bluuebunny/crossref_metadata_2025 huggingface dataset:
Pinning of the Fermi Level in CuFeO2 by Polaron Formation Limiting the Photovoltage for Photochemical Water Splitting
Authors: Hermans Yannick , Klein Andreas , Sarker Hori Pada , Huda Mohammad N. , Junge Henrik , Toupance Thierry , Jaegermann Wolfram
Published: January 2020

CuFeO2 is recognized as a potential photocathode for photo(electro)chemical water splitting. However, photocurrents with CuFeO2‐based systems are rather low so far. In order to optimize charge carrier separation and water reduction kinetics, defined CuFeO2/Pt, CuFeO2/Ag, and CuFeO2/NiOx(OH)y heterostructures are made in this work through a photodeposition procedure based on a 2H CuFeO2 hexagonal nanoplatelet shaped powder. However, water splitting performance tests in a closed batch photoreactor show that these heterostructured powders exhibit limited water reduction efficiencies. To test whether Fermi level pinning intrinsically limits the water reduction capacity of CuFeO2, the Fermi level tunability in CuFeO2 is evaluated by creating CuFeO2/ITO and CuFeO2/H2O interfaces and analyzing the electronic and chemical properties of the interfaces through photoelectron spectroscopy. The results indicate that Fermi level pinning at the Fe3+/Fe2+ electron polaron formation level may intrinsically prohibit CuFeO2 from acquiring enough photovoltage to reach the water reduction potential. This result is complemented with density functional theory calculations as well.
Sensitive Direct Converting X‐Ray Detectors Utilizing Crystalline CsPbBr3 Perovskite Films Fabricated via Scalable Melt Processing
Authors: Matt Gebhard J. , Levchuk Ievgen , Knüttel Judith , Dallmann Johannes , Osvet Andres , Sytnyk Mykhailo , Tang Xiaofeng , Elia Jack , Hock Rainer , Heiss Wolfgang , Brabec Christoph J.
Published: January 2020

Here the fabrication of an inorganic metal‐halide perovskite CsPbBr3 based X‐ray detector is reported utilizing a simple, scalable, and cost‐sensitive melt processing directly on substrate of any size. X‐ray diffraction analysis on the several 100 mm thick melt processed films confirms crystalline domains in the cm2 range. The CsPbBr3 film features a resistance of 8.5 GΩ cm and a hole mobility of 18 cm2 V−1 s−1. An X‐ray to current conversion rate of 1450 µC Gyair−1 cm−2 at an electric field of 1.2 × 104 V cm−1 and a detection limit in the sub µGyair s−1 regime is demonstrated. The high crystallinity and chemical purity of the melt processed CsPbBr3 films are suggested to be responsible for a performance which is on par to current state‐of‐the‐art Cd(Zn)Te based X‐ray detector technology.
All‐Optical Control of Microfiber Knot Resonator Based on 2D Ti2CTx MXene
Authors: Wu Qing , Huang Weichun , Wang Yunzheng , Wang Cong , Zheng Zheng , Chen Hong , Zhang Meng , Zhang Han
Published: January 2020

All‐optical devices based on 2D materials have attracted great attention for desirable applications, such as communications and signal processing. However, the previously reported all‐fiber all‐optical devices utilizing the interferometer structures greatly limit their practical applications due to the poor anti‐interference ability and slow modulation rate. In this work, an all‐optical device has been demonstrated based on a microfiber knot resonator (MKR) deposited with Ti2CTx MXene, exhibiting a large photothermal conversion efficiency and high thermal conductivity. Experimental results show that the proposed all‐optical device is capable of producing a high‐performance phase and intensity modulation with a high modulation efficiency, fast response time, and good stability. Therefore, it is anticipated that the MKR‐based all‐optical devices based on 2D materials can pave the way to a new design of high‐performance all‐optical devices and have great potentials in the future optical information processing.
Electrically Switchable Color Tags Based on Active Liquid‐Crystal Plasmonic Metasurface Platform
Authors: Sharma Mukesh , Hendler Netta , Ellenbogen Tal
Published: January 2020

Recent demonstrations of metasurfaces show their great potential to realize flat and multifunctional optical elements, viable for many new device applications. Yet, a major frontier in this field is to develop active, tunable, and reconfigurable metasurface platforms. These are highly desirable in modern technologies that require dynamic modulation of light. To achieve this goal, in this work an active liquid‐crystal (LC) plasmonic metasurface integrated system is developed and studied. It is specifically used to demonstrate electrically switchable plasmonic‐metasurface‐based color tags. The active tags utilize the ability to rotate the polarization of incident light, by application of an external electric field on twisted nematic liquid crystal configuration. Combined with the wavelength and polarization‐selective response of the metasurface, it allows to obtain electrically controlled transmission colors potentially spanning the entire visible spectrum. It is experimentally demonstrated that the dynamic wavelength shift in the devices is greater than 100 nm at a low driving voltage varying from 0 to 5 V. These experimental results indicate the potential of active LC‐plasmonic metasurface platforms to realize the next‐generation dynamic optical devices.
Chameleon‐Like Thermochromic Luminescent Materials with Controllable Response Behaviors for Multilevel Security Printing
Authors: Ma Yun , Dong Yafang , Liu Suyi , She Pengfei , Lu Jinyu , Liu Shujuan , Huang Wei , Zhao Qiang
Published: January 2020

