bluuebunny/crossref_metadata_2025 huggingface dataset:
The influence of leaf litter diversity and soil fauna on initial soil erosion in subtropical forests
Authors: Seitz Steffen , Goebes Philipp , Zumstein Pascale , Assmann Thorsten , Kühn Peter , Niklaus Pascal A. , Schuldt Andreas , Scholten Thomas
Published: February 2015

Although the protective role of leaf litter cover against soil erosion is known for a long time, little research has been conducted on the processes involved. Moreover, the impact of soil meso‐ and macrofauna within the litter layer on erosion control is not clear. To investigate how leaf litter cover and diversity as well as meso‐ and macrofauna influence sediment discharge in subtropical forest ecosystems, a field experiment has been carried out in Southeast China. A full‐factorial random design with 96 micro‐scale runoff plots and 7 domestic leaf species was established and erosion was triggered by a rainfall simulator. Our results demonstrate that leaf litter cover protects soil from erosion (−82 % sediment discharge on leaf covered plots) by rainfall and this protection is removed as litter decomposes. The protective effect is influenced by the presence or absence of soil meso‐ and macrofauna. Fauna presence increases soil erosion rates significantly by 58 %, while leaf species diversity shows a non‐significant negative trend. We assume that the faunal effect arises from arthropods slackening and processing the soil surface as well as fragmenting and decomposing the protecting leaf litter covers. Even though the diversity level did not show a significant influence, single leaf species in monocultures show rather different impacts on sediment discharge and thus, erosion control. In our experiment, runoff plots with leaf litter fromMachilus thunbergiishowed the highest sediment discharge (68.0 g m−2) whereas plots withCyclobalanopsis glaucashowed the smallest rates (7.9 g m−2). Copyright © 2015 John Wiley & Sons, Ltd.
Progress Possible on Disposal of Nuclear Waste
Authors: McMurrian Katrina
Published: February 2015

The midterm elections of 2014 breathed new life into an old but critical issue—the safe and timely disposal of a growing inventory of spent nuclear fuel and high‐level radioactive waste from commercial electricity production.
Citywide Wi‐Fi Internet Access Through Utilities Successful in Selected Areas
Authors: Crawley David L.
Published: February 2015

The US realization of the Internet as a global utility infrastructure with local implications took off when Simdesk Technologies signed a contract with the city of Houston in 2001.
The Enteric Glia: Identity and Functions
Authors: Coelho‐Aguiar Juliana de Mattos , Bon‐Frauches Ana Carina , Gomes Ana Lúcia Tavares , Veríssimo Carla Pires , Aguiar Diego Pinheiro , Matias Diana , Thomasi Beatriz Bastos de Moraes , Gomes Antoniella Souza , Brito Gerly Anne de Castro , Moura‐Neto Vivaldo
Published: February 2015

Enteric glial cells were first described at the end of the 19th century, but they attracted more interest from researchers only in the last decades of the 20th. Although, they have a different embryological origin, the enteric GLIA share many characteristics with astrocytes, the main glial cell type of the central nervous system (CNS), such as in their expression of the same markers and in their functions. Here we review the construction of the enteric nervous system (ENS), with a focus on enteric glia, and also the main studies that have revealed the action of enteric glia in different aspects of gastrointestinal tract homeostasis, such as in the intestinal barrier, in communications with neurons, and in their action as progenitor cells. We also discuss recent discoveries about the roles of enteric glia in different disorders that affect the ENS, such as degenerative pathologies including Parkinson's and prion diseases, and in cases of intestinal diseases and injury. GLIA 2015;63:921–935
Cognitive functioning throughout the treatment history of clinical late‐life depression
Authors: Dzierzewski Joseph M. , Potter Guy G. , Jones Richard N. , Rostant Ola S. , Ayotte Brian , Yang Frances M. , C. Sachs Bonnie , Feldman Betsy J. , Steffens David C.
Published: February 2015

Objective

Previous investigations into the relationship between late‐life depressive symptoms and cognitive functioning have resulted in mixed findings concerning whether or not depressive symptoms and cognitive functioning are related. The mixed reports may be due in part to differences in clinical and nonclinical samples and to inadequate consideration of the dynamic nature (i.e., fluctuating course) of depressive symptoms and cognitive functioning in older adults. The current study examined the chronic, acute, and longitudinal relationships between depressive symptoms and cognitive functioning in older adults in an ongoing treatment study of major depressive disorder (MDD).

Methods

The neurocognitive outcomes of depression in the elderly study operates in a naturalistic treatment milieu using a pharmacological treatment algorithm and regular psychiatric assessment. Four hundred and fifty‐three older adults [mean age 70 years, standard deviation (SD) = 7.2] meeting criteria for MDD at study enrollment received annual neuropsychological testing and depressive symptom monitoring for an average of 8.5 years (SD = 4.5).

Results

Hierarchical linear modeling revealed that higher age, lower education, and higher average/chronic levels of depressive symptoms were related to lower cognitive functioning. Additionally, results revealed that when an individual's depressive symptoms are higher than is typical for a specific individual, general cognitive function was worse than average. There was no evidence of lagged/longitudinal relationships between depressive symptoms and cognitive functioning in older adults in treatment for MDD.

