bluuebunny/crossref_metadata_2025_split huggingface dataset:
Dosimetric characterization of Elekta stereotactic cones
Authors: Borzov Egor , Nevelsky Alexander , Bar‐Deroma Raquel , Orion Itzhak 
Published: December 2017

AbstractPurposeDosimetry of small fields defined by stereotactic cones remains a challenging task. In this work, we report the results of commissioning measurements for the new Elekta stereotactic conical collimator system attached to the Elekta VersaHD linac and present the comparison between the measured and Monte Carlo (MC) calculated data for the 6 MV FFF beam. In addition, relative output factor (ROF) dependence on the stereotactic cone aperture variation was studied and penumbra comparison for small MLC‐based and cone‐based fields was performed.MethodsCones with nominal diameters of 15 mm, 12.5 mm, 10 mm, 7.5 mm, and 5 mm were employed in our study. Percentage depth dose (PDD), off‐axis ratios (OAR), and ROF were measured using a stereotactic field diode (SFD). BEAMnrc code was used for MC simulations.ResultsMC calculated and measured PDDs for all cones agreed within 1%/0.5 mm, and OAR profiles agreed within 1%/0.5 mm. ROF obtained from the measurements and MC calculations agreed within 2% for all cone sizes. Small‐field correction factors for the SFD detector Kfield,3 × 3(SFD) were derived using MC calculations as a baseline and were found to be 0.982, 0.992, 0.997, 1.015, and 1.017 for the 5, 7.5, 10, 12.5, and 15‐mm cones respectively. The difference in ROF was about 10%, 6%, 3.5%, 3%, 2.5%, and 2% for ±0.3 mm variations in 5, 7.5, 10, 12.5, and 15‐mm cone aperture respectively. In case of single static field, cone‐based collimation produced a sharper penumbra compared to the MLC‐based.ConclusionsAccurate MC simulation can be an effective tool for verification of dosimetric measurements of small fields. Due to the very high sensitivity of output factors on the cone diameter, manufacture‐related variations in cone size may lead to considerable variations in dosimetric characteristics of stereotactic cones.
Design and implementation of an adaptive Kalman filtering for the launcher of multiple launch rocket system
Authors: Li Bo , Rui Xiaoting , Yang Fufeng , Wang Guoping 
Published: December 2017

SummaryPractical application for performing an adaptive Kalman filtering with a digital signal processor is studied. A multiple launch rocket system (MLRS) is considered, and an adaptive Kalman filtering is designed for the state estimation of the launcher by using the measured outputs from a fiber optical gyro mounted on the MLRS. The proposed algorithm remains convergent in the presence of noise covariance errors. The performance of the proposed method is demonstrated by simulations and compared with other types of Kalman filtering algorithms. Eventually, an experiment is implemented for the state estimation of the launcher of MLRS using the TMS320F2812 digital signal processor.
The Significant Role of Hydrophilic and Hydrophobic Interfaces in Graphene‐Based 1D Heterostructures for Highly Enhanced Electron Emission
Authors: Huang Bohr‐Ran , Kathiravan Deepa , Tu Chao‐wei , Saravanan Adhimoorthy 
Published: December 2017

AbstractThe role of hydrophilic and hydrophobic substrate with graphene is crucial to define the interfacial properties of graphene (G)‐based heterostructures in the field of electronic device applications. Herein, the novel strategy of graphene wrapped hydrophilic/hydrophobic silicon nanowires (SiNWs) heterostructure is reported for highly enhanced electron field emission (EFE) studies with low turn‐on field. The combined effect of sharp edged graphene layers induced by different kinds of SiNWs is envisioned to enhance field enhancement factors and turn‐on voltage. The systematic results show the best EFE properties of hydrophilic SiNWs‐G based field emitters, with a lower turn‐on voltage of 0.53 V µm−1, a current density of 2.7 mA cm−2, and a higher field enhancement factor (β) of 14825. In addition, both the SiNWs‐G‐based field emitters are tested as the practical flat panel displays, where the hydrophilic‐based display exhibits at low voltage as 210 V. The superior EFE performance of hydrophilic SiNWs‐G based field emitters are ascribed to their large distortion field. Since more electrons can be trapped for easy tunneling, this increases the emission sites, and thereby contributes to a high enhancement field. This striking result from hydrophilic SiNWs‐G field emitters can be tailored for high‐performance EFE device applications.
Enhanced NOx Gas Sensing Properties of Ordered Mesoporous WO3/ZnO Prepared by Electroless Plating
Authors: Han Ji , Wang Tian‐yang , Li Tian‐tian , Yu Hui , Yang Ying , Dong Xiang‐ting 
Published: December 2017