Materials exhibiting reversible changes of their photoluminescence properties upon exposure to heat have an immense potential in various advanced photonic applications. Particularly, the control over an on‐demand response of thermochromic luminescent materials (TLMs) similar to a chameleon is of great importance. However, it is still difficult and challenging to achieve it. Therefore, this paper reports a simple and effective way to construct TLMs, which involves the incorporation of the metal–ligand complexes into polyethylene glycol (PEG). Ratiometric or off–on response modes of these TLMs can be tuned by incorporating metal complexes based on either Zn2+ or Co2+ into PEG and by taking advantage of reversible metal–ligand coordination, dissociation, or excited‐state conformation changes of the resulting materials. Moreover, by choosing PEG matrices with different molecular weights, the thermochromic transition temperatures of these TLMs can be tuned. It is also demonstrated that the controllable response behavior of these chameleon‐like TLMs can be used in applications related to real‐life anti‐counterfeiting and security printing. This work opens novel opportunities for the development of smart materials with controllable responses useful for advanced photonic applications.
Property Predictions for Dual‐Phase Steels Using Persistent Homology and Machine Learning
Authors: Wang Zhi‐Lei , Ogawa Toshio , Adachi Yoshitaka
Published: January 2020

Materials informatics seeks to establish microstructure–property linkage hidden in materials. A topological analysis of persistent homology and machine learning are combined to model microstructure–property linkage for dual‐phase steels, where a descriptor of persistent images is employed to characterize the microstructure and stress–strain curves are predicted using an artificial neural network. The correlations between stress and microstructure descriptor of persistent images are estimated using sensitivity analysis, Bayesian information criterion, and the least absolute shrinkage and selection operator (LASSO), respectively. The three methods identify consistent correlations, indicating that persistent images are capable of interpreting properties. Furthermore, the established artificial neural network model exhibits good accuracy and satisfactory property prediction performance. The proposed approach is expected to provide a new avenue for materials informatics and thus promote materials research.
A Soft Transporter Robot Fueled by Light
Authors: Pilz da Cunha Marina , Ambergen Sebastiaan , Debije Michael G. , Homburg Erik F. G. A. , den Toonder Jaap M. J. , Schenning Albert P. H. J.
Published: January 2020

Mobile organisms with ability for locomotion and transportation, such as humans and other animals, utilize orchestrated actuation to perform actions. Mimicking these functionalities in synthetic, light‐responsive untethered soft‐bodied devices remains a challenge. Inspired by multitasking and mobile biological systems, an untethered soft transporter robot with controlled multidirectional locomotion with the ability of picking up, transporting, and delivering cargo driven entirely by blue light is created. The soft robot design is an ensemble of light‐responsive liquid crystalline polymers that can harness motion either collectively or individually to obtain a high degree of motion control for the execution of advanced tasks in a dry environment. Through orchestrated motion of the device's “legs”, single displacement strides, which exceed 4 mm and can be taken in any direction, allow for locomotion around objects. Untethered cargo transportation is demonstrated by a pickup and release mechanism using the device's “arms”. This strategy demonstrates the constructive harnessing of orchestrated motion in assemblies of established actuators, performing complex functions, mimicking constructive behavior seen in nature.
High‐Valence Nickel Single‐Atom Catalysts Coordinated to Oxygen Sites for Extraordinarily Activating Oxygen Evolution Reaction
Authors: Li Yaguang , Wu Zhong‐Shuai , Lu Pengfei , Wang Xiao , Liu Wei , Liu Zhibo , Ma Jingyuan , Ren Wencai , Jiang Zheng , Bao Xinhe
Published: January 2020

Single‐atom catalysts (SACs) are efficient for maximizing electrocatalytic activity, but have unsatisfactory activity for the oxygen evolution reaction (OER). Herein, the NaCl template synthesis of individual nickel (Ni) SACs is reported, bonded to oxygen sites on graphene‐like carbon (denoted as Ni‐O‐G SACs) with superior activity and stability for OER. A variety of characterizations unveil that the Ni‐O‐G SACs present 3D porous framework constructed by ultrathin graphene sheets, single Ni atoms, coordinating nickel atoms to oxygen. Consequently, the catalysts are active and robust for OER with extremely low overpotential of 224 mV at current density of 10 mA cm−2, 42 mV dec−1 Tafel slope, oxygen production turn over frequency of 1.44 S−1 at 300 mV, and long‐term durability without significant degradation for 50 h at exceptionally high current of 115 mA cm−1, outperforming the state‐of‐the‐art OER SACs. A theoretical simulation further reveals that the bonding between single nickel and oxygen sites results in the extraordinary boosting of OER performance of Ni‐O‐G SACs. Therefore, this work opens numerous opportunities for creating unconventional SACs via metal–oxygen bonding.
H‐Bonds‐Assisted Molecular Order Manipulation of Nonfullerene Acceptors for Efficient Nonannealed Organic Solar Cells
Authors: Liu Xuan , Wang Xuchao , Xiao Yejun , Yang Qing , Guo Xin , Li Can
Published: January 2020

