bluuebunny/crossref_metadata_2025_split huggingface dataset:
Plant‐soil feedbacks on free‐living nitrogen fixation over geological time
Authors: Winbourne Joy B. , Houlton Benjamin Z. 
Published: August 2018

AbstractFree‐living heterotrophic nitrogen fixation (FNF) is a widespread nitrogen input pathway in terrestrial ecosystems. However, questions remain over the relative influence of co‐occurring controls on patterns of heterotrophicFNFactivity, especially across generalized stages of primary succession, from biomass accumulation to retrogressive phases. Here, we experimentally test two alternative hypotheses regardingFNFrates during ecosystem development: (H1) site (i.e., changes in soil fertility during succession) is the primary driver of leaf‐litterFNFrates, vs. (H2) leaf‐litter chemistry is the primary determinant ofFNFactivity across a broad range of ecosystem conditions. We evaluated these hypotheses across a well‐studied soil chronosequence in California (i.e., the Ecological Staircase), which spans ~1 million years of ecosystem development and displays extreme ranges in plant‐soil nutrient conditions, culminating in the nutrient depleted and stunted Pygmy forest. Across this successional gradient, we implemented a reciprocal leaf‐litter transplant and a common garden litter bag decomposition experiment with senesced needles ofPinus muricata. Our results support H1: rates ofFNFwere similar for all leaf‐litter types decomposed at the same site regardless of initial leaf‐litter C and nutrient contents.FNFrates sharply declined from the maximal to retrogressive stage of succession. Trends in P dynamics during decomposition suggest an important role of P in regulatingFNF. For example,P. muricatalitter collected from the infertile Pygmy site displayed substantially higherFNFrates when decomposed at the fertile site, in part by immobilizing significant quantities of P from the soil at the fertile site. Conversely,P. muricatalitter collected from the fertile site decomposed more slowly at the Pygmy site, with concomitant declines inFNFrates that matched those of Pygmy site litter decomposed in situ. These results are consistent with the idea that, over millennia, long‐term declines in P availability feedback to constrainFNFrates, in part explaining the emergence of extremely nutrient‐poor and retrograded ecosystems.
Empagliflozin reduces Ca/calmodulin‐dependent kinase II activity in isolated ventricular cardiomyocytes
Authors: Mustroph Julian , Wagemann Olivia , Lücht Charlotte M. , Trum Maximilian , Hammer Karin P. , Sag Can Martin , Lebek Simon , Tarnowski Daniel , Reinders Jörg , Perbellini Filippo , Terracciano Cesare , Schmid Christof , Schopka Simon , Hilker Michael , Zausig York , Pabel Steffen , Sossalla Samuel T. , Schweda Frank , Maier Lars S. , Wagner Stefan 
Published: August 2018

AbstractAimsThe EMPA‐REG OUTCOME study showed reduced mortality and hospitalization due to heart failure (HF) in diabetic patients treated with empagliflozin. Overexpression and Ca2+‐dependent activation of Ca2+/calmodulin‐dependent kinase II (CaMKII) are hallmarks of HF, leading to contractile dysfunction and arrhythmias. We tested whether empagliflozin reduces CaMKII‐ activity and improves Ca2+‐handling in human and murine ventricular myocytes.Methods and resultsMyocytes from wild‐type mice, mice with transverse aortic constriction (TAC) as a model of HF, and human failing ventricular myocytes were exposed to empagliflozin (1 μmol/L) or vehicle. CaMKII activity was assessed by CaMKII–histone deacetylase pulldown assay. Ca2+ spark frequency (CaSpF) as a measure of sarcoplasmic reticulum (SR) Ca2+ leak was investigated by confocal microscopy. [Na+]i was measured using Na+/Ca2+‐exchanger (NCX) currents (whole‐cell patch clamp). Compared with vehicle, 24 h empagliflozin exposure of murine myocytes reduced CaMKII activity (1.6 ± 0.7 vs. 4.2 ± 0.9, P < 0.05, n = 10 mice), and also CaMKII‐dependent ryanodine receptor phosphorylation (0.8 ± 0.1 vs. 1.0 ± 0.1, P < 0.05, n = 11 mice), with similar results upon TAC. In murine myocytes, empagliflozin reduced CaSpF (TAC: 1.7 ± 0.3 vs. 2.5 ± 0.4 1/100 μm−1 s−1, P < 0.05, n = 4 mice) but increased SR Ca2+ load and Ca2+ transient amplitude. Importantly, empagliflozin also significantly reduced CaSpF in human failing ventricular myocytes (1 ± 0.2 vs. 3.3 ± 0.9, P < 0.05, n = 4 patients), while Ca2+ transient amplitude was increased (F/F0: 0.53 ± 0.05 vs. 0.36 ± 0.02, P < 0.05, n = 3 patients). In contrast, 30 min exposure with empagliflozin did not affect CaMKII activity nor Ca2+‐handling but significantly reduced [Na+]i.ConclusionsWe show for the first time that empagliflozin reduces CaMKII activity and CaMKII‐dependent SR Ca2+ leak. Reduced Ca2+ leak and improved Ca2+ transients may contribute to the beneficial effects of empagliflozin in HF.
The detrimental potential of arrhythmia‐induced cardiomyopathy
Authors: Eiringhaus Jörg , Hamer Okka W. , Hollemann David , Brochhausen Christoph , Vollmann Dirk , Maier Lars S. , Sossalla Samuel 
Published: August 2018

