bluuebunny/crossref_metadata_2025 huggingface dataset:
Reversible swelling as a strategy in the development of smart membranes from electrospun polyvinyl alcohol nanofiber mats
Authors: Cimadoro Jonathan , Goyanes Silvia
Published: February 2020

This work presents an electrospun nanofibrous membrane for water treatment, designed to reduce its pores through polymer swelling to retain contaminants, and after that, reopening them for easy cleaning. It consists of a polyvinyl alcohol (PVA) mat crosslinked with a natural agent to avoid water solubility but allow a high swelling of its nanofibers. Then, when the membrane is brought into contact with water, a transitory state occurs during which nanofibers increase their diameter 68%, closing the pores between them. For studying the swelling reversal effect, distilled water filtering was used observing a decrease in the permeate flow over time until a steady state is reached. This phenomenon is explained by the closure of pores, and it is described with a fouling model widely used in the literature. Thanks to this decrease in the pore size, the membrane achieves a rejection rate much higher than conventional PVA electrospun membranes, being capable to retain 20 nm nanoparticles with a rejection rate up to 99%. Swelling is reversible through a simple drying process, which allows reopening the pores and cleaning the fouling easily. Both the membrane and its use strategy extend the capacity of electrospun mats in a sustainable way.
Characterization of mixed solutions of hyperbranched and linear polystyrenes by a combination of size‐exclusion chromatography and analytical ultracentrifugation
Authors: Zhang Miao , Hao Nairong , Gao Yating , Li Lianwei , Ye Xiaodong
Published: February 2020

Separation and characterization on mixed solutions of hyperbranched and linear polystyrenes was achieved using size‐exclusion chromatography (SEC) as the first dimension and analytical ultracentrifugation (AUC) as the second dimension. The results show that linear and hyperbranched polystyrenes with similar hydrodynamic sizes (one fraction from SEC) can be separated by AUC according to the molar mass, and the separation efficiency decreases with the increasing of the retention volume in SEC. Moreover, the molar masses determined by AUC are consistent with the values measured by SEC‐refractive index (RI) and SEC‐multi‐angle light scattering (MALS) detection. Furthermore, the result shows that the separation efficiency decreases with the increasing of the subchain length of hyperbranched polystyrenes. Our study lays a solid foundation for future studies to separate polymers with different topologies by a combination of SEC and AUC.
The relationship of hypertension with obesity and obstructive sleep apnea in adolescents
Authors: Khan Masrur A. , Mathur Kanika , Barraza Giselle , Sin Sanghun , Yang Christina J. , Arens Raanan , Sutton Nicole , Mahgerefteh Joseph
Published: February 2020

Objectives

To assess the independent relationships of obesity and obstructive sleep apnea (OSA) with hypertension/elevated blood pressure (EBP) in adolescent patients.

Study Design

A retrospective cohort analysis was performed on 501 patients (age 13‐21 years) with three separate blood pressure measurements within 6 months of polysomnography. EBP was defined as average systolic blood pressure (SBP) ≤120 mm Hg; obesity as body mass index Z‐score ≤1.65; and OSA as obstructive apnea‐hypopnea index <1. Pearson correlations and multivariable analyses were performed to assess the independent effects of the apnea‐hypopnea index and body mass index Z‐score on SBP.

Results

Of 501 patients (mean age 16 ± 2 years), 246 (49%) were male. OSA was present in 329 (66%) patients, obesity in 337 (67%), and EBP in 262 (52%). EBP was present in 70% of obese adolescents and 60% of adolescents with OSA. Univariable correlation showed a significant relationship between SBP, body mass index Z‐score, and apnea‐hypopnea index. Multivariable linear regression analysis showed blood pressure was significantly associated with body mass index Z‐score (β = .46; P < .01), age (β = .25; P < .01), and height Z‐score (β = .14; P < .01), but not apnea‐hypopnea index (β = .01; P = .72).

Conclusions

The relationship between OSA and EBP in adolescents is most closely associated with the degree of obesity. Further studies are needed to assess the effect of the treatment of obesity and OSA on blood pressure in adolescents.
Determination of hazard ratio for progression‐free survival considering the tumor assessment schedule in sample size calculation
Authors: Tanase Takanori
Published: February 2020

Progression‐free survival is recognized as an important endpoint in oncology clinical trials. In clinical trials aimed at new drug development, the target population often comprises patients that are refractory to standard therapy with a tumor that shows rapid progression. This situation would increase the bias of the hazard ratio calculated for progression‐free survival, resulting in decreased power for such patients. Therefore, new measures are needed to prevent decreasing the power in advance when estimating the sample size. Here, I propose a novel calculation procedure to assume the hazard ratio for progression‐free survival using the Cox proportional hazards model, which can be applied in sample size calculation. The hazard ratios derived by the proposed procedure were almost identical to those obtained by simulation. The hazard ratio calculated by the proposed procedure is applicable to sample size calculation and coincides with the nominal power. Methods that compensate for the lack of power due to biases in the hazard ratio are also discussed from a practical point of view.
Effects of green tea or green tea catechin on liver enzymes in healthy individuals and people with nonalcoholic fatty liver disease: A systematic review and meta‐analysis of randomized clinical trials
Authors: Mahmoodi Marzieh , Hosseini Razieh , Kazemi Asma , Ofori‐Asenso Richard , Mazidi Mohsen , Mazloomi Seyed Mohammad
Published: February 2020

