Litter cover was the key environmental variable associated with the interaction between grazing and habitat: it increased with increasing distance from water in mulga and was virtually absent from Chandler. Analysis of only larger species revealed the same patterns of variation in ant abundance, species richness and composition in relation to habitat and grazing as shown by entire ant communities. Our findings support the hypothesis that disturbance impacts on faunal communities increase with increasing habitat complexity. An appreciation of such habitat contingency is important for a predictive understanding and therefore effective management of disturbances such as rangeland grazing. Our findings also show that simplified assessment can provide robust information on the responses of highly diverse ant communities to disturbance, which enhances their feasibility for use as bio‐indicators in land management.
Effect of climate change in lizards of the genusXenosaurus(Xenosauridae) based on projected changes in climatic suitability and climatic niche conservatism
Authors: Berriozabal‐Islas Christian , Rodrigues João Fabrício Mota , Ramírez‐Bautista Aurelio , Becerra‐López Jorge L. , Nieto‐Montes de Oca Adrián
Published: June 2018

Accelerated climate change represents a major threat to the health of the planet's biodiversity. Particularly, lizards of the genusXenosaurusmight be negatively affected by this phenomenon because several of its species have restricted distributions, low vagility, and preference for low temperatures. No study, however, has examined the climatic niche of the species of this genus and how their distribution might be influenced by different climate change scenarios. In this project, we used a maximum entropy approach to model the climatic niche of 10 species of the genusXenosaurusunder present and future suitable habitat, considering a climatic niche conservatism context. Therefore, we performed a similarity analysis of the climatic niche between each species of the genusXenosaurus. Our results suggest that a substantial decrease in suitable habitat for all species will occur by 2070. Among the most affected species,X. tzacualtipantecuswill not have suitable conditions according to its climatic niche requirements andX. phalaroanthereonwill lose 85.75% of its current suitable area. On the other hand, we found low values of conservatism of the climatic niche among species. Given the limited capacity of dispersion and the habitat specificity of these lizards, it seems unlikely that fast changes would occur in the distribution of these species facing climate change. The low conservatism in climatic niche we found inXenosaurussuggests that these species might have the capacity to adapt to the new environmental conditions originated by climate change.
Distance and size matters: A comparison of six wildlife camera traps and their usefulness for wild birds
Authors: Randler Christoph , Kalb Nadine
Published: June 2018

Camera traps are increasingly used in ecological research. However, tests of their performance are scarce. It is already known from previous work that camera traps frequently fail to capture visits by animals. This can lead to a misinterpretation of ecological results such as density estimates or predation events. While previous work is mainly based on mammals, for birds, no data about if and how camera traps can be successfully used to estimate species diversity or density are available. Hence, the goal of our study was an empirical validation of six different camera traps in the field. We observed a total number of N = 4567 events (independent visits of a bird) in 100 different sessions from March 2017 until January 2018 while camera traps were deployed. In addition, N = 641 events are based on a comparison of the two close‐up camera traps especially designed for birds. These events were all directly observed by the authors. Thus, the cameras can be compared against the human observer. To give an overall assessment and a more generalizable result, we combined the data from the six camera traps and showed that bird size category (effect size = 0.207) and distance (effect size = 0.132) are the most important predictors for a successful trigger. Also, temperature had a small effect, and flock size had an impact with larger flocks being captured more often. The approach of the bird, whether it approached the camera frontally or laterally had no influence. In Table , we give some recommendations, based on our results, at which distances camera traps should be placed to get a 25%, 50%, and 75% capture rate for a given bird size.
Morphometric and genetic differentiation among populations of flat‐headed cusimanse (Crossarchus platycephalus) in Nigeria
Authors: Oguntuase Bukola G. , Ogunjemite Babafemi G. , Meisel Richard P.
Published: June 2018

Geographic barriers can partition genetic diversity among populations and drive evolutionary divergence between populations, promoting the speciation process and affecting conservation goals. We integrated morphological and genomic data to assess the distribution of variation in the flat‐headed cusimanse (Crossarchus platycephalus), a species of least conservation concern, on either side of the River Niger in Nigeria. Ecological disturbances affect the conservation status of many other animals in this region. The two populations were differentiated in the snout and fore limbs, with greater morphological diversity in the western population. We used Restriction site Associated DNA sequencing (RAD‐seq) and identified two genotypic clusters in a STRUCTURE analysis. Individuals from the eastern population are almost entirely assigned to one cluster, whereas genotypes from the western population are a mixture of the two clusters. The population from west of the River Niger also had higher heterozygosity. The morphological and population genetic data are therefore in agreement that the population from west of the River Niger is more diverse than the eastern population, and the eastern population contains a subset of the genetic variation found in the western population. Our results demonstrate that combining morphological and genotypic measures of diversity can provide a congruent picture of the distribution of intraspecific variation. The results also suggest that future work should explore the role of the River Niger as a natural barrier to migration in Nigeria.
Exploring the Use of Structure and Polymer Incorporation to Tune Silver Ion Release and Antibacterial Activity of Silver Coordination Polymers
Authors: Young Rosemary J. , Begg Stephanie L. , Coghlan Campbell J. , McDevitt Christopher A. , Sumby Christopher J.
Published: June 2018

