bluuebunny/crossref_metadata_2025_split huggingface dataset:
Nicht‐unschuldiger Methylen‐Linker in verbrückten Lewis‐Paar‐ Initiatoren
Authors: Weger Michael , Grötsch Raphael K. , Knaus Maximilian G. , Giuman Marco M. , Mayer David C. , Altmann Philipp J. , Mossou Estelle , Dittrich Birger , Pöthig Alexander , Rieger Bernhard 
Published: May 2019

AbstractDie Deprotonierung tritt in der Regel als unerwünschte Nebenreaktion bei der Lewis‐Paar‐Polymerisation von Michael‐Akzeptoren auf, bei der die konjugierte Addition der Lewis‐Base an das säureaktivierte Monomer der gängige Initiationsmechanismus ist. Dies wurde auch für B‐P‐basierte verbrückte Lewis‐Paare (Bridged Lewis Pairs, BLPs) berichtet, die makrozyklische Additionsprodukte bilden. Wir konnten zeigen, dass bei Al‐P‐basierten BLPs die bisher unerwünschte Deprotonierung der wahrscheinliche Initiationsweg ist. In einer detaillierten Studie mit einer Reihe von Al‐P‐basierten BLPs unter Verwendung von Einkristalldiffraktometrie (Röntgen und Neutronen) und mechanistischen Untersuchungen (experimentell und rechnerisch) wurde eine aktive Rolle der Methylenbrücke aufgedeckt, die als Base für die α‐aziden Monomere agiert. Darüber hinaus bewiesen Polymerisationsstudien ein lebendes Verhalten in Kombination mit signifikant hohen Aktivitäten, engen Molmassenverteilungen und der Möglichkeit zur Copolymerisation.
Total Syntheses of Rhodomolleins XX and XXII: A Reductive Epoxide‐Opening/Beckwith–Dowd Approach
Authors: Yu Kuan , Yang Zhen‐Ning , Liu Chun‐Hui , Wu Shao‐Qi , Hong Xin , Zhao Xiao‐Li , Ding Hanfeng 
Published: May 2019

AbstractA new TiIII‐mediated reductive epoxide‐opening/ Beckwith–Dowd rearrangement process efficiently assembles the bicyclo[3.2.1]octane framework of highly oxidized grayanane diterpenoids. By incorporation of a Cu(tbs)2‐catalyzed (tbs=N‐tert‐butylsalicylaldiminato) intramolecular cyclopropanation, a diastereoselective oxidative dearomatization‐induced Diels–Alder cycloaddition and a MeReO3‐catalyzed Rubottom oxidation, this approach has enabled the first total syntheses of rhodomolleins XX and XXII in 23 and 22 steps, respectively.
Evaluation of electron beam‐induced crosslinking of poly(ε‐caprolactone)—Effect of elevated temperatures
Authors: Huang Ying , Gohs Uwe , Müller Michael Thomas , Zschech Carsten , Wiessner Sven 
Published: May 2019

ABSTRACTThe effect of elevated temperatures (40, 80, and 170 °C) on the electron beam (EB)‐induced crosslinking and degradation of poly(ε‐caprolactone) (PCL) in nitrogen atmosphere without adding crosslinking agents has been investigated. The increased mass average molecular mass of EB modified masticated PCL (mPCL) samples were measured by size exclusion chromatography. The sol–gel investigation showed that mPCL tended to dominating crosslinking at a temperature of 170 °C. At this temperature, the maximum gel content of 56% was observed for an EB treatment with a dose of 100 kGy. In addition, the ratio of chain scission density to density of crosslinked units amounted to 0.25. The dynamic rheological test demonstrated that EB treatment at 170 °C led to the most remarkable elasticity enhancement behavior with enhanced viscosity, modulus, and decreased loss factor (tan δ). The occurrence of branching structure was evidently detected by van Gurp–Palmen plot in combination with the Cole–Cole plot for dose values ≤50 kGy. Less δ and a broadened relaxation process can be observed due to the introduction of some branched structures into mPCL. The results of enhanced molar mass and gel content analysis were confirmed by the dynamic rheological measurements. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47866.
Formation mechanism of asymmetric porous polymer films by photoinduced phase separation in the presence of solvent
Authors: Yoshihara Hirokazu , Yamamura Masato 
Published: May 2019

