bluuebunny/crossref_metadata_2025_split huggingface dataset:
Numerical Techniques for the Solution of the Molecular Weight Distribution in Polymerization Mechanisms, State of the Art
Authors: Saldívar‐Guerra Enrique 
Published: July 2020

AbstractThe molecular weight distribution (MWD) is possibly the most important characteristic of a polymer. Polymers derive many of their physical properties from their MWD. Therefore, since the origins of polymer science, the theory provides a link between the kinetic mechanism and the mathematical expression of the MWD, and there are analytical solutions for ideal cases. However, the MWD formed in real‐life polymerization processes is usually more complex; the solution of the mathematical models that describe them can be quite challenging and has been the focus of enormous research efforts. These models may consist of systems of very large dimension: thousands of differential equations, often stiff, which demand special numerical techniques for their solution. In this paper the numerical techniques that can be used to solve this challenging problem are reviewed and contrasted, including weighted residual methods, direct integration, numerical inversion of transformed equations, and lumping methods. Stochastic techniques are also surveyed.
Job strain in nonprofit human service agencies: Job demands and job control's additive effects, and goal‐related feedback's mediating role
Authors: Preston Mark S. 
Published: July 2020

AbstractFew quantitative studies in the nonprofit literature have examined job demands' strain‐inducing impact. The classic demand‐control (DC) model predicts a positive main effect for job demands and a negative main effect for job control on job strain, respectively. However, four decades of DC model studies have uncovered modest support for this additive model. As a means of addressing both issues, the present study tested a recently introduced modified additive model using 621 employees from two different types of nonprofit human service agencies located in the city of New York. Two mediational analyses, structural equation modelling and bootstrapping, corroborated goal‐related feedback's intervening role on the control‐strain relationship. Findings not only replicate and extend prior research, but also make a unique contribution to the nonprofit literature. Implications for the stress management of nonprofit human service employees, as well as recommendations for the DC model literature are also discussed.
Applying the three‐dimensional block‐pulse functions to solve system of Volterra–Hammerstein integral equations
Authors: Xie Jiaquan , Gong Xiaoyuan , Shi Wei , Li Ruili , Zhao Weici , Wang Tao 
Published: July 2020

AbstractIn this paper, a numerical scheme is utilized to solve three‐dimensional nonlinear system of Volterra‐Hammerstein integrals equations, which is based on the three‐dimensional block‐pulse functions (3D‐BPFs) and their operational matrices. Then the primary nonlinear system is transferred into a linear system of algebraic equations by applying the approximate expression and operational matrices, which can be easily solved through any numerical techniques. According to the convergence of 3D‐BPFs, the new convergence analysis and error estimation theorem of the research system is detailed investigated. Lastly illustrative examples are included to demonstrate the validity and applicability of the technique.
A retrospective analysis of recurrent pediatric ependymoma reveals extremely poor survival and ineffectiveness of current treatments across central nervous system locations and molecular subgroups
Authors: Ritzmann Timothy A. , Rogers Hazel A. , Paine Simon M.L. , Storer Lisa C.D. , Jacques Thomas S. , Chapman Rebecca J. , Ellison David , Donson Andrew M. , Foreman Nicholas K. , Grundy Richard G. 
Published: July 2020