Conclusions

Cognitive functioning and depressive symptoms are concurrently associated in older adults with MDD, highlighting the potential importance for stabilizing mood symptoms as a means to manage cognitive deficits in late‐life depression. Copyright © 2015 John Wiley & Sons, Ltd.
Impact of aging on frontostriatal reward processing
Authors: Vink Matthijs , Kleerekooper Iris , van den Wildenberg Wery P. M. , Kahn Rene S.
Published: February 2015

Healthy aging is associated with a progressive decline across a range of cognitive functions. An important factor underlying this decline may be the age‐related impairment in stimulus–reward processing. Several studies have investigated age‐related effects, but compared young versus old subjects. This is the first study to investigate the effect of aging on brain activation during reward processing within a continuous segment of the adult life span. We scanned 49 healthy adults aged 40–70 years, using functional MRI. We adopted a simple reward task, which allowed separate evaluation of neural responses to reward anticipation and receipt. The effect of reward on performance accuracy and speed was not related to age, indicating that all subjects could perform the task correctly. We identified a whole‐brain significant age‐related decline of ventral striatum activation during reward anticipation as compared to neutral anticipation. Importantly, the specificity of this finding was underscored by the observation that there was no general decline in activation during anticipation. Activation in the ventral striatum increased with age during reward receipt as compared to receiving neutral outcome. Finally, activation in the ventromedial prefrontal cortex during outcome was not affected by age. Our data demonstrate that the typical shift in striatal activation from reward receipt to reward anticipation in young adults disappears with healthy aging. These changes are consistent the well‐ocumented age‐related decline of striatal dopamine availability, and may provide a stepping stone for further research of age‐related neurodegenerative diseases. Hum Brain Mapp 36:2305–2317, 2015. © 2015 Wiley Periodicals, Inc.
Enhanced neural responsiveness to reward associated with obesity in the absence of food‐related stimuli
Authors: Opel Nils , Redlich Ronny , Grotegerd Dominik , Dohm Katharina , Haupenthal Cordula , Heindel Walter , Kugel Harald , Arolt Volker , Dannlowski Udo
Published: February 2015

Background

Obesity has been characterized by alterations in brain structure and function associated with emotion processing and regulation. Particularly, aberrations in food‐related reward processing have been frequently demonstrated in obese subjects. However, it remains unclear whether reward‐associated functional aberrations in obesity are specific for food‐related stimuli or represent a general deficit in reward processing, extending to other stimulus domains. Given the crucial role of rewarding effects in the development of obesity and the ongoing discussion on overlapping neurobiological traits of obesity and psychiatric disorders such as depression and substance‐related disorders, this study aimed to investigate the possibility of altered reward processing in obese subjects to occur in the absence of food‐related stimuli during a monetary reward condition.

Methods

Twenty‐nine healthy obese subjects (body mass index >30) and 29 healthy, age‐, and sex‐matched control subjects of normal weight underwent functional MRI during a frequently used card guessing paradigm. A Group × Condition (win vs. loss) ANOVA was conducted to investigate differences between obese and normal‐weight subjects.

Results

We found significant Group × Condition interaction effects in brain areas involved in emotion regulation and reward processing including the insula, the striatum, and the orbitofrontal cortex (OFC). This interaction was predominantly driven by a significant increase in blood oxygenation level dependent (BOLD) response in obese individuals while experiencing reward.

Conclusions

Enhanced neural activation in obesity during reward processing seems to be apparent even in the absence of food‐related stimuli and, thus, might point to generalized dysfunctions in reward‐related brain circuits in obese individuals. Hum Brain Mapp 36:2330–2337, 2015. © 2015 Wiley Periodicals, Inc.
Influence of spatial and temporal flow variability on solute transport in catchments
Authors: Selroos Jan‐Olof , Destouni Georgia
Published: February 2015

This study quantifies the separate and combined effects of spatial and temporal variability for waterborne solute transport through catchments. The questions addressed regard whether, when and why the different types of variability may dominate catchment‐scale transport. We utilize a versatile numerical solute transport code with a particle‐based Monte Carlo time‐domain random walk method to simulate waterborne transport through a generic catchment. Simulations are concretized and exemplified using data on spatiotemporal flow–transport variability from direct stream discharge observations and independently calculated advective solute travel time distributions for catchments within the water management district Northern Baltic Proper in Mid‐Eastern Sweden. A main conclusion is that the projections of catchment mass loading based on spatial variability alone are robust estimates of long‐term average solute transport development. This is especially true when annually aggregated mass load rather than finer temporal resolution of mass flux is considered. Temporal variability yields short‐term fluctuations around the long‐term average solute breakthrough development, and earlier or later arrival than the latter, depending on the timing and duration of solute input relative to the temporal flow variability. The exact temporal characteristics of future solute breakthrough are thus fundamentally uncertain, but their statistical expectation may be well quantified by accounting only for spatial variability. Copyright © 2015 John Wiley & Sons, Ltd.
Mechanistic Enzymology of the Radical SAM Enzyme DesII
Authors: Ruszczycky Mark W. , Liu Hung‐wen
Published: February 2015

DesII is a member of the radical SAM family of enzymes that catalyzes radical‐mediated transformations of TDP‐4‐amino‐4,6‐didexoy‐D‐glucose, as well as other sugar nucleotide diphosphates. Like nearly all radical SAM enzymes, the reactions begin with the reductive homolysis of SAM to produce a 5′‐deoxyadenosyl radical, which is followed by regiospecific hydrogen atom abstraction from the substrate. What happens next, however, depends on the nature of the substrate radical so produced. In the case of the biosynthetically relevant substrate, a radical‐mediated deamination ensues; however, when this amino group is replaced with a hydroxyl, one instead observes dehydrogenation. The factors that govern the fate of the initially generated substrate radical, as well as the mechanistic details underlying these transformations, have been a key focus of research into the chemistry of DesII. This review will discuss recent discoveries pertaining to the enzymology of DesII, how it may relate to understanding other radical‐mediated lyases and dehydrogenases, and the working hypotheses currently being investigated regarding the mechanism of DesII catalysis.
The Unpredictability of Research Directions and the Synergy between Theory and Experiment in Physical‐Organic Chemistry
Authors: Borden Weston Thatcher
Published: February 2015