ABSTRACTPhotoinduced phase separation in the presence of a nonreactive volatile solvent provides a simple, light‐tunable, and cost‐effective route for fabrications of porous polymer films. Here, we show that the short‐time (<10 s) ultraviolet irradiation of a photoreactive solution film promotes particular asymmetries in the composition and porosity across the thickness. Confocal Raman spectroscopy revealed that the compositional asymmetry is maximum at a certain critical light intensity. We discuss the film formation mechanism based on the light‐driven diffusion of the solvent and monomer. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47867.
Preparation and characterization of paraffin microcapsules for energy‐saving applications
Authors: Mert Mehmet Selçuk , Mert Hatice Hande , Yilmaz Gumus Cansu 
Published: May 2019

ABSTRACTA series of microencapsulated phase‐change materials (PCMs) with styrene–divinyl benzene shells composed of an n‐octadecane (OD or C18)–n‐hexadecane (HD or C16) mixture as the core were synthesized by an emulsion polymerization method. The effects of the core/shell ratio (C/S) and surfactant concentration (Csurf) on the thermal properties and encapsulation ratios of the PCMs were investigated. The chemical structures and morphological properties of the microcapsules were characterized by Fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy analysis, respectively. The characteristic peaks of the paraffin mixtures and shell material located in the FTIR spectrum of the microencapsulated PCMs proved that the encapsulation of the PCM mixture was performed successfully. The thermal properties of the paraffin microcapsules were determined by differential scanning calorimetry (DSC) and thermogravimetric analysis. DSC analysis demonstrated that the microcapsules containing the maximum amount of paraffin mixture (C/S = 2:1) and the minimum Csurf (45 mmol/L) had the highest latent heat value of 88 kJ/kg and a latent heat of temperature of 21.06°C. Moreover, the maximum encapsulation ratio of the paraffin mixture was found to be 56.77%. With respect to the analysis results, the encapsulated binary mixture, which consisted of OD–HD with a poly(styrene‐co‐divinyl benzene) shell, is a promising material for thermal energy storage applications operating at low temperatures, such as in the thermal control of indoor temperatures and air‐conditioning applications in buildings for desirable thermal comfort and energy conservation. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47874.
Synthesis and improved mechanical properties of twin‐mesogenic epoxy thermosets using siloxane spacers with different lengths
Authors: Harada Miyuki , Hirotani Mio , Ochi Mitsukazu 
Published: May 2019

ABSTRACTA series of twin‐mesogenic epoxy resins with siloxane (di‐, tri‐, and tetra‐siloxane) chain spacers of different lengths were successfully synthesized. Results showed that the melting point of the twin‐mesogenic epoxy monomers decrease by more than 50 °C due to the change of siloxane spacer length. In particular, the tri‐ and tetra‐incorporated siloxane twin‐mesogenic epoxy monomers showed a liquid crystalline (LC) phase below 100 °C during the cooling process. Epoxy thermosets with isotropic and smectic (Sm) LC phases were then prepared using an aromatic amine and the dependence on curing temperature was investigated. Furthermore, the relationship between the ordered network chain structure and mechanical properties was investigated. Results were compared with isotropic and Sm LC phases. The tensile strain and fracture energy in the Sm type LC thermosets increased without a decrease in the tensile modulus, and this occurred in all systems irrespective of siloxane spacer length. The maximum value of the fracture energy (283 kJ m−2) reached by LC thermosets with increased spacer lengths was twice as large as that using the alkyl chain spacer (144 kJ m−2). © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47891.
Water‐swellable, tough, and stretchable inorganic–organic sulfoaluminate cement/polyacrylamide double‐network hydrogel composites
Authors: Chu Y. Y. , Song X. F. , Zhao H. X. 
Published: May 2019