The use of silver as an antibacterial agent has seen renewed interest as a result of its ability to combat a broad range of bacterial species, including those resistant to multiple classes of antibiotics. Silver coordination polymers (CPs) provide the opportunity to control the release of silver ions, thus avoiding unwanted side effects and toxicity; however, the parameters that tune release remain poorly understood. Here, four silver CPs, namely [Ag2(Me4bpz)] as both four‐ and eightfold interpenetrated forms, and [Ag(dpzm)(ClO4)] in its open 3D and close‐packed 2D forms, were used to probe the role of structure in the release of silver ions. Release was measured by inductively‐coupled plasma mass spectrometry (ICP‐MS) and shown to be more marked for the charged networks, [Ag(dpzm)(ClO4)] (complete dissolution). Incorporation of the silver CPs into inert polymer matrices, polyethylene and polycaprolactone, to provide surface coatings was also investigated, and shown to significantly retard silver ion release. The antibacterial activities of all materials as their polymer composites were analysed by disk diffusion and bacterial growth assays. All CPs showed antibacterial activity, with the Gram‐positive Staphylococcus aureus exhibiting greater sensitivity to silver than the Gram‐negative Escherichia coli. Metal–ligand bond strength and anion availability were found to influence silver release into aqueous solution but this did not always correlate with the in vitro antibacterial activity.
Substituent‐Directed Activation of CH Bonds in Activated Olefins by Ru5(µ5‐C)(CO)15
Authors: Adams Richard D. , Smith Mark D. , Tedder Jonathan D.
Published: June 2018

Reactions of [Ru5(µ5‐C)(CO)15] with methylacrylate and vinyl acetate have yielded the products [Ru5(µ5‐C)(CO)14[CH=CHC(=O)OMe](µ‐H)] (2) and [Ru5(µ5‐C)(CO)14[C(=CH2)OC(OMe)](µ‐H)] (3), formed by cluster‐opening transformations accompanied by the activation of alkenyl CH bonds at the β‐ and α‐carbon atoms of the vinyl groups, respectively, of the olefins. In each case, the activated olefin forms a five‐membered chelate ring system to one of the ruthenium atoms of the opened pentaruthenium cluster. The location of the CH activation site is dependent on the number of atoms in the substituent that are included in the five‐membered chelate ring.
Powerless people don't yell but tell: The effects of social power on direct and indirect expression of anger
Authors: Petkanopoulou Katerina , Rodríguez‐Bailón Rosa , Willis Guillermo B. , van Kleef Gerben A.
Published: June 2018

Expressing anger can engender desired change, but it can also backfire. In the present research we examined how power shapes the expression of anger. In Study 1, we found that powerless individuals were less inclined to express their anger directly but more inclined to express it indirectly by sharing it with others. Powerless participants’ reluctance to express anger directly was mediated by negative social appraisals. In Study 2, we replicated the effect of power on direct anger expression in a situation in which participants had actual power (or not). Anger was evoked in the laboratory using an ecologically valid procedure, and participants were given an opportunity to express anger. Study 3 showed that powerless participants expected direct anger expression to arouse more anger than fear in the target, whereas the opposite was true for indirect anger expression. Powerful participants always expected to elicit more fear than anger in the target.
The association of insomnia and depressive symptoms with all‐cause mortality among middle‐aged and old adults
Authors: Leggett Amanda N. , Sonnega Amanda J. , Lohman Matthew C.
Published: June 2018

Objectives

Insomnia and depressive symptoms are commonly reported by adults and have independently been found to be associated with mortality, though contrasting findings are reported. Given the high comorbidity and interrelatedness between these symptoms, we tested whether insomnia symptoms explain risk of death independent of depressive symptoms. We examined insomnia symptoms and depressive symptoms, in addition to other health and demographic covariates, as predictors of all‐cause mortality.

Methods

The sample included 15 418 adults aged 51 and older drawn from a nationally representative, population‐based study of adults in the United States, the Health and Retirement Study. Cox survival models were used to analyze time to death between the 2002 and 2014 study waves (5 waves). Controlling for health and demographic covariates, in 3 separate models, depressive symptoms and insomnia symptoms were independently and then together considered as risk factors for all‐cause mortality (drawn from the National Death Index).

Results

After adjustment for covariates, insomnia symptoms (HR = 1.10, CI:1.07‐1.13) and depressive symptoms (HR = 1.14, CI:1.12‐1.16) each were associated with a greater hazard of death. When considered together, however, depressive symptoms fully accounted for the association between insomnia symptoms and mortality.