Various substituents have been incorporated into nonfullerene acceptors (NFAs) to modulate absorption scopes and energy levels for boosting efficiencies of organic solar cells (OSCs). The manipulation of the NFAs' molecular order and crystallinity via those substitutions is equally crucial to OSC performances, which yet remains interesting and challenging. The hydroxyl group, which can potentially form strong intermolecular hydrogen bonds (H‐bonds) for improving molecular arrangements, has, however, never been considered. Herein, two hydroxyl‐functionalized NFAs, IT‐OH with one hydroxyl and IT‐DOH with two hydroxyls, are synthesized to tune the molecular packing and crystallinity. The ordered molecular arrangement and higher crystallinity are observed for the IT‐OH and IT‐DOH than the parent ITIC. This is assigned to the formation of intermolecular H‐bonds induced by the hydroxyls, which elongates molecular conjugated planes leading to long‐range‐ordered structures via π–π stacking. By the appropriate crystallinity and miscibility with donor polymer, an IT‐DOH‐based nonannealed OSC affords an efficiency of 12.5% with good device stability. This work provides a promising strategy to tune the molecular packing and crystallinity to design NFAs by introducing hydroxyl groups.
Genome‐wide SNP typing of ancient DNA: Determination of hair and eye color of Bronze Age humans from their skeletal remains
Authors: Schmidt Nicole , Schücker Katharina , Krause Ina , Dörk Thilo , Klintschar Michael , Hummel Susanne
Published: January 2020

Objective

A genome‐wide high‐throughput single nucleotide polymorphism (SNP) typing method was tested with respect of the applicability to ancient and degraded DNA. The results were compared to mini‐sequencing data achieved through single base extension (SBE) typing. The SNPs chosen for the study allow to determine the hair colors and eye colors of humans.

Material and methods

The DNA samples were extracted from the skeletal remains of 59 human individuals dating back to the Late Bronze Age. The 3,000 years old bones had been discovered in the Lichtenstein Cave in Lower Saxony, Germany. The simultaneous typing of 24 SNPs for each of the ancient DNA samples was carried out using the 192.24 Dynamic Array™ by Fluidigm®.

Results

Thirty‐eight of the ancient samples (=64%) revealed full and reproducible SNP genotypes allowing hair and eye color phenotyping. In 10 samples (=17%) at least half of the SNPs were unambiguously determined, in 11 samples (=19%) the SNP typing failed. For 23 of the 59 individuals, a comparison of the SNP typing results with genotypes from an earlier performed SBE typing approach was possible. The comparison confirmed the full concordance of the results for 90% of the SNP typings. In the remaining 10% allelic dropouts were identified.

Discussion

The high genotyping success rate could be achieved by introducing modifications to the preamplification protocol mainly by increasing the DNA input and the amplification cycle number. The occurrence of allelic dropouts indicates that a further increase of DNA input to the preamplification step is desirable.
Symptomatic infrarenal aortic aneurysm sac expansion 5 years post‐endovascular repair without an identifiable endoleak
Authors: Derboghossian Teal , Cavaye Thomas , Quinn Simon , Pinto Nigel
Published: January 2020

A 71‐year‐old male presented with a symptomatic expanding 11 cm infrarenal aortic aneurysm 5 years post‐endovascular aortic repair. Duplex ultrasound and angiography showed no identifiable endoleak but confirmed an enlarging aneurysm sac with a new saccular configuration. The ultrasound findings were particularly unusual in that the aneurysm sac was a mixture of hardened echogenic material and an anechoic fluid‐like substance, with the echogenic material appearing to float around the sac with gravitational dependence. Open surgical intervention was performed. The aneurysm appeared pressurised with forceful expulsion of the sac contents post‐incision, though again no endoleak was identified. The sac contents were confirmed as a mixture of clear fluid and hardened haematoma. At 6 weeks follow‐up there was complete return of the aneurysm sac almost to its pre‐open surgery state. Multiple endoleak theories were considered from initial imaging through to follow‐up.
Clinical and Molecular Aspects of Senataxin Mutations in Amyotrophic Lateral Sclerosis 4
Authors: Grunseich Christopher , Patankar Aneesh , Amaya Joshua , Watts Jason A. , Li Dongjun , Ramirez Prisila , Schindler Alice B. , Fischbeck Kenneth H. , Cheung Vivian G.
Published: January 2020

Objective

To determine the clinical and molecular features in patients with amyotrophic lateral sclerosis 4 (ALS4) due to mutations in the senataxin (SETX) gene and to develop tools for evaluating SETX variants.

Methods

Our study involved 32 patients, including 31 with mutation in SETX at c.1166 T>C (p.Leu389Ser) and 1 with mutation at c.1153 G>A (p.Glu385Lys). Clinical characterization of the patients included neurological examination, blood tests, magnetic resonance imaging (MRI), and dual‐energy x‐ray absorptiometry (DEXA). Fibroblasts and motor neurons were obtained to model the disease and characterize the molecular alteration in senataxin function.

Results

We report key clinical features of ALS4. Laboratory analysis showed alteration of serum creatine kinase and creatinine in the Leu389Ser ALS4 cohort. MRI showed increased muscle fat fraction in the lower extremities, which correlates with disease duration (thigh fat fraction R2 = 0.35, p = 0.01; lower leg fat fraction R2 = 0.49, p < 0.01). DEXA measurements showed lower extremities are more affected than upper extremities (average fat z scores of 2.1 and 0.6, respectively). A cellular assay for SETX function confirmed that like the Leu389Ser mutation, the Glu385Lys variant leads to a decrease in R loops, likely from a gain of function.

