bluuebunny/crossref_metadata_2025_split huggingface dataset:
Characterization and modification of the molecular weight distribution within dissolved organic matter using flow field‐flow fractionation
Authors: Fu Xiaowei , Pan Jizheng , Xu Huacheng 
Published: August 2020

AbstractDissolved organic matter (DOM) exists ubiquitously in the aquatic environment with varying chemical compositions and a wide molecular weight (MW) distribution, which, as a result, exhibits differing impacts on the behavior and fate of contaminants. The current methods for the MW characterization of DOM usually possess some weaknesses and therefore, some novel techniques are needed. In this study, the feasibility and sensitivity of flow field‐flow fractionation (FlFFF) system were studied for the MW characterization of DOMs from various origins. The systematic evaluation of FlFFF indicated that a mobile phase consisting of 10 mM NaCl and 5 mM H3BO3 and with a pH of 8 was optimal, and the fractionation program with a cross‐flow rate of 2 mL/min and a focusing time of 2 min resulted in the most efficient MW fractionation. Compared to natural waters, the standard DOM materials possessed a high proportion of humic‐like substances and narrow MW distribution. The quantification analysis showed that chromophoric organic ligands were mainly distributed in the high (i.e., 100 kDa–0.45 μm) and low (i.e., 0.3–1 kDa) MW fractions for natural waters, but in the medium (i.e., 1–100 kDa) and low MW fractions for the standard DOM materials. However, the fluorescent humic‐like substances were predominantly distributed within the medium and low MW fractions, irrespective of DOM types. This study showed the feasibility and sensibility of FlFFF in fractionating DOM samples, and can be used to quantify the different MW distribution of chromophoric and fluorescent components in standard and natural DOM.
Evaluation of diagnostic pigments to estimate phytoplankton size classes
Authors: Chase Alison P. , Kramer Sasha J. , Haëntjens Nils , Boss Emmanuel S. , Karp‐Boss Lee , Edmondson Mimi , Graff Jason R. 
Published: August 2020

AbstractPhytoplankton accessory pigments are commonly used to estimate phytoplankton size classes, particularly during development and validation of biogeochemical models and satellite ocean color‐based algorithms. The diagnostic pigment analysis (DPA) is based on bulk measurements of pigment concentrations and relies on assumptions regarding the presence of specific pigments in different phytoplankton taxonomic groups. Three size classes are defined by the DPA: picoplankton, nanoplankton, and microplankton. Until now, the DPA has not been evaluated against an independent approach that provides phytoplankton size calculated on a per‐cell basis. Automated quantitative cell imagery of microplankton and some nanoplankton, used in combination with conventional flow cytometry for enumeration of picoplankton and nanoplankton, provide a novel opportunity to perform an independent evaluation of the DPA. Here, we use a data set from the North Atlantic Ocean that encompasses all seasons and a wide range of chlorophyll concentrations (0.18–5.14 mg m−3). Results show that the DPA overestimates microplankton and picoplankton when compared to cytometry data, and subsequently underestimates the contribution of nanoplankton to total biomass. In contrast to the assumption made by the DPA that the microplankton size class is largely made up of diatoms and dinoflagellates, imaging‐in‐flow cytometry shows significant presence of diatoms and dinoflagellates in the nanoplankton size class. Additionally, chlorophyll bis commonly attributed solely to picoplankton by the DPA, but Chl b‐containing phytoplankton are observed with imaging in both nanoplankton and microplankton size classes. We suggest revisions to the DPA equations and application of uncertainties when calculating size classes from diagnostic pigments.
Morphometric Optical Imaging of Microporated Nail Tissue: An Investigation of Intermethod Agreement, Reliability, and Technical Limitations
Authors: Ortner Vinzent K. , Holmes Jon , Haedersdal Merete , Philipsen Peter A. 
Published: August 2020

