bluuebunny/crossref_metadata_2025 huggingface dataset:
Assessment of multilayered graphene technology for flexible antennas at microwave frequencies
Authors: Elmobarak Husameldin A. , Rahim Sharul K. A. , Abedian Mohammad , Soh Ping Jack , Vandenbosch Guy A. E. , Yew Chiong Lo
Published: July 2017

As it has outstanding electrical and mechanical properties, like high conductivity, durability, and flexibility, graphene may be an interesting material also for conformal and wearable antennas. Whereas mono‐atomic graphene layers have been proven to perform inadequately at microwave frequencies, in this article the performance of multilayered graphene‐based sheets (GBS) fabricated onto a polymer substrate is assessed when used as flexible planar and conformal antennas. This is accomplished through studying a simple microstrip antenna topology. Challenges related to the fabrication process of these antennas are discussed, for example adhesion issues and the occurrence of air gaps on the substrate layer. The graphene‐based technology is compared to a classical technology involving copper as metal. Bending of the antennas is also discussed. The main conclusion is that multilayered graphene does perform adequately as conductor in antennas at microwave frequencies, with the possibility of providing a slightly higher gain than copper.
Gain enhancement of a compact 2.4‐GHz meander antenna using inductive feed and capacitive load
Authors: Chen Ja‐Hao , Yang Chun‐Kai , Cheng Chen‐Yang , Yu Cheng‐Chi , Hsu Cheng‐Hsing
Published: July 2017

In this study, a compact printed meander antenna with enhanced peak gain for 2.4‐GHz applications was investigated. Inductive feed and capacitive load techniques were used in the meander antenna's design to optimize peak gain performance. A measured maximum peak gain of 4.49 dBi, input reflection coefficient of −15 dB, and fractional bandwidth of 7.23% were achieved using a 1.6‐mm‐thick FR4 substrate. The low‐profile antenna occupied an area of 26 × 15.6 mm2. The proposed antenna can be implemented in standard printed circuit board processes without any lumped elements or via holes, and it introduces very little fabrication complexity.
Dual‐band impedance transformer using two parallel open‐ and shorted‐stubs with total quarter guided wavelength
Authors: Ma Xing‐Bing , Jiang Ting
Published: July 2017

This article presents a dual‐band (DB) impedance transformer with novel parallel‐stubs‐loaded structure. The proposed transformer consists of a traditional single band matching network (SBMN) and a DB stubs‐loaded transmission‐line network in series. The DB stubs‐loaded MN features an open‐stub and a shorted‐stub in parallel with total length λ1/4 (λ1 is guided wavelength from lower f1 of two matching frequencies). The considered load has frequency‐dependent complex impedance at two uncorrelated frequencies (f1, f2). Design equations are presented, and required circuit parameters are all obtained adopting derived analytical design formula. Good agreements between simulation and measurement are observed.
Compact tunable lowpass filter with sharp roll‐off and low insertion loss
Authors: Zhang Ting , Cai Zongqi , Yang Yang , Bao Jingfu , Wang Yiwen
Published: July 2017

A novel continuously tunable lowpass filter (LPF) with compact size, sharp roll‐off and low insertion loss is presented in this paper. The filter employs two varactor diodes, a pair of open‐ended coupled lines and a U‐shape step impedance line (SIL) with an open‐ended stub loaded at the center of the SIL to form a very compact layout. The odd‐ and even‐mode analysis and equivalent circuit model are demonstrated for estimation of the transmission characteristics. Tuning the DC voltage applied on the varactor diodes, the varactor capacitance accordingly changes leading to a varying cutoff frequency fc. The measured results show that the achieved 3‐dB fc tuning range is 60.6% (1.15–2.15 GHz). The measured insertion loss (IL) and roll‐off rate are 0.2‐0.4 dB and 50–73 dB/GHz, respectively. The overall size of the LPF is only 0.005λg2, which shows a competitive advantage comparing with the state‐of‐the‐art work.
A tri‐band slot antenna loaded with split ring resonators
Authors: Paul Princy Maria , Kandasamy Krishnamoorthy , Sharawi M. S.
Published: July 2017

A compact tri‐band slot antenna with independent tuning capability of its resonant frequencies is proposed in this article. A microstrip line fed square slot is loaded with split ring resonators (SRR) to obtain multiband characteristics. The slot is designed to resonate at 2.6 GHz. Two SRRs with single and multiple splits are loaded with the slot, which provide additional resonances at 4.3 and 4.7 GHz, respectively. Parametric analysis of the antenna shows that its resonance frequencies are controlled independently. The proposed antenna is fabricated on an FR4 substrate with a size of 60 × 60 × 1.56 mm2. The proposed design offers stable omnidirectional patterns and >3.8 dBi at all the resonating frequency bands.
Forming a transparent atmospheric optical channel by use of vortical laser beam
Authors: Artyschenko Stepan V. , Pasternak Yury G. , Proskurin Dmitry K. , Fedorov Sergey M.
Published: July 2017

It was shown that promising way to reduce a power loss of optical waves transmitted through atmosphere is use of spatially inhomogeneous optical waves with phase front in form of flat spiral. Vortical optical beam used to separate aerosol (due to light pressure on water particles) and create a cone wherein droplets concentration is substantially reduced. Unlike known method to create a transparent atmospheric optical channel based on use evaporation of aerosol particles via high‐power laser radiation, proposed method is substantially less energy‐consuming since when moving aqueous aerosol particle from area of laser beam propagation no evaporation occurs.
Design of curved frequency selective surface with high roll off
Authors: Begam Nurnihar , Samaddar Poulami , Saha Snehasish , Sarkar Sushanta , Chanda (Sarkar) Debasree , Sarkar Partha P.
Published: July 2017