AbstractHere we discuss a case of arrhythmia‐induced cardiomyopathy (AIC) with consecutive severe multiple organ failure. In relation to this imposing case, we discuss the significance of this potentially underestimated cause of newly occurred left‐ventricular systolic dysfunction and concomitant arrhythmia. We further delineate the diagnostic algorithm and differential diagnoses of AIC.
Pressure pain thresholds: Subject factors and the meaning of peak pressures
Authors: Melia Michael , Geissler Britta , König Jochem , Ottersbach Hans Jürgen , Umbreit Matthias , Letzel Stefan , Muttray Axel 
Published: August 2018

AbstractBackgroundThe assessment of pressure pain has become an integral part in pain research. The distribution of pressure under a plunger can be uneven. However, measurements based on conventional devices show the applied force or mean pressure, failing to take local pressure peaks into account. Our main question was whether peak pressures under the probe are responsible for pain onset.MethodsA force‐controlled algometer was fitted with a newly developed pressure‐indicating film. Pressure pain thresholds (PPTs) of 100 healthy subjects (57 men, age 18–66 years) were assessed at 29 sites across the body. Each site was measured three times, nonconsecutively and presented in randomized order. Forty subjects were manual labourers.ResultsPressure distributions on hard tissue (bone) were more heterogeneous and showed more prominent peaks beneath the probe when reaching the PPT. Soft tissue (e.g. muscle) created a distinct distribution, with higher pressure especially around the corners of the probe. A high variability of PPTs between subjects and different measurement sites was observed. Men as well as manual labourers had comparatively higher adjusted pressure pain thresholds (force and pressure).ConclusionsPeak pressures could be relevant for pain onset and should be accounted for in mechanical pain studies. The probe, indentation depth and tissue properties have a major impact on pressure distributions and may therefore affect the perception of pressure pain. Due to higher intra‐individual differences regarding peak pressures at the spinous processes, breastbone, forehead and abdomen caution are needed when interpreting those sites.SignificanceThis study adds some important considerations for the use of pressure algometers. It was found that during pressure pain thresholds readings distinct peak pressure profiles could arise, which may influence the perception of pain. Peak pressure could be another contributing factor, which may explain some of the high variability in pressure pain readings.
Energy‐Efficient Methanol to Dimethyl Ether Processes Combined with Water‐Containing Methanol Recycling: Process Simulation and Energy Analysis
Authors: Zhang Chundong , Jun Ki‐Won , Kwak Geunjae , Kim Sungtak 
Published: August 2018

