bluuebunny/crossref_metadata_2025 huggingface dataset:
Modelling approach towards tailored grain structure in laser processing
Authors: Pustal B. , Vossel T. , Bührig‐Polaczek A. , Arntz D. , Haeusler A. , Gillner A. , Poprawe R. , Schwedt A. , Mayer J. , Jansen U. , Schöler C. , Schulz W.
Published: January 2018

Due to the change in grain size during laser processing in the heat‐affected zone and the solidifying material, the potential of cracking, surface hardening, and decrease in weldability, corrosion resistance and fatigue life may result. It is shown that through combining state‐of‐the‐art temperature simulation of laser processes with thermo‐mechanical volume averaging grain formation simulation, the resulting grain density can be predicted within the order of magnitude found in the two experiments carried out for laser fusion cutting and spot welding of A356. However, fundamental knowledge about the grain density function during rapid solidification, the prediction of the transition from epitactic growth to globular grains and defined validation experiments are needed in order to provide a realistic virtual microstructure.
Development of an A356 die casting setup for determining the heat transfer coefficient depending on cooling conditions, gap size, and contact pressure
Authors: Wolff N. , Pustal B. , Vossel T. , Laschet G. , Bührig‐Polaczek A.
Published: January 2018

In this paper, the development of an experimental die casting setup to perform simultaneous in‐situ measurements of temperatures, air‐gap formation and contact pressures is presented. The derivation of the resulting heat transfer coefficients between mold and melt is also included. To take the influence of different cooling rates into account, an active die tempering is applied. For the implementation of this experimental setup, a special mold for a rotationally symmetrical test specimen is developed which incorporates the necessary measuring technique and can be adapted to different cooling conditions by means of exchangeable die inserts. Concluding, first results and the corresponding heat transfer coefficients are presented.
Formation of the reaction zone between tin‐copper brazing fillers and aluminum‐silicon‐magnesium alloys: Experiments and thermodynamic analysis
Authors: Bobzin K. , Öte M. , Wiesner S. , Schmidt A. , Apel M. , Berger R. , Aretz A. , Mayer J.
Published: January 2018

A primary challenge in brazing is the controlled formation of phases resulting from interactions of elements of the liquid filler metal with those of the base material. The morphology of the brazed joint, which is decisive for the mechanical properties of the joint, is influenced by present elements and process parameters such as brazing temperature and time. Furthermore, the wetting of the base material is a crucial factor in joining of aluminum because of the low wettability of the alumina layer by molten brazing filler metals. In order to remove the alumina and prevent reoxidation of the substrate surface, the brazing process can be conducted in vacuum or inert gas atmosphere. Again, selection of process parameters is crucial for the quality of the brazed seam. In this work, we focus on the influence of the process parameters on the wetting behavior and the formation of aluminum‐copper phases theoretically by means of thermodynamic calculations using a CALPHAD database as well as by means of in‐situ observations in the large‐chamber scanning electron microscope (LC‐SEM) and by brazing experiments. Both the critical temperatures with respect to the wetting and the reaction kinetics as well as the crucial stages of the brazing process and the resulting phases were determined.
Microstructural analysis of germanium modified tin‐copper brazing filler metals for transient liquid phase bonding of aluminium
Authors: Iskandar R. , Schwedt A. , Mayer J. , Rochala P. , Wiesner S. , Öte M. , Bobzin K. , Weirich T.E.
Published: January 2018

The present contribution summarises first results that have been achieved with the new brazing material Sn75Cu20Ge5 (wt‐%) for transient liquid phase (TLP) bonding of aluminium cast alloy AlSi7Mg0.3 (wt‐%). The microstructure of the braze ribbons and the obtained joints have been thoroughly investigated on different length‐scales using scanning and transmission electron microscopy as well. Whereas the braze ribbon material is only composed of beta‐tin, η‐phase (Cu6Sn5) and some germanium rich precipitates, the transient liquid phase joint displays a much more complex microstructure that consist mainly of beta‐tin and different aluminium‐copper and aluminium‐germanium phases. In addition small silicon oxide rods and a hitherto unreported hexagonal aluminium‐copper‐magnesium‐germanium phase with approximated lattice parameters a = 0.7123 nm, c = 2.40 nm have been found in the seam of the joint.
Residual stress measurement in AlSi alloys
Authors: Reisgen U. , Sharma R. , Gach S. , Olschok S. , Francis J. , Bobzin K. , Oete M. , Wiesner S. , Knoch M. , Schmidt A.
Published: January 2018

In this work, the relaxation of residual stresses inside a sample made of the aluminum alloy AlSi7Mg0.3 after tempering is described. The comparison of stress evaluation by X‐ray diffraction and incremental hole drilling method combined with electronic speckle pattern interferometry strain determination gives the opportunity to evaluate micro stresses together with first order macro stresses. Compressive stresses within the surface of a cold worked sample are relaxed by tempering. The X‐ray diffraction evaluation is supported by the analysis of a stress‐free sample through incremental hole drilling method.
An automatable algorithm for measurement of fluid flow during laser fusion cutting using in‐situ trim cut analysis
Authors: Jansen U. , Arntz D. , Petring D. , Schulz W. , Poprawe R.
Published: January 2018