Interpretation

We identified clinical laboratory and radiological features of ALS4, and hence they should be monitored for disease progression. The molecular characterization of R‐loop levels in patient‐derived cells provides insight into the disease pathology and assays to evaluate the pathogenicity of candidate mutations in the SETX gene. ANN NEUROL 2020;87:547–555
Integrating Allyl Electrophiles into Nickel‐Catalyzed Conjunctive Cross‐Coupling
Authors: Tran Van T. , Li Zi‐Qi , Gallagher Timothy J. , Derosa Joseph , Liu Peng , Engle Keary M.
Published: January 2020

Allylation and conjunctive cross‐coupling represent two useful, yet largely distinct, reactivity paradigms in catalysis. The union of these two processes would offer exciting possibilities in organic synthesis but remains largely unknown. Herein, we report the use of allyl electrophiles in nickel‐catalyzed conjunctive cross‐coupling with a non‐conjugated alkene and dimethylzinc. The transformation is enabled by weakly coordinating, monodentate aza‐heterocycle directing groups that are useful building blocks in synthesis, including saccharin, pyridones, pyrazoles, and triazoles. The reaction occurs under mild conditions and is compatible with a wide range of allyl electrophiles. High chemoselectivity through substrate directivity is demonstrated by the facile reactivity of the β‐γ alkene of the starting material, whereas the ϵ‐ζ alkene of the product is preserved. The generality of this approach is further illustrated through the development of an analogous method with alkyne substrates. Mechanistic studies reveal the importance of the dissociation of the weakly coordinating directing group to allow the allyl moiety to bind and facilitate C(sp3)−C(sp3) reductive elimination.
Effects of dual‐crosslinking networks on shape memory performance of polynorbornene
Authors: Gong Xiaowen , Yin Hao , Zhang Maolin , Shi Xinyan
Published: January 2020

In this article, Polynorbornene (PNB)/Zinc dimethacrylate (ZDMA)/Dicumyl peroxide (DCP) composites can form dual‐crosslinking networks, which contain an ionic crosslinking network, and a part of the C─C covalent crosslinking network. DCP was used to initiate the polymerization of ZDMA to form ionic crosslinking bonds. With the increase of ZDMA, the total crosslink density (Vr) and ionic crosslink density (Vr2) increased. DCP was consumed in ZDMA polymerization, which made the PNB reduce the covalent crosslinking networks. Leading to the covalent crosslink density (Vr1) decreased. Compared with covalent crosslinking network, the dual‐crosslinking networks stored more energy when deformed, provided better restoring force and a higher shape recovery ratio for materials. When ZDMA exceeded 3.9 wt%, the ZDMA aggregates hindered the movement of molecular chains leading to the shape recovery ratio slightly decreased. When ZDMA was 2.4 wt%, the composite had an optimum shape fixing and shape recovery ratio. This article provided the experimental basis for the research of PNB dual‐crosslinking networks, also widened the research of PNB shape memory materials. © 2020 Wiley Periodicals Inc. J. Appl. Polym. Sci. 2020, 137, 48955.
Compatibilities and properties of poly lactide/poly (methyl acrylate) grafted chicken feather composite: Effects of graft chain length
Authors: Chen Sikai , Hori Naruhito , Kajiyama Mikio , Takemura Akio
Published: January 2020

Surface modified poly(methyl acrylate) (PMA) grafted chicken feather fiber was applied as a reinforcement for polylactide (PLA)‐based composite film. The PMA grafted feather fiber with different PMA lengths were obtained for surface initiated Cu(0)‐mediated reversible‐deactivation radical polymerization. PLA‐based composite films with different unmodified or PMA‐grafted chicken feather fiber loading were prepared by solvent casting. Grafting PMA onto feather fiber enhanced interfacial bonding. Cracks and voids between matrix and fiber were eliminated. Thermal stability of these films also improved after introducing PMA. Feather fiber with high graft ratio showed worse dispersity in PLA due to its self‐aggregation. The heterogeneous nucleation agent behavior of feather grafted with longer PMA was also suppressed. Tensile tests showed that after modification, tensile strength and modulus was able to increase twice at 20% fiber loading. However, increasing PMA length improved break elongation but strength and modulus would drop slightly. These results indicated that grafting short PMA chain onto feather fiber surface was an effective and optimized method to improve dispersity and mechanical properties especially for higher filler loading.
Enhanced dielectric properties of sandwich‐structured biaxially oriented polypropylene by grafting hyper‐branched aromatic polyamide as surface layers
Authors: Han Chengcheng , Zhang Xianhong , Chen Dong , Ma Yuhong , Zhao Changwen , Yang Wantai
Published: January 2020

This work represents multilayer films with sandwich structure by grafting hyper‐branched aromatic polyamide (HBP) on both sides of biaxially oriented polypropylene (BOPP) (HBPBOPPHBP). BOPP serves as the middle layer to offer high breakdown strength and HBP acts as surface layers to boost the dielectric constant. As a result, the dielectric constant increases significantly from 2.2 of control BOPP to 5.5 (almost increased 1.5 times) after grafting 2.06 μm HBP surface layers, while the dielectric loss still remains at a very low level (<0.03). In addition, all HBPBOPPHBP sandwich‐structured films show higher charge energy density than that of unmodified BOPP. For instance, the discharge energy density of HBPBOPPHBP (1‐20‐1) film is up to 2.38 J/cm3 at an applied electric field of 400 kV/mm, which increases about 36% over that of pure BOPP (i.e., 1.75 J/cm3). Meanwhile, charge–discharge efficiency retains about 90%. This work offers a simple strategy to fabricate polymer‐based high performance dielectric composites.
Predictions of electrical percolation of graphene‐based nanocomposites by the three‐dimensional Monte Carlo simulation
Authors: Liu Yue , Wu Chen , Zhou Huanfeng , Liu Ping , Liu Caixia , Wu Hao , Zhao Junnan , Zhang Yugang , Ma Yuanming , Huang Ying , Song Aiguo , Ge Yunjian
Published: January 2020