Conclusion

Though their effects are small relative to health and demographic characteristics, both insomnia symptoms and depressive symptoms were associated with a greater hazard of death. Yet depressive symptoms accounted for the insomnia association when both were considered in the model. Screening for depression and providing validated treatments may reduce mortality risk in old adults with depressive symptoms.
Long‐term and seasonal hydrologic performance of an extensive green roof
Authors: Todorov Dimitar , Driscoll Charles T. , Todorova Svetoslava
Published: June 2018

Sustainable strategies such as green roofs have been implemented as stormwater management tools to mitigate disturbance of the hydrologic cycle resulting from urbanization. Green roofs, also referred to as vegetated roofs, can improve the urban landscape by reducing heat island effects, providing ecosystem services, and facilitating the retention and treatment of stormwater. Green roofs have received particular attention because they do not require acquisition and development of land and represent an application of biomimicry in design and construction. In this paper, we evaluate the effects of precipitation, evapotranspiration (ET), antecedent dry period (ADP), and seasonal variation on the run‐off quantity and distribution of an extensive, sedum covered, green roof on a commercial building in Syracuse, NY, USA. The green roof greatly facilitated retention of precipitation events without significant changes over the 4‐year study. The green roof retained on average 95.9 ± 3.6% (6.5 ± 5.6 mm) per rainfall event, with a range from 75% to 99.6% (33.2 to 3.3 mm). However, as precipitation quantity increased, the retention of water decreased. This high water retention capacity was the result of the combined effects of ET, stormwater storage (plants, growth media, and stormwater retention layer), and limited surface run‐off from the roof deck due to variation in the sloping of the green roof and the tapered insulation to the deck drains. The water retention capacity of the green roof did not change significantly between growing and nongrowing seasons. Slightly greater precipitation during the growing season coincided with increased ET. Average potential ET during the growing season was approximately 3 times greater than during the nongrowing season. The hydrologic performance of the green roof was not significantly impacted by an ADP greater than 2 days.
Identifying evaporation fractionation and streamflow components based on stable isotopes in the Kaidu River Basin with mountain–oasis system in north‐west China
Authors: Haiyan Chen , Yaning Chen , Weihong Li , Xinming Hao , Yupeng Li , Qifei Zhang
Published: June 2018

Based on stable isotopes in stream water, groundwater, and meltwater in the Kaidu River Basin, NW China, we estimated the evaporation enrichment of stable oxygen isotopes in different types of water and separated the contribution of each streamflow component in river run‐off. Our results indicated that δ18O and δ2H in stream water did not vary with altitude regularly but with seasons, with low concentrations in spring and high concentrations in summer. However, the seasonal variations of δ18O and δ2H in groundwater were not as obvious. The mean evaporation enrichment was between 26% and 44% for δ18O. Of the various water types under investigation, we found glaciers were influenced the most, showing an evaporation enrichment of 44%, followed by oasis groundwater (37%), stream water (36%), and mountain groundwater (26%). Overall, meltwater and groundwater were the predominant streamflow components, with their contributions were governed by temperature, and varied both temporally and specially. In the oasis region, groundwater was the predominant contributor (64% in spring, 50% in summer, and 66% in autumn), whereas in the mountains, groundwater was the dominant in spring (53%) and autumn (51%), and meltwater contributed the most in summer (52%). Precipitation contributed less than 15% to the streamflow.
Climate change and hydrology at the prairie margin: Historic and prospective future flows of Canada's Red Deer and other Rocky Mountain rivers
Authors: Philipsen Laurens J. , Gill Karen M. , Shepherd Anita , Rood Stewart B.
Published: June 2018

The South Saskatchewan River Basin of southern Alberta drains the transboundary central Rocky Mountains region and provides the focus for irrigation agriculture in Canada. Following extensive development, two tributaries, the Oldman and Bow rivers, were closed for further water allocations, whereas the Red Deer River (RDR) remains open. The RDR basin is at the northern limit of the North American Great Plains and may be suitable for agricultural expansion with a warming climate. To consider irrigation development and ecological impacts, it is important to understand the regional hydrologic consequences of climate change. To analyse historic trends that could extend into the future, we developed century‐long discharge records for the RDR, by coordinating data across hydrometric gauges, estimating annual flows from seasonal records, and undertaking flow naturalization to compensate for river regulation. Analyses indicated some coordination with the Pacific decadal oscillation and slight decline in summer and annual flows from 1912 to 2016 (−0.13%/year, Sen's slope). Another forecasting approach involved regional downscaling from the global circulation models, CGCMI‐A, ECHAM4, HadCM3, and NCAR‐CCM3. These projected slight flow decreases from the mountain headwaters versus increases from the foothills and boreal regions, resulting in a slight increase in overall river flows (+0.1%/year). Prior projections from these and other global circulation models ranged from slight decrease to slight increase, and the average projection of −0.05%/year approached the empirical trend. Assessments of other rivers draining the central and northern Rocky Mountains revealed a geographic transition in flow patterns over the past century. Flows from the rivers in Southern Alberta declined (around −0.15%/year), in contrast to increasing flows in north‐eastern British Columbia and the Yukon. The RDR watershed approaches this transition, and this study thus revealed regional differentiation in the hydrological consequences from climate change.
Effects of the geometry of two‐dimensional fractures on their hydraulic aperture and on the validity of the local cubic law
Authors: Hajjar Ahmad , Scholtès Luc , Oltéan Constantin , Buès Michel Antoine
Published: June 2018