AbstractTwo methanol‐to‐dimethyl ether (MTD) process scenarios were proposed to develop new MTD processes with improved energy efficiency by recycling water‐containing methanol to the MTD reactor. In both scenarios, a water‐tolerant K‐modified H‐ZSM‐5 was used in the MTD reactor as the methanol dehydration catalyst. Process modeling was implemented by using Aspen Plus to obtain the quantitative energy analysis results. Both scenarios are mainly comprised of a methanol preheating unit, a methanol dehydration unit, a DME separation unit, a methanol separation unit, and a methanol recycling unit. The two modelled scenarios have differing flow paths of the methanol recycle stream. That is, in option 1, after separating DME, a portion of the water‐containing methanol was recycled directly to the MTD reactor without entering the methanol separation unit. Whereas, in option 2, all of the water‐containing methanol was sent to the methanol separation unit. However, the less‐purified methanol was obtained and recycled. The process performance of both proposed scenarios was investigated by varying the recycle ratio or the recycled methanol purity in scenarios 1 and 2, respectively. Compared with the conventional γ‐Al2O3 based MTD process, both of the proposed scenarios were found to be more beneficial in saving both energy and capital cost, which can be seen from the high energy saving rate and smaller equipment size of the separation units in the newly proposed MTD process scenarios 1 and 2.
EdgeCloudSim: An environment for performance evaluation of edge computing systems
Authors: Sonmez Cagatay , Ozgovde Atay , Ersoy Cem 
Published: August 2018

AbstractEdge computing is a fast growing field of research that covers a spectrum of technologies bringing the cloud computing services closer to the end user. Growing interest in this area yields many edge computing approaches that need to be evaluated and optimized. Experimenting on the real cloud environments is not always feasible due to the operational cost and the scalability. Despite increasing research activity, this field lacks a simulation tool that supports the modeling of both computational and networking resources to handle the edge computing scenarios. Existing network simulators can model the network behavior at different levels of granularity. The cloud computing simulators support the modeling and simulation of the computational infrastructures and services efficiently. Starting from the available simulators, a significant programming effort is required to obtain a simulation tool meeting the actual needs. On the other hand, designing a new edge computing tool has many challenges such as the scalability, extensibility, and modeling the mobility, network, and virtualized resources. To decrease the barriers, a new simulator tool called EdgeCloudSim streamlined for the edge computing scenarios is proposed in this work. EdgeCloudSim builds upon CloudSim to address the specific demands of edge computing research and support the necessary functionalities. To demonstrate the capabilities of EdgeCloudSim, an experiment setup based on different edge architectures is simulated. In addition, the effect of the edge server capacity and the mobility on the overall system performance are investigated.
Parallel genetic adaptation across environments differing in mode of growth or resource availability
Authors: Turner Caroline B. , Marshall Christopher W. , Cooper Vaughn S. 
Published: August 2018

AbstractEvolution experiments have demonstrated high levels of genetic parallelism between populations evolving in identical environments. However, natural populations evolve in complex environments that can vary in many ways, likely sharing some characteristics but not others. Here, we ask whether shared selection pressures drive parallel evolution across distinct environments. We addressed this question in experimentally evolved populations founded from a clone of the bacterium Burkholderia cenocepacia. These populations evolved for 90 days (approximately 600 generations) under all combinations of high or low carbon availability and selection for either planktonic or biofilm modes of growth. Populations that evolved in environments with shared selection pressures (either level of carbon availability or mode of growth) were more genetically similar to each other than populations from environments that shared neither characteristic. However, not all shared selection pressures led to parallel evolution. Genetic parallelism between low-carbon biofilm and low-carbon planktonic populations was very low despite shared selection for growth under low-carbon conditions, suggesting that evolution in low-carbon environments may generate stronger trade-offs between biofilm and planktonic modes of growth. For all environments, a population's fitness in a particular environment was positively correlated with the genetic similarity between that population and the populations that evolved in that particular environment. Although genetic similarity was low between low-carbon environments, overall, evolution in similar environments led to higher levels of genetic parallelism and that genetic parallelism, in turn, was correlated with fitness in a particular environment.
Concentration of pistachio hull extract antioxidants using membrane separation and reduction of membrane fouling during process
Authors: Seifzadeh Negin , Sahari Mohammad Ali , Barzegar Mohsen , Ahmadi Gavlighi Hasan 
Published: August 2018