Irregularities inside the fluid flow in laser fusion cutting of sheet metals cause quality defects like large striation depths or adhered dross. Trim‐cut analysis is used to measure the flow velocities of the molten material by high speed imaging. The so‐called streak analysis creates a repetitive pattern for multiple melt waves and the angle of these patterns is assignable to specific flow velocities. In this article, a discrete fourier transform is used to automatically determine the spatial distribution of flow velocities. The results show that identifying the velocity domains and assigning them to the parameters of the cutting process and quality characteristics is a promising approach to enhance the understanding and to achieve higher quality cuts.
Beam steering by using a gradient refractive index metamaterial planar lens and a gradient phase metasurface planar lens
Authors: Liu Yahong , Liu Congcong , Jin Xueyu , Zhang Beiyi , Zhang Yinghuai , Zhu Xinqi , Su Bin , Zhao Xiaopeng
Published: January 2018

Metamaterials are composed of periodic or quasi‐periodic subwavelength structures, having electric and/or magnetic responses. Metamaterials can arbitrarily tailor the refractive index by artificially tailoring the unit‐cell geometries and dimensions. Recent years, as the two dimensional equivalent of bulk metamaterials, metasurfaces have caused considerable attentions due to the lower profile and simpler to fabricate than bulk metamaterials. Metasurfaces can impart discontinuities on electromagnetic wavefronts and can achieve the arbitrary transmission phase of the whole period range. Metamaterials and metasurfaces have led to the realizations of novel electromagnetic properties and functionalities through tailoring subwavelength structures and integrating functional materials. In this letter, two planar lenses are respectively proposed to control the beam direction of the horn antenna by using a gradient refractive index (GRIN) metamaterial and a gradient phase (GRPH) metasurface. It is shown that the antenna beam direction can be steered by controlling the refractive index of the GRIN metamaterial or the transmission phase of the GRPH metasurface. The differences between the two planar lenses for controlling the antenna beam are illustrated.
Quasi‐fractal antenna system based on asymmetric TEM‐horns nested into each other
Authors: Ashikhmin Aleksandr V. , Negrobov Alexander V. , Pasternak Yuriy G. , Pershin Pavel V. , Fedorov Sergey M.
Published: January 2018

In this article was studied a way to minimize the overall dimensions of a multiband antenna system operating in a number of ultra‐wideband frequency bands using the quasi‐fractal construction principle. The results of an experimental study of the designed antenna element, which is a set of asymmetrical self‐similar TEM‐rupors nested into each other, are presented.
Design of a miniaturized frequency reconfigurable antenna for rectenna in WiMAX and ISM frequency bands
Authors: Naqvi Syed Aftab , Khan Muhammad Saeed
Published: January 2018

A frequency reconfigurable miniaturized circular microstrip patch antenna operating in WiMAX (2.5–2.8 GHz) and ISM (2.4–2.48 GHz) frequency bands for the rectenna applications is proposed here. The theory of reconfigurability is employed to switch the operating frequency of the proposed antenna from 2.53 to 2.45 GHz. The electrical length of the radiated circular patch is increased while keeping the overall physical dimension of the antenna constant to provide different current distributions on the radiating patch for the phenomenon of frequency shift. The high permittivity substrate and microstrip transmission‐line feeding mechanism is used to reduce the size of antenna. To demonstrate the reduction in antenna size, a comparison of the proposed antenna with the latest antennas for rectenna applications in literature is presented.
Sext‐band bandpass filter with compactness based on cascading stage of SIRs
Authors: Li Xiaokun , Zhang Yonghong , Tang Yaozong , Xu Jingzhi , Zhang Jie , Yong Fan
Published: January 2018

Utilizing cascading stage of SIRs (CSIRs), a miniaturized sext‐band bandpass filter is investigated and fabricated. Purposely, two‐section SIRs with high/low impedance‐ratio are built up for not only enough spurious frequency for sext‐band application, but excellent control on these frequencies. In addition, architecture of CSIR, namely number and arrangement of employed SIRs, is optimized for widening potential frequency range with good response in each passband. Meanwhile, on account of transversal signal interaction concept together with mixed electric magnetic coupling of CSIRI,II, transmission zeros (TZs) and transmission poles (TPs) can be excited alternately. Since coupling is introduced by embedding CSIRs without adding any other structures, configuration of proposed design is compact. Moreover, tapped position of 0° feeding branch can be adjusted for improving filter performance. Therefore, design of miniaturized sext‐band bandpass filter becomes available. Good agreement between simulated and measured results validates the design method.
A new CPW‐fed broadband circularly polarized printed monopole antenna for UWB application
Authors: Zhai Huiqing , Yang Dong , Xi Lei , Feng Dan
Published: January 2018

A new coplanar‐waveguide (CPW) ‐fed circularly polarized (CP) printed monopole Antenna with a simply structure is presented. By utilizing an asymmetrical T‐shaped matching stub as feedline and nesting two strips of inverted‐L‐shaped and rectangle into both sides of the ground plane along the edge of the substrate, good impedance matching and CP radiation can be obtained. The proposed antenna is tested and its measured result is fairly identical with the simulated result. It exhibits that the impedance bandwidth for S11<−10 dB is as large as 115% (3.1–11.9 GHz) which can apply to the UWB communication. The 3‐dB axial‐ratio bandwidth (ARBW) reaches 62.6% from 3.4 GHz to 6.5 GHz.
Low group delay variation 3‐10 GHz 65 nm CMOS stacked power amplifier with 18.1 dBm peak 1 dB compression output power
Authors: Polge David , Ghiotto Anthony , Kerhervé Eric , Fabre Pascal
Published: January 2018