AbstractBackgroundRelapse occurs in 50% of pediatric ependymoma cases and has poor prognosis. Few studies have investigated the clinical progress of relapsed disease, and treatment lacks a standardized approach.Methods and materialsWe analyzed 302 pediatric ependymoma cases. Tumor, demographic, and treatment variables were investigated for association with relapse risk, time to recurrence, and survival after relapse. DNA methylation profiling was performed for 135/302 cases, and predominant subgroups were EPN_PFA (n = 95) and EPN_RELA (n = 24). Chromosome 1q status was ascertained for 185/302 cases by fluorescent in‐situ hybridization (FISH), multiplex ligation‐dependent probe amplification (MLPA), and DNA methylation profiles.ResultsSixty‐two percent of cases relapsed, with a median of two recurrences with no difference between posterior fossa and supratentorial locations (66% vs 55% relapse rate). One hundred seventeen (38%) cases relapsed within two years and five (2%) beyond 10 years. The late relapses were clinically heterogeneous. Tumor grade and treatment affected risk and time to relapse variably across subgroups. After relapse, surgery and irradiation delayed disease progression with a minimal impact on survival across the entire cohort. In the EPN_PFA and EPN_RELA groups, 1q gain was independently associated with relapse risk (subhazard ratio [SHR] 4.307, P = 0.027 and SHR 1.982, P = 0.010, respectively) while EPN_PFA had increased relapse risk compared with EPN_RELA (SHR = 0.394, P = 0.018).ConclusionsRecurrent pediatric ependymoma is an aggressive disease with poor outcomes, for which current treatments are inadequate. We report that chromosome 1q gain increases relapse risk in common molecular subgroups in children but a deeper understanding of the underlying biology at relapse and novel therapeutic approaches are urgently needed.
Functionalized‐graphene reinforced polyethersulfone nanocomposites with improved physical and mechanical properties
Authors: Ahmad Md. Wasi , Dey Baban , Al Saidi Abdullah Khamis Ali , Choudhury Arup 
Published: July 2020

AbstractWe have explored graphene oxide (GO) and sulfonic acid‐functionalized graphene oxides (GOSO3H) as efficient reinforcements to improve the performances of the polyethersulfone (PES). In contrast to GO, the numerous terminal SO3− groups in GOSO3H nanosheets not only promoted the filler dispersion in PES matrix, but also formed strong interfacial adhesion via H‐bonding and dipole‐dipole interactions. The tensile strength of PES was enhanced by around 3‐folds and 5‐folds upon incorporation 5 wt% GO and GOSO3H nanosheets, respectively. The improvement of tensile modulus of PES is considerably higher with GOSO3H nanosheets compared to GO. The superior tensile properties of the PES/GOSO3H nanocomposites could be ascribed to the better dispersion of GOSO3H nanosheets and the efficient stress transfer between PES matrix and GOSO3H nanosheets, which is well supported by X‐ray diffraction and morphological analyses. The loading capacity of the GOSO3H was found be higher than that of GO. The dc conductivity of the PES/GOSO3H nanocomposites was recorded greater than that of the GO‐reinforced nanocomposites. The thermo‐oxidative stability of the PES matrix was substantially improved upon inclusion of both the GO and GOSO3H, but the GOSO3H showed better effects. Overall, the as‐prepared PES/GOSO3H hybrid nanocomposite can be used as potential material in different membrane applications.
Der kontrollierte Stoß
Authors: Mathelitsch Leopold , Thaller Sigrid 
Published: July 2020

ZusammenfassungDas Billardspiel ist über ein halbes Jahrtausend alt. Seine Physik fasziniert die Forschung seit Huygens bis heute. Die aus der Perspektive der Physik entscheidenden Elemente sind der Stoß mit dem Queue, der Kontakt zwischen den Bällen und der Kontakt zwischen Ball und Bande. Gestoßen werden kann die Kugel zentral, ober‐ oder unterhalb ihres Mittelpunkts sowie seitlich versetzt. Davon hängt ihr Verhalten ab, ob sie rollt, gleitet, etwa einen Topspin oder einen sonstigen Effet mitbekommt. Während der Kontakt zwischen zwei Bällen wegen der geringen Reibung wie ein elastischer Stoß behandelbar ist, spielt der Effet beim Kontakt mit der Bande eine wichtige Rolle. Beim Sinai‐Billard besitzt der Tisch runde Ecken oder ein rundes Hindernis, die Folge ist chaotisches Verhalten. Das wurde mit ultrakalten Atomen in entsprechend geformten Lichtpotentialen demonstriert.
Mit Ionen ist zu rechnen
Authors: Linke Norbert , Müller Markus 
Published: July 2020

