bluuebunny/crossref_metadata_2025_split huggingface dataset:
Dilemma of Non‐Steady State in Lakes – Development and Predictability of In‐Lake P Concentration in Dimictic Lake Scharmützelsee (Germany) after Abrupt Load Reduction
Authors: Grüneberg Björn , Rücker Jacqueline , Nixdorf Brigitte , Behrendt Horst 
Published: November 2011

AbstractBased on measured and calculated long‐term data on external phosphorus (P) load (1920–2009), hypolimnetic P accumulation and trophic parameters for the dimictic Lake Scharmützelsee, we aimed to identify factors which cause variable P net sedimentation and the importance of internal P loading for different time periods especially focusing on non‐steady state after abrupt external load reduction in 1988. P retention (R) decreased from 0.85 during the high external P loading (0.37 g m–2 a–1) phase (1950–1988) to 0.71 during the following transient phase, and increased to 0.81 for the present recovery phase (0.17 g m–2 a–1) beginning in 2003. Mean net sedimentation coefficients for the same periods were 0.47, 0.22 and 0.30. Our results show that a) empirical models overestimate R during the high loading phase and underestimate R during the transient phase after load reduction, and b) the application of simple one‐box models which assume that a portion of in‐lake P stock is retained requires the consideration of the variability of the net sedimentation coefficient. We identified multiple reasons for variable gross sedimentation (e.g., particle trapping in the elongated lake; efficient accumulation of sewage P) as well as release of P (delayed release of mobile P from sediment; changes in plant colonization and food webs), so that their relation (net sedimentation) varies. Despite a new equilibrium reached in 2003, it is still unclear when the lake will reach mesotrophic reference conditions and a good ecological status. Historical data and elevated Cl– concentration (22 mg L–1) indicate that P import from sewage contaminated groundwater still continues, so that the mean in‐lake P concentration is still too high (53 µg L–1), and biological structures have not fully recovered yet. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Polymer coatings that display specific biological signals while preventing nonspecific interactions
Authors: Ameringer Thomas , Fransen Peter , Bean Penny , Johnson Graham , Pereira Suzanne , Evans Richard A. , Thissen Helmut , Meagher Laurence 
Published: November 2011

AbstractControl over cell‐material surface interactions is the key to many new and improved biomedical devices. It can only be achieved if interactions that are mediated by nonspecifically adsorbed serum proteins are minimized and if cells instead respond to specific ligand molecules presented on the surface. Here, we present a simple yet effective surface modification method that allows for the covalent coupling and presentation of specific biological signals on coatings which have significantly reduced nonspecific biointerfacial interactions. To achieve this we synthesized bottle brush type copolymers consisting of poly(ethylene glycol) methyl ether methacrylate and (meth)acrylates providing activated NHS ester groups as well as different spacer lengths between the NHS groups and the polymer backbone. Copolymers containing different molar ratios of these monomers were grafted to amine functionalized polystyrene cell culture substrates, followed by the covalent immobilization of the cyclic peptides cRGDfK and cRADfK using residual NHS groups. Polymers were characterized by GPC and NMR and surface modification steps were analyzed using XPS. The cellular response was evaluated using HeLa cell attachment experiments. The results showed strong correlations between the effectiveness of the control over biointerfacial interactions and the polymer architecture. They also demonstrate that optimized fully synthetic copolymer coatings, which can be applied to a wide range of substrate materials, provide excellent control over biointerfacial interactions. © 2011 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2012.
Rigid‐CLL: Avoiding constant‐distance computations in cell linked‐lists algorithms
Authors: de Angulo V. Ruiz , Cortés J. , Porta J. M. 
Published: November 2011