AbstractA kind of novel n–n combined ordered mesoporous WO3/ZnO (OM‐WO3/ZnO) sensor are successfully fabricated in this study. A soft‐template method is used to synthesize the ordered mesoporous ZnO matrix. Surfaces of the ZnO matrix are innovatively modified using silane coupling agent (mark as: OM‐ZnO‐Si), and then a layer of WO3 film is assembled on the surfaces of the OM‐ZnO‐Si by chemical plating method for the first time, and the OM‐WO3/ZnO material is obtained. The prepared OM‐WO3/ZnO sample shows a kind of regular hexagon‐sheet structure. The prepared OM‐WO3/ZnO sensor shows the much better response, much shorter response time, much lower detection limit, and the more excellent selectivity toward NOx gas. When oxynitride (NOx) gas concentration is 100 ppm, the response reaches to 82.64%, the response time is only 6 s at room temperature. The detection limit is only 0.01 ppm. The unique loose porous structure and the synergistic effect of the n–n heterojunction structure endow the prepared OM‐WO3/ZnO material with the superior gas sensing properties. The n–n combined OM‐WO3/ZnO material shows the vast development potential in gas sensor field.
Effects of Grain Boundary Density on the Gas Sensing Properties of Triethylsilylethynyl‐Anthradithiophene Field‐Effect Transistors
Authors: Seo Yena , Lee Jung Hun , Anthony John E. , Nguyen Ky V. , Kim Yeon Hoo , Jang Ho Won , Ko Sunglim , Cho Younghoon , Lee Wi Hyoung 
Published: December 2017

AbstractIn this study, triethylsilylethynyl‐anthradithiophene (TES‐ADT) films with different density of grain boundaries are used for systematic investigation of effects of grain boundary density on gas sensing properties of TES‐ADT field‐effect transistors (FETs). Grain boundary density is simply controlled by changing mixing time of TES‐ADT solution. Higher mixing time leads to higher grain boundary density, and field‐effect mobility decreases with increased grain boundary density. However, gas sensing properties exhibit the opposite behavior. Drain current and field‐effect mobility of FETs based on TES‐ADT film with higher grain boundary density increase much more upon exposure of NO2 with electron withdrawing character. In addition, dynamic gas sensing tests reveal that response rate and sensitivity of a TES‐ADT sensor are enhanced remarkably by an increase of grain boundary density in TES‐ADT films. Grain boundaries provide a pathway for diffusion of gas molecules into channel regions and thus increase of grain boundary density is beneficial for development of highly sensitive OFET gas sensors.
Optical Control of a Biological Reaction–Diffusion System
Authors: Glock Philipp , Broichhagen Johannes , Kretschmer Simon , Blumhardt Philipp , Mücksch Jonas , Trauner Dirk , Schwille Petra 
Published: December 2017