ZusammenfassungQuantencomputer versprechen, spezielle, für Anwendungen hochinteressante Aufgaben zu lösen. An diesen NP‐harten Problemen scheitern herkömmliche Supercomputer. Eine Technik, die intensiv erforscht wird, ist der Ionen‐Quantencomputer. An ihm demonstriert dieser Artikel, wie der Quanten‐Suchalgorithmus von Lov Grover funktioniert. Programmiert werden solche Quantencomputer über einen Software‐Stack. Er übersetzt die Befehle der Nutzeroberfläche über verschiedene Stufen in die Laser‐Manipulation der Ionen‐Qubits. Bei den aktuell in Laboren laufenden Quantencomputern sind etwa zehn Ionen die Grenze, ab der das Rauschen der Quantengatter für zu große Fehler in den Rechnungen sorgt. In Zukunft soll eine Quantenfehlerkorrektur, die mehrere physische Qubits zu einem logischen Qubit verknüpft, Fehler erkennen können. Um die Zahl der Ionen zu steigern, soll die Kontrolle über die Laserpulse und die Fallenpotenziale verbessert werden. Zudem wird daran geforscht, mehrere Ionenfallen zum Beispiel via Photonenverschränkung miteinander zu verbinden. Mikrochip‐Ionenfallen sollen Ionen‐Quantencomputer miniaturisieren.
Time‐based replacement policies for a fault tolerant system subject to degradation and two types of shocks
Authors: Dong Wenjie , Liu Sifeng , Cao Yingsai , Bae Suk Joo 
Published: July 2020

AbstractA single component nonrepairable system suffering from both an internal stochastic degradation process and external random shocks is investigated in this paper. More specifically, the Wiener process with a positive drift coefficient is introduced to describe the gradual deterioration and the arrival number of external shocks is counted with a nonhomogeneous Poisson process (NHPP). Meanwhile, fault tolerant design is incorporated into the stochastically deterioration system so as to protect it from shock failures to some extent and is consummately addressed via a generalized m − δ shock model. From the actual engineering point of view, external shocks are typically classified into two distinct categories in this current research, that is, a minor shock (Type I shock) increasing the damage load on current degradation level and a traumatic shock (Type II shock) resulting in system catastrophic failure immediately. The closed‐form expression of system survival function is derived analytically and is viewed as the generalization of existing reliability function for systems subject to dependent and competing failure processes. Based on which, two time‐based maintenance (TBM) policies including an age replacement model and a block replacement model are scheduled, where the expected long‐run cost rate (ELRCR) in each model is, respectively, optimized to seek the optimal replacement interval. In the illustrative example part, a subsea blowout preventer (BOP) control system is arranged to validate the theoretical results numerically. To compare which policy is more profitable under different conditions, the relative gain on optimal maintenance cost rate of the two TBM policies is presented.
Consensus of linear multi‐agent systems with stochastic noises and binary‐valued communications
Authors: Wang Ting , Hu Min , Zhao Yanlong 
Published: July 2020

SummaryThis article studies consensus problems of discrete‐time linear multi‐agent systems with stochastic noises and binary‐valued communications. Different from quantized consensus of first‐order systems with binary‐valued observations, the quantized consensus of linear multi‐agent systems requires that each agent observes its neighbors' states dynamically. Unlike the existing quantized consensus of linear multi‐agent systems, the information that each agent in this article gets from its neighbors is only binary‐valued. To estimate its neighbors' states dynamically by using the binary‐valued observations, we construct a two‐step estimation algorithm. Based on the estimates, a stochastic approximation‐based distributed control is proposed. The estimation and control are analyzed together in the closed‐loop system, since they are strongly coupled. Finally, it is proved that the estimates can converge to the true states in mean square sense and the states can achieve consensus at the same time by properly selecting the coefficient in the estimation algorithm. Moreover, the convergence rate of the estimation and the consensus speed are both given by O(1/t). The theoretical results are illustrated by simulations.
Spatiotemporally Controlling the Release of Biological Effectors Enhances Their Effects on Cell Migration and Neurite Outgrowth
Authors: Xue Jiajia , Wu Tong , Qiu Jichuan , Xia Younan 
Published: July 2020