The therapeutic potential of green tea as a rich source of antioxidants and anti‐inflammatory compounds has been investigated by several studies. The present study aimed to systematically review and analyze randomized clinical trials (RCTs) assessing the effects of green tea, catechin, and other forms of green tea supplementation on levels of liver enzymes. PubMed, SCOPUS, EMBASE, and Cochrane databases were searched until February 2019. All RCTs investigating the effect of green tea or its catechin on liver enzymes including alanine transaminase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), and bilirubin were included. A total of 15 RCTs were included. The overall effect of green tea on liver enzymes was nonsignificant (ALT [Standardized mean difference (SMD)= −0.17, CI −0.42 to 0.08, p = .19], AST [SMD = −0.07, CI −0.43 to 0.29, p = .69], and ALP [SMD = −0.17, CI −0.45 to 0.1, p = .22]). However, subgroup analyses showed that green tea reduced the levels of liver enzymes in participants with nonalcoholic fatty liver disease (NAFLD) but in healthy subjects, a small significant increase in liver enzymes was observed. In conclusion, the results of this study suggest that the effect of green tea on liver enzymes is dependent on the health status of individuals. While a moderate reducing effect was observed in patients with NAFLD, in healthy subjects, a small increasing effect was found.
Quantum embedding for material chemistry based on domain separation and open subsystems
Authors: Mosquera Martín A. , Jones Leighton O. , Ratner Mark A. , Schatz George C.
Published: February 2020

This perspective considers two theories we recently proposed to perform quantum embedding calculations for chemical systems: domain‐separated density functional theory (DS‐DFT) and locally coupled open subsystems (LCOS). The development includes both the fundamentals of each theory as well as potential applications, some technical aspects, and related challenges. DS‐DFT is suited to study intramolecular effects, where one can apply a high level of theory (based on DFT or wave function theory) to a region of interest inside a molecule or solid and lower level theory elsewhere, with smooth switching between the regions. LCOS, in contrast, is a fragment‐based embedding, which offers computational advantages to study intermolecular behavior such as electron hopping, spin‐environment interaction, and charge‐transfer excitations. However, both theories can exchange roles when appropriate. In addition, these theories allow for control of computational scaling of their algorithms. We explore paths to determine the charge‐transfer operator used in LCOS, and suggest an auxiliary energy minimization that can provide a practical estimate to this operator. We also briefly discuss how to implement density fitting techniques in domain separation, and how domain separation can be used for pure wave function‐based embedding.
Au21 cage structures and their magic number tri‐cations
Authors: Ehlert Christopher , Liu Xiaojing J. , Hamilton Ian P.
Published: February 2020

We examine the stability and properties of three Au21 cage structures, one with D3 symmetry and denoted as Au21 (D3), which is novel, and the other two with C2v symmetry. One, denoted as Au21 (C2v‐1), has been previously reported but the other, denoted as Au21 (C2v‐2), is novel. As reference Au21 structures, we also examine a sheet isomer and a compact isomer, Au21 (Cs‐Tetra), formed by adsorbing an Au atom on Au20 (Td). For all structures, we consider charge ranging from −1 to +4. For the Au21 cage structures, a primary property of interest is their spherical aromaticity, as measured by their nucleus independent chemical shift. Our focus is on charge +3 since each gold atom is assumed to contribute one (6s) valence electron, and 18 is a magic number for shell closing. We find that, although Au21 (D3)+3 has the largest aromaticity, it is not the most stable cage species. Surprisingly, Au21 (C2v‐2), which is not even stable as a neutral cage species, is the most stable tri‐cation cage species. We also examine the stability of (neutral) Au21Xn cage structures relative to Au21Xn structures derived from Au21 (Cs‐Tetra) (with X = F, Cl, Br, I and n = 1, 3, 5). We find that, although Au21F3 derived from Au21 (D3) has the largest aromaticity, it is not the most stable Au21F3 cage structure. Nonetheless, all cage structures are stabilized relative to Au21 (Cs‐Tetra) and, remarkably, for the trichlorinated, tribrominated, and triiodineated clusters, at least one cage structure is more stable than its Au21 (Cs‐Tetra) counterpart.
Automation of boron chromatographic purification for δ11B analysis of coral aragonite
Authors: de la Vega Elwyn , Foster Gavin L. , Martínez‐Botí Miguel Angel , Anagnostou Eleni , Field M. Paul , Kim M. Hwan , Watson Paul , Wilson Paul A.
Published: February 2020

Rationale

To detect the small changes in past pH, the boron isotope ratio of coral carbonates, expressed as the δ11B value, needs to be both precise and accurate (2sd <<1‰). Boron measurements by Multi‐Collector Inductively Coupled Plasma Mass Spectrometry (MC‐ICPMS) require the boron to be carefully purified before analysis, which is time consuming, and requires specialist training. Here, we use the prepFAST‐MC method that enables the automatic extraction of B (up to 25 ng load) from a CaCO3 matrix.

Methods

Samples were purified using the prepFAST‐MC automated system with a ~25‐μL column of Amberlite IRA743 resin. Boron isotope measurements were performed by MC‐ICPMS. The effects of matrix load, speed of sample loading onto the column, and blank contamination were tested to evaluate the effects on the purification process. The optimised protocol was tested on various standards and samples of aragonite corals.

