bluuebunny/crossref_metadata_2025_split huggingface dataset:
Mass spectrometry and ion mobility study of poly(ethylene glycol)‐based polyurethane oligomers
Authors: Harris Rachel A. , Picache Jaqueline A. , Tomlinson Ian D. , Zlibut Emanuel , Ellis Berkley M. , May Jody C. , McLean John A. , Hercules David M. 
Published: November 2019

RationaleCommercial‐grade polymer synthesis is performed via melt polymerization, which leads to polydispersion. The work reported herein provides a synthetic strategy to produce mono‐dispersive polyurethane oligomers and an analytical strategy to distinguish these oligomers, providing chemists with the tools necessary to synthesize and identify specific polymer structures that exhibit a desired property.MethodsThree isomeric poly(ethylene glycol)–polyurethane (PEG‐PUR) oligomers were synthesized and analyzed via flow‐injection ion mobility mass spectrometry (IM‐MS). Each polymer oligomer was injected and run independently via flow injection at 100 μL•min−1 and analyzed in positive ion mode on a drift tube quadrupole time‐of‐flight (QTOF) instrument. Mobility measurements were determined using a single‐field approach. For tandem mass spectrometry (MS/MS) experiments, the sodium‐adducted singly charged precursor ion was isolated in the quadrupole and subjected to a range of collision energies.ResultsIn MS experiments, both +1 and +2 sodium‐adducted species were observed for each oligomer at m/z 837.4 and 430.2, respectively. When isolated and fragmented via MS/MS, the +1 precursor yielded distinct product ions for each of the three isomeric oligomers. Fragmentation generally occurred at urethane linkages via 1,3‐ and 1,5‐H shift mechanisms. IM was also used to distinguish the three isomers, with greater IM separation observed for the +2 versus the +1 species.ConclusionsMono‐disperse PEG‐PUR oligomers were synthesized and analyzed. Although the polymeric oligomers analyzed in this study are quite small and structurally simple, this work serves as a model system for the synthesis and structural characterization of larger, more complex block copolymers.
Dermatophilus congolensis associated bronchopneumonia in an alpaca
Authors: Horadagoda Neil U. , Biasutti Sara , Gimeno Marina , Dart Andrew 
Published: November 2019

AbstractA severe, chronic, locally extensive granulomatous bronchopneumonia was diagnosed on post‐mortem and histopathological examination of an adult alpaca. Dermatophilus congolensis organisms were isolated from the lungs and genotypic identification of aerobic culture was confirmed by sequence analysis of the entire 16S rDNA gene. This is the first report of D. congolensis‐associated bronchopneumonia in any species.
The zero limit of thermal diffusivity for the 2D density‐dependent Boussinesq equations with vacuum
Authors: Ye Xia , Zhu Mingxuan 
Published: November 2019

AbstractThis paper is concerned with the initial boundary problem to the two‐dimensional density‐dependent Boussinesq equations with vacuum. The global solution of the density‐dependent Boussinesq equations with zero thermal diffusivity will be obtained. We also show the asymptotic behavior of the solutions of the Boussinesq equations as the thermal diffusivity tends to zero. If the initial data , the solutions of the Boussinesq equations converge to those of zero thermal diffusivity Boussinesq equations as the thermal diffusivity tends to zero.
Little strings, long strings, and fuzzballs
Authors: Martinec Emil J. , Massai Stefano , Turton David 
Published: November 2019

Abstract
At high energy densities, fivebranes are populated by a Hagedorn phase of so- called little strings, whose statistical mechanics underlies black fivebrane thermodynamics. A particular limit of this phase yields BTZ black holes in AdS3, leading us to the idea that in this context fuzzballs and highly excited little strings are one and the same. We explore these ideas through an analysis of D-brane probes of fivebrane supertube backgrounds. String theory dynamics on these backgrounds is described by an exactly solvable null- gauged WZW model. We develop the formalism of null gauging on worldsheets with boundaries, and find that D-branes wrapping topology at the bottom of the supertube throat are avatars of the “long string” structure that dominates the thermodynamics of the black hole regime, appearing here as excitations of supertubes lying near but slightly outside the black hole regime.
Gravitational collapse in SYK models and Choptuik-like phenomenon
Authors: Dhar Avinash , Gaikwad Adwait , Joshi Lata Kh , Mandal Gautam , Wadia Spenta R. 
Published: November 2019