AbstractIt is a major challenge to coordinate topographic cues from scaffolds with the on‐demand, sustained release of biological effectors to maximize their performance in tissue regeneration. Here, a system involving masked, photo‐triggered release of biological effectors from a temperature‐sensitive scaffold for augmented cell migration and neurite outgrowth is reported. The scaffold contains microparticles of a phase‐change material (PCM) sandwiched between two layers of electrospun fibers. The biological effectors are co‐loaded with a photothermal dye in the PCM microparticles. Under irradiation with a near‐infrared laser, the PCM will be melted to swiftly release the biological effectors. By imposing a photomask between the scaffold and the laser, only those microparticles in the irradiated region are melted, enabling a spatial control over the release. By adjusting the photomask, different regions of the scaffold can be sequentially irradiated at designated times, realizing on‐demand and sustained release of the biological effectors with spatiotemporal controls. In one demonstration, this method is used to accelerate the directional migration of NIH‐3T3 fibroblasts along the uniaxial or radial direction of fiber alignment by controlling the release of epidermal growth factor. In another demonstration, the release of nerve growth factor is managed to significantly promote neurite outgrowth from PC12 cells.
Competitive blind spots and the cyclicality of investment: Experimental evidence
Authors: Rodet Cortney S. , Smyth Andrew 
Published: July 2020

AbstractWe report laboratory experiments investigating the cyclicality of profit‐enhancing investment in a competitive environment. In our setting, optimal investment is counter‐cyclical when investment costs fall following market downturns. However, we do not observe counter‐cyclical investment. Instead, we see much less strategic behavior than our rational investment model anticipates. Our participants exhibit what Porter (1980) terms a competitive blind spot, and heuristic investment models where individuals invest a fixed percentage of their liquidity, or a fixed percentage of anticipated market demand, better fit our data than does optimal investment. We also report a control treatment without cost changes and a treatment with asymmetric investment liquidity. Both of these extensions support our main result.
Biosorption of chromium (VI) from textile waste water using luffa cylindrica activated carbon
Authors: Nwosu‐Obieogu Kenechi , Okolo Bernard I 
Published: July 2020

AbstractLuffa cylindrica was applied as a low‐cost adsorbent for removing chromium (VI) from textile industry effluent in this study. The adsorbent was characterized using scanning electron micrograph (SEM). A batch mode experiment was conducted to study the effect of pH, contact time, and adsorbent dosage on the adsorptive potential of the prepared luffa cylindrica activated carbon. The characterization results from SEM indicate that the adsorbents' potential was fully exploited in this study. A significance test conducted using ANOVA indicated that contact time and adsorbent dosage had the most effect on the adsorptive removal of Cr (VI). The optimum removal efficiency was 99.90% at pH 8.0, 99.8% at 60 min of contact time, and 99.82% at an adsorbent dosage of 1.0 g. The experimental results were analyzed using the Langmuir and Freundlich adsorption isotherm models, and the Freundlich isotherm provided a better correlation for Cr (VI) adsorption. The kinetic data by the pseudo‐first‐order kinetic model gave a better fit than the pseudo‐second‐order kinetic model.
Mass deformations of unoriented quiver theories
Authors: Bianchi Massimo , Bufalini Davide , Mancani Salvo , Riccioni Fabio 
Published: July 2020