Disk model is usually used to represent graphene nanoplatelets (GNPs) which are considered as frame‐like structure with edges and corners, and it has lack of quantitative accuracy. In order to minimize error caused by morphology, distribution, and interaction between GNPs and matrix, square and folded plate models were constructed to predict the percolation volume fraction (ϕc) of GNPs‐based nanocomposites by calculating connection possibility. Meanwhile, disk model is used for comparison. The results revealed that the ϕc of square and folded plate models is smaller than that of disk model with consistent parameters, and it is concluded that the ϕc of GNPs‐based nanocomposites predicted by disk model should be higher than that of experimental. The correctness of mixed model of square and folded plate is also verified by experimental. Due to the agglomeration of GNPs under the actual situation, the result of simulation is slightly smaller than that of experiment.
KOtBu‐Catalyzed Michael Addition Reactions Under Mild and Solvent‐Free Conditions
Authors: Thiyagarajan Subramanian , Krishnakumar Varadhan , Gunanathan Chidambaram
Published: January 2020

Designed transition metal complexes predominantly catalyze Michael addition reactions. Inorganic and organic base‐catalyzed Michael addition reactions have been reported. However, known base‐catalyzed reactions suffer from the requirement of solvents, additives, high pressure and also side‐reactions. Herein, we demonstrate a mild and environmentally friendly strategy of readily available KOtBu‐catalyzed Michael addition reactions. This simple inorganic base efficiently catalyzes the Michael addition of underexplored acrylonitriles, esters and amides with (oxa‐, aza‐, and thia‐) heteroatom nucleophiles. This catalytic process proceeds under solvent‐free conditions and at room temperature. Notably, this protocol offers an easy operational procedure, broad substrate scope with excellent selectivity, reaction scalability and excellent TON (>9900). Preliminary mechanistic studies revealed that the reaction follows an ionic mechanism. Formal synthesis of promazine is demonstrated using this catalytic protocol.
Stabilization of a new commensurate/incommensurate fractional order chaotic system
Authors: Gholamin P. , Sheikhani A.H. Refahi , Ansari A.
Published: January 2020

In the current article, agreeing on the stability theory of fractional order systems, the conditions for the asymptotic stability of nonlinear fractional order systems are presented. We discuss the stabilization of new fractional order chaotic system where the state equations contain the same or different fractional orders. Then we design a control strategy for stabilization of new fractional order chaotic system. Our aim is to stabilize the unstable equilibrium points of fractional order chaotic systems by planning a fit linear state feedback controller. In the following, a comparison between linear state feedback controller and sliding mode control for commensurate and incommensurate new fractional order chaotic systems is conducted. Numerical simulations approve the validity of the presented results.
Control charts for monitoring ship operating conditions and CO2 emissions based on scalar‐on‐function regression
Authors: Capezza Christian , Lepore Antonio , Menafoglio Alessandra , Palumbo Biagio , Vantini Simone
Published: January 2020

To respond to the compelling air pollution programs, shipping companies are nowadays setting‐up on their fleets modern multisensor systems that stream massive amounts of observational data, which can be considered as varying over a continuous domain. Motivated by this context, a novel procedure is proposed, which extends classical multivariate techniques to the monitoring of multivariate functional data and a scalar quality characteristic related to them. The proposed procedure is shown to be also applicable in real time and is illustrated by means of a real‐case study in the maritime field on the continuous monitoring of operating conditions (ie, the multivariate functional data) and total CO2 emissions (ie, the scalar quality characteristic) at each voyage of a cruise ship. The real‐time monitoring is particularly helpful for promptly supporting managerial decision making by indicating if and when an anomaly occurs during the navigation.
Optimization of maintenance policy under warranty length‐based demand with consideration of both manufacturer and buyer satisfaction
Authors: Salmasnia Ali , Baratian Maryam
Published: January 2020

This study proposes a model to optimize postsale services consisting of four factors: (a) the basic warranty length, (b) the extended warranty length, (c) the preventive maintenance level, and (d) the preventive maintenance interval. Furthermore, consumer demand for the product and extended warranty are considered as functions of the length of the basic warranty and extended warranty periods, respectively. Because buyer dissatisfaction with a product can lead to the loss of potential buyers and the switch of current customers to the competitors, both manufacturer and buyer satisfaction are considered in the model. Three comparative studies are done for showing the effectiveness of the model. The first one compares the results of simultaneous optimization from the two perspectives of manufacture and customer with the single‐objective optimization results from each of the mentioned viewpoints. The second comparison studies the provision of extended warranty contract in the proposed model, and the third comparison investigates the effect of preventive maintenance actions on the results of the model.
Enzymatic depolymerization of industrial lignins by laccase‐mediator systems in 1,4‐dioxane/water
Authors: Dillies Justine , Vivien Céline , Chevalier Mickael , Rulence Alexandre , Châtaigné Gabrielle , Flahaut Christophe , Senez Vincent , Froidevaux Renato
Published: January 2020