Research projects in physical‐organic chemistry can go in unpredictable directions. One such project, described herein, began with the discovery of a large, imaginary, calculated vibrational frequency and soon led to the prediction that cyclobutanetetraone (CO)4 had a triplet ground state. Molecular orbital (MO) theory provided the understanding of why (CO)4 was calculated to have a planar triplet ground state and why, in contrast, (SiO)4 was calculated to have a tetrahedral singlet ground state. Qualitative MO theory, as well as calculations, also predicted that (CO)3, (CO)5, and (CO)6 should all be found to have singlet ground states. Testing experimentally these predictions about (CO)n molecules, n=3–6, led to a very fruitful collaboration with Dr. Xuebin Wang, who obtained the negative ion photoelectron (NIPE) spectra of the radical anions of these four molecules and also of (CS)4. Assignments of the signals in these five NIPE spectra required computing the vibrational progressions in them. The necessary acquisition of the ability to simulate the signals in NIPE spectra resulted in the successful analysis of the very complex spectrum of meta‐benzoquinone (MBQ) radical anion, which Dr. Wang had already obtained and published. Analysis of this spectrum confirmed the prediction, made more than 20 years previously, that the ordering of the two lowest singlet states in MBQ was reversed from that in meta‐benzoquinodimethane (MBQDM). The research described herein illustrates not only the unpredictability of where some research projects will eventually lead, but also the synergy between calculations and experiments in physical‐organic chemistry.
Functional Peptide Monolayers at Interfaces
Authors: Baruch Leshem Avigail , Zarzhitsky Shlomo , Rapaport Hanna
Published: February 2015

Amphiphilic peptides can be designed to form ordered supramolecular structures at hydrophilic‐hydrophobic interfaces. These systems rely on the ability of peptides to fold into certain secondary structures at interfaces. This review focuses on the design of amphiphilic β‐sheet peptide assemblies in monolayers at interfaces, and their relevance to inducing mineralization and interactions with specific ions. In addition, the review discusses recent studies demonstrating the applicability of designed amphiphilic β‐sheet peptides to detection of specific small molecules and to elucidating intermolecular interactions relevant to drug delivery and enzyme catalysis systems.
On the Emergence of RNA
Authors: Krishnamurthy Ramanarayanan
Published: February 2015

Whether there was an RNA world or not, it is indisputable that there was RNA; when, where, and how is yet to be settled. The question of whether “pristine” RNA assembled directly from its components (“prebiotic clutter”), or whether it was a descendant of “simpler” ancestral system(s), is central to the ongoing debate about RNA’s origins. In this review, we look at the facts that suggest RNA is an emergent system and that each component of RNA may have been decided at the level of the oligomer/polymer, and not at the level of the prebiotic clutter, nor at the level of monomer nucleotides. The critical interdependence of RNA’s components – ribofuranose, phosphodiester backbone, and purine‐pyrimidine base‐pairing – for the functioning of RNA seems to be evident, and manifests itself only at the level of the polymer. Based on the power of such nuanced selections at the polymer level, and coupling it with the reality of the prebiotic mixtures at the monomer level, a scenario is presented wherein the combinatorial interactions of diverse prebiotic (systems) chemistry leads first to chimeric‐heterogeneous (aka “pre‐RNA”) systems, which can usher in a homogeneous system (RNA), capable of further evolution.
Randomized study of teaching ultrasound‐guided vascular cannulation using a phantom and the freehand versus needle guide–assisted puncture techniques
Authors: Jaffer Usman , Normahani Pasha , Singh Prashant , Aslam Mohammed , Standfield Nigel J.
Published: February 2015

Purpose

The task of ultrasound‐guided vessel cannulation can be technically difficult. Needle guides have been designed to facilitate vessel puncture. We aimed to identify and compare the learning curves of participants performing vessel puncture with conventional freehand (FH) and needle guide–assisted (NG) techniques.

Methods

Thirty‐six participants were randomly allocated to either the FH or the NG group. They were asked to consecutively perform as many as 30 vessel punctures on a simulated phantom model. Quantitative metrics (time taken and number of skin and posterior‐wall punctures) were recorded and compared between the two groups. The cumulative sum and moving F‐test statistical methods were used to delineate the learning curves.

Results

There was a significantly lower rate of posterior‐wall punctures in the NG group than in the FH group (15% versus 26%; p < 0.0001). Participants in the NG group also performed significantly fewer skin punctures than did those in the FH group (mean, 405 versus 515; p < 0.0001). Cumulative sum statistical method analysis showed that participants in the NG group surmounted the learning curve earlier (13 attempts; interquartile range, 10.3–17.0) than did those in the FH group (19 attempts; interquartile range, 15.0–27.5). The number of attempts to surmount the learning curve was significantly less for the FH group (7.2 versus 16 attempts; p = 0.007) when using the moving F‐test.