AbstractPatterns formed by reaction and diffusion are the foundation for many phenomena in biology. However, the experimental study of reaction–diffusion (R–D) systems has so far been dominated by chemical oscillators, for which many tools are available. In this work, we developed a photoswitch for the Min system of Escherichia coli, a versatile biological in vitro R–D system consisting of the antagonistic proteins MinD and MinE. A MinE‐derived peptide of 19 amino acids was covalently modified with a photoisomerizable crosslinker based on azobenzene to externally control peptide‐mediated depletion of MinD from the membrane. In addition to providing an on–off switch for pattern formation, we achieve frequency‐locked resonance with a precise 2D spatial memory, thus allowing new insights into Min protein action on the membrane. Taken together, we provide a tool to study phenomena in pattern formation using biological agents.
Antibody Responses to Citrullinated and Noncitrullinated Antigens in the Sputum of Subjects With Rheumatoid Arthritis and Subjects at Risk for Development of Rheumatoid Arthritis
Authors: Demoruelle M. Kristen , Bowers Emily , Lahey Lauren J. , Sokolove Jeremy , Purmalek Monica , Seto Nickie L. , Weisman Michael H. , Norris Jill M. , Kaplan Mariana J. , Holers V. Michael , Robinson William H. , Deane Kevin D. 
Published: December 2017

ObjectiveThe location and mechanisms involved in the initial generation of autoantibodies to citrullinated and noncitrullinated proteins/peptides during the natural history of rheumatoid arthritis (RA) development is incompletely understood. This study sought to explore individual antibody responses to citrullinated and noncitrullinated proteins/peptides in the sputum and associations with neutrophil extracellular traps (NETs) in subjects at risk for the future development of RA.MethodsSerum and sputum samples were obtained from 41 RA‐free subjects who were considered at risk for the development of RA based on familial or serologic risk factors, from 20 subjects classified as having RA, and from 22 healthy control subjects. Samples were evaluated using a bead‐based array for IgG reactivity to 29 citrullinated proteins/peptides and 21 noncitrullinated proteins/peptides. Cutoff levels for antibody positivity were established in a separate control group. NET levels in the sputum were measured using sandwich enzyme‐linked immunosorbent assays that quantitate DNA–myeloperoxidase and DNA–neutrophil elastase complexes.ResultsIn at‐risk subjects, antibody responses to the citrullinated forms of fibrinogen, apolipoprotein E, and fibronectin were highly prevalent. The most citrulline‐specific antibodies in the sputum of at‐risk subjects were those to fibrinogen, vimentin, and peptides of fibrinogen A and apolipoprotein A1. Patterns of sputum autoantibody positivity differed between at‐risk subjects and subjects with RA. In at‐risk subjects, increasing sputum NET levels significantly correlated with several citrullinated and some noncitrullinated antibody reactivities.ConclusionThese findings suggest that sputum antibody reactivity to particular citrullinated and noncitrullinated proteins/peptides is specific for RA and for subjects at risk of RA, and the association of these proteins/peptides with NETs may be a key feature of early RA–related autoimmunity in the lung. These results further support the hypothesis that the lung plays a role in early RA–related autoimmunity.
Mechanistic Insight into Enantioselective Palladium‐Catalyzed Oxidative Carbocyclization–Borylation of Enallenes
Authors: Qiu Youai , Mendoza Abraham , Posevins Daniels , Himo Fahmi , Kalek Marcin , Bäckvall Jan E. 
Published: December 2017

AbstractThe asymmetric palladium‐catalyzed oxidative carbocyclization–borylation of enallenes, employing a chiral phosphoric acid as co‐catalyst, constitutes an efficient and convenient entry into functionalized building blocks with cyclopentene scaffolds in high enantiopurity. Up till now there has been a lack of knowledge concerning the origin of enantioselectivity of this reaction as well as the absolute configuration of the product. Herein, we report the crystal structure of one of the compounds generated via this carbocyclization, providing the link between the configuration of the products and the configuration of the chiral phosphoric acid used in the reaction. Furthermore, the origin of the enantioselectivity is thoroughly investigated with density functional theory (DFT) calculations. By careful examination of different possible coordination modes, it is shown that the chiral phosphoric acid and the corresponding phosphate anion serve as ligands for palladium during the key stereoselectivity‐determining cyclization step. In addition, we examine reactions wherein an extra chiral reagent, a p‐benzoquinone containing a chiral sulfoxide, is used. The combined experimental and theoretical studies provide insight into the details of complexation of palladium with various species present in the reaction mixture, furnishing a general understanding of the factors governing the stereoselectivity of this and related catalytic reactions.
Bimetallic Bi‐Ni oxides over carbide supports for oxidative dehydrogenation of n‐butane: Experimental and kinetic modelling
Authors: Elmutasim Omer , Tanimu Gazali , Aljundi Isam H. , Al‐Khattaf Sulaiman 
Published: December 2017