AbstractMany of the existing molecular simulation tools require the efficient identification of the set of nonbonded interacting atoms. This is necessary, for instance, to compute the energy values or the steric contacts between atoms. Cell linked‐lists can be used to determine the pairs of atoms closer than a given cutoff distance in asymptotically optimal time. Despite this long‐term optimality, many spurious distances are anyway computed with this method. Therefore, several improvements have been proposed, most of them aiming to refine the volume of influence for each atom. Here, we suggest a different improvement strategy based on avoiding to fill cells with those atoms that are always at a constant distance of a given atom. This technique is particularly effective when large groups of the particles in the simulation behave as rigid bodies as it is the case in simplified models considering only few of the degrees of freedom of the molecule. In these cases, the proposed technique can reduce the number of distance computations by more than one order of magnitude, as compared with the standard cell linked‐list technique. The benefits of this technique are obtained without incurring in additional computation costs, because it carries out the same operations as the standard cell linked‐list algorithm, although in a different order. Since the focus of the technique is the order of the operations, it might be combined with existing improvements based on bounding the volume of influence for each atom. © 2011 Wiley Periodicals, Inc. J Comput Chem, 2012
Freezing tolerance and low molecular weight cryoprotectants in an invasive parasitic fly, the deer ked (Lipoptena cervi)
Authors: Nieminen Petteri , Paakkonen Tommi , Eerilä Harri , Puukka Katri , Riikonen Joakim , Lehto Vesa‐Pekka , Mustonen Anne‐Mari 
Published: November 2011

AbstractInsect cold hardiness is often mediated by low molecular weight cryoprotectants, such as sugars, polyols, and amino acids (AA). While many free‐living northern insects must cope with extended periods of freezing ambient temperatures (Ta), the ectoparasitic deer ked Lipoptena cervi imago can encounter subfreezing Ta only during a short autumnal period between hatching and host location. Subsequently, it benefits from the body temperature of the cervid host for survival in winter. This study investigated the cold tolerance of the species by determining its lower lethal temperature (100% mortality, LLT100) during faster and slower cold acclimation, by determining the supercooling point (SCP) and by measuring the concentrations of potential low molecular weight cryoprotectants. The LLT100 of the deer ked was approximately −16°C, which would enable it to survive freezing nighttime Ta not only in its current area of distribution but also further north. The SCP was −7.8°C, clearly higher than the LLT100, indicating that the deer ked displays freezing tolerance. The concentrations of free AA, especially nonessential AA, were higher in the cold‐acclimated deer keds similar to several other insects. The concentrations of proline increased together with γ‐aminobutyrate, arginine, asparagine, cystine, glutamate, glutamine, hydroxylysine, sarcosine, serine, and taurine. AA could be hypothesized to act as cryoprotectants by, e.g., protecting enzymes and lipid membranes from damage caused by cold. J. Exp. Zool. 317:1–8, 2012. © 2011 Wiley Periodicals, Inc.
NONFARM EMPLOYMENT AND INCOMES IN RURAL GHANA
Authors: Ackah Charles 
Published: November 2011

AbstractThis paper analyses the determinants of participation in nonfarm activities and the impact of nonfarm employment on household income. A clear empirical regularity is that women are significantly less likely than men to be in wage employment and more likely than men to be in self‐employment activities. We find also that households whose heads have completed secondary education or higher gravitate more toward wage employment. Nonfarm employment appears to be crucial for the alleviation from rural poverty in Ghana. With limited opportunities in agriculture, nonfarm employment is necessary to augment or supplement farm incomes. Copyright © 2011 John Wiley & Sons, Ltd.
Kinetic Modeling of ICAR ATRP
Authors: D'hooge Dagmar R. , Konkolewicz Dominik , Reyniers Marie‐Françoise , Marin Guy B. , Matyjaszewski Krzysztof 
Published: November 2011

AbstractKinetic modeling is used to better understand and optimize initiators for continuous activator regeneration atom‐transfer radical polymerization (ICAR ATRP). The polymerization conditions are adjusted as a function of the ATRP catalyst reactivity for two monomers, methyl methacrylate and styrene. In order to prepare a well‐controlled ICAR ATRP process with a low catalyst amount (ppm level), a sufficiently low initial concentration of conventional radical initiator relative to the initial ATRP initiator is required. In some cases, stepwise addition of a conventional radical initiator is needed to reach high conversion. Under such conditions, the equilibrium of the activation/deactivation process for macromolecular species can be established already at low conversion.magnified image
Bivariate simulation using copula and its application to probabilistic pile settlement analysis
Authors: Li Dian‐Qing , Tang Xiao‐Song , Phoon Kok‐Kwang , Chen Yi‐Feng , Zhou Chuang‐Bing 
Published: November 2011