In this article, band pass cylindrical double‐layer frequency selective surfaces (FSSs) are investigated using method of moment (MOM). “Plus”‐shaped slots are used to design the FSSs. The dielectric substrate is considered as air. A good bandwith and sharp roll off are achieved for curved FSS. Theoretical and measured investigations have been done by FEKO simulator and microwave test bench setup, respectively.
An ingestible capsule system for in‐body core temperature monitoring
Authors: Zhang Ke , Liu Changrong , Yang Xinmi , Liu Xueguan , Guo Huiping
Published: July 2017

An ingestible capsule system monitoring in‐body core temperature is presented and an in vitro measurement is carried out. The capsule system composed of essential electrical components, antenna, and power supply is codesigned for the sake of minimizing the overall size and maximizing the transmission distance. To meet these properties, a multilayered PIFA antenna is applied to be integrated with the circuit. The proposed capsule antenna is demonstrated experimentally at 433‐MHz industrial, scientific and medical (ISM) band. The total length of capsule is 31.4 mm and the volume of capsule antenna is 147 mm3. Experimental results are well agreed with theoretical predictions.
Design of multi‐port one‐radiator antenna for octa‐band mobile terminals
Authors: Lee Jae‐Gon , Kim Dong‐Jin , Lee Jeong‐Hae
Published: July 2017

In this article, a multi‐port one‐radiator antenna (MOA) is proposed for the effective design of octa‐band mobile antenna including the LTE secondary (penta‐band), GPS, and BT/Wi‐Fi (2.4 GHz and 5 GHz) band. The MOA is composed of one radiator, high‐pass filter (HPF), and two‐ports. The two‐ports connect to one radiator for the LTE secondary/GPS and the BT/Wi‐Fi band, respectively. To minimize the amount of interference between two ports, one port for BT/Wi‐Fi band has a gap coupled feed and HPF. The VSWRs and the efficiencies of octa‐band without and with the HPF have been measured and compared. The results show that the performance of integrated ports with the HPF is recovered to the same performance of isolated ports. These results indicate that the MOA could be an attractive solution as a compact antenna to cover LTE secondary, GPS, and BT/Wi‐Fi band at mobile terminals.
CFAR based morphological filter design to remove clutter from GB‐SAR images: An application to real data
Authors: Toktas Abdurrahim , Yigit Enes , Sabanci Kadir , Kayabasi Ahmet
Published: July 2017

Reconstructed ground based synthetic aperture radar (GB‐SAR) data generally presents high resolution images of objects on the ground. However ground and multipath reflections occurred from depression angle appear as a clutter signs in the image. Constant false alarm rate (CFAR) detector is commonly preferred threshold algorithm for removing the clutter. But there is challenge in tuning CFAR. By enlarging or shrinking the window size, the background data taken into account respectively increases or decreases, and thus the filtered image accordingly includes much clutter or less clutter with target information loss. In this study, a novel adaptive clutter removing procedure based on morphological filter (MF) is designed to compensate this tradeoff by applying after a large windowed detector. In order to test the proposed CFAR based MF (CFAR‐MF) method, two different examples of GB‐SAR experiments in which the images are reconstructed by back projection algorithm (BPA) were performed using stepped frequency continuous waveform operating. The performance of CFAR‐MF was then examined in terms of signal to clutter ratio and integrated side lobe ratio. The results show that the clutter remains of the CFAR detector are effectively cleared from the GB‐SAR image and targets were accurately detected at their true locations without any disorder.
Reconfigurable negative group delay circuit with low signal attenuation
Authors: Liu Gang , Xu Jinping
Published: July 2017

A novel circuit scheme is presented for the design of reconfigurable negative group delay circuit (RNGDC) with very low signal attenuation (SA), which is based on a lossy coupled‐line Microstrip (MS) resonator. Theoretical analysis indicates that reconfigurable characteristics in the proposed circuits can be obtained by tuning the resistance of the variable resistor, which is loaded at a specific point on the MS resonator. Based on the study of one‐stage RNGDC, a two‐stage RNGDC arranged in an anti‐symmetrical manner is designed to provide an extended reconfigurable negative group delay range. To validate the performance of the proposed circuit scheme, the prototypes of one‐stage and two‐stage RNGDC have been designed working at a center frequency of 1.73 GHz. Measured results of the two‐stage RNGDC exhibit a group delays variation of −2 ns to −10 ns with signal attenuation variation of −4.5 dB to −9.3 dB at the center frequency, which demonstrates much lower SA compared to the previously‐reported RNGDCs.
Reactive oxygen species as mediators of sperm capacitation and pathological damage
Authors: Aitken Robert J.
Published: July 2017