Abstractn‐butane oxidative dehydrogenation was studied over Bi‐Ni/TiC, Bi‐Ni/SiC, Bi‐Ni/Silicalite‐1, and unsupported Bi‐Ni catalyst. The co‐impregnation technique was followed, with fixed 0.30 and 0.20 g/g for Bi and Ni respectively. The physico‐chemical properties were measured by means of BET, XRD, CO2/NH3‐TPD, and H2‐TPR techniques. The catalytic test results revealed that bimetallic Bi‐Ni/TiC catalyst exhibited the highest n‐butane conversion of 16.6 % with dehydrogenation selectivity of 83.7 % (1,3‐butadiene and butenes selectivity of 50.7 % and 33 % respectively). As regards Bi‐Ni/TiC catalyst, the main operating parameters including O2/n‐C4H10 feed ratio, space velocity, and reaction temperature were varied. The Bi‐Ni/TiC catalyst showed adequate stability for a 10 h time on stream test. The high performance of Bi‐Ni‐O/TiC catalyst is attributed to the synergistic role of reducibility, presence of strong basic sites and weak acidic sites, and an increased metal species dispersion over the TiC support. A kinetic study of n‐butane oxidative dehydrogenation was carried out. The apparent activation energy for formation of butadiene was estimated to be the lowest (15 kJ/mol), while the highest activation energy (105 kJ/mol) is required for the undesirable cracking reaction.
Structure‐Based Design of Selective Noncovalent CDK12 Inhibitors
Authors: Johannes Jeffrey W. , Denz Christopher R. , Su Nancy , Wu Allan , Impastato Anna C. , Mlynarski Scott , Varnes Jeffrey G. , Prince D. Bryan , Cidado Justin , Gao Ning , Haddrick Malcolm , Jones Natalie H. , Li Shaobin , Li Xiuwei , Liu Yang , Nguyen Toan B. , O'Connell Nichole , Rivers Emma , Robbins Daniel W. , Tomlinson Ronald , Yao Tieguang , Zhu Xiahui , Ferguson Andrew D. , Lamb Michelle L. , Manchester John I. , Guichard Sylvie 
Published: December 2017

AbstractCyclin‐dependent kinase (CDK) 12 knockdown via siRNA decreases the transcription of DNA‐damage‐response genes and sensitizes BRCA wild‐type cells to poly(ADP‐ribose) polymerase (PARP) inhibition. To recapitulate this effect with a small molecule, we sought a potent, selective CDK12 inhibitor. Crystal structures and modeling informed hybridization between dinaciclib and SR‐3029, resulting in lead compound 5 [(S)‐2‐(1‐(6‐(((6,7‐difluoro‐1H‐benzo[d]imidazol‐2‐yl)methyl)amino)‐9‐ethyl‐9H‐purin‐2‐yl)piperidin‐2‐yl)ethan‐1‐ol]. Further structure‐guided optimization delivered a series of selective CDK12 inhibitors, including compound 7 [(S)‐2‐(1‐(6‐(((6,7‐difluoro‐1H‐benzo[d]imidazol‐2‐yl)methyl)amino)‐9‐isopropyl‐9H‐purin‐2‐yl)piperidin‐2‐yl)ethan‐1‐ol]. Profiling of this compound across CDK9, 7, 2, and 1 at high ATP concentration, single‐point kinase panel screening against 352 targets at 0.1 μm, and proteomics via kinase affinity matrix technology demonstrated the selectivity. This series of compounds inhibits phosphorylation of Ser2 on the C‐terminal repeat domain of RNA polymerase II, consistent with CDK12 inhibition. These selective compounds were also acutely toxic to OV90 as well as THP1 cells.
On efficient virtual cluster scaling across geo‐distributed data centers
Authors: Xu Xinping , Li Wenxin , Qi Heng , Li Keqiu 
Published: December 2017