Flow through rough fractures is investigated numerically in order to assess the validity of the local cubic law for different fracture geometries. Two‐dimensional channels with sinusoidal walls having different geometrical properties defined by the aperture, the amplitude, and the wavelength of the walls' corrugations, the corrugations asymmetry, and the phase shift between the two walls are considered to represent different fracture geometries. First, it is analytically shown that the hydraulic aperture clearly deviates from the mean aperture when the walls' roughness, the phase shift, and/or the asymmetry between the fracture walls are relatively high. The continuity and the Navier–Stokes equations are then solved by means of the finite element method and the numerical solutions compared to the theoretical predictions of the local cubic law. Reynolds numbers ranging from 0.066 to 66.66 are investigated so as to focus more particularly on the effect of flow inertial effects on the validity of the local cubic law. For low Reynolds number, typically less than 15, the local cubic law properly describes the fracture flow, especially when the fracture walls have small corrugation amplitudes. For Reynolds numbers higher than 15, the local cubic law is valid under the conditions that the fracture presents a low aspect ratio, small corrugation amplitudes, and a moderate phase lag between its walls.
Validating the KAGIS black‐box GIS‐based model in a Mediterranean karst aquifer: Case of study of Mela aquifer (SE Spain)
Authors: Valdes‐Abellan Javier , Pla Concepción , Fernandez‐Mejuto Miguel , Andreu José Miguel
Published: June 2018

Karst Aquifer GIS‐based model (KAGIS model) is developed and applied to Mela aquifer, a small karst aquifer located in a Mediterranean region (SE Spain). This model considers different variables, such as precipitation, land use, surface slope and lithology, and their geographical heterogeneity to calculate both, the run‐off coefficients and the fraction of precipitation which contributes to fill the soil water reservoir existing above the aquifer. Evapotranspiration uptakes deplete water, exclusively, from this soil water reservoir and aquifer recharge occurs when water in the soil reservoir exceeds the soil field capacity. The proposed model also obtains variations of the effective porosity in a vertical profile, an intrinsic consequence of the karstification processes. A new proposal from the Nash–Sutcliffe efficiency index, adapted to arid environments, is presented and employed to evaluate the model's ability to predict the water table oscillations. The uncertainty in the model parameters is determined by the Generalized Likelihood Uncertainty Estimation method. Afterwards, when KAGIS is calibrated, wavelet analysis is applied to the resulting data in order to evaluate the variability in the aquifer behaviour. Wavelet analysis reveals that the rapid hydrogeological response, typical of a wide variety of karst systems, is the prevailing feature of Mela aquifer. This study proves that KAGIS is a useful tool to quantify recharge and discharge rates of karst aquifers and can be effectively applied to develop a proper management of water resources in Mediterranean areas.
The role of operating parameters and irradiation on the electrochemical degradation of tetracycline on boron doped diamond anode in environmentally relevant matrices
Authors: Frontistis Zacharias , Meriç Sureyya
Published: June 2018

BACKGROUND

Nowadays, due to the inappropriate use of antibiotics, significant quantities have been detected in environmental samples. Therefore there is a need for a technology to eliminate the accumulation of pharmaceuticals in receiving water bodies. In recent years electrochemical oxidation showed superior efficiency for the purification of water from pharmaceuticals.

RESULTS

boron doped diamond (BDD) showed better efficiency than platinum electrode and stainless steel for the degradation of 500 µg L−1 tetracycline (TC) with 0.1 mol L−1·Na2SO4. The presence of 200 mg L−1 bicarbonates decreased the apparent kinetic constant from 0.328 to 0212 min−1. Instead, the addition of 200 mg L−1 NaCl increased the kinetic constant by almost four times, while the presence of 10 mg L−1 of humic acid decreased the kinetic constant by 18%. The process was favored in real environmental matrices like bottled water and wastewater in comparison with ultrapure water. The use of BDD as both anode and cathode enhanced the efficiency by almost 20%. The presence of UVA or solar radiation increased the decomposition of tetracycline by 14%. Changes in toxicity to Vibrio fisheri bacteria during treatment of TC in the secondary effluent are mainly attributed to the formation of intermediates of the water matrix itself and does not follow the TC removal.

