bluuebunny/crossref_metadata_2025_split huggingface dataset:
Alternating Placement of d‐ and l‐Alanine Moieties in the Polymer Side‐Chains
Authors: Goswami Krishna Gopal , Saha Biswajit , Mete Sourav , De Priyadarsi 
Published: November 2018

AbstractSynthesis of a sequence‐controlled polymer via reversible addition‐fragmentation chain transfer polymerization is reported herein, using an N‐substituted maleimide monomer bearing tert‐butyl carbamate (Boc)‐protected l‐alanine (M1) and Boc‐d‐alanine appended styrenic monomer (M2). The monomer sequence distribution along the polymer chain is thoroughly studied by 1H and 13C NMR spectroscopy and matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry, confirming the alternating placement of l‐alanine and d‐alanine throughout the polymer chain. Copolymers display fluorescence properties in various organic solvents. After the deprotection of Boc‐groups, the copolymers show fluorescence activity in water (and also in several organic solvents), and pH‐responsiveness in aqueous medium due to the protonation/deprotonation of the side‐chain ‐NH2 groups at varying aqueous solution pH. In addition, the presence of different enantiomeric structures of alanine in the side‐chain enables us to investigate the chiroptical properties of the polymers.
Transesterification in Alcohol‐Initiated ROPs of l‐ and meso‐Lactide Catalyzed by Sn(II) and Sn(IV) Compounds at Low Temperatures
Authors: Weidner Steffen M. , Kricheldorf Hans R. 
Published: November 2018

AbstractThe purpose of this study is to shed more light on the transesterification processes in alcohol‐initiated and tin(II) 2‐ethylhexanoate (SnOct2)‐catalyzed polymerizations of lactides at low or moderate temperatures. Ethanol‐initiated polymerizations are conducted in concentrated solutions at 80 °C and a strong dependence of even/odd equilibration on the alcohol/Sn ratio. Around or above 120 °C cyclization of poly(l‐lactide) via “backbiting” occurs as a third mechanism. However, poly(m‐lactide) shows a higher cyclization tendency and yields cyclics even at 100 °C. Combinations of ethanol and certain cyclic dibutyltin(IV) catalysts also yield cyclic oligomers of l‐lactide at 80 °C. Reaction conditions allowing for a total suppression of all transesterification reactions are not found, but even‐numbered poly(m‐lactide)s with a purity >95% are obtained at 70 or 60 °C.
3D Mass diffusion in ordered nanocomposite systems: Finite element simulation and phenomenological modeling
Authors: Zid Sarra , Zinet Matthieu , Espuche Eliane 
Published: November 2018

ABSTRACTThe optimization of polymer barrier properties is currently of crucial importance for a wide range of applications from packaging to building or even energy applications. To meet the requirements of these applications, polymer matrices are often combined with impermeable (nano) fillers. Different nanofiller natures, shapes, and contents have been experimentally used and a large range of barrier materials has been obtained. In the meantime, several numerical approaches have been developed to model gas diffusion properties of nanocomposite materials. However, these approaches often considered bidimensional systems. The aim of this work is to develop 3D Finite Element Model which would be used to predict gas barrier properties of nanocomposites for disk‐shaped nanofillers. The model thus obtained is valid in a wide range of fillers volume fraction values as well as aspect ratios, which makes it possible to go from diluted regimes to semidiluted or even concentrated ones. Furthermore, an analytical equation which describes gas diffusion through nanocomposites films has been built and validated with our finite element modeling model. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2019, 57, 51–61
Cloud‐aided online EEG classification system for brain healthcare: A case study of depression evaluation with a lightweight CNN
Authors: Ke Hengjin , Chen Dan , Shah Tejal , Liu Xianzeng , Zhang Xinhua , Zhang Lei , Li Xiaoli 
Published: November 2018