Results

The blank contribution for the approach is ~60 pg and is negligible given our sample size (<0.2% sample size). Efficiency of matrix removal is demonstrated with the addition of up to 1.6 mg of dissolved low‐B calcium carbonate to NIST SRM 951 with no impact on the accuracy of δ11B values. The Japanese Geological Survey Porites reference material JCp‐1, boric acid standard NIST SRM 951, and seawater, all processed on the prepFAST‐MC system, give δ11B values within error of literature values (δ11BJCp‐1 = 24.31 ± 0.20‰ (2sd, n = 20); δ11BNIST 951 = −0.02 ± 0.15‰ (2sd, n = 13) and δ11BSeawater = 39.50 ± 0.06‰ (2sd, n = 2)). Results obtained from the coral Siderastrea siderea purified with the prepFAST‐MC system show an average offset from the manual ion‐exchange protocols of Δδ11B = 0.01 ± 0.28‰ (2sd, n = 12).

Conclusions

Our study demonstrates the capacity of the prepFAST‐MC method to generate accurate and reproducible δ11B values for a range of materials, without fractionation, with efficient matrix removal and with negligible blank contribution.
Differential flatness‐based ADRC scheme for underactuated fractional‐order systems
Authors: Li Zongyang , Wei Yiheng , Zhou Xi , Wang Jiachang , Wang Jianli , Wang Yong
Published: February 2020

This article mainly studies the fractional‐order active disturbance rejection control (FOADRC) schemes for the underactuated commensurate fractional‐order systems (FOSs). The FOADRC framework for linear FOSs‐based fractional proportion integration differentiation is constructed by using the fractional‐order tracking differentiator and the fractional‐order extended state observer, and the necessary conditions for the system to have stable controllers are provided. The FOADRC scheme for underactuated FOSs based on differential flatness is proposed. For underactuated FOSs, a set of flat output expressions with a fixed format is given under the controllable condition of the system. Moreover, making the flat output as the equivalent of the system output is simple and easy to analyze and calculate. Subsequently, the FOADRC scheme is designed by using the flat output. Finally, the scheme proposed in this article is verified by a simulation example.
Interfacial Engineering Coupled Valence Tuning of MoO3 Cathode for High‐Capacity and High‐Rate Fiber‐Shaped Zinc‐Ion Batteries
Authors: Liu Yi , Wang Jing , Zeng Yinxiang , Liu Jie , Liu Xiaoqing , Lu Xihong
Published: February 2020

Aqueous Zn‐ion batteries (ZIBs) have garnered the researchers' spotlight owing to its high safety, cost effectiveness, and high theoretical capacity of Zn anode. However, the availability of cathode materials for Zn ions storage is limited. With unique layered structure along the [010] direction, α‐MoO3 holds great promise as a cathode material for ZIBs, but its intrinsically poor conductivity severely restricts the capacity and rate capability. To circumvent this issue, an efficient surface engineering strategy is proposed to significantly improve the electric conductivity, Zn ion diffusion rate, and cycling stability of the MoO3 cathode for ZIBs, thus drastically promoting its electrochemical properties. With the synergetic effect of Al2O3 coating and phosphating process, the constructed Zn//P‐MoO3−x@Al2O3 battery delivers impressive capacity of 257.7 mAh g−1 at 1 A g−1 and superior rate capability (57% capacity retention at 20 A g−1), dramatically surpassing the pristine Zn//MoO3 battery (115.8 mAh g−1; 19.7%). More importantly, capitalized on polyvinyl alcohol gel electrolyte, an admirable capacity (19.2 mAh cm−3) as well as favorable energy density (14.4 mWh cm−3; 240 Wh kg−1) are both achieved by the fiber‐shaped quasi‐solid‐state ZIB. This work may be a great motivation for further research on molybdenum or other layered structure materials for high‐performance ZIBs.
A multivocal study to improve the implementation of global requirements change management process: A client‐vendor prospective
Authors: Akbar Muhammad Azeem , Mahmood Sajjad , Alsanad Ahmed , Alsanad Abeer Abdul‐Aziz , Gumaei Abdu , Qadri Syed Furqan
Published: February 2020

Software development is a complex task, and the introduction of multi‐site development teams spread across the globe makes it even harder. Requirement changes during the software development process are inevitable, and failing to manage evolving requirements is one of the contributors to project failures. Requirements change management (RCM) becomes difficult in global software development (GSD) projects due to the need to communicate and coordinate between stakeholders in a distributed environment. This research work aims to identify the factors that have positive impacts on RCM activities in GSD. We conducted a multi‐vocal literature review (MLR) and a questionnaire survey study to identify the RCM success factors. The results of the t‐test (ie, t = 0.0347 and P = .700 > .05) and correlation (rs (25) = 0.573, P = .003) indicates that there is no significant difference between the findings of MLR and the questionnaire survey. The identified factors were further analyzed in the context of client and vendor organizations to better understand the RCM success factors in both types of GSD firms. The findings of this study can provide a useful framework for tackling problems associated with RCM in a GSD environment that is significant to the progression of GSD firms.
Composite floor system with cold‐formed trussed beams and prefabricated concrete slab
Authors: de Seixas Leal Luiz Alberto Araújo , de Miranda Batista Eduardo
Published: February 2020