AbstractThe purpose of this study was to concentrate the polyphenolic compounds in pistachio hull extract as a rich source of natural antioxidants using the membrane process and the reduction of membrane fouling during the process. After the optimization of the membrane performance includes chamber pressure and stirring rate by monitoring flux and membrane fouling, pectinase and tannase enzymes were compared in order to reduce fouling. Pectinase showed a better potential in decreasing membranous fouling. Enzyme concentration was optimized, and treatment with 17.4 (U) was selected. The permeate obtained from optimized membrane condition and enzyme level treatment was enriched in total phenol (120.31 ± 0.35 mgGAE/g) and flavonoid (34.54 ± 0.09 mgCE/g), while the amount of anthocyanin was not remarkable.
Optimization of the extraction of natural antioxidants from Coffea robusta leaves and evaluation of their ability to preserve palm olein from oxidation during accelerated storage
Authors: Teboukeu Gires Boungo , Djikeng Fabrice Tonfack , Klang Mathilde Julie , Karuna Mallampalli Sri Lakshmi , Womeni Hilaire Macaire 
Published: August 2018

AbstractResponse surface methodology (RSM) was used to optimize the extraction of phenolic antioxidants of Coffea robusta leaves and to evaluate the effect of optimized extract and storage time on the stability of palm olein. The optimization of the extraction process was conducted, and the total polyphenol value of 127.06 mg GAE/g and scavenging activity of 90.65% were obtained under optimal extraction conditions. The phenolic antioxidants of the optimized extract and their thermal stability were determined using HPLC‐DAD (high‐performance liquid chromatography‐diode array detector) and Rancimat test, respectively. The effect of concentration of the optimized extract and storage time on the stability of palm olein was also evaluated. Results showed that the optimized extract contains gallic acid, vanillic acid, cafeic acid and was efficient in retarding palm olein oxidation during 32 months at room temperature. Coffea robusta can be recommended as good source of antioxidants for stabilization of palm olein.
Heavy metal and microbial safety assessment of raw and cooked pumpkin and Amaranthus viridis leaves grown in Abakaliki, Nigeria
Authors: Azi Fidelis , Odo Micheal O. , Okorie Peter A. , Njoku Helen A. , Nwobasi Veronica N. , David Esther , Onu Theresa C. 
Published: August 2018

AbstractIn this study, heavy metal and microbial safety assessment of raw and cooked pumpkin and Amaranthus viridis leaves grown in Abakaliki, Nigeria, was examined. The levels of lead (Pb), arsenic (As), chromium (Cr), cadmium (Cd), and mercury (Hg) were evaluated using atomic absorption spectrophotometer. The microbial cells were counted and further identified to species level using 16S rDNA and ITS rDNA sequencing analysis at CABI microbial identification services United Kingdom (UK). The results showed that the heavy metal concentrations of lead (10.5, 12.0), arsenic (7.5, 8.5), chromium (0.9, 0.1), and mercury (13.1, 14.0) in the pumpkin and A. viridis leaves, respectively, were above maximum acceptable limit according to relevant national and international food regulatory agencies (Tables and ). Cooking significantlyreduced the concentrations of the heavy metals at (p > 0.05) to or below, lead (6.8, 8.4), arsenic (5.1, 6.1), chromium (0.6.0.1), and mercury (9.5, 11.4) in the pumpkin and A. viridis leaves, respectively, but still not to international safe limit. The result of the microbial safety assessment showed that the microbial load of both the pumpkin and Amaranthus viridis leaves were above acceptable limit and the contaminating organisms were identified as Escherichia coli (504743), Klebsiella pneumonia (504744b), and Aspergillus flavus (504740).This study therefore shows that the vegetables (pumpkin and A. viridis leaves) contain unacceptable levels of toxic heavy metals and potentially dangerous pathogenic microorganisms, thus present significant health risk for the consumers.
Economic research relating to a 200 MWe oxy‐fuel combustion power plant
Authors: Haibo Wu , Zhaohui Liu 
Published: August 2018