SummaryBrain healthcare, when supported by Internet of Things, can perform online and accurate analysis of brain big data for the classification of multivariate Electroencephalogram (EEG), which is a prerequisite for the recent boom in neurofeedback applications and clinical practices. However, it remains a grand research challenge due to (1) the embedded intensive noises and the intrinsic nonstationarity determined by the evolution of brain states; and (2) the lack of a user‐friendly computing platform to sustain the complicated analytics. This study presents the design of an online EEG classification system aided by Cloud centering on a lightweight Convolutional Neural Network (CNN). The system incrementally trains the CNN on Cloud and enables hot deployment of the trained classifier without the need to restart the gateway to adapt to the users' needs. The classifier maintains a High Convolutional Layer to gain the ability of processing high‐dimensional EEG segments. The number of hidden layers is minimized to ensure the efficiency of training. The lightweight CNN adopts an “hourglass” block of fully connected layers to reduce the number of neurons quickly toward the output end. A case study of depression evaluation has been performed against raw EEG datasets to distinguish between (1) Healthy and Major Depression Disorder with an accuracy, sensitivity, and specificity of [98.59% ± 0.28%], [97.77% ± 0.63%], and [99.51% ± 0.19%], respectively; and (2) Effective and Noneffective treatment outcome with an accuracy, sensitivity, and specificity of [99.53% ± 0.002%], [99.50% ± 0.01%], and [99.58% ± 0.02%], respectively. The results show that the classification can be completed several magnitudes faster when EEG is collected on the gateway (several milliseconds vs. 4 seconds).
Probing analytical and numerical integrability: the curious case of (AdS5 × S5)η
Authors: Banerjee Aritra , Bhattacharyya Arpan 
Published: November 2018

AbstractMotivated by recent studies related to integrability of string motion in various backgrounds via analytical and numerical procedures, we discuss these procedures for a well known integrable string background (AdS5×S5)η. We start by revisiting conclusions from earlier studies on string motion in (ℝ ×S3)ηand (AdS3)ηand then move on to more complex problems of (ℝ ×S5)ηand (AdS5)η. Discussing both analytically and numerically, we deduce that while (AdS5)ηstrings do not encounter any irregular trajectories, string motion in the deformed five-sphere can indeed, quite surprisingly, run into chaotic trajectories. We discuss the implications of these results both on the procedures used and the background itself.
Occult Contralateral Lateral Lymph Node Metastases in Unilateral N1b Papillary Thyroid Carcinoma
Authors: Bohec Hélène , Breuskin Ingrid , Hadoux Julien , Schlumberger Martin , Leboulleux Sophie , Hartl Dana M. 
Published: November 2018

AbstractObjectiveTherapeutic lateral neck dissection (ND) is recommended for N1b papillary thyroid carcinoma (PTC), while prophylactic contralateral lateral ND is not. Given the paucity of data, we investigated the frequency of and risk factors for occult lymph node metastases (LNM) in the contralateral lateral neck for N1b patients.Patients and methodsThis is a retrospective study conducted at a cancer center. Inclusion criteria were: unilateral PTC and ipsilateral lateral LNM confirmed by fine‐needle aspiration biopsy. Patients with contralateral lateral LNM or bilateral tumor on ultrasound were excluded. All patients were treated with total thyroidectomy, bilateral central ND, ipsilateral therapeutic lateral ND and prophylactic contralateral ND of levels III–IV, followed by radioactive iodine.ResultsSixty‐three patients met the inclusion criteria. Occult contralateral lateral LNM were found in 23/63 patients (36.5%) who had more LNM in ispilateral (p = .01) and contralateral level VI (p < .0001), more frequent microscopic tumor in the contralateral lobe (p = .017) and a trend toward being at high risk (p = .06). Using receiver operating characteristic analysis, a cutoff of >4 LNM in ipsilateral level VI optimized sensitivity and specificity for predicting contralateral lateral LNM, with a sensitivity of 74%, specificity of 65%, positive predictive value of 55% and negative predictive value of 81%. Neck recurrence occurred in 14%, with only 1 patient recurring only in the contralateral lateral neck (1.5%).ConclusionOccult LNM in the contralateral lateral neck was found in 36.5% of patients. Five or more ipsilateral central LNM may aid in predicting contralateral lateral LNM, and high‐risk patients may be more at risk. The clinical benefit of prophylactic contralateral lateral ND remains doubtful, however.
Native Plant Recovery following Three Years of Common Reed (Phragmites australis) Control
Authors: Zimmerman Christopher L. , Shirer Rebecca R. , Corbin Jeffrey D. 
Published: November 2018