A 3‐10 GHz stacked power amplifier (PA) with low group delay variation and 18.1 dBm peak 1 dB compression output power (P1dB) in 65 nm CMOS bulk technology is presented. It is intended for ultra‐wideband or multiband telecommunication, sensing, and instrumentation systems operating in the 3‐10 GHz frequency range situated in the S, C, and X bands. Its design, based on stacked transistors allowing a supply voltage as high as 4 V to achieve a high 1 dB compression output power, is detailed. In the 3–10 GHz band, the proposed PA provides measured gain, P1dB, and maximum power added efficiency (PAEmax) of 12.65 ± 1.25 dB, 16 ± 2.1 dBm, and 20.15 ± 7.55%, respectively. In addition, in its frequency range of operation, this PA achieves an excellent measured group delay variation of ±21.55 ps. To the authors’ knowledge, this wideband PA offers the lowest group delay variation in this frequency range of operation.
Dual wide‐band miniaturized negative group delay circuit using open circuit stubs
Authors: Taher Hany , Farrell Ronan
Published: January 2018

In this letter, dual band negative group delay circuit (DBNGDC) utilizing a couple of one quarter guided wave length (
) open circuited stubs (OCSs) is presented. The centre frequencies (
) are fully controlled with the stub lengths. On the other hand, the target negative group delay (NGD) is obtained using couple of resistors (
) that connect each OCS to the main microstrip line. The designed DBNGDC accomplishes 52% size diminution compared with smallest size has ever been achieved before. Moreover, 0.2 and 0.4 GHz zero‐NGD bandwidths (BW) are achieved.
Liquids electrical characterization sensor using a hybrid SIW resonant cavity
Authors: Caleffo Ricardo Caranicola , Correra Fatima Salete
Published: January 2018

A new sensor based on substrate integrated waveguide (SIW) technology is proposed as an option for liquids electrical characterization. The sensor employs a rectangular waveguide resonant cavity filled with air, with two opposite side walls implemented by closely spaced metallic vias. The resulting structure is a hybrid SIW resonant cavity. The two noncontinuous walls of the hybrid SIW cavity allow the liquid insertion, filling its entire internal volume. The resonance frequency of the hybrid SIW cavity is used to determine the dielectric constant of the liquid to be characterized. A sensor using a hybrid SIW cavity operating in TE101 mode was designed to resonate at 5.9 GHz when filled with air. The sensor was employed to measure the dielectric constant of binary mixtures of distilled water and ethanol. Dielectric constants ranging from 21 to 79 were obtained, corresponding to measured resonance frequencies from 1,247 to 647 MHz, respectively. Good agreement was observed between computational electromagnetic simulation and experimental results. The dependence of the volumetric fraction of ethanol in the binary mixture on the sensor resonance frequency was expressed using a third‐order polynomial approximation.
Compact dual band slotted triangular monopole antenna for RFID applications
Authors: Dehmas M. , Azrar A. , Mouhouche F , Djafri K. , Challal M.
Published: January 2018

This paper presents a compact monopole antenna for radio frequency identification (RFID) systems. The proposed antenna is a dual band structure that can operate in the frequency ranges [0.797–1.004 GHz] and [2.234–2.934 GHz]. Consequently, the antenna covers widely the two UHF bands dedicated for RFID applications which are [0.860–0.960 GHz] and [2.380–2.520 GHz]. Moreover, the antenna is compact and its wide band nature makes it suitable for several applications other than RFID (GSM, UMTS, Wi‐Fi, Bluetooth, etc.). The proposed antenna has been fabricated and its reflection coefficient measured where a good agreement is observed with the simulated results.
Vivaldi tapered slot reflectarray loaded with dumbbell‐shaped ring resonator
Authors: Phua Y. N. , Lim E. H. , Chung B. K.
Published: January 2018

The Vivaldi tapered slot antenna is incorporated with a dumbbell‐shaped microstrip ring resonator for designing a reflectarray that can achieve a maximum phase range of 371° and a −1‐dB gain bandwidth of 10.6%. Use of travelling‐wave radiator has made possible full phase range and low phase sensitivity.
A directivity enhanced structure for the Vivaldi antenna using coupling patches
Authors: Gao Chong , Li En , Zhang Yunpeng , Guo Gaofeng
Published: January 2018

A novel structure to improve the directivity of the Vivaldi antenna by adding three metal patches on the end‐fire is introduced. The two side patches that were close to the radiator change the E‐field distribution of the traveling wave, and the middle patch was a director. The strong coupling between the radiator and side patches led to the constraint of much E‐field energy between the side coupling patches, and this structure reduces the current on the end of radiation aperture. Compared with the other antennas, the Vivaldi antenna with the two side coupling patches did not compromise the frequency range, but decreased the radiation of the side lobes especially at high frequencies. The measured results showed that this proposed antenna operated in an ultra‐wide frequency range of 2 GHz to 18.7 GHz. The directivity of the proposed antenna has been greatly improved, with a maximum increment of 4 dB at 15 GHz. This enhanced structure showed good universality for the other Vivaldi antennas.
Current tunable barium hexaferrite millimeter wave resonator
Authors: Popov M. A. , Zavislyak I. V. , Srinivasan G.
Published: January 2018