Background and ObjectivesWhile optical imaging is a useful technique to quantitate morphological differences and treatment effects, comparative investigations of the various techniques are lacking. This study aimed at evaluating intermethod agreement, reliability, and technical limitations of wide‐field microscopy (WFM), reflectance confocal microscopy (RCM), and optical coherence tomography (OCT) for morphometry by assessing fractionally ablated nail tissue.Study Design/Materials and MethodsFifty healthy nail clippings were processed with a fractionated CO2‐laser (20 mJ/microbeam, density 15%), measured with calipers, and imaged using WFM, OCT, and RCM. Images were assessed for nail plate thickness, micropore dimensions, degree of poration, and artifacts. Repeated measurements (2–5) were taken to evaluate method repeatability using Cronbach's α and coefficients of variation (CoV), and estimate the intermethod correlation through linear correlation assessment (Pearson correlation coefficient [PCC]), ranked correlation (Kendall's tau; tau‐c), and intraclass correlation (Shrout‐Fleiss reliability coefficient; ICC).ResultsThe repeatability varied substantially between methods and target measurements. The level of intermethod agreement for thickness measurements performed with calipers, WFM, and OCT was high (tau‐c ≥ 0.7; ICC ≥ 0.8; PCC ≥ 0.9). RCM could only image 28 out of 50 samples due to its limited penetration depth. OCT demonstrated the highest repeatability of all imaging techniques (CoV 4–7%) and nail thickness showed the highest measurement reliability (α = 0.92). Micropore dimensions correlated strongest between OCT and RCM (tau‐c/ICC/PCC ≥ 0.5). All modalities were prone to artifacts, which may have adversely affected measurement variation and intermethod agreement.ConclusionIntermethod agreement and reliability appear to be highly dependent on the specific modality and target measurement. To reap the benefits of each technique while mitigating their limitations, an integrated approach to optical imaging is recommended. Lasers Surg. Med. © 2020 Wiley Periodicals LLC
Follistatin treatment modifies DNA methylation of the CDX2 gene in bovine preimplantation embryos
Authors: Ashry Mohamed , Rajput Sandeep K. , Folger Joseph K. , Yang Chunyan , Knott Jason G. , Smith George W. 
Published: August 2020

AbstractCDX2 plays a crucial role in the formation and maintenance of the trophectoderm epithelium in preimplantation embryos. Follistatin supplementation during the first 72 hr of in vitro culture triggers a significant increase in blastocyst rates, CDX2 expression, and trophectoderm cell numbers. However, the underlying epigenetic mechanisms by which follistatin upregulates CDX2 expression are not known. Here, we investigated whether stimulatory effects of follistatin are linked to alterations in DNA methylation within key regulatory regions of the CDX2 gene. In vitro‐fertilized (IVF) zygotes were cultured with or without 10 ng/ml of recombinant human follistatin for 72 hr, then cultured without follistatin until Day 7. The bisulfite‐sequencing analysis revealed differential methylation (DM) at specific CpG sites within the CDX2 promoter and intron 1 following follistatin treatment. These DM CpG sites include five hypomethylated sites at positions −1384, −1283, −297, −163, and −23, and four hypermethylated sites at positions −1501, −250, −243, and +20 in the promoter region. There were five hypomethylated sites at positions +3060, +3105, +3219, +3270, and +3545 in intron 1. Analysis of transcription factor binding sites using MatInspector combined with a literature search revealed a potential association between differentially methylated CpG sites and putative binding sites for key transcription factors involved in regulating CDX2 expression. The hypomethylated sites are putative binding sites for FXR, STAF, OCT1, KLF, AP2 family, and P53 protein, whereas the hypermethylated sites are putative binding sites for NRSF. Collectively, our results suggest that follistatin may increase CDX2 expression in early bovine embryos, at least in part, by modulating DNA methylation at key regulatory regions.
Voiding dynamics in women with urinary incontinence but without voiding symptoms
Authors: Valdevenito Juan P. , Mercado‐Campero Alejandro , Naser Michel , Castro Daniela , Ledesma Marta , Arribillaga Leandro 
Published: August 2020