Lignin is the second most abundant polymer after cellulose in lignocellulosic biomass. Its aromatic composition and recalcitrant nature make its valorization a major challenge for obtaining low molecular weight aromatics compounds with high value‐added from the enzymatic depolymerization of industrial lignins. The oxidation reaction of lignin polymer using laccases alone remains inefficient. Therefore, researches are focused on the use of a laccase‐mediator system (LMS) to facilitate enzymatic depolymerization. Until today, the LMS system was studied using water‐soluble lignin only (commercial lignins, modified lignins, or lignin model compounds). This work reports a study of three LMS systems to depolymerize the three major industrial lignins (organosolv lignin, Kraft lignin, and sodium lignosulfonate). We show that an enzymatic depolymerization of these lignins can be achieved by LMS using laccase from Trametes versicolor, 2,2′‐azino‐bis(3‐ethylbenzothiazoline‐6‐sulfonic acid) diammonium salt as mediator and a cosolvent (25% of 1,4‐dioxane) to enhance the solubilization of lignins.
A design criterion for symmetric model discrimination based on flexible nominal sets
Authors: Harman Radoslav , Müller Werner G.
Published: January 2020

Experimental design applications for discriminating between models have been hampered by the assumption to know beforehand which model is the true one, which is counter to the very aim of the experiment. Previous approaches to alleviate this requirement were either symmetrizations of asymmetric techniques, or Bayesian, minimax, and sequential approaches. Here we present a genuinely symmetric criterion based on a linearized distance between mean‐value surfaces and the newly introduced tool of flexible nominal sets. We demonstrate the computational efficiency of the approach using the proposed criterion and provide a Monte‐Carlo evaluation of its discrimination performance on the basis of the likelihood ratio. An application for a pair of competing models in enzyme kinetics is given.
Modeling tails for collinear data with outliers in the English Longitudinal Study of Ageing: Quantile profile regression
Authors: Liu Xi , Liverani Silvia , Smith Kimberley J. , Yu Keming
Published: January 2020

Research has shown that high blood glucose levels are important predictors of incident diabetes. However, they are also strongly associated with other cardiometabolic risk factors such as high blood pressure, adiposity, and cholesterol, which are also highly correlated with one another. The aim of this analysis was to ascertain how these highly correlated cardiometabolic risk factors might be associated with high levels of blood glucose in older adults aged 50 or older from wave 2 of the English Longitudinal Study of Ageing (ELSA). Due to the high collinearity of predictor variables and our interest in extreme values of blood glucose we proposed a new method, called quantile profile regression, to answer this question. Profile regression, a Bayesian nonparametric model for clustering responses and covariates simultaneously, is a powerful tool to model the relationship between a response variable and covariates, but the standard approach of using a mixture of Gaussian distributions for the response model will not identify the underlying clusters correctly, particularly with outliers in the data or heavy tail distribution of the response. Therefore, we propose quantile profile regression to model the response variable with an asymmetric Laplace distribution, allowing us to model more accurately clusters that are asymmetric and predict more accurately for extreme values of the response variable and/or outliers. Our new method performs more accurately in simulations when compared to Normal profile regression approach as well as robustly when outliers are present in the data. We conclude with an analysis of the ELSA.
False discovery rate control for multiple testing based on discretep‐values
Authors: Chen Xiongzhi
Published: January 2020

For multiple testing based on discretep‐values, we propose a false discovery rate (FDR) procedure “BH+” with proven conservativeness. BH+ is at least as powerful as the BH (i.e., Benjamini‐Hochberg) procedure when they are applied to superuniformp‐values. Further, when applied to mid‐p‐values, BH+ can be more powerful than it is applied to conventionalp‐values. An easily verifiable necessary and sufficient condition for this is provided. BH+ is perhaps the first conservative FDR procedure applicable to mid‐p‐values and top‐values with general distributions. It is applied to multiple testing based on discretep‐values in a methylation study, an HIV study and a clinical safety study, where it makes considerably more discoveries than the BH procedure. In addition, we propose an adaptive version of the BH+ procedure, prove its conservativeness under certain conditions, and provide evidence on its excellent performance via simulation studies.
Overexpression of transcription factor Foxa1 and target genes remediate therapeutic protein production bottlenecks in Chinese hamster ovary cells
Authors: Berger Audrey , Le Fourn Valérie , Masternak Jacqueline , Regamey Alexandre , Bodenmann Iris , Girod Pierre‐Alain , Mermod Nicolas
Published: January 2020

Despite extensive research conducted to increase protein production from Chinese hamster ovary (CHO) cells, cellular bottlenecks often remain, hindering high yields. In this study, a transcriptomic analysis led to the identification of 32 genes that are consistently upregulated in high producer clones and thus might mediate high productivity. Candidate genes were associated with functions such as signaling, protein folding, cytoskeleton organization, and cell survival. We focused on two engineering targets, Erp27, which binds unfolded proteins and the Erp57 disulfide isomerase in the endoplasmic reticulum, and Foxa1, a pioneering transcription factor involved in organ development. Erp27 moderate overexpression increased production of an easy‐to‐express antibody, whereas Erp27 and Erp57 co‐overexpression increased cell density, viability, and the yield of difficult‐to‐express proteins. Foxa1 overexpression increased cell density, cell viability, and easy‐ and difficult‐to‐express protein yields, whereas it decreased reactive oxygen species late in fed‐batch cultures. Foxa1 overexpression upregulated two other candidate genes that increased the production of difficult‐ and/or easy‐to‐express proteins, namely Ca3, involved in protecting cells from oxidative stress, and Tagap, involved in signaling and cytoskeleton remodeling. Overall, several genes allowing to overcome CHO cell bottlenecks were identified, including Foxa1, which mediated multiple favorable metabolic changes that improve therapeutic protein yields.
A versatile oscillating‐flow microfluidic PCR system utilizing a thermal gradient for nucleic acid analysis
Authors: Kopparthy Varun L. , Crews Niel D.
Published: January 2020