CONCLUSIONS

Electrochemical oxidation was favored for removal of TC in real water matrices due to the presence of chlorides. The use of BDD as both anode and cathode with simultaneous solar irradiation is a promising technology for water remediation from TC. © 2018 Society of Chemical Industry
Behavioral variation in nesting phenology may offset sex‐ratio bias in tuatara
Authors: Nelson Nicola J. , Keall Susan N. , Refsnider Jeanine M. , Carter Anna L.
Published: June 2018

The nest environment for eggs of reptiles has lifelong implications for offspring performance and success, and, ultimately, for population viability and species distributions. However, understanding the various abiotic and biotic drivers of nesting is complex, particularly regarding variation in nesting behavior of females and consequences for sex ratios in species with temperature‐dependent sex determination (TSD). We investigated how nest construction and nesting phenology affect the incubation environment of a reptile with TSD, the tuatara (Sphenodon punctatus), a species that is at risk from climate‐mediated male bias in population sex ratios. Using longitudinal behavioral data, we addressed the following questions. (1) Does nesting behavior vary with seasonal or location cues? (2) Does variation in nesting phenology or nest construction affect the incubation environment? We aimed to investigate whether female tuatara could modify nesting behavior to respond to novel environments, including a warming climate, allowing for successful incubation and balanced population sex ratios, maintaining population viability throughout their historic range. We predicted that earlier nesting after warm winters increased the likelihood that females will be produced, despite the sex determining system where males are produced from warmer temperatures. Further research is needed to understand the extent to which nesting behavior varies by individual through time, and across the range of tuatara, and the importance of habitat variability in maintaining production of females under future climate warming.
Sensitive monitoring of taurine biomarker in unprocessed human plasma samples using a novel nanocomposite based on poly(aspartic acid) functionalized by graphene quantum dots
Authors: Shadjou Nasrin , Alizadeh Salar , Hasanzadeh Mohammad
Published: June 2018

The rapid and accurate determination of the level of taurine biomarker in various tissues and body fluids can be of great interest in the early diagnosis of several important pathologies and diseases. For the first time, this study reports on the electropolymerization of a low toxic and biocompatible nanocomposite “poly(aspartic acid)–graphene quantum dots (GQDs)” as a novel strategy for surface modification of glassy carbon electrode and preparation a new interface for measurement of taurine. Electrochemical deposition, as a well‐controlled synthesis procedure, has been used for subsequently layer‐by‐layer preparation of GQDs nanostructures on poly(aspartic acid) using cyclic voltammetry techniques in the regime of −1.5 to 2 V. The field emission scanning electron microscopy indicated immobilization of uniformly GQDs onto poly(aspartic acid) film. The modified electrode appeared as an effective electroactivity for detection of taurine biomarker using cyclic voltammetry, chronoamperometry, and differential pulse voltammetry. Enhancement of peak currents is ascribed to the fast heterogeneous electron transfer kinetics that arise from the synergistic coupling between the excellent properties of poly(aspartic acid) as semiconducting polymer, GQDs as high density of edge plane sites, and subtle electronic characteristics to chemical modification. Under the optimized analysis conditions, the prepared sensor for detection of taurine showed a low limit of quantification 0.001mM. Finally, the resulting prepared sensor allow the quantification of these biomarkers directly in biological samples without need of derivatization schemes or sample pretreatment.
Potential use of soilborne lytic Podoviridae phage as a biocontrol agent against Ralstonia solanacearum
Authors: Elhalag Kamel , Nasr‐Eldin Mohamed , Hussien Ahmed , Ahmad Abdelmonim
Published: June 2018

A new podovirus RsPod1EGY Ralstonia phage (GenBank accession no MG711516) with a specific action against R. solanacearum phylotype IIa, sequevar I (race 3, biovar 2) was isolated from Egyptian soil. The potential efficacy of the isolated phage to be used as biocontrol agent was evaluated in vitro and under greenhouse conditions. The podovirus phage produced a plaque size of 3.0–4.0 mm in diameter and completed its infection cycle in 180 min after infection with a burst size of ∼27 virions per infected cell. On the basis of restriction endonuclease analysis, the genome size of the phage was about 41 kb of double‐stranded DNA. In vitro studies showed that RsPod1EGY is stable at higher temperatures (up to 60 °C), and at a wide pH range (5–9). SDS–PAGE analysis indicated the major structural protein to be approximately 32 kDa. Bacteriolytic activity of RsPod1EGY against R. solanacearum was detected at different multiplicity of infection (MOI). RsPod1EGY proved to be effective in reduction and prevention of formation of surface polysaccharides of R. solanacearum, during the exponential growth phase of the latter. Interestingly, RsPod1EGY was effective in suppression of R. solanacearum under greenhouse conditions. All Phage‐treated tomato plants showed no wilt symptoms or any latent infection during the experimental period, whereas all untreated plants have wilted by 10 days post‐infection. The lytic stability of RsPod1EGY phage at higher temperature as well as its effective suppression of wilting symptoms under greenhouse conditions would contribute to biocontrol the bacterial wilt disease in Egypt under field conditions.
Genetic support vector machines as powerful tools for the analysis of biomedical Raman spectra
Authors: Hunter Robert , Anis Hanan
Published: June 2018