Abstract
SYK model is a quantum mechanical model of fermions which is solvable at strong coupling and plays an important role as perhaps the simplest holographic model of quantum gravity and black holes. The present work considers a deformed SYK model and a sudden quantum quench in the deformation parameter. The system, as in the undeformed case, permits a low energy description in terms of pseudo Nambu Goldstone modes. The bulk dual of such a system represents a gravitational collapse, which is characterized by a bulk matter stress tensor whose value near the boundary shows a sudden jump at the time of the quench. The resulting gravitational collapse forms a black hole only if the deformation parameter ∆𝜖 exceeds a certain critical value ∆𝜖c and forms a horizonless geometry otherwise. In case a black hole does form, the resulting Hawking temperature is given by a fractional power Tbh∝ (∆𝜖 − ∆ 𝜖c)1/2, which is reminiscent of the ‘Choptuik phenomenon’ of critical gravitational collapse.
APS η-invariant, path integrals, and mock modularity
Authors: Dabholkar Atish , Jain Diksha , Rudra Arnab 
Published: November 2019

Abstract
We show that the Atiyah-Patodi-Singer η-invariant can be related to the temperature-dependent Witten index of a noncompact theory and give a new proof of the APS theorem using scattering theory. We relate the η-invariant to a Callias index and compute it using localization of a supersymmetric path integral. We show that the η-invariant for the elliptic genus of a finite cigar is related to quantum modular forms obtained from the completion of a mock Jacobi form which we compute from the noncompact path integral.
Doped holographic superconductor in an external magnetic field
Authors: Correa Diego , Grandi Nicolás , Hernández Alejo 
Published: November 2019

Abstract
We add the magnetic field axis to the holographic model for a doped superconductor proposed by Kiritsis and Li. We explore the resulting superconducting dome, in a particular region of parameters in which the equations for the superconductor can be mapped into the previously known undoped case.
Linearizability on hardware weak memory models
Authors: Smith Graeme , Winter Kirsten , Colvin Robert J. 
Published: November 2019

Abstract

Linearizability is a widely accepted notion of correctness for concurrent objects. Recent research has investigated redefining linearizability for particular hardware weak memory models, in particular for TSO. In this paper, we provide an overview of this research and show that such redefinitions of linearizability are not required: under an interpretation of specification behaviour which abstracts from weak memory effects, the standard definition of linearizability is sound and complete on
all
hardware weak memory models.We prove our result with respect to a definition of object refinement which takes a weak memory model as a parameter. The main consequence of our findings is that we can leverage the range of existing techniques and tools for standard linearizability when verifying concurrent objects running on hardware weak memory models.
How to accurately assess surfactant biodegradation-impact of sorption on the validity of results
Authors: Cierniak Dorota , Woźniak-Karczewska Marta , Parus Anna , Wyrwas Bogdan , Loibner Andreas P. , Heipieper Hermann J. , Ławniczak Łukasz , Chrzanowski Łukasz 
Published: November 2019

AbstractSurfactants not only are widely used in biotechnological processes but also constitute significant contaminants of the modern world. Among many reports, there is a shortage of works which summarize the issue of surfactant sorption to biomass in a way that would elucidate the biological factors for analysts and analytical factors for microbiologists. The main factor, which is not as obvious as one would expect, is associated with the susceptibility of analytical approaches to errors resulting from incorrect handling of biomass. In case of several publications reviewed in the framework of this study, it was not possible to establish whether the decrease of the analytical signal observed by the authors actually resulted from biodegradation of the surfactant. This review emphasizes the necessity to consider the possibility of surfactant sorption to microbial cells, which may result in significant detection errors as well as conceptual inconsistency. In addition, a reference study regarding representative surfactants (cationic, anionic and non-ionic) as well as yeast, Gram-negative, Gram-positive bacteria, and activated sludge was provided to highlight the possible errors which may arise from disregarding sorption processes when determining degradation of surfactants. This particularly applies to systems which include ionic surfactants and activated sludge as sorption may account for 90% of the observed depletion of the surfactant. Therefore, a systematic approach was proposed in order to improve the credibility of the obtained results. Finally, the need to employ additional procedures was highlighted which may be required in order to verify that the decrease of surfactant concentration results from biodegradation processes.
Effect of fine particles on strength and stiffness of cement treated sand
Authors: Moon Sung-Woo , Vinoth Ganapathiraman , Subramanian Sathya , Kim Jong , Ku Taeseo 
Published: November 2019