Steel‐concrete composite floor systems represent a common solution for buildings, leading to reduced material consumption and improving the structural strength and flexural stiffness. Lightweight steel frame construction systems, based on the combination of thin‐walled cold‐formed steel members (CFS) and panels (e.g. wood, cementitious, gypsum plaster), may also benefit from the composite behaviour in the case of concrete slabs. In this context, full‐scale experimental tests were conducted to evaluate the structural behaviour of a floor system conceived with 0.95 mm thick CFS trussed beams and prefabricated concrete slabs. An innovative solution for shear connectors was designed and tested in order to ensure full interaction between the CFS trussed beam and the concrete slab. The thin‐walled channel (TWC) connector is based on a lipped channel CFS attached to the top chord of the truss by standard self‐drilling screws. Experimental results indicate efficient behaviour of the TWC shear connectors with improved bending capacity of the floor system.
Bearing monitoring in the wind turbine drivetrain: A comparative study of the FFT and wavelet transforms
Authors: Strömbergsson Daniel , Marklund Pär , Berglund Kim , Larsson Per‐Erik
Published: February 2020

Wind turbines are often plagued by premature component failures, with drivetrain bearings being particularly subjected to these failures. To identify failing components, vibration condition monitoring has emerged and grown substantially. The fast Fourier transform (FFT) is the major signal processing method of vibrations. Recently, the wavelet transforms have been used more frequently in bearing vibration research, with one alternative being the discrete wavelet transform (DWT). Here, the low‐frequency component of the signal is repeatedly decomposed into approximative and detailed coefficients using a predefined mother wavelet. An extension to this is the wavelet packet transform (WPT), which decomposes the entire frequency domain and stores the wavelet coefficients in packets. How wavelet transforms and FFT compare regarding fault detection in wind turbine drivetrain bearings has been largely overlooked in literature when applied on field data, with non‐ideal placement of sensors and uncertain parameters influencing the measurements. This study consists of a comprehensive comparison of the FFT, a three‐level DWT, and the WPT when applied on enveloped vibration measurements from two 2.5‐MW wind turbine gearbox bearing failures. The frequency content is compared by calculating a robust condition indicator by summation of the harmonics and shaft speed sidebands of the bearing fault frequencies. Results show a higher performance of the WPT when used as a field vibration measurement analysis tool compared with the FFT as it detects one bearing failure earlier and more clearly, leading to a more stable alarm setting and avoidable, costly false alarms.
Maximizing the returns of LIDAR systems in wind farms for yaw error correction applications
Authors: Bakhshi Roozbeh , Sandborn Peter
Published: February 2020

Wind energy is an important source of renewable energy with significant untapped potential around the world. However, the cost of wind energy production is high, and efforts to lower the cost of energy generation will help enable more widespread use of wind energy. Yaw error reduces the efficiency of turbines as well as lowers the reliability of key components in turbines. Light detection and ranging (LIDAR) devices can correct the yaw error; however, they are expensive, and there is a trade‐off between their costs and benefits. In this study, a stochastic discrete‐event simulation was developed that models the operation of a wind farm. We maximize the net present value (NPV) changes associated with using LIDAR devices in a wind farm and determine the optimum number of LIDAR devices and their associated turbine stay time as a function of number of turbines in the wind farm for specific turbine sizes. The outcome of this work will help wind farm owners and operators make informed decisions about purchasing LIDAR devices for their wind farms.
Correlation functions, entanglement and chaos in the $$ T\overline{T}/J\overline{T} $$-deformed CFTs
Authors: He Song , Shu Hongfei
Published: February 2020

Abstract

In this paper, we regard the $$ T\overline{T}/J\overline{T} $$
T

T
¯

/
J

T
¯

-deformed CFTs as perturbation theories and calculate the first order correction of the correlation functions due to the $$ T\overline{T}/J\overline{T} $$
T

T
¯

/
J

T
¯

­deformation. As applications, we study the Rényi entanglement entropy of excited state in the $$ T\overline{T}/J\overline{T} $$
T

T
¯

/
J

T
¯

-deformed two-dimensional CFTs. We find, up to the first order perturbation of the deformation, the Rényi entanglement entropy of locally excited states will acquire a non­trivial time dependence. The excess of the Rényi entanglement entropy of locally excited state is changed up to order O(c). Furthermore, the out of time ordered correlation function is investigated to confirm that the $$ T\overline{T}/J\overline{T} $$
T

T
¯

/
J

T
¯

-deformations do not change the maximal chaotic behavior of holographic CFTs up to the first order of the deformations.
Extended dynamical symmetries of Landau levels in higher dimensions
Authors: Kürkçüoğlu S. , Ünal G. , Yurduşen İ.
Published: February 2020

Abstract

Continuum models for time-reversal (TR) invariant topological insulators (Tis) in d ≥ 3 dimensions are provided by harmonic oscillators coupled to certain SO(d) gauge fields. These models are equivalent to the presence of spin-orbit (SO) interaction in the oscillator Hamiltonians at a critical coupling strength (equivalent to the harmonic oscillator frequency) and leads to flat Landau Level (LL) spectra and therefore to infinite degeneracy of either the positive or the negative helicity states depending on the sign of the SO coupling. Generalizing the results of [1] to d ≥ 4, we construct vector operators commuting with these Hamiltonians and show that SO(d, 2) emerges as the non-compact extended dynamical symmetry. Focusing on the model in four dimensions, we demonstrate that the infinite degeneracy of the flat spectra can be fully explained in terms of the discrete unitary representations of SO(4,2), i.e. the doubletons. The degeneracy in the opposite helicity branch is finite, but can still be explained exploiting the complex conjugate doubleton representations. Subsequently, the analysis is generalized to d-dimensions, distinguishing the cases of odd and even d. We also determine the spectrum generating algebra in these models and briefly comment on the algebraic organization of the LL states w.r.t. an underlying “deformed” AdS geometry as well as on the organization of the surface states under open boundary conditions in view of our results.
Expectation value of $$ \mathrm{T}\overline{\mathrm{T}} $$ operator in curved spacetimes
Authors: Jiang Yunfeng
Published: February 2020