AbstractAimsTo describe the voiding pattern (VP) of women with urinary incontinence but without voiding symptoms and compare their clinical and urodynamic features between those voiding with and without a measurable detrusor contraction (DET‐cont).MethodsRetrospective analysis of a prospectively built database of female urodynamic studies (UDS). Women with voiding symptoms and having medical history of different factors that could alter the lower urinary tract function were excluded. All UDS were performed following the ICS guidelines. DET‐cont and abdominal straining (ABD‐strain) were defined as an increase ≥10 cm H2O over the baseline for pdet and pabd at Qmax, respectively.ResultsA total of 186 women were included in the analysis. Mean age was 58 ± 10.7 years (24‐83). Most women showed a VP with DET‐cont (77.4%), with or without ABD‐strain. When compared to women voiding without DET‐cont, those with DET‐cont were younger (P = .004), more likely to have detrusor overactivity (P = .035) and better urinary sphincter competency in the UDS (P = .018). On multivariate analysis, the presence of DET‐cont was associated with age ≤50 years (P = .004) and the absence of urodynamic stress urinary incontinence (SUI) or SUI with abdominal leak point pressure ≥100 cm H2O (P = .008).ConclusionsMost women without voiding symptoms show a VP characterized by a measurable detrusor contraction, with or without ABD‐strain. The results suggest that the VP may vary independently with aging and with changes in the state of the urinary sphincter, emphasizing that for the interpretation of micturition in women different aspects must be considered.
Fixed interval scheduling with third‐party machines
Authors: Fridman Ilia , Kovalyov Mikhail Y. , Pesch Erwin , Ryzhikov Andrew 
Published: August 2020

AbstractWe study a problem of scheduling n jobs on machines of two types: in‐house machines and third‐party machines. Scheduling on in‐house machines incurs no additional costs, while using third‐party machines implies costs depending on their number and the time of usage. Each job has a fixed time interval for being processed which can be divided and allocated among several machines, as long as there is only one machine processing the job at any time. No machine can process more than one job at a time. Jobs can be rejected, and they are of different importance that is reflected in the weight of each job. The objective is to find a subset of the jobs and the number of third‐party machines for any period of time so that the accepted jobs can be feasibly scheduled, the total weight of the accepted jobs is maximized, and the total machine usage costs does not exceed a given upper bound. We also study a similar problem in which the objective is to maximize the total time at which at least one job is processed. Both problems are encountered in situations in which certain activities with given start and completion times have to be serviced by human operators. Examples are air traffic control and the monitoring safe vehicle unloading. Other examples are the employment of subcontractors in agriculture, construction or transportation. We will present NP‐hardness proofs, polynomial and pseudo‐polynomial optimal algorithms and an approximation algorithm for these problems and their special cases. These problems admit graph‐theoretical interpretations associated with finding independent sets and a proper vertex coloring in interval graphs.
Improved thermal and electrical properties of epoxy resin composites by dopamine and silane coupling agent modified hexagonal BN
Authors: Zhang Yiran , Tuo Rui , Yang Wei , Wu Jiale , Zhu Jie , Zhang Chong , Lin Jun , Bian Xingming 
Published: August 2020

AbstractThe high thermal conductivity epoxy resin composites filled with inorganic filler can improve the low thermal conductivity of epoxy resin. However, a large number of fillers with high thermal conductivity will reduce other properties of the composites, which limits their use under high voltage, high temperature and strong mechanical force during operation. In this study, the dopamine‐modified BN (DBN) and k‐DBN (DBN modified by coupling agent KH‐560) were prepared by employed the dopamine with catechol groups and coupling agent to modify boron nitride. The thermal conductivity, thermal stability, and dielectric properties of composites with different contents of modified fillers were studied. The results showed that surface modification improved the dispersibility of BN in the resin matrix and compatibility with the resin. Among BN/EP, DBN/EP, k‐DBN/EP composites, k‐DBN/EP composites had the highest thermal conductivity at the same number of additions. When the k‐DBN/EP content was 30 wt%, the thermal conductivity of the composite was 0.892 W/(m·K), which was an increase of 25.5% compared with the BN/EP composite. The appropriate amount of BN filling (20 wt%) can improve the breakdown strength of the composite material.
Application of semi‐in situ liquid exfoliation of graphite to the scalable production of graphene‐epoxy nanocomposites
Authors: Orawiec Marcin , Belton Daniel , Telford Richard , Surtees Alexander 
Published: August 2020