SummaryVirtual cluster has recently emerged as a common abstraction for cloud applications or tenants to specify and reserve resources. Such virtual cluster brings valuable insights into the cloud elasticity when scaling up or down the number of resources on demand. Unfortunately, for global‐scale applications running on geo‐distributed datacenters, it is always a challenge to scale the virtual cluster. Due to the fact that the inter‐datacenter bandwidth is an expensive and scarce resource, it is increasingly important yet typically hard to achieve cost‐minimizing bandwidth guarantees when scaling. However, existing approaches mainly focus on the scaling within intra‐datacenter networks and cannot be simply extended to the inter‐datacenter scenario. In this paper, we study the problem of scaling up a virtual cluster with consideration of both bandwidth cost minimization and bandwidth guarantees fulfillment targeting inter‐datacenter networks. Specifically, we first propose an efficient algorithm to scale up the virtual cluster without changing its original VM placement. With the observation that such VM placement can hinder the cluster scalability, we further present an optimized algorithm, which exploits VM migration when scaling. Finally, we conduct extensive simulations to demonstrate the effectiveness of our algorithms, in terms of both bandwidth cost and the acceptance rate of scaling requests with bandwidth guarantees.
A performance spectrum for parallel computational frameworks that solve PDEs
Authors: Chang J. , Nakshatrala K.B. , Knepley M.G. , Johnsson L. 
Published: December 2017

SummaryImportant computational physics problems are often large‐scale in nature, and it is highly desirable to have robust and high performing computational frameworks that can quickly address these problems. However, it is no trivial task to determine whether a computational framework is performing efficiently or is scalable. The aim of this paper is to present various strategies for better understanding the performance of any parallel computational frameworks for solving PDEs. Important performance issues that negatively impact time‐to‐solution are discussed, and we propose a performance spectrum analysis that can enhance one's understanding of critical aforementioned performance issues. As proof of concept, we examine commonly used finite element simulation packages and software and apply the performance spectrum to quickly analyze the performance and scalability across various hardware platforms, software implementations, and numerical discretizations. It is shown that the proposed performance spectrum is a versatile performance model that is not only extendable to more complex PDEs such as hydrostatic ice sheet flow equations but also useful for understanding hardware performance in a massively parallel computing environment. Potential applications and future extensions of this work are also discussed.
Annealing‐Free Cr2O3 Electron‐Selective Layer for Efficient Hybrid Perovskite Solar Cells
Authors: Dong Jia , Wu Jihuai , Jia Jinbiao , He Xin , Lan Zhang , Fan Leqing , Lin Jianming , Huang Miaoliang 
Published: December 2017

AbstractThe electron‐selective layer (ESL) plays a pivotal role in the performance of perovskite solar cells (PSCs). In this study, amorphous dispersible chromium oxide (Cr2O3) nanosheets are synthesized by a facile solvothermal reaction, and a Cr2O3 ESL is prepared by spin‐coating Cr2O3 ink on fluorine‐doped tin oxide substrates without need for further annealing. By using Cr2O3 as the electron‐selective layer and Cs0.05(MA0.17FA0.83)0.95Pb(I0.83Br0.17)3 as the light‐absorption layer, a planar hybrid perovskite solar cell is fabricated. The spin‐coating speed is optimized, the structure and morphology of samples are observed, the photoelectrical properties of ESLs are characterized, and the photovoltaic behaviors of devices are measured. Results show that the as‐prepared Cr2O3 layer has high optical transmittance and superb electron extraction and carrier transport property. The planar hybrid PSC based on the optimized Cr2O3 ESL achieves a power conversion efficiency of 16.23 %, which is comparable to devices based on a conventional high‐temperature‐calcined TiO2 ESL. These results demonstrate a low‐cost and facile route to highly effective perovskite solar cells.
Physicochemical Properties of Enzymatically Produced Palm‐Oil‐Based Cocoa Butter Substitute (CBS) With Cocoa Butter Mixture
Authors: Biswas Nirupam , Cheow Yuen Lin , Tan Chin Ping , Siow Lee Fong 
Published: December 2017