AbstractProjects that aim to control invasive species often assume that a reduction of the target species will increase native species abundance. However, reports of the responses of native species following exotic species control are relatively rare. We assessed the recovery of the native community in five tidal wetland locations in which we attempted to eradicate the invasive common reed [Phragmites australis(Cav.) Trin. ex Steud.]. We tested whether 3 yr of treatment were able to eradicatePhragmitesand promote recovery of the native plant community. After 3 yr of treatment,Phragmitesdensity declined sharply in all treated stands, though it was not eradicated in any of them. Native plant cover increased significantly in treated areas, and community composition, particularly in smaller stands, converged toward that of uninvaded habitat. Thus, even within the relatively short timescale of the treatments and monitoring, significant progress was made toward achieving the goals of controllingPhragmitesinfestations and promoting native biodiversity. There was a trend toward greater promise for success in smaller stands than larger stands, as has been observed in other studies. A greater emphasis on monitoring whole-community responses to exotic plant control, across a range of conditions, would enhance our ability to plan and design successful management strategies.
Multi-Level State Capitalism: Chinese State-Owned Buisness Groups
Authors: Arnoldi Jakob , Villadsen Anders Ryom , Chen Xin , Na Chaohong 
Published: November 2018

ABSTRACTWe argue that vertical interlocks in Chinese state-owned business groups are important mechanisms for coordination and information exchange between the apex firm and affiliated firms, and that they are also mechanisms for government owners of the business groups to exercise control. By combining resource dependence theory with elements from transaction cost economics and agency theory, we propose that the need for interlocks increases the higher the level of government ownership. The central government is therefore more likely to use vertical interlocks than the provincial governments, which again are more likely to use vertical interlocks than the municipal governments. We develop three hypotheses based on these arguments. A regression analysis of a hand-collected data set finds strong support for our hypotheses. Our results shed light on coordination and governance issues within the state-owned sector in China and on an important means for mitigating these issues used by the government owners and firms affiliated with state-owned groups.
14C release from irradiated stainless steel
Authors: de Visser-Týnová Eva , Swanton Stephen W , Williams Stephen J , Stijkel Marcel P , Walker Alison J , Otlet Robert L 
Published: November 2018

ABSTRACTRadiocarbon (14C or carbon-14, half-life 5730 yr) is a key radionuclide in the assessment of the safety of a geological disposal facility (GDF) for radioactive waste. In particular, the radiological impact of gaseous carbon-14 bearing species has been recognized as a potential issue. Irradiated steels are one of the main sources of carbon-14 in the United Kingdom’s radioactive waste inventory. However, there is considerable uncertainty about the chemical form(s) in which the carbon-14 will be released. The objective of the work was to measure the rate and speciation of carbon-14 release from irradiated 316L(N) stainless steel on leaching under high-pH anoxic conditions, representative of a cement-based near field for low-heat generating wastes. Periodic measurements of carbon-14 releases to both the gas phase and to solution were made in duplicate experiments over a period of up to 417 days. An initial fast release of carbon-14 from the surface of the steel is observed during the first week of leaching, followed by a drop in the rate of release at longer times. Carbon-14 is released primarily to the solution phase with differing fractions released to the gas phase in the two experiments: about 1% of the total release in one and 6% in the other. The predominant dissolved carbon-14 releases are in inorganic form (as 14C-carbonate) but also include organic species. The predominant gas-phase species are hydrocarbons with a smaller fraction of 14CO (which may include some volatile oxygen-containing carbon-species). The experiments are continuing, with final sampling and termination planned after leaching for a total of two years.
Effect of Heavy Metals Contamination from Cigarette Smoke on Sound and Caries-Like Enamel
Authors: Theobaldo Jéssica D. , Vieira-Junior Waldemir F. , Catelan Anderson , Mainardi Maria do Carmo A. , Ysnaga Orlando A. , Rodrigues-Filho Ubirajara P. , Marchi Giselle Maria , Lima Débora A. , Aguiar Flávio H. B. 
Published: November 2018