AbstractNaturally available sands are always found with finer particles of varying sizes and proportions which are generally not accounted for in the geotechnical design of a cemented soil system. This paper explores the behavior of cemented sand with fine particles in smaller proportions. Two types of cements: (1) ordinary portland cement (OPC), (2) calcium sulfoaluminate cement (CSA); three cement contents: 3%, 5%, 7% and four fine (kaolin powder) contents: 0%, 1%, 3%, 5% are considered in this study. The ultrasonic pulse velocity (UPV), shear wave velocity ($$V_{s}$$Vs) and unconfined compressive strength (UCS) are measured to investigate the effects of fine particles on the cemented sand. The results show that fine particles do affect quite significantly the mechanical properties of cement-treated sand, even at negligent proportions. The strength and stiffness increase with fine content in both types of cement. The increase in strength and stiffness with increasing fine contents is attributed to the increased density with kaolin acting as a filler material facilitating more contact points among the particles. The results also show that the effect of fine particles on cemented sand depends not only on their relative volume and mineralogy but also on the type of the binding material.
Pembrolizumab versus chemotherapy in recurrent, advanced urothelial cancer in Japanese patients: a subgroup analysis of the phase 3 KEYNOTE-045 trial
Authors: Nishiyama Hiroyuki , Yamamoto Yoshiaki , Sassa Naoto , Nishimura Kazuo , Fujimoto Kiyohide , Fukasawa Satoshi , Yokoyama Minato , Enokida Hideki , Takahashi Kenichi , Tanaka Yoshinobu , Imai Kentaro , Shimamoto Takashi , Perini Rodolfo , Frenkl Tara , Bajorin Dean , Bellmunt Joaquim 
Published: November 2019

Abstract
Background
The open-label, randomized, active-controlled KEYNOTE-045 study (NCT02256436) showed that second-line pembrolizumab significantly improved overall survival (OS) of patients with advanced/metastatic urothelial cancer (UC) that progressed after first-line platinum-containing chemotherapy, compared with standard chemotherapy (paclitaxel, docetaxel, or vinflunine). Pembrolizumab is approved for patients with bladder cancer in Japan.

Patients and methods
Analysis was performed in the subgroup of Japanese patients enrolled in the KEYNOTE-045 study. Coprimary end points were OS and progression-free survival (PFS). Objective response rate (ORR) and safety were secondary end points.

Results
Fifty-two Japanese patients (pembrolizumab, n = 30; chemotherapy, n = 22) were followed up for a median of 26.1 months. Patients who received pembrolizumab compared with chemotherapy had a 19% lower risk for death (hazard ratio [HR] 0.81, 95% CI 0.44–1.50); after adjusting for baseline covariates, the HR for OS was 0.61 (95% CI 0.32–1.15). The 24-month OS rate was higher with pembrolizumab (26.9% vs 14.3%). PFS was 2.0 and 4.9 months for pembrolizumab and chemotherapy, respectively (HR 1.71, 95% CI 0.95–3.08). ORR was similar for pembrolizumab and chemotherapy (20.0% vs 18.2%); durability of response was higher with pembrolizumab: 67% and 33% of patients, respectively, maintained a response for > 12 months. Treatment-related adverse events, including grade 3–5 events, occurred less frequently with pembrolizumab.