Conclusions

The NG puncture allows a greater number of trainees to cross the learning threshold and offers the advantages of fewer posterior‐wall punctures and skin punctures. The use of NG puncture may result in a shorter path to proficiency, allowing trainees to attempt needle puncture earlier and with a greater degree of safety. © 2015 Wiley Periodicals, Inc. J Clin Ultrasound 43:469–477 2015
Sonographic appearances of torsion of the appendix testis and appendix epididymis in children
Authors: Lev Mikahl , Ramon Jacob , Mor Yoram , Jacobson Jeffrey M. , Soudack Michalle
Published: February 2015

Purpose

The most common cause of acute scrotum in prepubertal boys is torsion of the testicular or epididymal appendages. The purpose of this retrospective study was to characterize the features of these lesions as viewed on sonographic (US) and color Doppler US examination.

Methods

During a 220‐week period, 527 male patients 0–17 years old had been referred from the pediatric emergency department for scrotal US evaluation. Torsion of the appendix testis or appendix epididymis had been diagnosed in 19 (3.6%) patients, 3–14 years old (mean, 9.4 years); those patients became our study cohort. The clinical diagnoses in 15 of those patients had been suspected testicular torsion (n = 7), trauma (n = 4), suspected epididymitis and/or orchitis (n = 3), and suspected hydrocele (n = 1). The remaining four patients had been referred owing to nonspecific pain. None of the 19 patients had had the “blue‐dot sign” on physical examination.

Results

In the 19 patients diagnosed with torsion of the intrascrotal appendages, color Doppler US demonstrated a round or oval avascular lesion with heterogeneous echotexture (n = 18), posterior enhancement (n = 13), and hyperemia of the surrounding structures (n = 15). All lesions (appendages) were adjacent (n = 16) or in close proximity (n = 3) to the upper pole of the testis. Fifteen of the appendages were adjacent to both the testis and the epididymis, four were adjacent to the epididymis alone, and none were adjacent to the testis alone. Owing to the close proximity of the upper pole of the testis, the epididymis, and the appendage, differentiation between testicular and epididymal appendages was not possible.

Conclusions

Torsion of the intrascrotal appendages has a typical appearance on color Doppler US; thus, we believe that it is the method of choice for diagnosing torsion of the scrotal appendages and safely ruling out other disorders as well as avoiding unwarranted surgical intervention or antibiotic treatment. © 2015 Wiley Periodicals, Inc. J Clin Ultrasound 43:485–489 2015
Do Democracies Tax More? Political Regime Type and Taxation
Authors: Garcia Maria Melody , von Haldenwang Christian
Published: February 2015

A growing body of literature suggests that political regime type matters in determining taxation. However, research on the relationship of political regimes to taxation yields mixed results. To what extent does the democratic or authoritarian character of the polity impact on the level of taxation? The paper investigates the relationship between political regimes and tax‐to‐gross domestic product ratio, using a panel dataset of 131 countries and covering the period 1990–2008. Findings suggest that the character of the polity affects taxation, but there is no linear trend in favour of democracy. Rather, the results indicate a U‐shaped relationship between polity and tax ratio. Copyright © 2015 John Wiley & Sons, Ltd.
Impact of the processes of testicular regression and recrudescence in the prostatic complex of the bat Myotis nigricans (Chiroptera: Vespertilionidae)
Authors: Beguelini Mateus R. , Góes Rejane M. , Rahal Paula , Morielle‐Versute Eliana , Taboga Sebastião R.
Published: February 2015

Myotis nigricans is a species of vespertilionid bat, whose males show two periods of total testicular regression during the annual reproductive cycle in the northwest São Paulo State, Brazil. Thus, the aim of this study was to investigate the impact of total testicular regression on the prostatic morphophisyology and its regulation. The prostatic complex (PC) of animals from the four periods of the reproductive cycle (active, regressing, regressed, and recrudescence) was analyzed by different histological, morphometric, and immunohistochemical procedures to characterize its variations, analyze its hormonal regulation and evaluate whether the prostate is affected by the processes of testicular regression and recrudescence. The results indicated a decrease in the prostatic parameters from the active to regressed periods, which are related to decreases in the testicular production of testosterone and in the prostatic expression of androgen receptor (AR), estrogen receptor α (ERα) and aromatase. However, in regressed‐recrudescence periods, the prostatic expression of AR, ERα and aromatase increased, indicating the reactivation of the PC. Despite this, the PC appears to have a slower reactivation and seems not to follow the testicular recrudescence in morphological and morphometric terms. With these data, we demonstrate that the prostatic physiology is directly affected by total testicular regression and conclude that it is regulated by testosterone and estrogen, via the production of testosterone by the testes, its conversion to dihydrotestosterone by 5α‐redutase and to estrogen by aromatase, and the activation/deactivation of AR and ERα in epithelial cells, which regulate cell expression and proliferation. J. Morphol. 276:721–732, 2015. © 2015 Wiley Periodicals, Inc.
Setup of a bone aging experimental model in the rabbit comparing changes in cortical and trabecular bone: Morphological and morphometric study in the femur
Authors: Pazzaglia Ugo E. , Sibilia Valeria , Congiu Terenzio , Pagani Francesca , Ravanelli Marco , Zarattini Guido
Published: February 2015