Abstract

We study the expectation value of the $$ \mathrm{T}\overline{\mathrm{T}} $$
T

T
¯

operator in maximally symmetric spacetimes. We define an diffeomorphism invariant biscalar whose coinciding limit gives the expectation value of the $$ \mathrm{T}\overline{\mathrm{T}} $$
T

T
¯

operator. We show that this biscalar is a constant in flat spacetime, which reproduces Zamolodchikov’s result in 2004. For spacetimes with non-zero curvature, we show that this is no longer true and the expectation value of the $$ \mathrm{T}\overline{\mathrm{T}} $$
T

T
¯

operator depends on both the one- and two-point functions of the stress-energy tensor.
Conformally-regulated direct integration of the two-loop heptagon remainder
Authors: Bourjaily Jacob L. , Volk Matthias , von Hippel Matt
Published: February 2020

Abstract

We reproduce the two-loop seven-point remainder function in planar, maximally supersymmetric Yang-Mills theory by direct integration of conformally-regulated chiral integrands. The remainder function is obtained as part of the two-loop logarithm of the MHV amplitude, the regularized form of which we compute directly in this scheme. We compare the scheme-dependent anomalous dimensions and related quantities in the conformal regulator with those found for the Higgs regulator.
SUSY threshold corrections to quark and lepton mixing inspired by SO (10) GUT models
Authors: Muramatsu Yu , Shigekami Yoshihiro
Published: February 2020

Abstract

In the standard model (SM), the Cabibbo-Kobayashi-Maskawa (CKM) matrix is the only origin of flavor violations (FVs). On the other hand, in general, there are a lot of sources of the FVs in a physics beyond the SM, through the diagonalizing matrices which make Yukawa matrices diagonal. Although most of the diagonalizing matrices are unknown ones, grand unified theories (GUTs) can fix these matrices. In particular, if we consider a GUT model based on the SO(10) group, these diagonalizing matrices are strongly related to each other because of the matter unification. However, this unification causes the problem on the realization of measured SM fermion masses and mixing angles. Up to now, many people showed that supersymmetric (SUSY) threshold corrections can solve this problem, especially unfavorable fermion mass relations. In this paper, we show that how these SUSY threshold corrections affect unknown diagonalizing matrices. Since these contributions are also related to the FVs induced by SUSY particles, we can estimate the maximal effect to the diagonalizing matrices. We found that the (1, 3) and (3, 1) elements of diagonalizing matrices for quarks can be as large as the corresponding mixing angle of the CKM matrix. Moreover, we found that the higher SUSY scale can predict the larger mixing angles, although strong cancellation between the Higgs mass parameters is needed to realize the electroweak symmetry breaking.
On the Random Wave Conjecture for Dihedral Maaß Forms
Authors: Humphries Peter , Khan Rizwanur
Published: February 2020

We prove two results on arithmetic quantum chaos for dihedral Maaß forms, both of which are manifestations of Berry’s random wave conjecture: Planck scale mass equidistribution and an asymptotic formula for the fourth moment. For level 1 forms, these results were previously known for Eisenstein series and conditionally on the generalised Lindelöf hypothesis for Hecke–Maaß eigenforms. A key aspect of the proofs is bounds for certain mixed moments of L-functions that imply hybrid subconvexity.
Beobachtungsstudie ärztlicher und pflegerischer Aktivitäten in der Notaufnahme
Authors: Weigl M. , Händl T. , Wehler M. , Schneider A.
Published: February 2020

Hintergrund

Systematische und vergleichende Analysen der Tätigkeiten des ärztlichen und pflegerischen Personals in der Notaufnahme fehlen für den deutschsprachigen Bereich.

Ziel der Arbeit

Analyse der Aktivitäten des pflegerischen und ärztlichen Personals einer Notaufnahme sowie der Anteile direkten Patientenkontakts und stündlicher Tätigkeitswechsel.

Material und Methoden

Tätigkeitsanalysen auf Basis teilnehmender Beobachtungen (je 90 min) bei Pflegekräften und Ärzt*innen einer interdisziplinären Notaufnahme eines süddeutschen Krankenhauses der Maximalversorgung. Beobachtete Tätigkeiten wurden anhand eines Klassifikationssystems mitsamt Zeitdauern kodiert. Insgesamt wurden 160 Einzelbeobachtungen (mit einer Gesamtzeit von ca. 240 h) durchgeführt; 99 bei Pflegekräften sowie 61 bei Ärzt*innen.

Ergebnisse

Notaufnahmeärzt*innen arbeiten 30 % ihrer Zeit in direktem Patientenkontakt, Pflegekräfte hingegen 44 %. Für die Einzeltätigkeiten entfielen die größten Zeitanteile ärztlicher Tätigkeit auf Dokumentation und Schriftarbeit (29,3 %), interne Kommunikation mit Personal (16,9 %) sowie mit Patient*innen (13,6 %). Pflegekräfte verwenden die meiste Zeit auf therapeutische und Behandlungsaktivitäten (27,6 %) sowie interne Kommunikation (17,9 %). Diese Tätigkeiten waren stark fragmentiert: Im Durchschnitt erfassten wir 41,3 Einzeltätigkeiten pro Stunde mit einer durchschnittlichen Dauer von 1,5 min. Pflegekräfte hatten signifikant kürzere Tätigkeitsdauern als Ärzt*innen (F[df = 1] = 4,5;p = 0,04). Tätigkeitsspezifische Analysen ergaben weitere Professionsunterschiede.