This report is on non‐linear magneto‐electric (ME) interactions due to an electric current in single crystal M‐type barium hexaferrite (BaM). The interaction results in variations in the magnetic order parameters and manifests as tuning of magnetic modes in a BaM resonator in the U‐band. A DC current along the c‐axis of the ferrite is found to tune the frequency of the magnetic mode by 400 MHz when the sample is in the single‐domain state and by 70 MHz in the multi‐domain state for currents up to 20 mA and applied voltages up to 75 V. The current tuning of the frequency is found to be linear with electric power for both single‐domain and multi‐domain resonances. The shift in mode frequency due to current is found to be an order of magnitude higher than shift that could be attributed to Joule heating. The current tuning of the resonator demonstrated here is of interest for miniature, self‐biased millimeter wave ferrite devices.
Novel wideband chaotic approach LNA with microcontroller compatibility for 5G wireless secure communication
Authors: Jayawickrama Chamindra , Kumar Sandeep , Song Hanjung
Published: January 2018

The tremendous growth of recent technologies toward secure communication networks requires two application goals: (1) encrypted message signal and (2) wide bandwidth operation. This work proposes a wide bandwidth disembodied polynomial chaos approach low‐noise amplifier (LNA) with microcontroller compatibility for 5G wireless secure communication. Two different architectures are proposed for achieve desired goal. First architecture approach uses three‐state variable Lorenz system which novitiate into discrete mode by using Euler method and make compatibility with microcontroller. The characteristics of output chaotic waveforms from first approach realized by using bifurcation and Lyapunov exponent methods. The propose first novel design methodology reproduce its dynamical behavior with conventional continuous‐time system and provides three output chaotic states which is used to encrypt message at the physical layer and achieves security in the telecommunication technologies. While in second architecture, LNA is designed using disembodied polynomial chaos approach which reproduce chaotic output signal over wide bandwidth ranging from 2 to 10 GHz. The LNA is implemented and fabricated using TSMC 45 nm commercial process and reveals minimum noise figure up to 1.5 dB. The fabrication chip of chaos approach LNA under the power consumption of 3.2 mW made good correlation with simulation ones.
Study of a parasitic U‐slot patch array antenna with characteristic mode analysis
Authors: Yeung Sai Ho , Wang Chao‐Fu
Published: January 2018

This letter presents and analyses a novel parasitic U‐slot patch array antenna, designed by combining the characteristic of U‐slot patch antenna and the characteristic of parasitically coupled antenna elements. Characteristic mode analysis is performed on the novel antenna to reveal the potential of the new radiating structure.
Comments on: Design and implementation of second‐order microwave integrators
Authors: Gupta Mridul , Upadhyay Dharmendra Kumar
Published: January 2018

We comment on “Design and implementation of second‐order microwave integrators” (Microw Opt Tech Lett. 53 (2011), 1983–1986).
Reduced size of the λg/4 transmission line using immitance scaling for RF device applications
Authors: Lee Tae‐Hyeon , Yoon Ki‐Cheol , Son Kwang‐Chul
Published: January 2018

This article presents the proposed reduced size of the λg/4 transmission line (TL) using immitance scaling. The proposed compact size of the TL is used for immitance scaling, which is composed of folded open stubs and series TL. It can be the design for distributed elements instead of lumped elements in a shunt capacitor, which is therefore called the folded open stubs. The proposed compact TL can be applied to a Wilkinson power divider (combiner), hybrid branch line coupler, and stub band‐pass filter in microwave applications.
Simplified optical generation of microwave signal based on polarization multiplexing using an optical phase modulator
Authors: Xu Wenjing , Gao Xinlu , Zhao Mingyang , Xie Mutong , Huang Shanguo
Published: January 2018

A new method to generate microwave signal with frequency doubled of the RF signal using an optical phase modulator by simply adjusting the polarization angle of the polarizer without any optical filters is experimentally proposed. The optical carrier is 19 dB lower than the 2 first‐order sidebands, which is better than the traditional optical carrier suppression double sideband modulation scheme. After detected by a high speed photodiode, a high spectrum purity 28 GHz microwave signal is generated easily. In addition, as pure optical carrier can also be recovered easily, the proposed scheme is cost‐effective and may be useful for the radio over fiber system with wavelength reuse.
Electromagnetic band gap waveguide and bends substrate integrated waveguide
Authors: Grine Farouk , Djerafi Tarek , Khalef Rostom , Benhabiles Mohamed Ttaoufik , Riabi Mohamed Lahdi
Published: January 2018

A planar waveguide and a rounded bend is proposed, designed, and implemented through a hybrid structure of substrate integrated waveguide (SIW) and electromagnetic bandgap (EBG) material. In order to design the EBG waveguide, a square lattice of air holes situated between two metal plates is used. The SIW line and bend are inserted on EBG waveguide to enhance performance. These devices were fabricated and measured. The experimental results show a homogeneous agreement with the simulation. The combination EBG‐SIW covers almost the whole EBG bandwidth of 6 GHz (17%) around 35 GHz. The proposed hybrid integration technique presents a competitive candidate for the development of millimeter‐wave circuits and systems.
The economic burden of overactive bladder in the United States: A systematic literature review
Authors: Powell Lauren C. , Szabo Shelagh M. , Walker David , Gooch Katherine
Published: January 2018

Aims

Overactive bladder (OAB) affects up to 17% of the United States (US) population. This study aimed to synthesize estimates of direct and indirect costs of OAB in the US and compare costs among those with and without OAB.