SUMMARYThis paper aims to propose a procedure for modeling the joint probability distribution of bivariate uncertain data with a nonlinear dependence structure. First, the concept of dependence measures is briefly introduced. Then, both the Akaike Information Criterion and the Bayesian Information Criterion are adopted for identifying the best‐fit copula. Thereafter, simulation of copulas and bivariate distributions based on Monte Carlo simulation are presented. Practical application for serviceability limit state reliability analysis of piles is conducted. Finally, four load–test datasets of load–displacement curves of piles are used to illustrate the proposed procedure. The results indicate that the proposed copula‐based procedure can model and simulate the bivariate probability distribution of two curve‐fitting parameters underlying the load–displacement models of piles in a more general way. The simulated load–displacement curves using the proposed procedure are found to be in good agreement with the measured results. In most cases, the Gaussian copula, often adopted out of expedience without proper validation, is not the best‐fit copula for modeling the dependence structure underlying two curve‐fitting parameters. The conditional probability density functions obtained from the Gaussian copula differ considerably from those obtained from the best‐fit copula. The probabilities of failure associated with the Gaussian copula are significantly smaller than the reference solutions, which are very unconservative for pile safety assessment. If the strong negative correlation between the two curve‐fitting parameters is ignored, the scatter in the measured load–displacement curves cannot be simulated properly, and the probabilities of failure will be highly overestimated. Copyright © 2011 John Wiley & Sons, Ltd.
Health Consequences of Obesity
Authors: Berenson Gerald S. ,   for the Bogalusa Heart Study group
Published: November 2011

AbstractEpidemiologic studies have established that cardiovascular (CV) risk factors including obesity are identifiable in childhood. Childhood risk factors are predictive of adult cardiac risk and even premature death [Franks et al. (2010) N Engl J Med 362:485–493]. In the United States, CV diseases remains the leading causes of death. In fact, heart disease has become the major cause of death worldwide, surpassing undernutrition and infectious diseases, largely related to obesity in childhood [Wang and Lobstein (2006) Int J Pediatr Obes 1:11–25]. The concept that adult heart diseases begin in childhood is an outgrowth of extensive long‐term epidemiologic studies in youth, that is, the Bogalusa Heart Study [Berenson et al. (1986) Causation of cardiovascular risk factors in children: Perspectives on cardiovascular risk in early life, Raven Press Books Ltd]. Pediatr Blood Cancer 2012; 58: 117–121. © 2011 Wiley Periodicals, Inc.
Is the distribution grid ready to accept large‐scale photovoltaic deployment? State of the art, progress, and future prospects
Authors: Braun Martin , Stetz Thomas , Bründlinger Roland , Mayr Christoph , Ogimoto Kazuhiko , Hatta Hiroyuki , Kobayashi Hiromu , Kroposki Ben , Mather Barry , Coddington Michael , Lynn Kevin , Graditi Giorgio , Woyte Achim , MacGill Iain 
Published: November 2011

ABSTRACTThe installed capacity of photovoltaic (PV) systems has recently increased at a much faster rate than the development of grid codes to effectively and efficiently manage high penetrations of PV within the distribution system. In a number of countries, PV penetrations in some regions are now raising growing concerns regarding integration. Management strategies vary considerably by country—some still have an approach that PV systems should behave as passive as possible, whereas others demand an active participation in grid control. This variety of grid codes also causes challenges in learning from “best practice.” This paper provides a review of current grid codes in some countries with high PV penetrations. In addition, the paper presents a number of country‐specific case studies on different approaches for improved integration of PV systems in the distribution grid. In particular, we consider integration approaches using active and reactive power control that can reduce or defer expensive grid reinforcement while supporting higher PV penetrations. Copyright © 2011 John Wiley & Sons, Ltd.
The Beetroot Component Betanin Modulates ROS Production, DNA Damage and Apoptosis in Human Polymorphonuclear Neutrophils
Authors: Zielińska‐Przyjemska Małgorzata , Olejnik Anna , Kostrzewa Artur , Łuczak Michał , Jagodziński Paweł P. , Baer‐Dubowska Wanda 
Published: November 2011