Conclusions
Pembrolizumab provided durable antitumor activity in patients with locally advanced/metastatic UC that progressed after platinum-containing chemotherapy in the overall population and in the Japanese subgroup; safety profile was consistent with that previously observed for pembrolizumab.
Stochastic Seismic Waveform Inversion Using Generative Adversarial Networks as a Geological Prior
Authors: Mosser Lukas , Dubrule Olivier , Blunt Martin J. 
Published: November 2019

AbstractWe present an application of deep generative models in the context of partial differential equation constrained inverse problems. We combine a generative adversarial network representing an a priori model that generates geological heterogeneities and their petrophysical properties, with the numerical solution of the partial-differential equation governing the propagation of acoustic waves within the earth’s interior. We perform Bayesian inversion using an approximate Metropolis-adjusted Langevin algorithm to sample from the posterior distribution of earth models given seismic observations. Gradients with respect to the model parameters governing the forward problem are obtained by solving the adjoint of the acoustic wave equation. Gradients of the mismatch with respect to the latent variables are obtained by leveraging the differentiable nature of the deep neural network used to represent the generative model. We show that approximate Metropolis-adjusted Langevin sampling allows an efficient Bayesian inversion of model parameters obtained from a prior represented by a deep generative model, obtaining a diverse set of realizations that reflect the observed seismic response.
Assessment of meteorological droughts over Saudi Arabia using surface rainfall observations during the period 1978–2017
Authors: Almazroui Mansour 
Published: November 2019

AbstractThis paper discusses the preliminary results of meteorological drought analysis over Saudi Arabia for the period 1978–2017. In conjunction with meteorological observations, datasets from the Climate Prediction Center (CPC), the Merged Analysis of Precipitation (CMAP), the Climatic Research Unit (CRU), and the Tropical Rainfall Measuring Mission (TRMM) are utilized to understand the impact of the spatial distribution of rainfall on drought events. Applying precipitation thresholds allows rainfall classifications such as deficit, scanty, and surplus. Precipitation thresholds are also used to define meteorological droughts in the country, which are categorized as usual, moderate, and severe. It is found that drought events occur in Saudi Arabia due to shortfalls in the dry season, even though there is above normal rainfall in the wet season. There is no case of a shortfall in both the wet and dry seasons causing drought. Saudi Arabian droughts of all categories occurred mostly in the dry season, with fewer in the wet season. Results show that in Saudi Arabia, the last month of the wet season (April) is less prone to drought while the first and last months of the dry season (June and September respectively) are more prone to drought. Spatial distribution of drought climatology is obtained by calculating the Standardized Precipitation Index (SPI) and the Palmer Drought Severity Index (PDSI). Further application-driven studies of projections are needed based on drought indices and climate model output.
Design of converging-diverging nozzles with constant-radius centerbody
Authors: Flock Andreas K. , Gülhan Ali 
Published: November 2019

AbstractSeveral flow phenomena, such as recirculating wake flows or noise generation, occur in aerodynamic configurations with backward facing steps. In this context, subsonic nozzles with constant-radius centerbodies exist, which enable fundamental research of these phenomena for $$M < 1$$M<1. For the supersonic regime, however, the existing database and knowledge are limited. Therefore, this work presents a design approach for a converging-diverging nozzle with constant-radius centerbody. For the nozzle throat, Sauer’s method is modified to include a centerbody. The method of characteristics is used for the subsequent supersonic portion. Comparing the analytical calculations to numerical simulations results in very good agreement and therefore underlines the feasibility of the chosen approach. Viscosity reduced the Mach number on the exit plane by 1.0–1.2% and therefore had little influence.
Adaptive Bayesian credible bands in regression with a Gaussian process prior
Authors: Sniekers Suzanne , van der Vaart Aad 
Published: November 2019