Bone aging was studied in an experimental model (rabbit femur) in three populations aged 0.5, 1.5, and 7.5 years. Cortical bone histology was compared with a data set from a 1.5‐month‐old population of an earlier published paper. From 0.5‐year‐old onward, the mean femur length did not increase further. Thereafter, the mean marrow area increased and the cortical area decreased significantly with aging. This was associated with a structural pattern transformation from plexiform to laminar and then Haversian‐like type. The distal meta‐epiphysis bone trabecular density of the oldest populations also was significantly lower in specific regions of interest (ROI). Percentage sealed primary vascular canals in laminar bone significantly increased with aging without variation of percentage sealed secondary osteons. Remodeling rate reflected by the density of cutting cones did not significantly change among the age populations. These data suggest that laminar bone vascular pattern is more functional in the fast diaphyseal expansion but not much streamlined with the renewal of blood flow during secondary remodeling. Bone aging was characterized by: 1) secondary remodeling subendosteally; 2) increment of sealed primary vascular canals number; 3) increased calcium content of the cortex; 4) cortical and trabecular bone mass loss in specific ROIs. Taken together, the present data may give a morphological and morphometric basis to perform comparative studies on experimental models of osteoporosis in the rabbit. J. Morphol. 276:733–747, 2015. © 2015 Wiley Periodicals, Inc.
MRI of the Hip for the evaluation of femoroacetabular impingement; past, present, and future
Authors: Riley Geoffrey M. , McWalter Emily J. , Stevens Kathryn J. , Safran Marc R. , Lattanzi Riccardo , Gold Garry E.
Published: February 2015

The concept of femoroacetabular impingement (FAI) has, in a relatively short time, come to the forefront of orthopedic imaging. In just a few short years MRI findings that were in the past ascribed to degenerative change, normal variation, or other pathologies must now be described and included in radiology reports, as they have been shown, or are suspected to be related to, FAI. Crucial questions have come up in this time, including: what is the relationship of bony morphology to subsequent cartilage and labral damage, and most importantly, how is this morphology related to the development of osteoarthritis? In this review, we attempt to place a historical perspective on the controversy, provide guidelines for interpretation of MRI examinations of patients with suspected FAI, and offer a glimpse into the future of MRI of this complex condition. J. Magn. Reson. Imaging 2015;41:558–572. © 2014 Wiley Periodicals, Inc.
Candidate Distributions for Climatological Drought Indices (SPI and SPEI)
Authors: Stagge James H. , Tallaksen Lena M. , Gudmundsson Lukas , Van Loon Anne F. , Stahl Kerstin
Published: February 2015

The Standardized Precipitation Index (SPI), a well‐reviewed meteorological drought index recommended by the World Meteorological Organization (WMO), and its more recent climatic water balance variant, the Standardized Precipitation‐Evapotranspiration Index (SPEI), both rely on selection of a univariate probability distribution to normalize the index, allowing for comparisons across climates. Choice of an improper probability distribution may impart bias to the index values, exaggerating or minimizing drought severity. This study compares a suite of candidate probability distributions for use in SPI and SPEI normalization using the 0.5° × 0.5° gridded Watch Forcing Dataset (WFD) at the continental scale, focusing on Europe. Several modifications to the SPI and SPEI methodology are proposed, as well as an updated procedure for evaluating SPI/SPEI goodness of fit based on the Shapiro–Wilk test. Candidate distributions for SPI organize into two groups based on their ability to model short‐term accumulation (1–2 months) or long‐term accumulation (>3 months). The two‐parameter gamma distribution is recommended for general use when calculating SPI across all accumulation periods and regions within Europe, in agreement with previous studies. The generalized extreme value distribution is recommended when computing the SPEI, in disagreement with previous recommendations.
Influence of homogenized residues of anaerobic digestate on the physicochemical properties of differently textured soils
Authors: Voelkner Amrei , Holthusen Dörthe , Horn Rainer
Published: February 2015

Because of the focus on renewable energy, new biogas digesters are being built with the consequence of an increased production of anaerobic digestates (AD) as a by‐product. Although they can be used as organic fertilizer on arable fields, negative impacts of these digestates also may occur. Therefore, it was the aim of this laboratory study to investigate the effect of a normally applied volume of 30 m3 ha−1 of anaerobic digestates derived from a ground input substrate of maize (Zea mays L.) , sugar beet (Beta vulgaris L.), and wheat (Triticum aestivum L.) in different ratios (100 /80 / 20%) on the properties of two soils. The soils, which were homogenized (sieved to ≤ 2 mm) and placed in columns with a defined bulk density of 1.45 g cm−3, were a Cambic Luvisol (sandy loam) derived from glacial till and a Podzol (sandy sand) derived from glazial outwash. Physicochemical parameters [pH, electrical conductivity (EC)] and the wetting behavior of the soils were analyzed by measuring the contact angle (CA) by using the Wilhelmy–Plate‐Method (WPM) and the Repellency Index (RI) from the sorptivity of water and ethanol. To determine the risk of soil dispersion as a consequence of digestate amendment, the amount of readily dispersible clay (RDC) was determined by detecting the turbidity of a soil suspension. The application of 30 m3 ha−1 of AD decreased the wettability of the sandy sand as compared to the untreated soil, while the wettability of the loamy sand remained unaffected by the digestate amendment. The amount of RDC was higher in the loamy sand compared to the sandy sand, but the AD‐amended soil did not exhibit a significant change in dispersibility. While the loamy soil exhibited acidification of the soil after digestate application, the sandy soil showed an alkalinization of soil columns. Overall, the soil texture was identified to be a main factor controlling the effect of the digestates on soil properties. The results of this lab study showed that this study can be used as a first approach for the quantification of digestate amendment under practical conditions.
Effect of different macronutrient cation ratios on macronutrient and water uptake by melon (Cucumis melo) grown in recirculating nutrient solution
Authors: Neocleous Damianos , Savvas Dimitrios
Published: February 2015