Oxidative stress plays a major role in the life and death of mammalian spermatozoa. These gametes are professional generators of reactive oxygen species (ROS), which appear to derive from three potential sources: sperm mitochondria, cytosolic L‐amino acid oxidases, and plasma membrane Nicotinamide adenine dinucleotide phosphate oxidases. The oxidative stress created via these sources appears to play a significant role in driving the physiological changes associated with sperm capacitation through the stimulation of a cyclic adenosine monophosphate/Protein kinase A phosphorylation cascade, including the activation of Extracellular signal regulated kinase‐like proteins, massive up‐regulation of tyrosine phosphorylation in the sperm tail, as well as the induction of sterol oxidation. When generated in excess, however, ROS can induce lipid peroxidation that, in turn, disrupts membrane characteristics that are critical for the maintenance of sperm function, including the capacity to fertilize an egg. Furthermore, the lipid aldehydes generated as a consequence of lipid peroxidation bind to proteins in the mitochondrial electron transport chain, triggering yet more ROS generation in a self‐perpetuating cycle. The high levels of oxidative stress created as a result of this process ultimately damage the DNA in the sperm nucleus; indeed, DNA damage in the male germ line appears to be predominantly induced oxidatively, reflecting the vulnerability of these cells to such stress. Extensive evaluation of antioxidants that protect the spermatozoa against oxidative stress while permitting the normal reduction‐oxidation regulation of sperm capacitation is therefore currently being undertaken, and has already proven efficacious in animal models.
Preparation and properties of copolymer resin based on polybenzimidazole and bisoxazoline
Authors: Kimura Hajime , Fukuoka Hironao , Kishi Hajime
Published: July 2017

Reaction between the NH groups in polybenzimidazole (PBI) and bisoxazoline compounds (1,3‐phenylene bisoxazoline, 1,3‐PBO) resulted in the successful preparation of novel network polymers. Adjusting the amount of the bisoxazoline compound, which is a cross‐linking agent for the preparation of network polymers, and obtaining dynamic mechanical measurements, electrical resistivity measurements, thermomechanical measurements, and tensile tests allowed the determination of the heat resistance and mechanical strength of these novel network polymers. Examination of the elementary reaction of PBI and the1,3‐PBO curing reaction by using model compounds revealed that the NH group in the PBI structure reacted with the oxazoline group of 1,3‐PBO. Comparison of noncross‐linked PBI with the PBI network polymers obtained through cross‐linking reaction with bisoxazoline compounds demonstrated improvements in heat resistance and mechanical strength of the PBI‐bisoxazoline network polymers.
Foam injection molding of glass fiber reinforced polypropylene composites with laminate skins
Authors: Kasemphaibulsuk Pibulchai , Holzner Marcel , Kuboki Takashi , Hrymak Andrew
Published: July 2017

Sandwich panels which consist of discontinuous glass‐fiber reinforced polypropylene composite foam core and continuous glass‐fiber reinforced polypropylene laminate skins were manufactured using industry‐scale equipment in a streamlined manner. The streamlined process included two stages: (1) continuous glass‐fiber reinforced polypropylene laminates as the face skins were produced using an automated, rapid tape layup machine and a hydraulic press, and (2) discontinuous glass‐fiber reinforced polypropylene composite as the core was foam injection‐molded onto the laminate skins (i.e., overmolding), which eliminated bonding process of the foam core and laminate skins, with a physical blowing agent, nitrogen. Optical microscopy results suggested that the increase of void fraction by the core‐back (or mold opening) technique increased the average cell size and cell size distribution, but had little effect on the cell density of the foam core. Mechanical test results suggested that the addition of laminate skins increased the flexural modulus and flexural strength of the solid as well as foam composites significantly. In addition, the material indices were calculated for the sandwich panels manufactured in this study, and the results suggested that the addition of the laminate skins and foaming by the core‐back (or mold opening) technique can greatly reduce the weight of material needed to have the same bending stiffness and maximum bending force. COMPOS., 39:4322–4332, 2018. © 2017 Society of Plastics Engineers
Multiwalled carbon nanotube/montmorillonite hybrid filled ethylene‐co‐vinyl acetate nanocomposites with enhanced mechanical properties, thermal stability, and dielectric response
Authors: Bhuyan B. , Roy A. , Srivastava S. K. , Mittal V.
Published: July 2017

Homogeneous multiwalled carbon nanotube/montmorillonite hybrid filler (HMM) dispersion was prepared by co‐ultrasonication and was subsequently used to prepare ethylene‐co‐vinyl acetate (EVA) nanocomposites by solution blending method. XRD and TEM analysis of HMM confirm significant interaction between the montmorillonite (MMT) layers and multiwalled carbon nanotubes (MWCNT) in line with previous reports. Analysis of the nanocomposites shows the constituent fillers to be homogeneously dispersed in EVA matrix. Mechanical properties of neat EVA are remarkably improved with HMM content up to 3 wt% followed by reversion. Maximum improvement observed in tensile strength, elongation at break, and toughness are 424%, 109%, and 1122%, respectively. Results show maximum thermal stability at 4 wt% and best dielectric response at 1 wt% HMM content. Exceptional mechanical and dielectric properties of EVA nanocomposites attained may be attributed to homogeneous dispersion of fillers and improved polymer–filler interaction. Comparison shows excellent synergy between MWCNT and MMT towards mechanical reinforcement of EVA. POLYM. ENG. SCI., 58:1155–1165, 2018. © 2017 Society of Plastics Engineers
How Social Media Construct “Truth” Around Crisis Events: Weibo's Rumor Management Strategies After the 2015 Tianjin Blasts
Authors: Zeng Jing , Chan Chung‐hong , Fu King‐wa
Published: July 2017