Abstract
We study the interplay between mass deformations and unoriented projections of super-conformal quiver gauge theories resulting from D3-branes at (toric) Calabi-Yau singularities. We focus on simple orbifold cases (ℂ3/ℤ3 and ℂ3/ℤ4) and their non-orbifold descendants. This allows us to generalize the construction rules and clarify points that have been previously overlooked. In particular we spell out the conditions of anomaly cancellations as well as super-conformal invariance that typically require the introduction of flavour branes, which in turn may spoil toric symmetry. Finally, we discuss duality cascades in this context and the interplay between Seiberg/toric duality and unoriented projection with (or without) mass deformations.
High-Degree Middle Cerebral Artery Stenosis
Authors: Guan Min , Lin Jia’xing , Huang Sheng’ming , Leng Xin’yi , Shi Chang’zheng , Qiao Hong’yu , Wang Xiang’yu , Huang Li’an 
Published: July 2020

Abstract
Purpose
Endovascular treatment in severe middle cerebral artery (MCA) stenosis is controversial owing to high rates of periprocedural complications, especially occlusion of the lenticulostriate arteries (LSA). The characteristics of LSAs and the spatial relationships between MCA plaques and LSAs using the fusion of three-dimensional (3D) digital subtraction angiography (DSA) and magnetic resonance imaging (3D DSA-MRI fusion) were investigated.

Methods
We retrospectively analyzed data from 32 ischemic stroke or transient ischemic attack patients with severe MCA stenosis, who underwent MRI and DSA within 2 weeks after symptom onset. The patients were divided into culprit and non-culprit MCA stenosis groups. The 3D DSA-MRI fusion was performed on dedicated workstations, which allowed automated overlays of the target vessels. The characteristics of LSAs, plaque distribution and lesion patterns, and their relationships were evaluated.

Results
The 3D DSA-MRI fusion image was able to illustrate the spatial relationships between MCA plaques and LSA orifices. Of 42 LSA stems in 32 patients, 10 had MCA plaque over the LSA orifice and were all found in the culprit MCA stenosis group. Over half (51.9%) of the LSA stems in patients with culprit MCA stenosis originated from the stenotic MCA segment. The MCA plaque-LSA orifice spatial relationships were classified into four types, which were significantly different between the two groups (p = 0.016).

Conclusion
The 3D DSA-MRI fusion technique enables visualization of the LSA orifice and MCA plaque and their spatial relationships. This classification of the type of spatial relationships can provide insights into the pathogenesis of MCA stroke and useful guides for treatment strategies.
Thermische Belastung von Bewohnern in Städten bei Hitzewellen am Beispiel von Freiburg (Breisgau)
Authors: Matzarakis Andreas , Muthers Stefan , Graw Kathrin 
Published: July 2020

ZusammenfassungHintergrundMenschen sind im Zuge des Klimawandels immer stärker von Hitze und deren negativen gesundheitlichen Auswirkungen betroffen. Oftmals wird die Lufttemperatur als Maßzahl verwendet. Um jedoch Auswirkungen von Hitze auf den Menschen zu charakterisieren, müssen neben der Lufttemperatur weitere Faktoren berücksichtigt werden.Ziel der ArbeitZiel dieses Beitrags ist es, den Hitzestress von Bewohnern in Städten mithilfe der Gefühlten Temperatur während Hitzewellen zu charakterisieren und mit derjenigen von Bewohnern auf dem Land zu vergleichen sowie Unterschiede zur Lufttemperatur hervorzuheben.Material und MethodenDaten der Stadtstation Freiburg und der Station Freiburg-Flugplatz für 2019 des Deutschen Wetterdienstes (DWD) wurden für die Analyse der Lufttemperatur sowie für die Berechnung der Gefühlten Temperatur mithilfe des Klima-Michel-Modells für Freiburg verwendet. Zusätzlich werden die Hitzewarntage für Freiburg dargestellt und die nächtlichen Bedingungen der Innenraumtemperaturen des Hitzewarnsystems analysiert.Ergebnisse und DiskussionDie Gefühlte Temperatur übersteigt die Lufttemperatur während Hitzewellen um bis zu 10 °C. Während der klassische Wärmeinseleffekt anhand der Differenz der nächtlichen Lufttemperatur hoch und tagsüber gering ist, ist bei der Gefühlten Temperatur die Differenz nicht nur nachts, sondern auch tagsüber deutlich höher.FazitUm negative Auswirkungen zu quantifizieren, wird nicht nur die Lufttemperatur benötigt, sondern auch die Kenntnis über weitere Faktoren, die den Hitzestress beschreiben und steuern. Stadt-Land-Unterschiede bei Lufttemperatur und Gefühlter Temperatur bilden eine gute Möglichkeit der Quantifizierung von Hitze. Anpassungsmaßnahmen in Städten unter Berücksichtigung des Hitzestresses für Menschen sind notwendig.
Urologische Prostatakrebsvorsorge im Rahmen der Movember-Gesundheitsinitiative 2019 am Universitätsklinikum Frankfurt
Authors: Wenzel M. , Humke C. , Wicker S. , Mani J. , Engl T. , Hintereder G. , Vogl T. J. , Wild P. , Köllermann J. , Rödel C. , Asgharie S. , Theissen L. , Welte M. , Kluth L. A. , Mandel P. , Chun F. K. H. , Preisser F. , Becker A. 
Published: July 2020