Diskussion

Unsere Ergebnisse liefern erstmalig fundierte Einsichten in die Verteilung und Dauer von ärztlichen sowie pflegerischen Tätigkeiten in der akutmedizinischen Versorgung in der Notaufnahme. Zukünftige Arbeiten sollten sich insbesondere einhergehenden Auswirkungen auf die Leistungsfähigkeit und Beanspruchung des Personals wie auch der Sicherheit und Qualität der Versorgung widmen.
Does design matter when visualizing Big Data? An empirical study to investigate the effect of visualization type and interaction use
Authors: Perkhofer Lisa , Walchshofer Conny , Hofer Peter
Published: February 2020

The need for good visualization is increasing, as data volume and complexity expand. In order to work with high volumes of structured and unstructured data, visualizations, supporting the ability of humans to make perceptual inferences, are of the utmost importance. In this regard, a lot of interactive visualization techniques have been developed in recent years. However, little emphasis has been placed on the evaluation of their usability and, in particular, on design characteristics. This paper contributes to closing this research gap by measuring the effects of appropriate visualization use based on data and task characteristics. Further, we specifically test the feature of interaction as it has been said to be an essential component of Big Data visualizations but scarcely isolated as an independent variable in experimental research. Data collection for the large-scale quantitative experiment was done using crowdsourcing (Amazon Mechanical Turk). The results indicate that both, choosing an appropriate visualization based on task characteristics and using the feature of interaction, increase usability considerably.
Dysbiosis of the gut and lung microbiome has a role in asthma
Authors: Hufnagl Karin , Pali-Schöll Isabella , Roth-Walter Franziska , Jensen-Jarolim Erika
Published: February 2020

Worldwide 300 million children and adults are affected by asthma. The development of asthma is influenced by environmental and other exogenous factors synergizing with genetic predisposition, and shaping the lung microbiome especially during birth and in very early life. The healthy lung microbial composition is characterized by a prevalence of bacteria belonging to the phylaBacteroidetes,Actinobacteria, andFirmicutes. However, viral respiratory infections are associated with an abundance ofProteobacteriawith generaHaemophilusandMoraxellain young children and adult asthmatics. This dysbiosis supports the activation of inflammatory pathways and contributes to bronchoconstriction and bronchial hyperresponsiveness. Exogenous factors can affect the natural lung microbiota composition positively (farming environment) or negatively (allergens, air pollutants). It is evident that also gut microbiota dysbiosis has a high influence on asthma pathogenesis. Antibiotics, antiulcer medications, and other drugs severely impair gut as well as lung microbiota. Resulting dysbiosis and reduced microbial diversity dysregulate the bidirectional crosstalk across the gut-lung axis, resulting in hypersensitivity and hyperreactivity to respiratory and food allergens. Efforts are undertaken to reconstitute the microbiota and immune balance by probiotics and engineered bacteria, but results from human studies do not yet support their efficacy in asthma prevention or treatment. Overall, dysbiosis of gut and lung seem to be critical causes of the increased emergence of asthma.
Atrial inflammation in different atrial fibrillation subtypes and its relation with clinical risk factors
Authors: Wu Linghe , Emmens R. W. , van Wezenbeek J. , Stooker W. , Allaart C. P. , Vonk A. B. A. , van Rossum A. C. , Niessen H. W. M. , Krijnen P. A. J.
Published: February 2020

Objective

Inflammation of the atria is an important factor in the pathogenesis of atrial fibrillation (AF). Whether the extent of atrial inflammation relates with clinical risk factors of AF, however, is largely unknown. This we have studied comparing patients with paroxysmal and long-standing persistent/permanent AF.

Methods

Left atrial tissue was obtained from 50 AF patients (paroxysmal = 20, long-standing persistent/permanent = 30) that underwent a left atrial ablation procedure either or not in combination with coronary artery bypass grafting and/or valve surgery. Herein, the numbers of CD45+ and CD3+ inflammatory cells were quantified and correlated with the AF risk factors age, gender, diabetes, and blood CRP levels.

Results

The numbers of CD45+ and CD3+ cells were significantly higher in the adipose tissue of the atria compared with the myocardium in all AF patients but did not differ between AF subtypes. The numbers of CD45+ and CD3+ cells did not relate significantly to gender or diabetes in any of the AF subtypes. However, the inflammatory infiltrates as well as CK-MB and CRP blood levels increased significantly with increasing age in long-standing persistent/permanent AF and a moderate positive correlation was found between the extent of atrial inflammation and the CRP blood levels in both AF subtypes.

Conclusion

The extent of left atrial inflammation in AF patients was not related to the AF risk factors, diabetes and gender, but was associated with increasing age in patients with long-standing persistent/permanent AF. This may be indicative for a role of inflammation in the progression to long-standing persistent/permanent AF with increasing age.