The aim of this study was to evaluate the effect of betanin, one of the beetroot major components, on ROS production, DNA damage and apoptosis in human resting and stimulated with phorbol 12‐myristate13‐acetate polymorphonuclear neutrophils, one of the key elements of the inflammatory response.Incubation of neutrophils with betanin in the concentration range 2–500 µm resulted in significant inhibition of ROS production (by 15–46%, depending on the ROS detection assay). The antioxidant capacity of betanin was most prominently expressed in the chemiluminescence measurements. This compound decreased also the percentage of DNA in comet tails in stimulated neutrophils, but only at the 24 h time point. In resting neutrophils an increased level of DNA in comet tails was observed. Betanin did not affect the activity of caspase‐3, in resting neutrophils, but significantly enhanced the enzyme activity in stimulated neutrophils. The western blot analysis showed, however, an increased level of caspase‐3 cleavage products as a result of betanin treatment both in resting and stimulated neutrophils. The results indicate that betanin may be responsible for the effect of beetroot products on neutrophil oxidative metabolism and its consequences, DNA damage and apoptosis. The dose and time dependent effects on these processes require further studies. Copyright © 2011 John Wiley & Sons, Ltd.
The Brewer–Dobson circulation inferred from ERA‐Interim
Authors: Seviour William J. M. , Butchart Neal , Hardiman Steven C. 
Published: November 2011

AbstractThe transformed Eulerian mean residual circulation is calculated from ERA‐Interim for 1989–2009. Known as the Brewer–Dobson circulation, this measures the tropical upwelling of mass from troposphere to stratosphere, the mean meridional mass transport in the stratosphere and the downwelling of mass in the Extratropics. Major features of the Brewer–Dobson circulation, including the seasonal migration of the tropical upwelling toward the summer pole, are well represented. In the tropical lower stratosphere vertical velocities are less noisy than in other reanalyses, though significant tidal variations demonstrate the need for 6‐hourly data. Throughout the year tropical lower stratospheric ascent rates are a minimum at the Equator and strongest in the Northern Hemisphere. In each hemisphere the maximum tropical ascent occurs during summer, whereas the strongest circulation and maximum in extratropical descent occur in the winter hemisphere. At 70 hPa the annual mean upwelling mass flux is 5.9 × 109 kg s−1, with the zonal drag from resolved waves and parametrized orographic gravity wave drag (OGWD) providing 70% and 4% of the driving, respectively. Hence it is concluded that the OGWD probably underestimates the momentum deposited above 70 hPa in addition to there being an absence of drag from non‐orographic gravity waves. A statistically significant trend of −5% per decade in the upwelling mass flux is considered unreliable because it is inconsistent with the negative temperature trend, assuming a mainly adiabatic temperature response at this level (70 hPa) to the changes in upwelling. Copyright © 2011 British Crown copyright, the Met Office. Published by John Wiley & Sons Ltd.
Detection of Erythrocytes in Patient With Iron Deficiency Anemia Using Atomic Force Microscopy
Authors: Zhang Yuping , Zhang Wei , Wang Shunqing , Wang Caixia , Xie Jianjin , Chen Xiaoyan , Xu Yanli , Mao Ping 
Published: November 2011

SummaryPurposeIron deficiency anemia (IDA) disturbs the morphology and function of erythrocytes at molecular level. The purpose of this study was to show that pathophysiological changes to erythrocytes could be detected at the nanometer scale, which is important for the early diagnosis and effective therapies of the anemia.MethodsBlood samples were taken from six healthy volunteers and six patients with IDA before and after therapy. Changes in the morphological and biomechanical properties of erythrocytes were studied at the nanometer level using atomic force microscopy (AFM).ResultsThere were dramatic overall shape and surface membrane deformations of the erythrocytes associated with pre‐ and post‐therapeutic IDA compared with healthy erythrocytes. Healthy and pathological erythrocytes of IDA could be distinguished by the morphologic parameters of width, length, the ratio of length to width, valley, peak, valley‐to‐peak, standard deviations, and surface fluctuation. Treatment effectiveness also could be evaluated by these parameters.ConclusionsAFM is a good tool for IDA study. Erythrocyte morphology is an important determinant for diagnosing and evaluating therapeutic effect of IDA disease. SCANNING 34: 215‐220, 2012. © 2011 Wiley Periodicals, Inc.
How long must a firm be great to rule out chance? Benchmarking sustained superior performance without being fooled by randomness
Authors: Henderson Andrew D. , Raynor Michael E. , Ahmed Mumtaz 
Published: November 2011