Zusammenfassung

Hintergrund
Männer in Deutschland sterben früher als Frauen und nehmen weniger häufig Krebsvorsorgeuntersuchungen wahr.

Fragestellung
Ziel war die prospektive Evaluation einer „Movember-Gesundheitsinitiative“ am Universitätsklinikum Frankfurt (UKF) im November 2019.

Methoden
Im Rahmen der „Movember-Gesundheitsinitiative“ wurde allen männlichen Mitarbeitern des UKF ab dem 45. Lebensjahr und bei erstgradiger familiärer Vorbelastung eines Prostatakarzinoms ab dem 40. Lebensjahr im November 2019 gemäß S3-Leitlinien der Deutschen Gesellschaft für Urologie (DGU) eine Prostatakarzinom-Vorsorgeuntersuchung angeboten.

Ergebnisse
Insgesamt nahmen 14,4 % der Mitarbeiter teil. Eine familiäre Vorbelastung gaben insgesamt 14,0 % Teilnehmer an. Das mediane Alter betrug 54 Jahre. Der mediane PSA(prostataspezifisches Antigen)-Wert lag bei 0,9 ng/ml, der mediane PSA-Quotient bei 30 %. Bei 5 % (n = 6) zeigte sich ein suspekter Tastbefund in der DRU (digital-rektale Untersuchung). Nach Altersstratifizierung (≤ 50 vs. > 50 Lebensjahre) zeigten sich signifikante Unterschiede im medianen PSA-Wert (0,7 ng/ml vs. 1,0 ng/ml, p < 0,01) und der bereits zuvor durchgeführten urologischen Vorsorge (12,1 vs. 42,0 %, p < 0,01). Vier Teilnehmer (3,3 %) zeigten erhöhte Gesamt-PSA-Werte. Bei 32,2 % der Teilnehmer zeigte sich mindestens ein kontrollbedürftiger Befund. Insgesamt wurden 6 Prostatabiopsien durchgeführt. Hierbei zeigte sich in einem Fall ein intermediate-risk Prostatakarzinom (Gleason 3 + 4, pT3a, pPn1, pNx, R0).

Schlussfolgerungung
Im Rahmen der UKF-Movember-Gesundheitsinitiative 2019 konnten durch ein Vorsorgeangebot 121 Männer für eine Prostatakrebs-Vorsorge inklusive PSA-Testung gewonnen werden. Auffällige/kontrollbedürftige Befunde zeigten sich bei 32,2 %. Bei einem Mitarbeiter wurde ein therapiebedürftiges Prostatakarzinom entdeckt und therapiert.