The growing number of applications of Raman spectroscopy in medicine necessitates the development of robust and accurate processing methods. The two major tasks for which Raman spectra are used are quantifying chemical species in a sample (regression) and discriminating chemically distinct samples (classification). Conventionally, linear techniques, primarily projection to latent structures (PLS), are used to perform these tasks. However, there are a number of nonlinearities that may arise when acquiring the Raman spectra of biomedical samples, such as scattering differences between tissues or autofluorescence variances, which makes nonlinear methods more suitable. To this end, we compared kernelized support vector machines (SVM) to PLS for a number of biomedical Raman datasets. Additionally, this work develops a genetic SVM, wherein the parameters of a SVM are selected by a classical genetic algorithm instead of the conventional grid search. This facilitates the use of complex kernels, which yield higher performance than simple kernel functions. We have found that this genetic SVM outperforms PLS in all of the regression tasks examined in this paper, while yielding equivalent results for classification tasks. Additionally, we have found that the genetic algorithm provides significant time savings in the optimization of the SVM parameters over grid search.
Synergistic thermo‐Raman and calorimetric kinetic study of the cation modifier's role in binary metaphosphate glasses
Authors: Sendova Mariana , Jiménez José A.
Published: June 2018

A comprehensive temperature‐dependent Raman spectroscopy and differential scanning calorimetry study has been performed on three metaphosphate glasses with different modifying cations (Ca2+, Ba2+, and Pb2+). The P–NBO (nonbridging oxygen) Raman spectral feature, the force constant, and the glass transition activation energy (AETg) are shown to be strongly correlated to the relative effective nuclear charge difference between the modifying and the glass former cations, ζ. In addition, the estimated AETg values between 3.6(2) and 4.7(2) eV are found to be in the range of the P–O bond energy values in the phosphate glasses. The study contributes to the enrichment of the bond exchange kinetic theory of the glass transition in general and to the bond modifying mechanism of the cations. The authors propose that Raman spectroscopy alone can be implemented reliably for evaluation not only of AETg, but for calculation of the Morse potential of the moiety crucial for the onset of glass transition. Alternatively, in glasses without Raman scattering, the force constant of the critical moiety can be deduced from calorimetric measurements alone. The proposed analytical methodology broadens Raman spectroscopy and calorimetric applications and offers a viable technique for all types of glass matrices.
Protein hydrolysates and ultrafiltered < 1 KDa fractions from Phaseolus lunatus, Phaseolus vulgaris and Mucuna pruriens exhibit antihyperglycemic activity, intestinal glucose absorption and α‐glucosidase inhibition with no acute toxicity in rodents
Authors: Nuñez‐Aragón Pablo N , Segura‐Campos Maira , Negrete‐León Elizabeth , Acevedo‐Fernández Juan J , Betancur‐Ancona David , Chel‐Guerrero Luis , Castañeda‐Corral Gabriela
Published: June 2018

BACKGROUND

Protein hydrolysates from food plants, such as legumes, have emerged as a new alternative to treat hyperglycemia, an important risk factor contributing to the development of type 2 diabetes mellitus (T2DM) and its complications. The aim of this work was to assess the antihyperglycemic activity and inhibition of α‐glucosidase, and intestinal glucose absorption, and acute toxicity of total hydrolysates and < 1 kDa fractions from Phaseolus lunatus L., Phaseolus vulgaris L., and Mucuna pruriens (L.) DC., obtained by hydrolysis with Alcalase®‐Flavourzyme® or pepsine‐pancreatin enzymatic systems.

RESULTS

In vivo results showed that three of six total hydrolysates and four of six < 1 kDa fractions suppressed starch‐induced postprandial hyperglycemia (ED50 range between 1.4 and 93 mg kg−1). In vitro, total hydrolysates and fractions, particularly from M. pruriens, inhibited carbohydrate intestinal absorption (from 19.2 to 40%), and α‐glucosidase activity (IC50 from 0.86 to 75 mg mL−1). Finally, none of the hydrolysates and fractions tested did not show any signs of toxicity (LD50 > 5000 mg kg−1).

CONCLUSION

These results suggest that hydrolysates and < 1 kDa fractions from P. lunatus, P. vulgaris and M. pruriens are suitable candidates to treat or prevent T2DM. © 2018 Society of Chemical Industry
PET imaging for assessing tumor response to therapy
Authors: Mankoff David A. , Katz Sharyn I.
Published: June 2018

Positron emission tomography (PET) is a radioisotope imaging technique capable of quantifying the regional distribution of molecular imaging probes targeted to biochemical pathways and processes allowing direct measurement of biochemical changes induced by cancer therapy, including the activity of targeted growth pathways and cellular populations. In this manuscript, we review the underlying principles of PET imaging, choices for PET radiopharmaceuticals, methods for tumor analysis and PET applications for cancer therapy response assessment including potential future directions.
Kinetics, mass transfer, and thermodynamic and statistical modeling study for esterification of valeric acid with n‐butanol: Homogeneous and heterogeneous catalysis
Authors: Khudsange Chandrakant R. , Wasewar Kailas L.
Published: June 2018