AbstractRecent advances in graphite wet exfoliation methods include new solvent systems, exfoliation‐assisting agents such as pyrophosphate and use of graphite‐intercalated compounds. These open new avenues for the scalable and versatile production of graphene/nanographite composites, with the prospect of reducing barriers to the adoption of these materials for real‐world applications. This article proposes a semi‐in situ exfoliation method in which graphite is exfoliated directly in the epoxy/cosolvent system via high‐shear mixing. The method is tested with three different solvent systems: epoxy/acetone; epoxy/N‐Methyl‐2‐pyrrolidone (NMP); and epoxy/NMP/water. Tailoring of mechanical properties of the composites is achieved by adjusting the mixing and centrifugation times and the temperature of the process. The incorporation of graphite microparticles in the composites has a positive influence on strength and flexibility at the expense of rigidity resulting in a 13.4% increase in ultimate tensile strength (UTS) and 73% in elongation at break (εmax) at 0.04 wt% loading. The proposed method also leads to nanocomposites with enhanced properties at low‐filler loadings. For example, the 0.01 wt% loading gave a 7.4% increase in Young's modulus, 10.6% in UTS, and 9.1% in εmax. The scalability and versatility of this method make it a promising alternative for industrial production of epoxy/graphene nanocomposites.
On the fixed‐time consensus problem for nonlinear uncertain multiagent systems under switching topology
Authors: Dávila Jorge , Pisano Alessandro 
Published: August 2020

SummaryThis article proposes a novel local interaction rule providing leader‐following and leader‐less consensus in a network of nonlinear uncertain first‐order agents communicating through a connected and switching graph topology. Particularly, the proposed interaction rule guarantees that consensus is achieved after a finite settling time, which admits an upper bound independent of the initial conditions of the agents' states. This property, called fixed‐time convergence, is achieved, thanks to homogeneous polynomial terms of suitable order in the local interaction rule. A Lyapunov‐based analysis is presented to support the convergence features of the proposed interaction protocol. Simulation results are presented in order to corroborate the theoretical findings.
Geographical addressing strategy for space‐ground integrated network
Authors: Xiao Yunlu , Zhang Tao , Sun Meng 
Published: August 2020

SummaryTo provide a connection between low earth orbit (LEO) satellite network and terrestrial Internet, a geographical addressing strategy for LEO network is proposed in this paper. When the IP geo‐subnet is divided based on location, the terrestrial users inside and satellite routers above each subnet could be allocated and maintain IP addresses under the regulation of IP network. The addressing strategy is implemented in the first hop and last hop of packet transmission. This paper proves that the application of geo‐subnets could effectively reduce the route table size and generation time in large‐scale space‐ground integrated network as well as maintain the stability of route table when the user condition alters. The performance loss of abnormal addressing caused by the change of satellite coverage would decrease with the reduction of geo‐subnet area. However, the decrease rate would decline during the subnet subdivision and therefore has limited optimization for abnormal addressing. The routing broadcast strategy proposed in this paper could effectively reduce the system packet loss brought by abnormal user at the same geo‐subnet division. Simulation confirms that the geographical addressing strategy combined with routing broadcast optimization in this paper could achieve more than 90% network throughput while reducing 76% of the routing cost.
Coupling PEDOT on Mesoporous Vanadium Nitride Arrays for Advanced Flexible All‐Solid‐State Supercapacitors
Authors: Chen Minghua , Fan He , Zhang Yan , Liang Xinqi , Chen Qingguo , Xia Xinhui 
Published: August 2020

AbstractTailored construction of advanced flexible supercapacitors (SCs) is of great importance to the development of high‐performance wearable modern electronics. Herein, a facile combined wet chemical method to fabricate novel mesoporous vanadium nitride (VN) composite arrays coupled with poly(3,4‐ethylenedioxythiophene) (PEDOT) as flexible electrodes for all‐solid‐state SCs is reported. The mesoporous VN nanosheets arrays prepared by the hydrothermal–nitridation method are composed of cross‐linked nanoparticles of 10–50 nm. To enhance electrochemical stability, the VN is further coupled with electrodeposited PEDOT shell to form high‐quality VN/PEDOT flexible arrays. Benefiting from high intrinsic reactivity and enhanced structural stability, the designed VN/PEDOT flexible arrays exhibit a high specific capacitance of 226.2 F g−1 at 1 A g−1 and an excellent cycle stability with 91.5% capacity retention after 5000 cycles at 10 A g−1. In addition, high energy/power density (48.36 Wh kg−1 at 2 A g−1 and 4 kW kg−1 at 5 A g−1) and notable cycling life (91.6% retention over 10 000 cycles) are also achieved in the assembled asymmetric flexible supercapacitor cell with commercial nickel–cobalt–aluminum ternary oxides cathode and VN/PEDOT anode. This research opens up a way for construction of advanced hybrid organic–inorganic electrodes for flexible energy storage.
Nanosized Zirconium Porphyrinic Metal–Organic Frameworks that Catalyze the Oxygen Reduction Reaction in Acid
Authors: Chen Gan , Stevens Michaela Burke , Liu Yunzhi , King Laurie A. , Park Jihye , Kim Taeho Roy , Sinclair Robert , Jaramillo Thomas F. , Bao Zhenan 
Published: August 2020