Methods

A systematic review was performed using MEDLINE/PubMed and Embase, from 2003 to 2016, following PRISMA guidelines. The target population was adults with idiopathic OAB or urge urinary incontinence from the US. Data were extracted on study and patient characteristics, all‐cause and OAB‐specific direct costs, resource use, and indirect costs. Costs were inflated to a common price year of 2016 USD.

Results

Eighteen studies were included. Mean insurer paid all‐cause total direct healthcare costs ranged from 8168 to 15 569 USD, and OAB‐specific costs ranged from 656 to 860 USD per‐patient annually. Estimates of the incremental costs for OAB patients compared to non‐OAB comparators ranged from 43% to 117%. One study estimated total annual indirect costs of OAB at 11 134 USD per‐patient.

Conclusions

The range of direct healthcare costs reported for managing patients with OAB varied, but was relatively small given the differing contributing data sources, study designs, and cost definitions. Direct costs were consistently higher among patients with OAB versus non‐OAB comparisons, from a 1.4‐ to >2‐fold increase annually. OAB‐specific costs made up a small proportion of all‐cause costs, highlighting the clinical and economic impact of OAB‐related conditions such as falls, urinary tract infection, and depression. Few studies were identified that examined the indirect costs of OAB in the US.
Pharmacist Intervention for Blood Pressure Control in Patients with Diabetes and/or Chronic Kidney Disease
Authors: Anderegg Maxwell D. , Gums Tyler H. , Uribe Liz , MacLaughlin Eric J. , Hoehns James , Bazaldua Oralia V. , Ives Timothy J. , Hahn David L. , Coffey Christopher S. , Carter Barry L.
Published: January 2018

Objectives

The objectives of this study were to determine if hypertensive patients with comorbid diabetes mellitus (DM) and/or chronic kidney disease (CKD) receiving a pharmacist intervention had a greater reduction in mean blood pressure (BP) and improved BP control at 9 months compared with those receiving usual care; and compare Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure (JNC 7) guideline and 2014 guideline (JNC 8) BP control rates in patients with DM and/or CKD.

Methods

This cluster randomized trial included 32 medical offices in 15 states. Clinical pharmacists made treatment recommendations to physicians at intervention sites. This post hoc analysis evaluated mean BP and BP control rates in the intervention and control groups.

Main results

The study included 335 patients (227 intervention, 108 control) when mean BP and control rates were evaluated by JNC 7 inclusion and control criteria. When JNC 8 inclusion and control criteria were applied, 241 patients (165 intervention, 76 control) remained and were included in the analysis. The pharmacist‐intervention group had significantly greater mean systolic blood pressure reduction compared with usual care at 9 months (8.64 mm Hg; 95% confidence interval [CI] −12.8 to −4.49, p<0.001). The pharmacist‐intervention group had significantly higher BP control at 9 months than usual care by either the JNC 7 or JNC 8 inclusion and control groups (adjusted odds ratio [OR] 1.97, 95% CI 1.01–3.86, p=0.0470 and OR 2.16, 95% CI 1.21–3.85, p=0.0102, respectively).

Principal conclusions

This study demonstrated that a physician‐pharmacist collaborative intervention was effective in reducing mean systolic BP and improving BP control in patients with uncontrolled hypertension with DM and/or CKD, regardless of which BP guidelines were used.
Structure, function and evolution of the hemerythrin‐like domain superfamily
Authors: Alvarez‐Carreño Claudia , Alva Vikram , Becerra Arturo , Lazcano Antonio
Published: January 2018

Hemerythrin‐like proteins have generally been studied for their ability to reversibly bind oxygen through their binuclear nonheme iron centers. However, in recent years, it has become increasingly evident that some members of the hemerythrin‐like superfamily also participate in many other biological processes. For instance, the binuclear nonheme iron site of YtfE, a hemerythrin‐like protein involved in the repair of iron centers in Escherichia coli, catalyzes the reduction of nitric oxide to nitrous oxide, and the human F‐box/LRR‐repeat protein 5, which contains a hemerythrin‐like domain, is involved in intracellular iron homeostasis. Furthermore, structural data on hemerythrin‐like domains from two proteins of unknown function, PF0695 from Pyrococcus furiosus and NMB1532 from Neisseria meningitidis, show that the cation‐binding sites, typical of hemerythrin, can be absent or be occupied by metal ions other than iron. To systematically investigate this functional and structural diversity of the hemerythrin‐like superfamily, we have collected hemerythrin‐like sequences from a database comprising fully sequenced proteomes and generated a cluster map based on their all‐against‐all pairwise sequence similarity. Our results show that the hemerythrin‐like superfamily comprises a large number of protein families which can be classified into three broad groups on the basis of their cation‐coordinating residues: (a) signal‐transduction and oxygen‐carrier hemerythrins (H‐HxxxE‐HxxxH‐HxxxxD); (b) hemerythrin‐like (H‐HxxxE‐H‐HxxxE); and, (c) metazoan F‐box proteins (H‐HExxE‐H‐HxxxE). Interestingly, all but two hemerythrin‐like families exhibit internal sequence and structural symmetry, suggesting that a duplication event may have led to the origin of the hemerythrin domain.
Protective effect of carvedilol alone and coadministered with diltiazem and prednisolone on doxorubicin and 5‐fluorouracil‐induced hepatotoxicity and nephrotoxicity in rats
Authors: Akindele Abidemi J. , Oludadepo Gabriel O. , Amagon Kennedy I. , Singh Dhirendra , Osiagwu Daniel D.
Published: January 2018