AbstractIn this study, we sought to evaluate the influence of cigarette smoke and pH cycling on the chemical composition and surface/cross-sectional enamel microhardness. A total of 40 dental blocks obtained from bovine incisors were divided into four groups (n=10): no treatment (control); exposure to cigarette smoke (CS); exposure to pH cycling (PC); and exposure to cigarette smoke and pH cycling (CS-PC). The samples were analyzed by synchrotron radiation micro X-ray fluorescence, bench mode X-ray fluorescence, as well as surface microhardness (SMH) and cross-sectional microhardness (CSMH) testing. The SMH results were submitted to analysis of variance (ANOVA) and Tukey’s test. The CSMH results were evaluated using split-plot ANOVA and Tukey’s test. A high amount of Cd and Pb and traces of Ni and As were observed in enamel and dentin after exposure to cigarette smoke (CS and CS-PC). The SMH and CSMH of CS were statistically higher when compared with the control. The PC and CS-PC showed lower SMH and CSMH. We conclude that exposure to cigarette smoke promoted heavy metal deposition in enamel/dentin. In addition, it increased the enamel microhardness but did not promote a protective effect on the in vitro development of caries. The clinical significance of this work is that there is significant bioaccumulation of heavy metals from cigarette smoke on the surface and in the enamel and dentin.
Best Scale for Detecting the Effects of Stratospheric Sulfate Aerosol Geoengineering on Surface Temperature
Authors: Lo Y. T. E. , Charlton‐Perez Andrew J. , Highwood Eleanor J. , Lott Fraser C. 
Published: November 2018

Stratospheric sulfate aerosol injection (SAI) has been proposed as a way to geoengineer climate. While swift global mean surface cooling is generally expected from tropical SAI, the regional impacts of such perturbation on near‐surface air temperature (SAT) are projected to be spatially inhomogeneous. By using existing simulations from the Geoengineering Model Intercomparison Project G4 scenario, where 5 Tg/year of sulfur dioxide (SO2) is injected into the tropical stratosphere to offset some of the warming in a midrange representative greenhouse gas concentration pathway (RCP4.5) between 2020 and 2070, we examine the regional detectability of the SAI surface cooling effect and attempt to find the best spatial scale for potential SAI monitoring. We use optimal fingerprint detection and attribution techniques to estimate the time horizon over which the SAI surface cooling effect would be detected after implementation in 2020 on subglobal scales, ranging from the near‐global in situ observational coverage down to subcontinental regions. We show that using the spatiotemporal SAT pattern across the Northern and Southern extratropics and the Tropics, and across the Northern and Southern Hemispheres, as well as averaging SATs over the whole globe robustly result in successful SAI detection within 10 years of geoengineering implementation in a majority of the included plausible geoengineering realizations. However, detecting the SAI effect on SAT within the first decade of implementation would be more challenging on subcontinental scales.
Slug Stability in Flaring Geometries and Ramifications for Lava Lake Degassing
Authors: Qin Zhipeng , Soldati Arianna , Velazquez Santana Liannie C. , Rust Alison C. , Suckale Jenny , Cashman Katharine V. 
Published: November 2018

AbstractLong‐lived, persistently active lava lakes are rare but have been studied extensively because they may provide a natural laboratory for studying magmatic convection in basaltic and other low‐viscosity volcanoes. However, lava lakes differ from other volcanic systems in various ways, particularly geometry: the presence of the lava lake requires a sudden and significant flaring of the conduit. The goal of this paper is to advance our understanding of the effect that a sudden increase in the conduit width has on the stability of large gas slugs and bubbles ascending from the plumbing system. We investigate this question by linking analog laboratory experiments to direct numerical simulations in two dimensions. We find that the rapid change in the geometry associated with the transition from the conduit to the lava lake causes large gas slugs to break up. The nondimensional regime over which we observe the breakup depends sensitively on the flare angle of the lava lake and the importance of inertial effects in the flow, implying that degassing‐related eruptive activity at open‐system volcanoes is sensitive to the upper conduit and lake geometries. Applying this idea to the likely geometries and viscosities of actual lava lakes, our study suggests that all lava lakes except Erebus fall well within the regime where large gas slugs are prone to breakup.
Assessing Ionospheric Convection Estimates From Coherent Scatter From the Radio Aurora
Authors: Rojas E. L. , Hysell D. L. , Munk J. 
Published: November 2018