AbstractOxy‐fuel combustion is one of the most promising technologies for large‐scale CO2 capture and storage in power plants. This flexible technology can be used in new power plants and in existing plant retrofits, with no technological barriers to its implementation. In this paper, economic research was conducted into a 200 MW power plant using oxy‐fuel combustion. The paper has important implications for the large‐scale application of oxy‐fuel combustion. Different combustion modes (conventional combustion, and oxy‐fuel combustion including dry and wet recycling) were considered. Several factors were taken into account, including the operation parameters of equipment and the parameters of the flue gas. The dynamic investment cost, the annual cost, the non‐taxable electricity price, energy consumption, and other data were obtained. It was concluded that, with a CO2 capture efficiency of 90%, the CO2 emission reduction cost of 200 MW under an oxy‐fuel combustion system is about 413 yuan/t. This research can provide accurate cost information for specific projects, and provide economic and cost references for other oxy‐fuel combustion projects. © 2018 Society of Chemical Industry and John Wiley & Sons, Ltd.
Better together: How multinationals come together with business groups in times of economic and political transitions
Authors: Bucheli Marcelo , Salvaj Erica , Kim Minyoung 
Published: August 2018

Research Summary: This article studies two interrelated questions. First, why did business groups in emerging markets thrive and prevail after pro‐market reforms were implemented in their countries? And, second, what type of adaptation strategies can multinational corporations develop in order to be competitive in economies dominated by business groups? By conducting an archive‐based historical network analysis of business groups in Chile during periods of major economic and political transitions, we maintain that business groups were created in periods of protectionism as a way to navigate economies with strong state participation or inefficient markets. In this process, these groups endogenously created an economy with market imperfections resulting from the dominance of these business groups. This means that the transition toward more open markets did not necessarily create more competitive environments and that elites in emerging economies were unwilling to abandon the advantages of having links between their businesses. Multinationals entering this economy adapted by becoming business groups themselves and creating links with other business groups. In sum, strategies devised as means to reduce market imperfections created new imperfections that incentivized the business groups to retain their structure and forced multinationals to become business groups.
Managerial Summary: Large diversified conglomerates known as business groups dominate the markets of emerging economies. These groups have survived important changes taking place in their own countries, including the abandonment of an import substitution industrialization model for an open market one or changes from military regimes to democratic ones. This article explores two aspects related to these transitions most emerging economies have gone through. First, why did some business groups survive despite the fact that many of them were created and grew during protectionist times? And, second, what strategies have multinational corporations developed when operating in economies dominated by those powerful business groups? We show, first, that some business groups survived the transition by rearranging the type of links they had with each other, and, second, that multinationals competing in economies dominated by those business groups opted for becoming business groups themselves.
Structural network topology correlates of microstructural brain dysmaturation in term infants with congenital heart disease
Authors: Schmithorst Vincent J. , Votava‐Smith Jodie K. , Tran Nhu , Kim Richard , Lee Vince , Ceschin Rafael , Lai Hollie , Johnson Jennifer A. , De Toledo Joan Sanchez , Blüml Stefan , Paquette Lisa , Panigrahy Ashok 
Published: August 2018

AbstractNeonates with complex congenital heart disease (CHD) demonstrate microstructural brain dysmaturation, but the relationship with structural network topology is unknown. We performed diffusion tensor imaging (DTI) in term neonates with CHD preoperatively (N = 61) and postoperatively (N = 50) compared with healthy term controls (N = 91). We used network topology (graph) analyses incorporating different weighted and unweighted approaches and subject‐specific white matter segmentation to investigate structural topology differences, as well as a voxel‐based analysis (VBA) to confirm the presence of microstructural dysmaturation. We demonstrate cost‐dependent network inefficiencies in neonatal CHD in the pre‐ and postoperative period compared with controls, related to microstructural differences. Controlling for cost, we show the presence of increased small‐worldness (hierarchical fiber organization) in CHD infants preoperatively, that persists in the postoperative period compared with controls, suggesting the early presence of brain reorganization. Taken together, topological microstructural dysmaturation in CHD infants is accompanied by hierarchical fiber organization during a protracted critical period of early brain development. Our methodology also provides a pipeline for quantitation of network topology changes in neonates and infants with microstructural brain dysmaturation at risk for perinatal brain injury.