We report the development of a versatile system based on the oscillating‐flow methodology in a thermal gradient system for nucleic acid analysis. Analysis of DNA and RNA samples were performed in the device, without additional temperature control and complexity. The technique reported in this study eliminates the need for predetermined fluidic channels for thermocycles, and complexity involved with additional incubation steps required for RNA amplification. A microfluidic device was fabricated using rapid prototyping by simply sandwiching dual side adhesive Kapton tape and a polydimethylsiloxane spacer between glass microscope slides. Amplification of the 181‐bp segment of a viral phage DNA (ΦX174) and B2M gene in human RNA samples was demonstrated using the system. The developed system enables simultaneous acquisition of amplification and melt curves, eliminating the need for postprocessing. A direct comparison between the oscillating‐flow system and a commercial real‐time polymerase chain reaction (PCR) instrument showed complete agreement in PCR data and improved sample‐to‐result time by eliminating an additional 30 min melt curve step required in commercial PCR systems.
Differential roles of exogenous protein disulfide isomerase A3 on proliferating cell and neuroblast numbers in the normal and ischemic gerbils
Authors: Yoo Dae Young , Cho Su Bin , Jung Hyo Young , Kim Woosuk , Nam Sung Min , Kim Jong Whi , Moon Seung Myung , Yoon Yeo Sung , Kim Dae Won , Choi Soo Young , Hwang In Koo
Published: January 2020

Introduction

We examined the effects of exogenous protein disulfide isomerase A3 (PDIA3) on hippocampal neurogenesis in gerbils under control and ischemic damage.

Methods

To facilitate the delivery of PDIA3 to the brain, we constructed Tat‐PDIA3 protein and administered vehicle (10% glycerol) or Tat‐PDIA3 protein once a day for 28 days. On day 24 of vehicle or Tat‐PDIA3 treatment, ischemia was transiently induced by occlusion of both common carotid arteries for 5 min.

Results

Administration of Tat‐PDIA3 significantly reduced ischemia‐induced spontaneous motor activity, and the number of NeuN‐positive nuclei in the Tat‐PDIA3‐treated ischemic group was significantly increased in the CA1 region compared to that in the vehicle‐treated ischemic group. Ki67‐ and DCX‐immunoreactive cells were significantly higher in the Tat‐PDIA3‐treated group compared to the vehicle‐treated control group. In vehicle‐ and Tat‐PDIA3‐treated ischemic groups, the number of Ki67‐ and DCX‐immunoreactive cells was significantly higher as compared to those in the vehicle‐ and Tat‐PDIA3‐treated control groups, respectively. In the dentate gyrus, the numbers of Ki67‐immunoreactive cells were comparable between vehicle‐ and Tat‐PDIA3‐treated ischemic groups, while more DCX‐immunoreactive cells were observed in the Tat‐PDIA3‐treated group. Transient forebrain ischemia increased the expression of phosphorylated cAMP‐response element‐binding protein (pCREB) in the dentate gyrus, but the administration of Tat‐PDIA3 robustly increased pCREB‐positive nuclei in the normal gerbils, but not in the ischemic gerbils. Brain‐derived neurotrophic factor (BDNF) mRNA expression was significantly increased in the Tat‐PDIA3‐treated group compared to that in the vehicle‐treated group. Transient forebrain ischemic increased BDNF mRNA levels in both vehicle‐ and Tat‐PDIA3‐treated groups, and there were no significant differences between groups.

Conclusions

These results suggest that Tat‐PDIA3 enhances cell proliferation and neuroblast numbers in the dentate gyrus in normal, but not in ischemic gerbils, by increasing BDNF mRNA and phosphorylation of pCREB.
The economic consequences of environmental regulation in China: From a perspective of the environmental protection admonishing talk policy
Authors: Tian Zhihua , Tian Yanfang , Chen Yang , Shao Shuai
Published: January 2020

Environmental regulation may lead to undesired economic consequences. China has tightened its environmental policies to deal with severe environmental pollution in recent years, but existing studies pay little attention to the economic consequences of China's environmental policies. Using the panel data of 211 prefecture‐level and above cities in China from 2003 to 2016, we for the first time estimate the economic impact of the environmental protection admonishing talk (EPAT) policy, a newly implemented environmental regulation policy in China. We use the difference‐in‐differences strategy to identify the economic effects of the EPAT policy combined with the propensity score matching method to control a potential selection problem. The results show that a relative decline occurs in gross domestic product per capita in target cities after the implementation of the EPAT, and the negative impact is exerted on the secondary industry rather than the tertiary industry. Furthermore, we find that target cities respond to the environmental protection requirements of higher authorities through a one‐size‐fits‐all approach of limiting the production activities of industrial enterprises. Meanwhile, the EPAT policy does not improve environmental efficiency. Such findings are instructive for policymakers who need to trade off economic welfare and environmental quality when formulating and implementing new environmental policies.
Integrated reporting of environmental, social, and governance and financial data: Does the market value integrated reports?
Authors: Landau Alexander , Rochell Janina , Klein Christian , Zwergel Bernhard
Published: January 2020

The concept of reporting nonfinancial information within the annual report, so‐called Integrated Reporting (IR) is a rising topic in reporting practice. Supporters claim that IR provides a better view regarding the value creation of a firm.