ABSTRACTEffectively improving the mechanical properties of the hydrogel can greatly broaden its application range. The design concept of forming a double‐network structure by organic–inorganic hybridization can greatly enhance the mechanical properties of traditional hydrogels. Here, a series of organic–inorganic double‐network (OIDN) polyacrylamide/(sulfoaluminate cement) (PAM/SAC) composite gels by solution polymerization were synthesized at room temperature. The OIDN composite gels not only retain the characteristics of water swelling but also exhibit excellent tensile properties (stress and strain are 12 MPa and 2500%, respectively) and compressive strength (stress and strain are 65 MPa and 80%, respectively). In the preparation process, a brittle inorganic network of hydrated sulfoaluminate (hydra‐SAC) and a ductile network of polyacrylamide (PAM) were formed by the manner of interpenetrating. The phase composition and thermal stability of the OIDN composite gels were characterized and determined by FTIR, XRD, SEM, and TGA, respectively. The effect of SAC on swelling and mechanical performance of the OIDN composite gels was also investigated. The results show that the use of SAC hybrid hydrogels can effectively improve the mechanical strength, and the OIDN composite gels are expected to be a potential grouting and plugging functional material. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47905.
Sustainable rigid polyurethane foams based on recycled polyols from chemical recycling of waste polyurethane foams
Authors: Shin Se‐Ra , Kim Han‐Na , Liang Jing‐Yu , Lee Sang‐Hyub , Lee Dai‐Soo 
Published: May 2019

ABSTRACTThe preparation and characteristics of rigid polyurethane foams (RPUFs) based on recycled polyol obtained by glycolysis of waste RPUF scraps from end‐of‐life refrigerators were investigated. To deactivate the amine adducts derived from isocyanates, the recycled product obtained after depolymerization was chemically modified via addition polymerization of propylene oxide. Two kinds of recycled polyols with different hydroxyl values and viscosity were blended with conventional virgin polyether polyol to prepare the RPUFs. The effects of the recycled polyols on the physical properties of RPUFs such as cell structures, compressive strength, thermal conductivity, and limiting oxygen index were discussed. It was found that the RPUFs from recycled polyols showed superior compressive strength, thermal insulation property, and self‐extinguishing property compared with conventional control foam. The results of this study reveal that the recycled polyols could be used as feedstock for RPUFs with superior performance. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47916.
Copper‐Catalyzed Alkylarylation of Unactivated Alkenes: Synthesis of 3‐Alkyl Indolines from N‐Allyl Anilines and Alkanes
Authors: Liang Deqiang , Huo Bojie , Dong Yongrui , Wang Yan , Dong Ying , Wang Baoling , Ma Yinhai 
Published: May 2019

AbstractA rare example of C(sp3)−H functionalization of simple alkanes with unactivated alkenes is presented. In the presence of a copper salt and di‐tert‐butyl peroxide (DTBP), N‐allyl anilines underwent exo‐selective alkylation/cyclization cascade with unactivated alkenic bonds as radical acceptors and simple alkanes as radical precursors, providing a direct access to 3‐alkyl indolines. The present protocol features simple operation, broad substrate scope and great exo selectivity.
Long Afterglow Room‐Temperature Phosphorescence from Nanopebbles: A Urea Pyrolysis Product
Authors: Patir Khemnath , Gogoi Sonit Kumar 
Published: May 2019

AbstractMaterials having long afterglow are highly sought after for various applications such as light‐emitting diodes, security signs and bioimaging. Herein, we report a simple, low‐cost synthesis of a purely organic room‐temperature phosphorescent nanomaterial with a pebble‐like structure by heating urea, a biocompatible and easily available precursor, at 200 °C with a high phosphorescence lifetime of 1.0365 s and a visible afterglow for up to 10 s. This urea derived phosphorescent nanocomposite (UPNC) can be mixed with commercially available acrylic paint base and common gum, which can be readily used as a phosphorescent pigment.
Robust maneuver strategy of observer for bearings‐only tracking
Authors: He Renke , Chen Shuxin , Wu Hao , Liu Zhuowei , Chen Jianhua 
Published: May 2019

AbstractFor the bearings‐only tracking problem, an observer's maneuver can enhance the accuracy of estimation. However, it may be idealistic to expect the observer to move in the free space during reconnaissance missions, because threats in the motion space can restrict the motion space of the observer. In this study, considering the constraint of threats avoidance on the motion space of the observer, an optimal maneuver strategy was proposed. Firstly, the adaptive cubature Kalman Filter method was established to improve the robustness and accuracy of state estimation. Then the finite horizon Markov Decision VProcess approach was improved to generate the optimal maneuver policy, in which the quantization method was responsible for discretizing the process and providing the transition matrix for Markov Decision Process, and the novel reward function was proposed as the criterion for optimization. Finally, the framework of the method was established. The numerical results verified the feasibility and advantage of the proposed method by comparing them with state of the art research in the field.
Scale effects of topographic ruggedness on precipitation over Qinghai‐Tibet Plateau
Authors: Lu Ning 
Published: May 2019