China's control of information online is often imposed by social media platforms in the name of “rumor management.” This article examines the content moderation strategies of Sina Weibo, China's largest microblogging platform, in regulating discussion of rumors following the 2015 Tianjin blasts. More than 100,000 Weibo posts were collected and categorized into three data sets: rumor discussion posts from the public, rumor‐debunking posts from Weibo's official rumor rebuttal accounts, and posts removed from the system. Two content‐moderation rumor strategies, namely rumor rebuttal and content removal, were identified. Clustering analysis and time series analysis was applied to test how these two strategies were used to filter posts of different topics and how they were associated with public discussion of rumor‐related topics. Our findings suggest that the platform's response to rumor varied depending on the political sensitivity of the topic. Time‐series analysis indicated that the implementation of both strategies was usually associated with a subsequent increase in general discussion about the rumor, suggesting that these strategies do not create a consistent chilling effect on public speech.
[1,2,5]thiadiazolo[3,4‐g]quinoxaline acceptor‐based donor–acceptor–donor‐type polymers: Effect of strength and size of donors on the band gap
Authors: Gokce Gurcan , Karabay Baris , Cihaner Atilla , Icli Ozkut Merve
Published: July 2017

Electrochromic polymers based on [1,2,5]thiadiazolo[3,4‐g]quinoxaline acceptor and thiophene, 3,4‐ethylenedioxythiophene and 3,3‐didecyl‐3,4‐proylenedioxythiophene donors, namely poly(6,7‐diphenyl‐4,9‐di(thiophen‐2‐yl)‐[1,2,5]thiadiazolo[3,4‐g]quinoxaline) (P1), poly(4‐(2,3‐dihydrothieno[3,4‐b][1,4]dioxin‐5‐yl)‐9‐(2,3‐dihydrothieno[3,4‐b][1,4]dioxin‐7‐yl)‐6,7‐diphenyl‐[1,2,5]thiadiazolo[3,4‐g]quinoxaline) (P2), and poly(4‐(3,3‐didecyl‐3,4‐dihydro‐2H‐thieno[3,4‐b][1,4]dioxepin‐6‐yl)‐9‐(3,3‐didecyl‐3,4‐dihydro‐2H‐thieno[3,4‐b][1,4]dioxepin‐8‐yl)‐6,7‐diphenyl‐[1,2,5]thiadiazolo[3,4‐g]quinoxaline) (P3), respectively, were electrochemically and/or chemically synthesized and characterized. Electrochemical and optical properties of the polymers were then investigated. The results, which were obtained electrochemically and optically, indicate that the polymers bearing the same acceptor and different donor units have a band gap range of 0.59–1.24 eV depending on the strength and size of the donor units and band gap determination method. A significant finding in this study was the phenomenon that when the acceptor is physically huge, the general rule that a weak donor would have a high band gap whereas a strong donor would have low band gap can be broken due to the torsional angles/steric hindrances involved with physically large donor molecules. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017, 55, 3483–3493
Protection motivation theory in predicting intention to receive cervical cancer screening in rural Chinese women
Authors: Bai Yang , Liu Qing , Chen Xinguang , Gao Yanduo , Gong Huiyun , Tan Xiaodong , Zhang Min , Tuo Jiyu , Zhang Yuling , Xiang Qunying , Deng Fenghua , Liu Guiling
Published: July 2017

Objective

Despite the significance of cervical cancer screening, motivating more women to participate remains a challenge in resource‐limited settings. In this study, we tested the protection motivation theory (PMT) in predicting screening intentions.

Methods

Participants were women from Wufeng, a typical rural county in China. Participants (n = 3000) with no cervical cancer history were recruited from 10 randomly selected villages. As mediating variables, 6 PMT constructs (Perceived Risk, Fear Arousal, Perceived Severity, Response Efficacy, Response Cost, and Self‐Efficacy) were measured using the standardized questionnaire. Structural equation modeling (SEM) method was employed to test PMT‐based prediction models.

Results

Of the total sample, 57.77% believed that regular screening may reduce cervical cancer risk, and 45.26% agreed that women should be screened regularly. Our data fit the PMT model well (GFI = 0.95, AGFI = 0.93, CFI = 0.90, RMSEA = 0.06, SRMR = 0.04, Chi‐square/df = 2.47). Knowledge of screening was directly and positively associated with screening intention. Age, annual income, and awareness of and prior experience with screening were significantly associated with screening intention by enhancing cervical cancer risk perception and by reducing response cost (P<0.05 for both).

Conclusion

PMT can be used as guidance to investigate cervical cancer screening intentions among rural women in China with focus on cancer knowledge, some demographic factors, and awareness of and previous experience with screening. These findings, if verified with longitudinal data, can be used for intervention program development.
Large‐area growth of multi‐layered MoS2 for violet (∼405 nm) photodetector applications
Authors: Lee Soo Hyun , Kim Sanghun , Lee Seunghyun , Yu Jae Su
Published: July 2017

The two‐dimensional multi‐layered molybdenum disulfide (MoS2) was grown over a large area by chemical vapor deposition process for violet (∼405 nm) photodetector (PD) applications. The high‐quality MoS2 layers were successfully fabricated and transferred on HfO2/Si substrate. The inherent surface structure originated from the surface oxidation was also analyzed. The electrical properties of the multi‐layered MoS2‐based violet PDs with various channel widths (Wch) were measured and compared under dark state and violet illumination operating at 405 nm. For the device with Wch of 4 µm, at the bias of −5 V, the photocurrent and on/off ratio were obtained to be 54.0 nA and 55.2, respectively. Under violet illumination, the photocurrent was ∼4.6 times higher compared to green illumination. At the bias of −5 V, the photoresponse properties of the device were characterized with average rise time and reset time of ∼55.7 and 46.0 s, respectively, during four cycles of operation.
Carrier activation in Mg implanted GaN by short wavelength Nd:YAG laser thermal annealing
Authors: Aid Siti Rahmah , Uneme Takahiro , Wakabayashi Naoki , Yamazaki Kazunori , Uedono Akira , Matsumoto Satoru
Published: July 2017