The aim of the present study was to determine uptake ratios between macronutrients and water for melon (Cucumis melo L. cv. Dikti) grown in a closed soilless cropping system. The obtained data can be used to establish standard nutrient solution compositions for melon crops grown in closed hydroponic systems under Mediterranean climatic conditions. Nutrient and water uptake by plants in the closed hydroponic system was compensated for by supplying replenishment nutrient solutions (RNS) differing either in the concentrations of K+, Ca2+, and Mg2+ or in their mutual ratio. The RNS, used as control treatment, had an electrical conductivity (EC) of 1.74 dS m−1 and contained 6.5 mM K+, 2.8 mM Ca2+, and 1.0 mM Mg2+ (K+ : Ca2+ : Mg2+ = 0.63 : 0.27 : 0.10). Control RNS was compared with two other RNS, both with a high Ca2+ level (4.2 mM). The K+ and Mg2+ levels in these two RNSs were: (1) not altered (corresponding to a ratio of K+ : Ca2+ : Mg2+ = 0.55 : 0.36 : 0.09; EC = 2.0 dS m−1) or (2) increased to maintain the same K+ : Ca2+ : Mg2+ ratio as in the control RNS (EC = 2.45 dS m−1). Nutrient to water uptake ratios, commonly termed uptake concentrations (UCs), were assessed by two alternative methods, i.e., (1) estimating the ratio between nutrient and water removal from the system or (2) estimating the ratio between the mass of the nutrient that was recovered from plant biomass and the water consumption. Over the two methods, mean UCs for N, P, K, Ca and Mg were 15.4, 1.31, 5.47, 3.78, and 1.02 mmol L−1, respectively, and tissue analysis resulted in a K : Ca : Mg molar ratio of = 0.55 : 0.34 : 0.11 in the whole plant. Moreover, the UCs tended to decrease as the crop aged although, in absolute values, the mass of nutrients absorbed increased following dry‐weight accumulation. Based on the obtained results, adapting the composition of the nutrient solution at least three times during the cropping period of melon is recommended. Further, the results revealed that the damage caused by the increase of the EC when attempting to maintain a target K+ : Ca2+ : Mg2+ ratio in the replenishment NS is higher than the benefits from the optimal cation ratio. Increasing K+ and Mg2+ concentration in addition to that of Ca2+ to maintain a standard K+ : Ca2+ : Mg2+ ratio raises the EC in the root zone (4.62 dS m−1), due to increased accumulation of nutrients, thereby reducing the mean fruit weight and concomitantly the total fruit yield (20% decrease). Leaf gas exchange, chlorophyll parameters and fruit taste quality were not influenced by the differences in macronutrient cation concentrations or ratios in the RNS, whereas phenolics and antioxidant capacity in melon fruit were enhanced by the increased root‐zone EC.
Involvement of nitrogen in salt resistance of Atriplex portulacoides is supported by split‐root experiment data and exogenous application of N‐rich compounds
Authors: Benzarti Maali , Rejeb Kilani Ben , Messedi Dorsaf , Abdelly Chedly , Debez Ahmed
Published: February 2015

Using a split‐root system, we aimed to identify the limiting factors for the growth of the halophyte Atriplex portulacoides L. under extreme salinity (800 mM NaCl) conditions. One half of the root system was immersed in complete nutrient solution at 0 or 800 mM NaCl and the other half was immersed in NaCl‐free medium, containing all nutrients or deprived of potassium (K+) or calcium (Ca2+) or nitrogen (N). Data indicate that at high salinity levels A. portulacoides growth is limited by the restrictions imposed by NaCl on N uptake. Next, the alleviation of the adverse impact by salt stress (800 mM NaCl) on plant growth was investigated through urea (U) and/or thiourea (TU) external addition through foliar application. Whether separately or supplied together, both components mitigated the negative impact of salinity on the plant growth by significantly improving the photosynthetic activity parameters [CO2 assimilation rate, stomatal conductance and maximum quantum efficiency of PSII photochemistry (Fv/Fm)], as well as shoot N concentration and the photosynthetic nitrogen‐use efficiency (PNUE). A concomitant increase of protein and free amino acid concentrations was also observed. As a whole, the present study highlights the significance of N in A. portulacoides response to high salinity and suggests that combined application of U and TU could promote the growth of this halophyte potentially useful for saline soil reclamation and revegetation purposes.
Maximal functions for multipliers on stratified groups
Authors: Choi Woocheol
Published: February 2015

In this paper we obtain a refined bound for maximal functions of the multiplier operators on stratified groups and maximal functions of the multi‐parameter multipliers on product spaces of stratified groups. As an application we find a refined bound for maximal functions of joint spectral multipliers on Heisenberg group.
Poly(ether‐imide) and related sepiolite nanocomposites: investigation of physical, thermal, and mechanical properties
Authors: Tabatabaei‐Yazdi Zahra , Mehdipour‐Ataei Shahram
Published: February 2015