This study investigated the protective effects of carvedilol alone and coadministered with prednisolone and diltiazem on doxorubicin (DOX) and 5‐fluorouracil (5‐FU)‐induced toxicity. Each of 2 pools of 70 female rats were randomly allotted into 10 groups of 7 animals each and treated as follows: Group 1: normal saline (10 mL/kg); Group 2: normal saline and DOX (40 mg/kg)/5‐FU (20 mg/kg) alone; Group 3: gallic acid (200 mg/kg) and DOX/5‐FU; Group 4: carvedilol (0.075 mg/kg) and DOX/5‐FU; Group 5: carvedilol (0.15 mg/kg) and DOX/5‐FU; Group 6: carvedilol (0.30 mg/kg) and DOX/5‐FU; Group 7: diltiazem (3.43 mg/kg) and DOX/5‐FU; Group 8: diltiazem (3.43 mg/kg), carvedilol (0.15 mg/kg), and DOX/5‐FU; Group 9: prednisolone (0.57 mg/kg) and DOX/5‐FU; and Group 10: prednisolone (0.57 mg/kg), carvedilol (0.15 mg/kg), and DOX/5‐FU. Treatments were done p.o. for 16/14 days for the DOX/5‐FU models. DOX/5‐FU was administered i.p. to the rats in Groups 2‐10 on day 14/10‐14. On day 17/15 (DOX/5‐FU), blood samples were collected, and liver and kidneys of rats were harvested for antioxidant and histopathological assessments. Carvedilol alone and coadministered with prednisolone significantly (P < .05) decreased alanine aminotransferase level compared with administration of DOX alone. Carvedilol alone and coadministered with diltiazem significantly (P < .05) decreased creatinine level compared with administration of DOX/5‐FU alone. Carvedilol alone and coadministered with diltiazem and prednisolone significantly (P < .05) increased the level of hepatic superoxide dismutase and catalase, and decreased malondialdehyde compared with DOX administration alone. Histopathological observations correlated with results of biochemical and antioxidant analyses. Carvedilol administered alone and coadministered with diltiazem and prednisolone reduced the effect of DOX/5‐FU‐induced hepatic and renal toxicities due to enhanced in vivo antioxidant activity. The protective effect was more prominent in the doxorubicin model compared with the 5‐fluorouracil test. Coadministration of carvedilol with either diltiazem or prednisolone did not show better protection relative to carvedilol alone.
Cover Image, Volume 74, Issue 2
Authors: Wu Chenxi , Davis Adam S , Tranel Patrick J
Published: January 2018

The cover image, by Chenxi Wu et al., is based on the Research Article Limited fitness costs of herbicide‐resistance traits in Amaranthus tuberculatus facilitate resistance evolution, DOI: 10.1002/ps.4706. Photo Credit: Chenxi Wu.

image
Effects of seed mixture sowing with resistant and susceptible rice on population dynamics of target planthoppers and non‐target stemborers and leaffolders
Authors: Li Zhuo , Wan Guijun , Wang Long , Parajulee Megha N , Zhao Zihua , Chen Fajun
Published: January 2018

BACKGROUND

The widespread planting of insect‐resistant crops has caused a dramatic shift in agricultural landscapes, thus raising concerns about the potential impact on both target and non‐target pests worldwide. In this study, we examined the potential effects of six seed mixture ratios of insect‐resistance dominance [100% (R100), 95% (S05R95), 90% (S10R90), 80% (S20R80), 60% (S40R60), and 0% (S100)] on target and non‐target pests in a 2‐year field trial in southern China.

RESULTS

The occurrence of the target pests Nilaparvata lugens and Sogatella furcifera decreased with an increase in the ratio of resistant rice, and mixture ratios with ≥90% resistant rice significantly increased the pest suppression efficiency, with the lowest occurrences of the non‐target pests Sesamia inferens, Chilo suppressalis and Cnaphalocrocis medinalis for S100 and S10R90 seed mixture ratios. Furthermore, there were no significant differences in the 1000‐grain dry weight and grain yield between R100 and other treatments with ≥80% resistant seeds in the mixture (S20R80, S10R90 and S05R95).