AbstractCoherent radar backscatter spectra from auroral E region plasma irregularities can be measured with great precision and accuracy. The Doppler spectra obtained from those measurements can be used to estimate auroral convection patterns using an empirical model. These estimates are consistent with rocket, optical, and incoherent scatter radar data, but direct comparison between the different data sets is not straightforward. In order to establish the quality of the empirical model, alternative approaches are then needed. In this work, we use the electrostatic nature of the convection electric field to assess the physical consistency of the empirical model: The model will be satisfactory to the extent that the convection patterns derived from them are incompressible. The incompressibility criteria were assessed for the estimated convection patterns obtained from the substorm of 20 December 2015. Two different approaches were used for this assessment. First, an electrostatic potential was fitted to the convection pattern produced by the empirical model. A good fit implies that there exists an incompressible convection pattern consistent with the Doppler spectra measurements. Second, the uncertainties on the Doppler spectral estimates where propagated through the empirical model to calculate the expected uncertainties on the divergence of the convection field obtained directly from the empirical model. The convection field will be incompressible if its divergence lies within the uncertainty estimates. Both approaches indicate that the evaluated convection patterns are consistently incompressible.
Genetic variation is associated with PTSD risk and aversive memory: Evidence from two trauma-Exposed African samples and one healthy European sample
Authors: Wilker Sarah , Schneider Anna , Conrad Daniela , Pfeiffer Anett , Boeck Christina , Lingenfelder Birke , Freytag Virginie , Vukojevic Vanja , Vogler Christian , Milnik Annette , Papassotiropoulos Andreas , J.-F. de Quervain Dominique , Elbert Thomas , Kolassa Stephan , Kolassa Iris-Tatjana 
Published: November 2018

AbstractThe probability to develop posttraumatic stress disorder (PTSD), characterized by vivid, intrusive emotional memories of the encountered traumatic events, depends - among other factors - on the number of previous traumatic experiences (traumatic load) and individual genetic vulnerability. So far, our knowledge regarding the biological underpinnings of PTSD is relatively sparse. Genome-wide association studies (GWAS) followed by independent replication might help to discover novel, so far unknown biological mechanisms associated with the development of traumatic memories. Here, a GWAS was conducted in N = 924 Northern Ugandan rebel war survivors and identified seven suggestively significant single nucleotide polymorphisms (SNPs; p ≤ 1 × 10−5) for lifetime PTSD risk. Of these seven SNPs, the association of rs3852144 on chromosome 5 was replicated in an independent sample of Rwandan genocide survivors (N = 370, p < .01). While PTSD risk increased with accumulating traumatic experiences, the vulnerability was reduced in carriers of the minor G-allele in an additive manner. Correspondingly, memory for aversive pictures decreased with higher number of the minor G-allele in a sample of N = 2698 healthy Swiss individuals. Finally, investigations on N = 90 PTSD patients treated with Narrative Exposure Therapy indicated an additive effect of genotype on PTSD symptom change from pre-treatment to four months after treatment, but not between pre-treatment and the 10-months follow-up. In conclusion, emotional memory formation seems to decline with increasing number of rs3852144 G-alleles, rendering individuals more resilient to PTSD development. However, the impact on therapy outcome remains preliminary and further research is needed to determine how this intronic marker may affect memory processes in detail.
Tradeoffs in demographic mechanisms underlie differences in species abundance and stability
Authors: Hallett Lauren M. , Farrer Emily C. , Suding Katharine N. , Mooney Harold A. , Hobbs Richard J. 
Published: November 2018

AbstractUnderstanding why some species are common and others are rare is a central question in ecology, and is critical for developing conservation strategies under global change. Rare species are typically considered to be more prone to extinction—but the fact they are rare can impede a general understanding of rarity vs. abundance. Here we develop and empirically test a framework to predict species abundances and stability using mechanisms governing population dynamics. Our results demonstrate that coexisting species with similar abundances can be shaped by different mechanisms (specifically, higher growth rates when rare vs. weaker negative density-dependence). Further, these dynamics influence population stability: species with higher intrinsic growth rates but stronger negative density-dependence were more stable and less sensitive to climate variability, regardless of abundance. This suggests that underlying mechanisms governing population dynamics, in addition to population size, may be critical indicators of population stability in an increasingly variable world.