The esterification of valeric acid with n‐butanol was studied with homogeneous and heterogeneous catalysts. The activity and performance of homogeneous p‐toluenesulfonic acid and heterogeneous cation exchange resin catalysts Amberlyst 36, Indion 190, and Amberlite IRC‐50 were evaluated. The pseudo‐homogeneous kinetic model was used to investigate the kinetic parameters of homogeneous‐ and heterogeneous‐catalyzed esterification. The UNIFAC (universal functional activity coefficient) approach was used to study the nonideality of the esterification reaction. The reaction was statistically modeled and optimized by the application of response surface methodology. The effects of independent variables such as reaction temperature, initial molar ratio, and catalyst loading on the conversion of valeric acid were investigated. The optimized conditions for the esterification reaction catalyzed by Amberlyst‐36 were found as temperature 360.4 K, initial molar ratio 3.8, and catalyst loading 6.7 wt%. The predicted conversion (89%) at these optimized conditions is in good agreement with the experimental conversion (87.3 ± 1.6%).
Nonstoichiometric Stille Coupling Polycondensation via an Intramolecular Pd(0) Catalyst Transfer Using Excess Phthalimide Monomer
Authors: Terayama Kosuke , Goto Eisuke , Higashihara Tomoya
Published: June 2018

Nonstoichiometric polycondensations via Stille coupling reactions are successfully used to obtain high‐molecular‐weight π‐conjugated polymers using 2,5‐bis(trimethylstannyl)thiophene and a dibromo phthalimide monomer, N‐hexyldecyl‐3,6‐dibromophthalimide (2), in excess from 1:1 to 1:10. The intramolecular Pd(0) catalyst transfer on 2 substituted at the polymer terminal occurs as suggested by the model reaction between 2‐(tributylstannyl)thiophene and an equimolar amount of N‐octyl‐3,6‐dibromophthalimide (4), and the reaction generates only the disubstituted compound and excess 4 in an almost 1:1 ratio. The effect of the structures of the ligands and monomers on the polymerization under nonstoichiometric conditions is investigated to elucidate the criteria for the successful intramolecular catalyst transfer. The combination of the imide structure and an electron‐rich ligand is important for promoting the catalyst transfer.
MicroRNA‐383 acts as a tumor suppressor in colorectal cancer by modulating CREPT/RPRD1B expression
Authors: Li Jian , Smith Amber R. , Marquez Rebecca T. , Li Jun , Li Kun , Lan Lan , Wu Xiaoqing , Zhao Linxi , Ren Fangli , Wang Yi , Wang Yinyin , Jia Baoqing , Xu Liang , Chang Zhijie
Published: June 2018

CREPT (Cell‐cycle‐related and expression‐elevated protein in tumor)/RPRD1B, a novel protein that enhances the transcription of Cyclin D1 to promote cell proliferation during tumorigenesis, was demonstrated highly expressed in most of tumors. However, it remains unclear how CREPT is regulated in colorectal cancers. In this study, we report that miR‐383 negatively regulates CREPT expression. We observed that CREPT was up‐regulated but the expression of miR‐383 was down regulated in both colon cancer cell lines and colon tumor tissues. Intriguingly, we found that enforced expression of miR‐383 inhibited the expression of CREPT at both the mRNA and protein level. Using a luciferase reporter, we showed that miR‐383 targeted the 3′‐UTR of CREPT mRNA directly. Consistently we observed that over expression of miR‐383 shortened the half‐life of CREPT mRNA in varieties of colorectal cancer cells. Furthermore, restoration of miR‐383 inhibited cell growth and colony formation of colon cancer cells accompanied by inhibition of expression of CREPT and related downstream genes. Finally, we demonstrated that stable over expression of miR‐383 in colon cancer cells decreased the growth of the tumors. Our results revealed that the abundant expression of CREPT in colorectal cancers is attributed to the decreased level of miR‐383. This study shed a new light on the potential therapeutic therapy strategy for colorectal cancers using introduced miRNA.
A study of fractional integral operators involving a certain generalized multi‐index Mittag‐Leffler function
Authors: Srivastava H. M. , Bansal Manish , Harjule Priyanka
Published: June 2018

Motivated by the demonstrated potential for their applications in various research areas such as those in mathematical, physical, engineering, and statistical sciences, our main object in this paper is to introduce and investigate a fractional integral operator that contains a certain generalized multi‐index Mittag‐Leffler function in its kernel. In particular, we establish some interesting expressions for the composition of such well‐known fractional integral and fractional derivative operators as (for example) the Riemann‐Liouville fractional integral and fractional derivative operators, the Hilfer fractional derivative operator, and the above‐mentioned fractional integral operator with the generalized multi‐index Mittag‐Leffler function in its kernel. The main findings in this paper are shown to generalize the results that were derived earlier by Kilbas et al and Srivastava et al. Finally, in this paper, we derive integral representations for the product of 2 generalized multi‐index Mittag‐Leffler functions in terms of the familiar Fox‐Wright hypergeometric function.
Unconditional superconvergence analysis of a linearized Galerkin FEM for nonlinear Schrödinger equation
Authors: Shi Dongyang , Wang Junjun
Published: June 2018