CONCLUSION

S10R90 produced a good yield and provided the most effective control of both target and non‐target pests, with the potential to significantly reduce the application of chemical pesticides for integrated pest management in paddy fields. It is further presumed that the strategy of seed mixture with resistant and susceptible rice would be advantageous for rice yield stability. © 2018 Society of Chemical Industry
Design, expression, and characterization of the hybrid antimicrobial peptide T‐catesbeianin‐1 based on FyuA
Authors: Xu Huihui , Tie Kunyuan , Zhang Yang , Feng Xin , Cao Yuan , Han Wenyu
Published: January 2018

The overuse of antibiotics has resulted in the emergence of antibiotic‐resistant bacteria, which presents an urgent need for new antimicrobial agents. At present, antimicrobial peptides have attracted a great deal of attention from researchers. However, antimicrobial peptides often affect a broad range of microorganisms, including the normal flora in a host organism. In the present study, we designed a novel hybrid antimicrobial peptide, expressed the hybrid peptide, and studied its specific target. The hybrid peptide, named T‐catesbeianin‐1, which includes the FyuA‐binding domain of pesticin and the peptide catesbeianin‐1, was designed and expressed in Pichia pastoris X‐33. Then, we determined the antimicrobial activity, cytotoxicity, and specific target of the peptide. T‐catesbeianin‐1 has strong antimicrobial activity and binds to FyuA to inhibit or kill Escherichia coli present in clinical specimens and mixed‐species culture. In summary, these findings suggested that T‐catesbeianin‐1 might be promising and specific antibiotic agent for therapeutic application against fyuA+ E. coli.
Antifungal dipeptides incorporating an inhibitor of homoserine dehydrogenase
Authors: Skwarecki Andrzej S. , Schielmann Marta , Martynow Dorota , Kawczyński Marcin , Wiśniewska Aleksandra , Milewska Maria J. , Milewski Sławomir
Published: January 2018

The antifungal activity of 5‐hydroxy‐4‐oxo‐l‐norvaline (HONV), exhibited under conditions mimicking human serum, may be improved upon incorporation of this amino acid into a dipeptide structure. Several HONV‐containing dipeptides inhibited growth of human pathogenic yeasts of the Candida genus in the RPMI‐1640 medium, with minimal inhibitory concentration values in the 32 to 64 μg mL−1 range. This activity was not affected by multidrug resistance that is caused by overexpression of genes encoding drug efflux proteins. The mechanism of antifungal action of HONV dipeptides involved uptake by the oligopeptide transport system, subsequent intracellular cleavage by cytosolic peptidases, and inhibition of homoserine dehydrogenase by the released HONV. The relative transport rates determined the anticandidal activity of HONV dipeptides.
Semi‐autonomous image‐guided brain tumour resection using an integrated robotic system: A bench‐top study
Authors: Hu Danying , Gong Yuanzheng , Seibel Eric J. , Sekhar Laligam N. , Hannaford Blake
Published: January 2018

Background

Complete brain tumour resection is an extremely critical factor for patients' survival rate and long‐term quality of life. This paper introduces a prototype medical robotic system that aims to automatically detect and clean up brain tumour residues after the removal of tumour bulk through conventional surgery.

Methods

We focus on the development of an integrated surgical robotic system for image‐guided robotic brain surgery. The Behavior Tree framework is explored to coordinate cross‐platform medical subtasks.

Results

The integrated system was tested on a simulated laboratory platform. Results and performance indicate the feasibility of supervised semi‐automation for residual brain tumour ablation in a simulated surgical cavity with sub‐millimetre accuracy. The modularity in the control architecture allows straightforward integration of further medical devices.

Conclusions

This work presents a semi‐automated laboratory setup, simulating an intraoperative robotic neurosurgical procedure with real‐time endoscopic image guidance and provides a foundation for the future transition from engineering approaches to clinical application.
A comparative analysis and guide to virtual reality robotic surgical simulators
Authors: Julian Danielle , Tanaka Alyssa , Mattingly Patricia , Truong Mireille , Perez Manuela , Smith Roger
Published: January 2018

Background

Since the US Food and Drug Administration approved robotically assisted surgical devices for human surgery in 2000, the number of surgeries utilizing this innovative technology has risen. In 2015, approximately 650 000 robot‐assisted procedures were performed worldwide. Surgeons must be properly trained to safely transition to using such innovative technology. Multiple virtual reality robotic simulators are now commercially available for educational and training purposes. There is a need for comparative evaluations of these simulators to aid users in selecting an appropriate device for their purposes.

Methods

We conducted a comparison of the design and capabilities of all dedicated simulators of the da Vinci robot – the da Vinci Skills Simulator (dVSS), dV‐Trainer (dVT), Robotic Skills Simulators (RoSS) and the RobotiX Mentor. This paper provides the base specifications of the hardware and software, with an emphasis on the training capabilities of each system.

Results

Each simulator contains a large number of training exercises for skills development: dVSS n = 40, dVT n = 65, RoSS n = 52, RobotiX Mentor n = 31. All four offer 3D visual images but use different display technologies. The dVSS leverages the real robotic surgical console to provide visualization, hand controls and foot pedals. The dVT, RoSS and RobotiX Mentor created simulated versions of all of these control systems. Each includes systems management services that allow instructors to collect, export and analyze the scores of students using the simulators.