Novel poly(ether‐imide) and sepiolite nanocomposites were synthesized based on a unique diamine monomer with the aim of improving physical and mechanical properties of final polyimide films. The diamine was polycondensed with 4,4′‐(hexafluoroisopropylidene) diphthalic anhydride to produce related poly(ether amic acid) prepolymer. Pure poly(ether‐imide) and nanocomposite films were prepared via thermal imidization process of poly(ether amic acid). Coexistence of ether, pyridine, and phenylene functional groups in the diamine chemical structure resulted in flexible polyimide films with significant thermal, physical, and mechanical properties. Thermal stability, glass‐transition temperature, dimensional stability, and tensile properties of polymer and nanocomposites were studied and compared. Morphology of nanocomposites was also investigated using scanning and transmission electron microscopic methods to study the distribution and dispersion behavior of sepiolite nanofibers in the polyimide matrix. By introduction of sepiolite nanoparticles, overall improvement of properties was observed in respect to pure polyimides. Copyright © 2015 John Wiley & Sons, Ltd.
Effects of nano graphene oxide as support on the product properties and performance of Ziegler–Natta catalyst in production of UHMWPE
Authors: Kheradmand Amanj , Ramazani S.A. Ahmad , Khorasheh Farhad , Baghalha Morteza , Bahrami Hiva
Published: February 2015

The synthesis of mono‐ and bi‐supported Ziegler–Natta catalysts using magnesium etoxide Mg(OEt)2 and graphene oxide (GO) as catalyst support for production of Ultra High Molecular Weight Polyethylene (UHMWPE) is reported in this investigation. Nano‐graphene oxide was prepared by the modified Hummer's method and its structure was analyzed by XRD and FTIR indicating the presence of hydroxyl groups on graphene oxide and the formation of an exfoliated structure. The activity of TiCl4/Mg(OEt)2, TiCl4/Mg(OEt)2‐GO, and TiCl4/GO catalysts in terms of grams of PE produced per mmol of Ti per hour was experimentally obtained for catalysts with different ratios of co‐catalyst (triisobutylaluminium) to TiCl4. For all three series of catalysts, the activity curve showed an optimum point at a specific Al/Ti molar ratio. Catalyst activity was highest for TiCl4/Mg(OEt)2 and lowest for TiCl4/GO. The characterization of UHMWPE products indicated that the viscosity average molecular weight (Mv) was highest for the polymer produced by TiCl4/Mg(OEt)2 and lowest for the polymer produced by TiCl4/GO. Furthermore, thermogravimetric analysis (TGA), dynamic mechanical thermal analysis (DMTA), and mechanical tensile testing were conducted on the prepared polymers indicating that the polymer produced by TiCl4/GO had the highest thermal and mechanical properties, while these properties were at their minimum for polymers produced by TiCl4/Mg(OEt)2. Copyright © 2015 John Wiley & Sons, Ltd.
Effect of polyethylene glycol on the crystallization and impact properties of polylactide‐based blends
Authors: Li Feng‐Jiao , Zhang Shui‐Dong , Liang Ji‐Zhao , Wang Jun‐Zhe
Published: February 2015

Polylactide (PLA) was plasticized by polyethylene glycols (PEGs) with five different molecular weights (Mw = 200–20,000 g/mol). The effects of content and molecular weight of PEG on the crystallization and impact properties of PLA were studied by wide‐angle X‐ray diffraction, differential scanning calorimetry, scanning electron microscopy, transmission electron microscopy, and V‐notched impact tests, respectively. The results revealed that PEG‐10,000 could significantly improve the crystallization capacity and impact toughness of PLA. When the PEG‐10,000 content ranged from 0 to 20 wt%, the increases in both V‐notched Izod and Charpy impact strengths of PLA/PEG‐10,000 blends were 206.10% and 137.25%, respectively. Meanwhile, the crystallinity of PLA/PEG‐10,000 blends increased from 3.95% to 43.42%. For 10 wt% PEG content, the crystallization and impact properties of PLA/PEG blends mainly depended upon PEG molecular weight. With increasing the Mw of PEG, the crystallinity and impact strength of PLA/PEG blends first decreased and then increased. The introduction of PEG reduced the intermolecular force and enhanced the mobility of PLA chains, thus improving the crystallization capacity and flexibility of PLA. Copyright © 2015 John Wiley & Sons, Ltd.
Effects of gestational age at enrollment in pregnancy exposure registries
Authors: Margulis Andrea V. , Mittleman Murray A. , Glynn Robert J. , Holmes Lewis B. , Hernández‐Díaz Sonia
Published: February 2015

Purpose

This study aims to explore the influence of gestational age at enrollment, and enrollment before or after prenatal screening, on the estimation of drug effects in pregnancy exposure registries.

Methods

We assessed the associations between first trimester antiepileptic drug (AED) exposure and risk of spontaneous abortion and major congenital malformations in the North American AED Registry (1996–2013). We performed logistic regression analyses, conditional or unconditional on gestational age at enrollment, to estimate relative risk (RR) for first trimester AED users compared with non‐users. We also compared first trimester users of valproic acid and lamotrigine. Analyses were repeated in women who enrolled before prenatal screening.

Results

Enrollment occurred earlier among 7029 AED users than among 581 non‐users; it was similar among AEDs. Comparing AED users with non‐users, RR (95% confidence interval) of spontaneous abortion (n = 359) decreased from 5.1 (2.3–14.1) to 2.0 (0.9–5.6) after conditioning on gestational week at enrollment and to 1.9 (0.8–5.4) upon further restriction to before‐screening enrollees. RR of congenital malformations (n = 216) changed from 3.1 (1.4–8.5) to 3.2 (1.4–9.0) after conditioning on gestational week at enrollment and to 2.0 (0.7–10.1) upon further restriction to before‐screening enrollees. When comparing valproic acid users and lamotrigine users, the RR of congenital malformations was not substantially changed by conditioning or restricting.