Graphic abstract
Organisation of extracellular matrix proteins laminin and agrin in pericapillary basal laminae in mouse brain
Authors: Hoddevik Eystein Hellstrøm , Rao Shreyas Balachandra , Zahl Soulmaz , Boldt Henning Bünsow , Ottersen Ole Petter , Amiry-Moghaddam Mahmood
Published: February 2020

Evidence suggests that extracellular matrix molecules of perivascular basal laminae help orchestrate the molecular assemblies at the gliovascular interface. Specifically, laminin and agrin are thought to tether the dystrophin-associated protein (DAP) complex to the astrocytic basal lamina. This complex includes α-syntrophin (α-Syn), which is believed to anchor aquaporin-4 (AQP4) to astrocytic endfoot membrane domains. We have previously shown that the size of the perivascular AQP4 pool differs considerably between brain regions in an α-Syn-dependent manner. Also, both AQP4 and α-Syn occur at higher densities in endfoot membrane domains facing pericytes than in endfoot membrane domains facing endothelial cells. The heterogeneous distribution of AQP4 at the regional and capillary level has been attributed to a direct interaction between AQP4 and α-Syn. This would be challenged (1) if the microdistributions of laminin and agrin fail to align with those of DAP and AQP4 and (2) if targeted deletion of α-Syn leads to a loss of laminin and/or agrin. Here, we provide the first detailed and quantitative analysis of laminin and agrin in brain basal laminae of mice. We show that the microdistributions of these molecules vary in a fashion that is well aligned with the previously reported microdistribution of AQP4. We also demonstrate that the expression patterns of laminin and agrin are insensitive to targeted deletion of α-Syn, suggesting that α-Syn deletion affects AQP4 directly and not indirectly via laminin or agrin. These data fill remaining voids in the current model of how key molecules are assembled and tethered at the gliovascular interface.
Ein Klumpfuß bis zur Pubertät
Authors: Kraus Tanja
Published: February 2020

Der Klumpfuß gehört zu den häufigsten angeborenen Fehlbildungen. Buben sind häufiger betroffen als Mädchen – in etwa 40% tritt ein Klumpfuß bilateral auf. Mit der Ponseti-Therapie können über 90% der Klumpfüße erfolgreich und überwiegend konservativ korrigiert werden. Die Ponseti-Therapie gilt heute als weltweiter Goldstandard. Ziel ist ein plantigrader, schmerzfreier, gut beweglicher Fuß. Im Folgenden wird über eine Patientin mit congenitalem Klumpfuß im Langzeitverlauf berichtet.
A Mutualism Between Unattached Coralline Algae and Seagrasses Prevents Overgrazing by Sea Turtles
Authors: Leemans Luuk , Martínez Isis , van der Heide Tjisse , van Katwijk Marieke M. , van Tussenbroek Brigitta I.
Published: February 2020

Seagrass meadows are threatened biodiversity hot spots that provide essential ecosystem services. Green sea turtles may overgraze meadows, further enhancing seagrass decline. However, we observed an unexpected, remarkable recovery of seagrasses in a previously overgrazed meadow with abundant unattached branched coralline algae, suggesting that turtle grazing had ceased. We hypothesize that this recovery is due to an effective grazing-protection mutualism, in which the spiny coralline algae structures protect the seagrass meadows from overgrazing, while the seagrasses protect the algae from removal by currents and waves. Removing coralline algae from recovered seagrass plots allowed the turtles to resume grazing, while addition of coralline algae to grazed plots caused cessation of grazing. Coralline algae that were placed on bare sand were quickly displaced by wave action, whereas those placed in grazed or ungrazed seagrass remained. Our experiments demonstrate a grazing-protection mutualism, which likely explains the witnessed recovery of an overgrazed seagrass meadow. To our knowledge, this is the first account of a plant–plant grazing-protection mutualism in an aquatic environment. Our findings show that grazing-protection mutualisms can be vital for the maintenance and recovery of ecosystems shaped by habitat-structuring foundation species, and highlight the importance of mutualisms in coastal ecosystems. As seagrasses, sea turtles and coralline algae share habitats along tropical shores worldwide, the mutualism may be a global phenomenon. Overgrazing is expected to increase, and this mutualism adds a new perspective to the conservation and restoration of these valuable ecosystems.
On norm compression inequalities for partitioned block tensors
Authors: Li Zhening , Zhao Yun-Bin
Published: February 2020

When a tensor is partitioned into subtensors, some tensor norms of these subtensors form a tensor called a norm compression tensor. Norm compression inequalities for tensors focus on the relation of the norm of this compressed tensor to the norm of the original tensor. We prove that for the tensor spectral norm, the norm of the compressed tensor is an upper bound of the norm of the original tensor. This result can be extended to a general class of tensor spectral norms. We discuss various applications of norm compression inequalities for tensors. These inequalities improve many existing bounds of tensor norms in the literature, in particular tightening the general bound of the tensor spectral norm via tensor partitions. We study the extremal ratio between the spectral norm and the Frobenius norm of a tensor space, provide a general way to estimate its upper bound, and in particular, improve the current best upper bound for third order nonnegative tensors and symmetric tensors. We also propose a faster approach to estimate the spectral norm of a large tensor or matrix via sequential norm compression inequalities with theoretical and numerical evidence. For instance, the complexity of our algorithm for the matrix spectral norm is$$O\left( n^{2+\epsilon }\right) $$On2+ϵwhere$$\epsilon $$ϵranges from 0 to 1 depending on the partition and the estimate ranges correspondingly from some close upper bound to the exact spectral norm.
Influence of Anaerobic Digestion Processes on the Germination of Weed Seeds
Authors: Zhou Lijun , Hülsemann Benedikt , Merkle Wolfgang , Guo Jianbin , Dong Renjie , Piepho Hans-Peter , Gerhards Roland , Müller Joachim , Oechsner Hans
Published: February 2020