AbstractDue to the complex topography in mountainous areas, the pattern of precipitation is impacted by the topographic ruggedness (TR) that is characterized from Digital Elevation Model and thus scale‐dependent. Scale effects on the precipitation–TR relationship have not been well known in the Qinghai‐Tibet Plateau. Based on station measurements of precipitation in the domain, this study uses the quantile regression method to investigate the response of precipitation quantiles in summer and winter to the TR changes at different spatial scales. It is found that the scale variations impede the validity analysis of precipitation–TR relations. Neither too large (>100 km) or too small (<1 km) scales are suitable for exploring summer precipitation, and the scales are better less than 30 km for high winter precipitation. The analyses address that the precipitation–TR relations depend on appropriate spatial scales, which is important for statistical downscaling and model projection of precipitation in the Qinghai‐Tibet Plateau.
Optimal inventory threshold for a dynamic service make‐to‐stock system with strategic customers
Authors: Zhang Xuelu , Wang Jinting 
Published: May 2019

AbstractWe consider a make‐to‐stock production system with one product type, dynamic service policy, and delay‐sensitive customers. To balance the waiting cost of customers and holding cost of products, a dynamic production policy is adopted. If there is no customer waiting in the system, instead of shutting down, the system operates at a low production rate until a certain threshold of inventory is reached. If the inventory is empty and a new customer emerges, the system switches to a high production rate where the switching time is assumed to be exponentially distributed. Potential customers arrive according to the Poisson process. They are strategic in the sense that they make decisions on whether to stay for product or leave without purchase on the basis of on their utility value and the system information on whether the number of products is observable to customers or not. The strategic behavior is explored, and a Stackelberg game between production manager and customers is formulated where the former is the game leader. We find that the optimal inventory threshold minimizing the cost function can be obtained by a search algorithm. Numerical results demonstrate that the expected cost function in an observable case is not greater than that in an unobservable case. If a customer's delay sensitivity is relatively small, these two cases are entirely identical. With increasing of delay sensitivity, the optimal inventory threshold might be positive or zero, and hence, a demarcation line is depicted to determine when a make‐to‐stock policy is advantageous to the manager.
Binding interaction study on human serum albumin with bactericidal gold nanoparticles synthesized from a leaf extract of Musa balbisiana: a multispectroscopic approach
Authors: Maji Anukul , Beg Maidul , Das Somnath , Sahoo Nandan Kumar , Jha Pradeep K. , Islam Md. Maidul , Hossain Maidul 
Published: May 2019

AbstractThis study describes the eco‐friendly, low‐cost and room‐temperature synthesis of gold nanoparticles from Musa balbisiana leaf extract, which acts as both reducing and stabilizing agent, and characterized by ultraviolet−visible (UV–vis) light spectroscopy, fourier transform infrared (FTIR) spectroscopy, field emission scanning electron microscopy (FE‐SEM), analytical transmission electron microscopy (TEM), energy‐dispersive X‐ray spectroscopy (EDAX) and dynamic light scattering (DLS) instruments. These nanoparticles showed an average diameter of 33.83 ± 3.39 nm, which was confirmed from the size distribution histogram. The bactericidal activity of these nanoparticles was confirmed using bacteria Escherichia coli and Staphylococcus aureus at 1 and 2 nM minimum inhibitory concentrations, respectively. The interaction between nanoparticles and human serum albumin (HSA) was investigated, as this plays significant roles in biological systems. The nature of interaction, binding parameters and structural variation of HSA in the presence of these nanoparticles have been evaluated using several useful spectroscopic approaches such as UV–vis, FTIR, time‐resolved and steady‐state fluorescence, and circular dichroism in addition to the measurement of zeta potential. This interaction study revealed that static quenching occurs in this process with minimal alteration in the secondary structure, but the native structure of HSA remained unaltered. The binding constant and thermodynamic parameters of this interaction process were also evaluated.
Achieving Sustainable Development Goals in the global food sector: A systematic literature review to examine small farmers engagement in contract farming
Authors: Vabi Vamuloh Vilbert , Panwar Rajat , Hagerman Shannon M. , Gaston Christopher , Kozak Robert A. 
Published: May 2019