Activation of Mg‐implanted GaN has been investigated by the combination of thermal and laser annealing. The laser annealing was carried out using third harmonic generation (λ = 355 nm) of a Nd:YAG laser. Mg ion activation and reduction of implanted‐defects after various annealing processes have been analyzed with Raman spectroscopy. The sample that was thermally annealed at 700 °C for 20 min; followed by laser annealing, with energy density of 0.35 mJ cm−2, is found to be effective for p‐type conversion in electrical characteristics. The value for sheet resistance and hole mobility is 1.7 × 103 Ω/□ and 40 cm2 Vs−1; respectively. Positron annihilation revealed that the vacancy clusters created in the sub‐surface region, by thermal annealing dissolved following laser annealing, leading to the p‐type conversion of GaN.
A new approach to constrained state estimation for discrete‐time linear systems with unknown inputs
Authors: Garcia Tirado Jose Fernando , Marquez‐Ruiz Alejandro , Botero Castro Hector , Angulo Fabiola
Published: July 2017

This paper addresses the problem of estimating the state for a class of uncertain discrete‐time linear systems with constraints by using an optimization‐based approach. The proposed scheme uses the moving horizon estimation philosophy together with the game theoretical approach to the
filtering to obtain a robust filter with constraint handling. The used approach is constructive since the proposed moving horizon estimator (MHE) results from an approximation of a type of full information estimator for uncertain discrete‐time linear systems, named in short
‐MHE and
–full information estimator, respectively. Sufficient conditions for the stability of the
‐MHE are discussed for a class of uncertain discrete‐time linear systems with constraints. Finally, since the
‐MHE needs the solution of a complex minimax optimization problem at each sampling time, we propose an approximation to relax the optimization problem and hence to obtain a feasible numerical solution of the proposed filter. Simulation results show the effectiveness of the robust filter proposed.
Active vibration control of large space flexible slewing truss using cable actuator with input saturation
Authors: Jin Qi‐Bao , Huang Jin
Published: July 2017

This paper proposes a composite approach to implementing attitude tracking and active vibration control of a large space flexible truss system. The system dynamic model is based on Hamilton's principle and discretized using the finite difference method. A nonlinear attitude controller for position tracking is developed based on the input‐output linearization of the discretized system, which can effectively improve system performance compared with a traditional proportional‐differential feedback controller. A taut cable actuator scheme is presented to suppress tip vibration because the mechanical model is a large large‐span spatial structure; furthermore, because the cable has the feature of unilateral input saturation constraint, which can provide only a pulling force, a nonlinear quadratic regulator controller is developed by introducing a piecewise nonquadratic cost function to suppress the vibration of the flexible structure. To investigate the factors that influence the damping effects of the cable, the parametrically excited instability of a cable under 2 supports is analyzed. Simulation results illustrate that the proposed attitude controller can implement the task of position tracking, and the vibration suppression control law is shown to be optimal for functional performance with input saturation.
Round‐robin test for the measurement of layer thickness of multilayer films by secondary ion mass spectrometry depth profiling
Authors: Kim Kyung Joong , Jang Jong Shik , Bennett Joe , Simons David , Barozzi Mario , Takano Akio , Li Zhanping , Magee Charles
Published: July 2017

An international round‐robin test (RRT) was performed to investigate a method to determine the interface location and the layer thickness of multilayer films by secondary ion mass spectrometry (SIMS) depth profiling as a preliminary study to develop a new work item proposal in ISO/TC‐201. Two types of reference materials were used in this RRT. A SiGe alloy (Si52.4Ge47.6) reference film was used to determine the relative sensitivity factors of Si and Ge. A Si/Ge multilayer reference film was used to determine the relative sputtering rates of the Si and Ge layers. The layer thicknesses were measured from the interfaces determined by a 50 atomic percent definition. Seven laboratories from 5 countries participated in this international RRT. The RRT reference expanded uncertainties for Si and Ge layers in a Si/Ge multilayer with similar thicknesses as the reference film were 0.76 and 1.17 nm, respectively. However, those in a thinner Si/Ge multilayer film were slightly larger at 1.04 and 1.59 nm, respectively. Most of the thickness ratios in the 2 Si/Ge multilayer films were consistent with the RRT reference value within their expanded uncertainties.
Catalyst‐Free, Glycerol‐Assisted Facile Approach to Imidazole‐Fused Nitrogen‐Bridgehead Heterocycles
Authors: Tufail Fatima , Singh Swastika , Saquib Mohammad , Tiwari Jyoti , Singh Jaya , Singh Jagdamba
Published: July 2017

A completely regioselective, environmentally benign strategy for the facile synthesis of biologically important imidazole‐fused nitrogen‐bridgehead heterocycles has been developed using glycerol/water 4:1 as a green promoting media. The methodology involves the simple coupling of 2‐halocarbonyl compounds with 2‐aminopyridines, 2‐aminopyrimidines, 2‐aminopyrazines to obtain a variety of 2‐aryl substituted imidazo‐pyridines, imidazo‐pyrimidines and imidazo‐pyrazines containing bridgehead nitrogen. This protocol eliminates the use of toxic catalysts and volatile organic solvents ‐ two key principles in the development of a green chemical process. Other significant highlights include mild reaction conditions, operational simplicity, short reaction times, easy workup and purification process, high yields and potential for scale‐up.
Engineering Globular Protein Vesicles through Tunable Self‐Assembly of Recombinant Fusion Proteins
Authors: Jang Yeongseon , Choi Won Tae , Heller William T. , Ke Zunlong , Wright Elizabeth R. , Champion Julie A.
Published: July 2017