Ternary‐blend of palm mid‐fraction/palm kernel oil/palm stearin shows comparable palmitic (P), oleic (O), and POP compositions to cocoa butter (CB) which is selected to produce cocoa butter substitute (CBS) using enzymatic interesterification. This study aims to investigate physicochemical properties of CBS and compatibility of CBS/CB. Fatty acid, triacylglycerol, melting profile, solid fat content (SFC), polymorphism, and crystal morphology are determined using GC, HPLC, DSC, pNMR, XRD, and PLM. Ternary‐blend and commercial stearic/oleic acids are mixed to produce blend (80% ternary‐blend/15% stearic/5% oleic) with three major fatty acids composition comparable to CB. Interesterified blend under optimized conditions of 4% lipase (w/w), incubation time of 6 h at 60 °C shows a melting endotherm at 33.5 °C, similar to CB. The composition of triacylglycerols (POSt and StOSt) of interesterified blend is significantly (P < 0.05) increased compared to non‐interesterified blend. SFC and polymorphism of interesterified fat are different from CB at 24 °C. Subsequently, the CBS (interesterified blend) is added into CB at varying concentrations (w/w). A total of 5–20% of CBS/CB shows similar melting behavior and polymorphism to CB. A desirable monotectic effect is observed at 15–25 °C for these blends. Therefore, interesterified blend is potentially used as CBS to be added up to 20% with CB for chocolate production.Practical Applications: Palm‐based CBS is feasible to be used in chocolate production at 5–20 wt.%.Ternary‐blend of palm mid‐fraction/palm kernel oil/palm stearin shows comparable palmitic (P), oleic (O), and POP compositions to cocoa butter (CB), which is selected to produce cocoa butter substitute (CBS) using enzymatic interesterification. This study aims to investigate physicochemical properties of CBS and compatibility of CBS/CB. An interesterified blend is explored that can potentially be used as CBS to be added up to 20% with CB for chocolate production.
Biotechnological production of the angiotensin‐converting enzyme inhibitory dipeptide isoleucine‐tryptophan
Authors: Michelke Lydia , Deussen Andreas , Kettner Karina , Dieterich Peter , Hagemann Diana , Kriegel Thomas M. , Martin Melanie 
Published: December 2017

AbstractPeptides with angiotensin‐converting enzyme (ACE)‐inhibitory and antihypertensive effects are suggested as innovative food additives to prevent or treat hypertension. Currently, these substances are isolated from food proteins following nonselective hydrolysis as a mixture of ACE‐inhibitory peptides and other protein fragments. This study presents an innovative biotechnological method, based on recombinant DNA technology that was established to specifically produce the ACE‐inhibitory dipeptide isoleucine‐tryptophan. In a first step, a repetitive isoleucine‐tryptophan construct fused to the maltose‐binding protein was generated and expressed in Escherichia coli BL21 cells. The chromatographically purified recombinant fusion protein was enzymatically hydrolyzed using α‐chymotrypsin to liberate the dipeptide isoleucine‐tryptophan. The identity of the liberated isoleucine‐tryptophan was confirmed by MS and derivatization of its N‐terminus. The ACE‐inhibitory effect of the recombinant dipeptide on soluble and membrane bound ACE was found to be indistinguishable from the inhibitory potential of the chemically produced commercially available dipeptide. The established experimental strategy represents a promising approach to the biotechnical production of sufficient amounts of recombinant peptide‐based ACE‐inhibitory and antihypertensive substances that are applicable as functional food additives to delay or even prevent hypertension.