AbstractContract farming, a common strategy among multinational companies in the global food sector, can help achieve Sustainable Development Goals (SDGs). However, it largely depends on whether or not small farmers can participate in contract farming programs, which has been a major issue globally. Our main objective in this systematic literature review is to identify the factors that drive small farmer participation in contract farming. We analyze 97 peer‐reviewed journal articles published between 1977 and 2017. Our review finds that farmer demographic characteristics, farm structure, farmer characteristics, and farmer attitudes influence participation in contract farming although causal mechanisms remain ambiguous. We therefore suggest the need for more comprehensive methodologies to examine small farmer participation in contract farming. In the meantime, global food sector companies must consider these factors as they develop plans toward achieving SDGs.
Does doing “good” always translate into doing “well”? An eco‐efficiency perspective
Authors: Broadstock David C. , Managi Shunsuke , Matousek Roman , Tzeremes Nickolaos G. 
Published: May 2019

AbstractDoes doing “good” always translate into doing “well”? Debate over the “value” of corporate social responsibility is high on the agenda of corporate finance research. Deeper understanding is required on managers' incentives to pursue and implement corporate social responsibility related strategies, as is more thorough comprehension of the effect of these strategies to firms' performance levels as well as shareholder and wider stakeholder valuations of the firm. This paper provides a new lens by approaching the subject from a different methodological paradigm, grounded in the performance benchmarking methods more commonly applied in operational research. In so doing, we provide novel evidence of the effect of corporate choices on environmental, social, and governance (ESG) strategic investment compliance (i.e., doing good) to firms' eco‐efficiency levels (doing well). In brief, our empirical findings suggest that ESG and firm's eco‐performance are nonlinearly related. Specifically, advanced ESG policies and disclosure levels are associated with a positive affect to firms' eco‐efficiency levels, but only up to a point, after which the effect becomes “neutral,” that is, ESG demonstrates a visible pattern of diminishing marginal returns. Thus, we may humbly conclude that a firm may “do well” by doing good, but it is not clear they should ever expect to “do great” just by “doing good.” The threshold at which this “neutrality” appears varies systematically with the characteristics of the sector in which the firm is operating, as well as dimensions of board diversity. Finally, it is evident that ESG implementation choices can be a source of managerial agency problems.
Practical management in Wolcott‐Rallison syndrome with associated hypothyroidism, neutropenia, and recurrent liver failure: A case report
Authors: Lundgren Markus , De Franco Elisa , Arnell Henrik , Fischler Björn 
Published: May 2019

Key Clinical MessageWolcott‐Rallison syndrome is a rare genetic syndrome of neonatal diabetes, liver failure, and growth retardation. We present a case with a EIF2AK3 p.(Arg902Ter) mutation, additionally complicated by hypothyroidism, impaired renal function, and exocrine pancreas insufficiency, focusing on clinical management. For its optimization, thorough care of multiple organ systems is needed.
Cathode Framework of Nanostructured Titanium Nitride/Graphene for Advanced Lithium–Sulfur Batteries
Authors: Zeng Wenduo , Cheng Mark Ming‐Cheng , Ng K. Y. Simon 
Published: May 2019

AbstractNanostructured titanium nitride (TiN) and graphene composite electrodes have been fabricated through a facile method, combining ultrasonication with melt‐diffusion of elemental sulfur. Nanostructured TiN particles and tube arrays mechanically mixed with graphene substrate leads to the formation of a porous, stabilized composite structure with enhanced electrical conductivity. Such a framework may facilitate accessibility of electrolyte and fast transfer of charges. The specific capacities of the Li−S batteries with TiN nanotubes/graphene and TiN nanoparticles/graphene composites are 1229 and 1085 mAh g−1, respectively, after 180 cycles under a 0.1 C rate, which are significantly better than pure TiN nanostructures. The specific capacity and capacity retention were investigated as a function of the TiN nanotube to graphene ratio. The optimal ratio was found to be 1 : 1 TiN/graphene, with the highest capacity retention of 87.5 % after 180 cycles. This 3D hybrid structure may provide a balance of high specific capacity and electrochemical stability, allowing durable and efficient energy storage and conversion over a long cycle life.