AbstractAlthough sustained superior firm performance may arise from skillful management or other valuable, rare, and inimitable resources, it can also result from randomness. Studying U.S. companies from 1965–2008, we benchmark how long a firm must perform at a high level to be confident that it is something other than the outcome of a time‐homogeneous stationary Markov chain defined on the state space of percentiles. We find (a) the number of sustained superior performers in Compustat, measured by ROA and Tobin's q, exceeds the number of false positives we would expect to be generated by such a process; yet (b) the occurrence of false positives is often enough to fool many observers, so (c) the identification of sustained superior performers requires particularly stringent benchmarks to enable valid study. Copyright © 2011 John Wiley & Sons, Ltd.
In vitro models
Authors: Mather Jennie Powell 
Published: November 2011

Abstract
The current resurgence of interest in the cancer stem cell (CSC) hypothesis as possibly providing a unifying theory of cancer biology is fueled by the growing body of work on normal adult tissue stem cells and the promise that CSC may hold the key to one of the central problems of clinical oncology: tumor recurrence. Many studies suggest that the microenvironment plays a role, perhaps a seminal one, in cancer development and progression. In addition, the possibility that the stem cell-like component of tumors is capable of rapid and reversible changes of phenotype raises questions concerning studies with these populations and the application of what we learn to the clinical situation. These types of questions are extremely difficult to study using in vivo models or freshly isolated cells. Established cell lines grown in defined conditions provide important model systems for these studies. There are three types of in vitro models for CSCs: (a) selected subpopulations of existing tumor lines (derived from serum-containing medium; (b) creation of lines from tumor or normal cells by genetic manipulation; or (c) direct in vitro selection of CSC from tumors or sorted tumor cells using defined serum-free conditions. We review the problems associated with creating and maintaining in vitro cultures of CSCs and the progress to date on the establishment of these important models.
Disclosure of potential conflicts of interest is found at the end of this article.
5-Aminoimidazole-4-carboxyamide Ribonucleoside Induces G1/S Arrest and Nanog Downregulation via p53 and Enhances Erythroid Differentiation
Authors: Chae Hee-Don , Lee Man-Ryul , Broxmeyer Hal E. 
Published: November 2011

AbstractMolecular mechanisms of how energy metabolism affects embryonic stem cell (ESC) pluripotency remain unclear. AMP-activated protein kinase (AMPK), a key regulator for controlling energy metabolism, is activated in response to ATP-exhausting stress. We investigated whether cellular energy homeostasis is associated with maintenance of self-renewal and pluripotency in mouse ESCs (mESCs) by using 5-aminoimidazole-4-carboxyamide ribonucleoside (AICAR) as an activator of AMPK. We demonstrate that AICAR treatment activates the p53/p21 pathway and markedly inhibits proliferation of R1 mESCs by inducing G1/S-phase cell cycle arrest, without influencing apoptosis. Treatment with AICAR also significantly reduces pluripotent stem cell markers, Nanog and stage-specific embryonic antigen-1, in the presence of leukemia inhibitory factor, without affecting expression of Oct4. H9 human ESCs also responded to AICAR with induction of p53 activation and repression of Nanog expression. AICAR reduced Nanog mRNA levels in mESCs transiently, an effect not due to expression of miR-134 which can suppress Nanog expression. AICAR induced Nanog degradation, an effect inhibited by MG132, a proteasome inhibitor. Although AICAR reduced embryoid body formation from mESCs, it increased expression levels of erythroid cell lineage markers (Ter119, GATA1, Klf1, Hbb-b, and Hbb-bh1). Although erythroid differentiation was enhanced by AICAR, endothelial lineage populations were remarkably reduced in AICAR-treated cells. Our results suggest that energy metabolism regulated by AMPK activity may control the balance of self-renewal and differentiation of ESCs.Disclosure of potential conflicts of interest is found at the end of this article.