AbstractPorphyrinic metal–organic frameworks (PMOFs) are very appealing electrocatalytic materials, in part, due to their highly porous backbone, well‐defined and dispersed metal active sites, and their long‐range order. Herein a series of (Co)PCN222 (PCN: porous coordination network) (nano)particles with different sizes are successfully prepared by coordination modulation synthesis. These particles exhibit stability in 0.1 m HClO4 electrolyte with no obvious particle size or compositional changes observed after being soaked for 3 days in the electrolyte or during electrocatalysis. This long‐term stability enables the in‐depth investigation into the electrocatalytic oxygen reduction, and it is further demonstrated that the (Co)PCN222 particle size correlates with its catalytic activity. Of the three particle sizes evaluated (characteristic length scales of 200, 500, and 1000 nm), the smallest size demonstrates the highest mass activity while the largest size has the highest surface area normalized activity. Together these results highlight the importance of determining the structural stability of framework catalysts and provide insights into the important roles of particle size, opening new avenues to investigate and improve the electrocatalytic performance of this class of framework material.
Impact of etcd deployment on Kubernetes, Istio, and application performance
Authors: Larsson Lars , Tärneberg William , Klein Cristian , Elmroth Erik , Kihl Maria 
Published: August 2020

SummaryThis experience article describes lessons learned as we conducted experiments in a Kubernetes‐based environment, the most notable of which was that the performance of both the Kubernetes control plane and the deployed application depends strongly and in unexpected ways on the performance of the etcd database. The article contains (a) detailed descriptions of how networking with and without Istio works in Kubernetes, based on the Flannel Container Networking Interface (CNI) provider in VXLAN mode with IP Virtual Server (IPVS)‐backed Kubernetes Services, (b) a comprehensive discussion about how to conduct load and performance testing using a closed‐loop workload generator, and (c) an open source experiment framework useful for executing experiments in a shared cloud environment and exploring the resulting data. It also shows that statistical analysis may reveal the data resulting from such experiments to be misleading even when careful preparations are made, and that nondeterministic behavior stemming from etcd can affect both the platform as a whole and the deployed application. Finally, it is demonstrated that using high‐performance backing storage for etcd can reduce the occurrence of such nondeterministic behaviors by a statistically significant (P < .05) margin. The implication of this experience article is that systems researchers studying the performance of applications deployed on Kubernetes cannot simply consider their specific application to be under test. Instead, the particularities of the underlying Kubernetes and cloud platform must be taken into account, in particular because their performance can impact that of etcd.
Exceptional avian pellet from the Paleocene of Patagonia and description of its content: a new species of calyptocephalellid (Neobatrachia) anuran
Authors: Muzzopappa Paula , Martinelli Agustín G. , Garderes Juan P. , Rougier Guillermo W. 
Published: August 2020

AbstractA fossil gastric pellet from the Danian ‘Banco Negro Inferior’ of the Salamanca Formation at Punta Peligro Locality (Chubut, Argentina) and its 3D preserved fossil content is studied herein. The structure of the pellet and the condition of the enclosed bones suggest that it was produced by a bird of prey, although birds of any kind are as yet unknown from osteological remains in the Banco Negro ecosystem. The content of the pellet originated from a single anuran individual, representing a new species of the genusCalyptocephalella, is described herein asC. sabrosasp. nov. The new find highlights the broad temporal, geographical and taxonomic diversity of this frog genus in Patagonia's geological past.