Conclusions

Spontaneous abortion rates were sensitive to gestational age at enrollment. Estimates of congenital malformation risks for AED users relative to non‐users were sensitive to before/after‐screening enrollment. This difference was not apparent between active drugs, likely due to similar gestational age at enrollment. Copyright © 2015 John Wiley & Sons, Ltd.
Balance and Gait in People with Multiple Sclerosis: A Comparison with Healthy Controls and the Immediate Change after an Intervention based on the Bobath Concept
Authors: Ilett P. , Lythgo N. , Martin C. , Brock K.
Published: February 2015

Background and purpose

The objective of this study is to compare the balance and gait of 11 people with multiple sclerosis (MS) to 11 healthy controls and to investigate the immediate change after a single intervention based on the Bobath concept on these activities in the MS group.

Methods

Balance was assessed by ground reaction forces (GRF) and centre of pressure movements during single limb standing (SLS), the Lateral Reach Test (LRT) and the Four Square Step Test (FSST). Gait was evaluated by GRF, ankle kinematics and spatiotemporal measures.

Results

Baseline measures in the MS group showed significantly greater vertical GRF variability (p = 0.008) during SLS reached less distance on the LRT (p = 0.001) and were slower completing the FSST (p < 0.001). During gait, the MS group walked slower (p = 0.005) and had less ankle plantarflexion (PF) (p = 0.001) than the control group. Less peak vertical GRF (p < 0.001) and peak propulsive GRF (p = 0.004) at terminal stance and increased vertical GRF in midstance (p = 0.005) were observed. The measures of balance and gait were re‐assessed in the MS group immediately after a 20‐min intervention based on the Bobath concept delivered to the most impaired foot and ankle. After the intervention, the MS group had significant changes towards the control group values with reduced mediolateral (p = 0.002) and vertical (p = 0.016) GRF variability in the SLS task, faster FSST time (p = 0.006) and increased ankle PF during gait (p = 0.002).

Discussion

This study provides further evidence of balance and gait limitations in people with MS and indicates that a single treatment based on principles of the Bobath concept to the foot and ankle can result in immediate improvements in balance and ankle PF during gait in people with MS. Copyright © 2015 John Wiley & Sons, Ltd.
Expression of adenosine receptor subclasses in malignant and adjacent normal human prostate tissues
Authors: Mousavi Samira , Panjehpour Mojtaba , Izadpanahi Mohammad Hossein , Aghaei Mahmoud
Published: February 2015

BACKGROUND

Adenosine, a purine nucleoside plays important roles in the pathogenesis of cancer initiation and promotion via interaction with four adenosine receptors. In the present study we examined the differential expression pattern of adenosine receptors in the malignant and adjacent normal human prostate tissues.

METHODS

Prostate cancer tissue samples and adjacent normal tissues were obtained from 20 patients undergoing radical prostatectomy and histopathological diagnosis was confirmed for each sample. Total RNA was extracted and reverse transcribed into cDNA and the mRNA expression levels of adenosine receptors were investigated by Taq‐man real‐time RT‐PCR experiment. Quantitative protein analysis was done by Western blotting experiment. Moreover, the mRNA and protein expression levels of adenosine receptors were measured after androgen treatment.

RESULT

Taq‐man real‐time RT‐PCR measurements show different expression levels of adenosine receptor transcripts. A2B adenosine receptor was predominantly expressed in tumor tissues (2.4‐fold) followed by significantly expression of A3 (1.6‐fold) and A2A adenosine receptors (1.5‐fold) compared to adjacent normal tissues. The presence of adenosine receptors at protein levels in prostate cancer tissues compared with normal tissues was shown the following rank order: A2B > A3 > A2A > A1. Androgen receptor regulates adenosine receptors mRNA and protein expression in AR‐positive LNCaP cells, which was not seen in AR‐negative PC‐3 cells.

CONCLUSION

These results indicated for the first time, the differential mRNA expression profile and protein levels of adenosine receptors in the human prostate cancer. Interestingly, the A2B adenosine receptor followed by A3 is highly expressed in prostate tumor samples in comparison with the adjacent normal tissues. The findings support the possible key role of A2B adenosine receptor in promoting cancer cell growth and suggest that A2B may be a novel target for prostate cancer treatment. Prostate 75:735–747, 2015. © 2015 Wiley Periodicals, Inc.
Structural, magnetic, and vibrational properties of stoichiometric clusters of CrN
Authors: Aguilera‐Granja Faustino , Carrete Jesús , Vega Andrés , Gallego Luis J.
Published: February 2015

We performed density‐functional‐theoretic calculations to investigate the structural, magnetic and vibrational properties of the stoichiometric clusters (CrN)n (
). We show that the building block of the ground‐state structures of these clusters is a square CrNCrN unit; the only exception with n > 2 occurs for (CrN)3, but this cluster has an isomer not very far in energy from the ground state consisting of a pair of CrNCrN squares sharing a CrN bond. In the smaller CrN, (CrN)2, and (CrN)3 clusters the magnetic moments of the N atoms are non‐negligible and antiparallel to those of the Cr atoms, but for the larger species (CrN)4, (CrN)5, (CrN)6, and (CrN)9 the cluster magnetic moments are almost entirely due to the Cr atoms. Lack of imaginary vibrational frequencies in the predicted ground‐state structures of (CrN)n (
) confirms that they are mechanically stable equilibrium states. © 2015 Wiley Periodicals, Inc.