AbstractA credible band is the set of all functions between a lower and an upper bound that are constructed so that the set has prescribed mass under the posterior distribution. In a Bayesian analysis such a band is used to quantify the remaining uncertainty on the unknown function in a similar manner as a confidence band. We investigate the validity of a credible band in the nonparametric regression model with the prior distribution on the function given by a Gaussian process. We show that there are many true regression functions for which the credible band has the correct order of magnitude to be used as a confidence set. We also exhibit functions for which the credible band is misleading.
Prediction of groundwater level in basement complex terrain using artificial neural network: a case of Ijebu-Jesa, southwestern Nigeria
Authors: Adiat K. A. N. , Ajayi O. F. , Akinlalu A. A. , Tijani I. B. 
Published: November 2019

AbstractEmpirical relationship between geoelectric parameters and groundwater level in boreholes/wells has not been established. Also, prediction of groundwater level from geoelectric parameters had hitherto not been reported. In order to overcome these challenges, the capability of artificial neural network (ANN) to model nonlinear system was explored in this study to predict groundwater level from geoelectric parameters. To achieve the above objectives, the ground water level (GWL) of all the accessible wells in the study area was obtained and this was used as the output parameter for the ANN model. A total of fifty-one (51) parametric vertical electrical soundings (VES) stations were occupied at each of the well location by adopting Schlumberger array configuration with electrode spacing (AB/2) ranging from 1 to 100 m. The VES data were quantitatively interpreted to generate geoelectric parameters believed to be controlling the groundwater flow and storage in the area. These parameters served as input for ANN model. The capability of ANN as a nonlinear modeling system was thereafter applied to produce a model that can predict the GWL from the input parameters. The efficiency of the model was evaluated by estimating the mean square error (MSE) and the regression coefficient (R) for the model. The results established that seasonal variation has little effect on the water fluctuation in the wells. Two aquifer types, weathered and fractured basement aquifer types, were delineated in the area. The results of the ANN model validation showed low MSE of 0.0014286 and the high regression coefficient (R) of 0.98731. This indicates that ANN can be used to predict GWL in a basement complex terrain with reasonably good accuracy. It is concluded that the ANN can effectively predict GWL from geoelectric parameters.
Secondary Metabolites Produced by an Endophytic Fungus Pestalotiopsis microspora
Authors: Nalin Rathnayake G. R. , Savitri Kumar N. , Jayasinghe Lalith , Araya Hiroshi , Fujimoto Yoshinori 
Published: November 2019

Abstract
An endophytic fungus Pestalotiopsis microspora isolated from the fruits of Manilkara zapota was cultured in potato dextrose broth media. Chromatographic separation of the EtOAc extract of the broth and mycelium led to the isolation of a new azaphilonoid named pitholide E (1), in addition to previously identified pitholide B (2), pitholide D (3), pestalotin (LL-P880α) (4), PC-2 (5), LL-P880β (6), tyrosol (7) and 4-oxo-4H-pyran-3-acetic acid (8). An endophytic fungus P. microspora from M. zapota and the isolation of compounds 1–5, 7 and 8 from P. microspora are reported here for the first time.

Graphic Abstract
Refining RNA solution structures with the integrative use of label-free paramagnetic relaxation enhancement NMR
Authors: Gong Zhou , Yang Shuai , Yang Qing-Fen , Zhu Yue-Ling , Jiang Jing , Tang Chun 
Published: November 2019

AbstractNMR structure calculation is inherently integrative, and can incorporate new experimental data as restraints. As RNAs have lower proton densities and are more conformational heterogenous than proteins, the refinement of RNA structures can benefit from additional types of restraints. Paramagnetic relaxation enhancement (PRE) provides distance information between a paramagnetic probe and protein or RNA nuclei. However, covalent conjugation of a paramagnetic probe is difficult for RNAs, thus limiting the use of PRE NMR for RNA structure characterization. Here, we show that the solvent PRE can be accurately measured for RNA labile imino protons, simply with the addition of an inert paramagnetic cosolute. Demonstrated on three RNAs that have increasingly complex topologies, we show that the incorporation of the solvent PRE restraints can significantly improve the precision and accuracy of RNA structures. Importantly, the solvent PRE data can be collected for RNAs without isotope enrichment. Thus, the solvent PRE method can work integratively with other biophysical techniques for better characterization of RNA structures.