This study investigates the value relevance of IR and the influence of certain characteristics such as assurance. Thus, this paper contributes to the existing literature by examining the actual advantages for firms when adopting an IR approach.

The Ohlson model is applied for the market valuation of 50 companies of the STOXX Europe 50 between the years 2010 and 2016. The results of this study support the cost‐concerned school by showing a negative influence on the market value. Nonetheless, the study suggests that the quality of the reports is relevant for market valuation, as the negative effect is mitigated by the quality of the reports.
Marshaling administrative data to study the prevalence of mental illness in assault on law enforcement cases
Authors: Agee Elisha R. , Zelle Heather , Kelley Sharon , Moore Steven J.
Published: January 2020

A substantial body of literature has investigated many issues surrounding police encounters with persons with mental illness. This paper focuses on a specific type of encounter – individuals with mental illness charged with assaulting officers because of their behavior during a psychiatric crisis – and uses administrative data to examine its prevalence in one state. Results suggest that individuals with mental health histories comprise a small but meaningful percentage (c. 9%) of assault on law enforcement charges, and c. 10% of these charges have an offense date within 14 days of an emergency mental health custody order, increasing the likelihood that psychiatric symptoms influenced their behavior at the time of the offense. Further results describe different categories of relevant charges, charge classifications, final dispositions, and sentences. Results are discussed in the context of outcomes for persons with mental illness and law enforcement as well as the role and limitations of forensic mental health assessment in these cases. The paper concludes with a call for similar data collection across jurisdictions.
The effect of high glucose on the biological characteristics of nucleus pulposus‐derived mesenchymal stem cells
Authors: Liu Yang , Li Yan , Nan Li‐ping , Wang Feng , Zhou Shi‐feng , Wang Jing‐cheng , Feng Xin‐min , Zhang Liang
Published: January 2020

Diabetes mellitus (DM) is a dependent risk factor in the progression of intervertebral disc degeneration (IVDD). High glucose supply has negative effects on nucleus pulpous (NP) cell and mesenchymal stem cell (MSC) biology. However, the effect of hyperglycaemia on the biological characterization of nucleus pulpous‐derived mesenchymal stem cell (NPMSC) has not been investigated previously. Therefore, further exploration of the effects of DM‐associated hyperglycaemia on NPMSC biology is important to better understand and develop endogenous repair strategies of DM patient‐associated IVDD. Therefore, the cell biological characteristics were compared between NPMSC cultured in media with low glucose concentration (LG‐NPMSC) and high glucose concentration (HG‐NPMSC). The results demonstrated that HG‐NPMSC showed significantly decreased cell proliferation, colony formation ability, migration and wound‐healing capability compared with those of LG‐NPMSC. HG‐NPMSC also showed significantly decreased expressions of stemness genes and mRNA and protein expressions of silent information regulator protein 1 (SIRT1), SIRT6, hypoxia inducible factor‐1α (HIF‐1α) and glucose transporter 1 (GLUT‐1), whereas increased cell apoptosis, cell senescence and caspase‐3 expression. These results suggest that high glucose may decrease proliferation and stemness maintenance ability and increase apoptosis and senescence of NPMSC.

Significance of the study

We found that high glucose concentration significantly decreased cell proliferation, colony formation ability, migration and wound‐healing capability of nucleus pulposus‐derived mesenchymal stem cells. Moreover, high glucose cultured nucleus pulposus‐derived mesenchymal stem cells showed significantly decreased expression of stemness genes, related mRNA and protein, whereas increased cell apoptosis, cell senescence and expression of caspase‐3. The present study indicated that better control of high concentration glucose in the early stage of diabetes mellitus should be recommended to prevent or limit intervertebral disc degeneration.
Tailor‐Designed Porous Catalysts: Nickel‐Doped Cu/Cu2O Foams for Efficient Glycerol Electro‐Oxidation
Authors: Rizk Mohamed R. , Abd El‐Moghny Muhammad G. , El‐Nagar Gumaa A. , Mazhar Amina A. , El‐Deab Mohamed S.
Published: January 2020

Herein, Cu/Cu2O foams with dendritic‐like structures were electrodeposited atop a smooth Cu electrode by using a dynamic hydrogen bubbles technique, and they were used as efficient electrocatalysts for glycerol electrooxidation. The morphology, structure, and composition of the as‐prepared Cu/Cu2O foams were tuned by using additives (e. g. KCl and NiCl2) in the copper deposition bath to maximize their electrocatalytic performance towards glycerol electrooxidation. The as‐synthesized Cu/Cu2O foams showed superior electrocatalytic activity towards the glycerol oxidation reaction, as demonstrated by the significant negative shift in the onset potential (ca. 400 mV) together with an oxidation current that is up to six times higher, compared to the Cu/Cu2O non‐porous film with the same loading. The performance of these foams was further improved by introducing optimum amounts of either Ni2+ and/or Cl− ions. These additives resulted in a significant change in the structure and shape of the electrodeposited Cu/Cu2O textures with a concurrent increase in their roughness. Material and electrochemical characterization (e. g. SEM, XRD, XPS, LSV and CV) techniques were used to link the observed enhancements to the morphology, composition, and structure of the as‐synthesized Cu/Cu2O foam materials.