Vesicles assembled from folded, globular proteins have potential for functions different from traditional lipid or polymeric vesicles. However, they also present challenges in understanding the assembly process and controlling vesicle properties. From detailed investigation of the assembly behavior of recombinant fusion proteins, this work reports a simple strategy to engineer protein vesicles containing functional, globular domains. This is achieved through tunable self‐assembly of recombinant globular fusion proteins containing leucine zippers and elastin‐like polypeptides. The fusion proteins form complexes in solution via high affinity binding of the zippers, and transition through dynamic coacervates to stable hollow vesicles upon warming. The thermal driving force, which can be tuned by protein concentration or temperature, controls both vesicle size and whether vesicles are single or bi‐layered. These results provide critical information to engineer globular protein vesicles via self‐assembly with desired size and membrane structure.
TiO2 Feather Duster as Effective Polysulfides Restrictor for Enhanced Electrochemical Kinetics in Lithium–Sulfur Batteries
Authors: Lei Tianyu , Xie Yiming , Wang Xianfu , Miao Shengyi , Xiong Jie , Yan Chenglin
Published: July 2017

The rechargeable lithium–sulfur battery is recognized as a promising candidate for electrochemical energy storage system because of their exceptional advance in energy density. However, the fast capacity decay of sulfur cathode caused by polysulfide dissolution and low specific capacity caused by poor electrical conductivity still impede the further development of lithium–sulfur battery. To address above issues, this study reports the synthesis of feather duster‐like TiO2 architecture by in situ growth of TiO2 nanowires on carbon cloth and further evaluates as sulfur host material. The strong chemical binding interaction between the polysulfides and TiO2 feather duster efficiently restrains the shuttle effect, leading to enhanced electrochemical kinetics. Besides, the in situ grown TiO2 NWs array also supply high surface for sulfur‐loading and fast path for electron transfer and ion diffusion. As results, the novel CC/TiO2/S composite cathode exhibits a high capacity of 608 mA h g−1 at 1.0 C after 700 cycles corresponding to capacity decay as low as 0.045% per cycle with excellent Coulombic efficiency higher than 99.5%.
Stopping on Nine: Evidence of Heuristic Managerial Decision‐Making in Major League Baseball Pitcher Substitutions
Authors: Phillips David C.
Published: July 2017

Economic agents who exhibit left digit bias over‐emphasize round numbers. Using data on managers' pitcher substitution decisions in Major League Baseball, I find that managers remove starting pitchers more often when the next pitch will result in a pitch count ending in zero. Unlike counts ending in nine, pitch counts ending in eight do not exhibit higher substitution rates despite the fact that pitchers usually throw multiple pitches before the manager's next decision opportunity. Managers apparently use rules‐of‐thumb that emphasize leftmost digits and ignore at least some future consequences of present actions. However, these significant biases disappear when the stakes are high. I find no evidence of disproportionate substitutions on the nine's in close games, and the final digit of the pitch count does not discontinuously affect the probability of winning. Managers act in a manner consistent with rational inattention, using heuristics only when the stakes are low.
Citrate esterified cassava starch: Preparation, physicochemical characterisation, and application in dairy beverages
Authors: Oltramari Karine , Madrona Grasiele Scaramal , Neto André Monge , de Morais Gutierrez Rodrigues , Baesso Mauro Luciano , de Cássia. Bergamasco Rita , de Moraes Flavio Faria
Published: July 2017

This study aimed to produce and characterise citrate esterified resistant starch (RS) from cassava, and apply it in a dairy beverage. The citrate esterified cassava starch (CECS) was prepared by thermo‐acid catalysed esterification and the product was characterised for RS content, solubility, swelling power, and water absorption. Scanning electron microscopy, viscoamylographic analysis, X‐ray diffraction and Fourier‐transform infrared spectroscopy were used. The CECS was added to a dairy beverage and then the rheological and sensory characteristics were evaluated. The results showed a 60.08% increase in RS content, revealing the occurrence of fissures and overlapping layers in the starch granules. There was a decrease in solubility, swelling power and water absorption, and formation of ester bonds. The rheological characteristics showed a non‐Newtonian pseudoplastic fluid behaviour for the CECS incorporated dairy beverage. The addition of 1.5% CECS to the dairy beverage influenced the colour, taste and consistency, while the addition of 0.5% CECS showed a greater purchase intention, providing an opportunity for development of functional dairy products. In conclusion, this work shows that the developed resistant starch is a promising functional ingredient, with promising applications in the food industry.
Concise Review: Stem Cells for Corneal Wound Healing
Authors: Saghizadeh Mehrnoosh , Kramerov Andrei A. , Svendsen Clive N. , Ljubimov Alexander V.
Published: July 2017

Corneal wound healing is a complex process that occurs in response to various injuries and commonly used refractive surgery. It is a significant clinical problem, which may lead to serious complications due to either incomplete (epithelial) or excessive (stromal) healing. Epithelial stem cells clearly play a role in this process, whereas the contribution of stromal and endothelial progenitors is less well studied. The available evidence on stem cell participation in corneal wound healing is reviewed, together with the data on the use of corneal and non-corneal stem cells to facilitate this process in diseased or postsurgical conditions. Important aspects of corneal stem cell generation from alternative cell sources, including pluripotent stem cells, for possible transplantation upon corneal injuries or in disease conditions are also presented.
A strain model for fatigue‐loaded concrete
Authors: von der Haar Christoph , Marx Steffen
Published: July 2017