A linearized backward Euler scheme with conforming finite element method for nonlinear Schödinger equation is studied, and the unconditional superconvergence result is deduced. A time‐discrete system is introduced to split the error into 2 parts, the temporal error and the spatial error. Firstly, a rigorous analysis for the regularity of the time‐discrete system is presented based on the proof of the temporal error skillfully. Secondly, the classical Ritz projection is applied to get the spatial error with order O(h2) in L2‐norm, which plays an important role in getting rid of the restriction of τ. Then, superclose estimates of order O(h2 + τ) in H1‐norm is arrived at with the above achievements and the relationship between the classical Ritz projection and the interpolated operator. Thirdly, global superconvergence result is deduced through interpolated postprocessing technique. At last, a numerical example is provided to confirm the theoretical analysis. Here, h is the subdivision parameter, and τ is the time step.
Novel Mechanism of Fatty Acid Sensing in Enteroendocrine Cells: Specific Structures in Oxo‐Fatty Acids Produced by Gut Bacteria Are Responsible for CCK Secretion in STC‐1 Cells via GPR40
Authors: Hira Tohru , Ogasawara Shono , Yahagi Asuka , Kamachi Minami , Li Jiaxin , Nishimura Saki , Sakaino Masayoshi , Yamashita Takatoshi , Kishino Shigenobu , Ogawa Jun , Hara Hiroshi
Published: June 2018

Scope

The secretion of gut hormones, such as cholecystokinin (CCK) is stimulated by fatty acids. Although a chain length–dependent mechanism has been proposed, other structural relationships to releasing activity remain unclear. We aimed to elucidate specific structures in fatty acids that are responsible for their CCK‐releasing activity, and related sensing mechanisms in enteroendocrine cells.

Methods and results

CCK secretory activities were examined in a murine CCK‐producing cell line STC‐1 by exposing the cells to various modified fatty acids produced by gut lactic acid bacteria. The effects of fatty acids on gastric emptying rate as a CCK‐mediated function were examined using acetaminophen and phenol red methods in rats. Out of more than 30 octadecanoic‐derived fatty acids tested, 5 oxo‐fatty acids potently stimulated CCK secretion without cytotoxic effects in STC‐1 cells. Three fatty acids had a distinct specific structure containing one double bond, whereas the other two had two double bonds, nearby an oxo residue. CCK secretion induced by representative fatty acids (10‐oxo‐trans‐11‐18:1 and 13‐oxo‐cis‐9,cis‐15‐18:2) was attenuated by a fatty acid receptor G‐protein coupled receptor 40 antagonist. Oral administration of 13‐oxo‐cis‐9,cis‐15‐18:2 lowered the gastric emptying rate in rats in a dose‐ and structure‐dependent manner.

Conclusion

These results reveal a novel fatty acid‐sensing mechanism in enteroendocrine cells.
Initial assessment versus gradual change in early childhood behavior problems―Which better foretells the future?
Authors: McDermott Paul A. , Rovine Michael J. , Buek Katharine W. , Reyes Roland S. , Chao Jessica L. , Watkins Marley W.
Published: June 2018

Leading research argues the distinct importance of earliest detection of childhood behavior problems and the value of discovering subsequent change patterns as children transition through the early education years. This study examined the relative contributions of earliest assessments of children's problem behaviors as compared to the changes in those behaviors over time for the prediction of important later outcomes. Focusing on the representative national sample from the Head Start Impact Study (n = 3,827), classroom behavior problems were assessed across 4 years spanning prekindergarten through first grade. Individual child indices were derived in multilevel growth modeling to reflect initial assessments and subsequent change patterns. These indices were thereafter applied in multilevel logistic regression and receiver operating characteristic curve analyses to predict later academic and social difficulties. Both children's initial assessments and their transitional changes proved to be good predictors of most outcomes, where the accuracy for initial assessments and transitional changes was effectively equivocal. The evidence clarifies that initial assessment of behavior problems is sufficient to predict later outcomes; additional assessments did not augment forecasting accuracy nor did the combination of both initial assessment and information about subsequent change improve accuracy. Implications are discussed for assessment theory and practice.
Advanced Organic Molecular Doping Applied to Si: Influence of the Processing Conditions on the Electrical Properties
Authors: Caccamo Sebastiano , Grimaldi Maria Grazia , Italia Markus , La Magna Antonino , Mannino Giovanni , Puglisi Rosaria A.
Published: June 2018

The molecular doping (MD) process consists of depositing a molecular precursor on a silicon substrate, covering the precursor with a cap layer and annealing the sample to decompose the precursor and diffuse dopant atoms within Si. In the literature, preliminary results have shown that dopant diffusion inside a substrate correlates with the presence or absence of the cap layer. The purpose of this work is to study how the cap coating changes the doping process and efficiency. The authors investigate and compare the electrical properties of silicon samples after MD doping with three different cap layers and without a cap layer. The authors examined a 500‐nm‐thick layer of SiO2 deposited by spin‐on‐glass (SOG), a 500‐nm‐thick layer of SiO2 deposited in a chemical vapor deposition (CVD) chamber at room temperature and a 100‐nm‐thick layer of oxidized silicon placed over and in contact with the samples to be doped. Spreading resistance profiling (SRP) measurements are then performed on these samples to monitor important doping features, such as carrier dose, carrier concentration, sheet resistance and junction depth, obtained with different capping conditions.