Anaerobic digestion (AD) produces bioenergy and bio-fertilizer. However, weed seeds can contaminate the substrates for biogas production. This work assesses seed viability of four weeds species origin from Germany and China under AD conditions at 37, 42 and 52 °C with different retention times. All investigated seeds were inactivated after 12 h at 52 °C, 128 h at 42 °C and 512 h at 37 °C under AD treatment. Inactivation duration varying between species and a global test showed that the countries of seeds origin have a significant effect on inactivation times. For two species, by contrast, short treatment times increased the germination rate which increases the risk of weed dispersal. An anoxic water bath treatment with identical temperatures resulted in longer deactivation times, indicating that other factors also play a role in the weed seeds elimination. The results indicate that the risk of weed seed spreading through digestate application can be minimized by an adequate retention time.
The use of aminated cotton fibers as an unconventional sorbent to remove anionic dyes from aqueous solutions
Authors: Jóźwiak Tomasz , Filipkowska Urszula , Brym Szczepan , Zyśk Malwina
Published: February 2020

This study aimed to investigate the sorption of anionic dyes (Reactive Black 5, Reactive Yellow 84, Acid Red 18, and Acid Yellow 23) by cotton fibers aminated with epichlorohydrin and ammonia water (ACFs) as well by unmodified cotton fibers (CFs). CFs and ACFs were characterized based on FTIR, elemental analysis (C/N content) and pHPZC. The effect of solution pH (pH 2–11) and contact time on the removal of dye was studied as well. The kinetic experimental data were fitted to pseudo-first order, pseudo-second order, and intraparticle diffusion model. Equilibrium isotherms were analyzed based on Langmuir and Freundlich isotherms. The efficiency of dye sorption on CFs was the most effective at pH 2, whereas on ACFs—at pH 3–4. ACFs and CFs changed the pH value of the sorption solution. The system tended to obtain a pH value close to the pHPZC value of the sorbent (pHPZC = 7.85 for CFs/pHPZC = 8.15 for ACFs). ACFs had a shorter dye sorption equilibrium time compared to the CFs. The sorption of dyes on cotton sorbents proceeded in 2 main phases. The best match to the experimental data was shown by the pseudo-secondary model. Having amine functional groups, the ACFs ensured far better sorption of anionic dyes than CFs did. The maximum Reactive Black 5 sorption capacity of ACFs was Qmax = 36.77 mg/g, which was 1240% higher than that of CFs (Qmax = 2.74 mg/g).
Phytohormone profiles are strongly altered during induction and symptom development of the physiological ripening disorder berry shrivel in grapevine
Authors: Griesser Michaela , Savoi Stefania , Supapvanich Suriyan , Dobrev Petre , Vankova Radomira , Forneck Astrid
Published: February 2020

The process of grape berry ripening follows three phases with distinct metabolic processes and complex regulations via phytohormones. The physiological ripening disorder berry shrivel (BS) is characterized by reduced sugar accumulation, low anthocyanin contents, and high acidity in affected berries. The processes leading to BS induction are unknown, but recent transcriptional data on reduced expression of switch genes hint towards a disturbed ripening onset. Herein we investigated the phytohormone composition throughout grape berry ripening in healthy and BS berries inVitis viniferaL. cultivar Blauer Zweigelt. Thereby we hypothesize that phytohormones are key players for BS induction and suppress the expression of switch genes at veraison. The presented metabolomics and RNAseq data describe two distinct phytohormone profiles in BS berries, differing between pre- and post-veraison with a clear ethylene precursor (aminocyclopropane-1-carboxylic acid, ACC) peak before veraison. Exogenous application of ACC led to BS symptoms, while ethephone application led to berry abscission. During post-veraison, we observed high ABA-glucose ester (ABA-GE) and low indole-3-acetate aspartate (IAA-Asp) and isopentenyladenine (iP) contents in BS berries and the transcriptional induction of several phytohormone pathways. The presented descriptive data provide valuable knowledge to further decipher the role of phytohormones in BS induction and BS symptom development.
Conceptual engineering for truth: aletheic properties and new aletheic concepts
Authors: Scharp Kevin
Published: February 2020

What is the property of being true like? To answer this question, begin with a Canberra-plan analysis of the concept of truth. That is, assemble the platitudes for the concept of truth, and then investigate which property might satisfy them. This project is aided by Friedman and Sheard’s groundbreaking analysis of twelve logical platitudes for truth. It turns out that, because of the paradoxes like the liar, the platitudes for the concept of truth are inconsistent. Moreover, there are so many distinct paradoxes that only small subsets of platitudes for truth are consistent. The result is that there is no property of being true. The failure of the Canberra plan analysis of the concept of truth, points the way toward a new methodology: a conceptual engineering project for the concept of truth. Conceptual engineering is assessing the quality of our concepts, and when they are found defective, offering new and better concepts to replace them for certain purposes. Still, there are many aletheic properties, which are properties satisfied by reasonably large subsets of platitudes for the concept of truth. We can treat these aletheic properties as a guide to the multitude of new aletheic concepts, which are concepts similar to, but distinct from, the concept of truth. Any new aletheic concept or team of concepts might be called on to replace the concept of truth. In particular, the concepts of ascending truth and descending truth are recommended, but the most important point is that we need a full-scale investigation into the space of aletheic properties and new aletheic concepts—that is, we need an Aletheic Principles Project (APP).