In this contribution, an additive strain model is used to describe the deformation behavior of concrete. The model assumes that elastic, viscous, thermal, and damage‐induced strains occur in concrete. The strain components develop independently of each other as a function of the number of load cycles, test duration, and characteristic parameters of the stress cycles. The focus of this paper is on the determination of a creep‐relevant stress level to estimate the magnitude of the viscous deformation component as a function of the fatigue stress. Experimentally measured strains of fatigue‐loaded concrete specimens are divided into the strain components assumed by the additive strain model and analyzed. The investigations yield new insights into the strain and material behavior of fatigue‐loaded concrete.
The Reaction of Diethylthiophosphinyl Iodide, Et2P(S)I, with Nucleophiles
Authors: Tsivgoulis Gerasimos M. , Kordopati Golfo G. , Vachliotis Dimitris G. , Ioannou Panayiotis V.
Published: July 2017

The compound Me2AsSI can exist in two different forms, either as dimethylarsinosulfenyl iodide [or (iodothio)dimethylarsane)], Me2As–S–I (A), or as dimethylthioarsinyl iodide (or dimethylarsinothioic iodide), Me2As(S)–I (B). To confirm that the structure of the product of the reaction between Bunsen's cacodyl disulfide Me2As(S)–S–AsMe2 and iodine is A and not B, the known diethylthiophosphinyl iodide (or diethylphosphinothioic iodide), Et2P(S)–I (2) was prepared and its hydrolytic stability and reactivity towards a variety of nitrogen, phosphorus(III), arsenic(III), oxygen, and sulfur(II) nucleophiles were studied. The results indicated that only a few reactions of 2 resembled those of A, thus strengthening the proposal that the reaction of Bunsen's cacodyl disulfide with iodine produced A and not B. A series of 31P NMR chemical shifts of diethylthiophosphinyl moiety is also reported. Et2P(S)–DMAP, synthesized and isolated during the presented study, is the ethyl analogue of Me2P(S)–DMAP, previously described as an important molecule. In our case, Et2P(S)–DMAP was found to be a good intermediate for the synthesis of phosphoryl or thiophosphoryl derivatives since it was more reactive than 2 towards nucleophiles.
Short‐Term Outcomes of Totally Laparoscopic Central Hepatectomy and Right Anterior Sectionectomy for Centrally Located Tumors: A Case‐Matched Study with Propensity Score Matching
Authors: Cho Chan Woo , Rhu Jinsoo , Kwon Choon Hyuck David. , Choi Gyu‐Seong , Kim Jong Man , Joh Jae‐Won , Koh Kwang‐Cheol , Kim Gaab Soo
Published: July 2017

Background

Recent advances in technology and accumulation of surgical experience have expanded the indications for laparoscopic liver resection (LLR). However, compared to open liver resection (OLR), the feasibility of laparoscopic anatomical liver resection for centrally located tumor (CLT) has not been clearly established. The aim of our study was to assess the feasibility and safety of laparoscopic anatomical major liver resection for CLT.

Methods

From April 2011 to March 2016, 20 cases of anatomical LLR and 86 cases of OLR for CLTs such as central hepatectomy (CH) and right anterior sectionectomy (RAS) were performed at a single institution. We performed one‐to‐one propensity score matching and analyzed short‐term outcomes between the LLR (n = 20) and OLR (n = 20) groups.

Results

Among 20 cases in the LLR group, two cases underwent open conversion due to common bile duct injury and anatomical distortion, respectively. There were no statistically significant difference between the LLR and OLR groups regarding clamping time of the Pringle maneuver (p = 0.502), blood loss (p = 0.746), surgical margin (p = 0.198), or length of hospital stay (p = 0.110). However, surgical time was significantly longer in the LLR group than in the OLR group (388 vs 268 min; p < 0.001). There were no significant differences between the two groups with regard to morbidity rate or mean comprehensive complication index (p = 0.716 and p = 0.819, respectively).

Conclusion

Total anatomical LLR can be performed safely in selected CLT patients by experienced surgeons. Laparoscopic CH or RAS appears feasible with non‐inferior perioperative outcomes compared to OLR.
Best friends' interactions and substance use: The role of friend pressure and unsupervised co‐deviancy
Authors: Tsakpinoglou Florence , Poulin François
Published: July 2017

Best friends exert a substantial influence on rising alcohol and marijuana use during adolescence. Two mechanisms occurring within friendship ‐ friend pressure and unsupervised co‐deviancy ‐ may partially capture the way friends influence one another. The current study aims to: (1) examine the psychometric properties of a new instrument designed to assess pressure from a youth's best friend and unsupervised co‐deviancy; (2) investigate the relative contribution of these processes to alcohol and marijuana use; and (3) determine whether gender moderates these associations. Data were collected through self‐report questionnaires completed by 294 Canadian youths (62% female) across two time points (ages 15–16). Principal component analysis yielded a two‐factor solution corresponding to friend pressure and unsupervised co‐deviancy. Logistic regressions subsequently showed that unsupervised co‐deviancy was predictive of an increase in marijuana use one year later. Neither process predicted an increase in alcohol use. Results did not differ as a function of gender.
The Effectiveness of Nurse Residency Programs on Retention: A Systematic Review
Authors: Van Camp Jennifer , Chappy Sharon
Published: July 2017

New graduates account for the highest numbers of nurses entering and exiting the profession. Turnover is costly, especially in specialty settings. Nurse residency programs are used to retain new graduates and assist with their transition to nursing practice. The purpose of this systematic review of the literature was to examine new graduate nurse residency programs, residents’ perceived satisfaction, and retention rates, and to make recommendations for implementation in perioperative settings. Results indicate increased retention rates for new graduates participating in residency programs and that residency participants experienced greater satisfaction with their orientation than those not participating in residency programs. Residency participants also perceived the residency as beneficial. Because residency programs vary in curricula and length, effectively comparing outcomes is difficult. More longitudinal data are needed. Data on residency programs specific to perioperative nursing are lacking. Considering the aging perioperative nursing workforce, residency programs could address critical needs for succession planning.
Guideline Implementation: Minimally Invasive Surgery, Part 2—Hybrid ORs
Authors: Cowperthwaite Liz , Fearon Mary C.
Published: July 2017

Performing both surgical and imaging procedures in a hybrid OR can increase efficiency by reducing the number of patient transfers between departments and the number of patient hand overs between personnel. A hybrid OR is, however, a complex environment that requires integrating the knowledge and skills of personnel from multiple disciplines to create a successful workflow. When magnetic resonance imaging (MRI) equipment is installed in the hybrid OR, additional precautions are required to help ensure the environment is safe for patients and personnel. AORN's updated “Guideline for minimally invasive surgery” provides guidance for personnel designing and working in hybrid ORs and MRI hybrid ORs. This article focuses on key points of the guideline that address hybrid OR configuration, hybrid OR staffing, and mitigating risks associated with intraoperative MRI. Perioperative RNs should review the complete guideline for additional information and for guidance when writing and updating policies and procedures.
Experimental investigation of the turbulence induced by a bubble swarm rising within incident turbulence
Authors: Alméras Elise , Mathai Varghese , Lohse Detlef , Sun Chao
Published: July 2017

This work reports an experimental characterisation of the flow properties in a homogeneous bubble swarm rising at high Reynolds numbers within a homogeneous and isotropic turbulent flow. Both the gas volume fraction $\unicode[STIX]{x1D6FC}$ and the velocity fluctuations $u_{0}^{\prime }$ of the carrier flow before bubble injection are varied, respectively, in the ranges $0\,\%<\unicode[STIX]{x1D6FC}<0.93\,\%$ and $2.3~\text{cm}~\text{s}^{-1}<u_{0}^{\prime }<5.5~\text{cm}~\text{s}^{-1}$. The so-called bubblance parameter ($b=V_{r}^{2}\unicode[STIX]{x1D6FC}/u_{0}^{\prime 2}$, where $V_{r}$ is the bubble relative rise velocity) is used to compare the ratio of the kinetic energy generated by the bubbles to the one produced by the incident turbulence, and is varied from 0 to 1.3. Conditional measurements of the velocity field downstream of the bubbles in the vertical direction allow us to disentangle three regions that have specific statistical properties, namely the primary wake, the secondary wake and the far field. While the fluctuations in the primary wake are similar to that of a single bubble rising in a liquid at rest, the statistics of the velocity fluctuations in the far field follow a Gaussian distribution, similar to that produced by the homogenous and isotropic turbulence at the largest scales. In the secondary wake region, the conditional probability density function of the velocity fluctuations is asymmetric and shows an exponential tail for the positive fluctuations and a Gaussian one for the negative fluctuations. The overall agitation thus results from the combination of these three contributions and depends mainly on the bubblance parameter. For $0<b<0.7$, the overall velocity fluctuations in the vertical direction evolve as $b^{0.4}$ and are mostly driven by the far-field agitation, whereas the fluctuations increase as $b^{1.3}$ for larger values of the bubblance parameter ($b>0.7$), in which the significant contributions come both from the secondary wake and the far field. Thus, the bubblance parameter is a suitable parameter to characterise the evolution of liquid agitation in bubbly turbulent flows.
Microstructure and thickening of dense suspensions under extensional and shear flows
Authors: Seto Ryohei , Giusteri Giulio G. , Martiniello Antonio
Published: July 2017

Dense suspensions are non-Newtonian fluids that exhibit strong shear thickening and normal stress differences. Using numerical simulation of extensional and shear flows, we investigate how rheological properties are determined by the microstructure that is built under flows and by the interactions between particles. By imposing extensional and shear flows, we can assess the degree of flow-type dependence in regimes below and above thickening. Even when the flow-type dependence is hindered, non-dissipative responses, such as normal stress differences, are present and characterise the non-Newtonian behaviour of dense suspensions.
The feasibility of imaging subglacial hydrology beneath ice streams with ground-based electromagnetics
Authors: KEY KERRY , SIEGFRIED MATTHEW R.
Published: July 2017

Subglacial hydrologic systems in Antarctica and Greenland play a fundamental role in ice-sheet dynamics, yet critical aspects of these systems remain poorly understood due to a lack of observations. Ground-based electromagnetic (EM) geophysical methods are established for mapping groundwater in many environments, but have never been applied to imaging lakes beneath ice sheets. Here, we study the feasibility of passive- and active-source EM imaging for quantifying the nature of subglacial water systems beneath ice streams, with an emphasis on the interfaces between ice and basal meltwater, as well as deeper groundwater in the underlying sediments. We describe a suite of model studies that exam the data sensitivity as a function of ice thickness, water conductivity and hydrologic system geometry for models representative of a subglacial lake and a grounding zone estuary. We show that EM data are directly sensitive to groundwater and can image its lateral and depth extent. By combining the conductivity obtained from EM data with ice thickness and geological structure from conventional geophysical techniques, such as ground-penetrating radar and active seismic surveying, EM data have the potential to provide new insights on the interaction between ice, rock and water at critical ice-sheet boundaries.