Conclusions

This study provides comparative information on the four simulators' functional capabilities. Each device offers unique advantages and capabilities for training robotic surgeons. Each has been the subject of validation experiments, which have been published in the literature. But those do not provide specific details on the capabilities of the simulators, which are necessary for an understanding sufficient to select the one best suited for an organization's needs. This article provides comparative information to assist with that type of selection.
Pd‐Catalyzed C‐H/N‐H Arylation: One‐Pot Synthesis of Indolo[1, 2‐f]phenanthridines
Authors: Kong Lingkai , Yao Qiyi , Wang Mengdan , Sun Ruizhuo , Li Yanzhong
Published: January 2018

A novel Pd‐catalyzed method for the synthesis of indolo[1, 2‐f]phenanthridines from 2‐bromo‐2′‐iodo‐1,1′‐biphenyl and indole derivatives has been reported. The reaction involves direct N−H and C2‐H arylation of indole. This Pd‐catalyzed double arylation provides a useful route to synthesize indolo[1, 2‐f]phenanthridine derivatives from simple and readily accessible starting materials.
Nickel‐Palladium‐Based Electrochemical Sensor for Quantitative Detection of Formaldehyde
Authors: Nachaki Ernest O. , Ndangili Peter M. , Naumih Noah M. , Masika Eric
Published: January 2018

Formaldehyde is a small organic molecule that has a wide range of uses in society despite its toxicity. Formaldehyde is classified as a “known carcinogen” by International Agency for Research on Cancer (IARC). Formaldehyde electrooxidation has become a subject of major interest in the recent past due to its potential application in fuel cell technology and the need for its detection at trace levels because of its toxicity. Many studies have been conducted on formaldehyde electrooxidation, most of which suffer electrode passivation as a result of adsorbed intermediates such as carbon monoxide adsorbed (COads) and formic acid adsorbed (H2COOads) formed from electrooxidation of formaldehyde. In this study a Nickel Palladium nanoparticles modified glassy carbon electrode (Ni−Pd/GCE) was fabricated for electrooxidation of formaldehyde. Palladium nanoparticles were electrochemically deposited onto a bare Glassy Carbon Electrode (GCE) from 2 mM PdCl2 in 0.1 M H2SO4 supporting electrolyte, at a controlled potential of −0.14 V for 240 seconds. The Nickel nanoparticles were electrochemically deposited onto the PdGCE from 0.5 M NiSO4 in 0.1 M H2SO4 supporting electrolyte, at a controlled potential of −1.25 V for 40 seconds. The modified glassy carbon electrode (Ni−Pd/GCE) was conditioned in 0.5 M NaOH for about 50 cycles or more to obtain a reproducible voltammogram. The fabricated electrode was characterized using Cyclic Voltammetry (CV) and Chronoamperometry (CA). The results showed that the electrode had good electrocatalytic properties with respect to formaldehyde electrooxidation as a result of the synergistic effect of Ni and Pd nanoparticles combined with the glassy carbon technology. A sensitive oxidation peak for 1 mM formaldehyde was observed at about 0.43 V vs. Ag/AgCl/KCl (3 M) in 0.5 M NaOH, with a current density of 17 mA/cm2. It had a linear detection range from 10 μM to 1 mM (R=0.9985) and a detection limit of 5.4 μM. The electrode showed significant electrocatalytic activity towards the electrooxidation of formaldehyde in aqueous solution, was selective, reproducible and stable, hence can be used to detect formaldehyde at trace levels and can find application in fuel cells.
Design, Synthesis, Biological Evaluation and Computational Study of Novel Imino‐4‐Aryloxymethyl‐2H‐chromen‐2‐one Derivatives as Potent Anti‐Microbial and Antiinflammatory Agents
Authors: Naik Soniya D. , Hosamani Kallappa M. , Barretto Delicia A. , Joshi Shrinivas D.
Published: January 2018

A simple and efficient methodology has been designed to synthesize a series of versatile and novel coumarin based scaffolds displaying several alkyl, halogen, and alkoxy groups from 4‐Bromomethylcoumarins and pre‐functionalized phenol. The title compounds have been evaluated for their in‐vitroanti‐microbial and anti‐inflammatory activity. Physiological properties like lipophilicity and IC50 value have also been calculated. To support the in vitro results, computational experiments were carried out to analyze probable binding modes. The interactions between substituted coumarins and bovine protein showed promising activity with higher C‐score values.
Carbon Nitride‐Supported Silver Nanoparticles: Microwave‐ Assisted Synthesis of Propargylamine and Oxidative C‐C Coupling Reaction
Authors: Patel Sunil B. , Vasava Dilip V.
Published: January 2018

In the present study we have, synthesized silver nanoparticles supported on carbon nitride AgNPs@g‐C3N4 and investigated its catalytic aspects by using microwave. We found that silver nanoparticles supported on g‐C3N4 were highly active in the A3‐coupling reaction of (Aldehyde, secondary amine and terminal alkynes) for the synthesis of propargylamines with excellent yield up to 97% and in C−C coupling reaction of terminal alkynes for the synthesis of 1, 3‐diyne with excellent yield up to 98%. We have achieved excellent TON (72932), TOF (3636 min−1), E‐factor (0.27) and atom economy AE (94%). Reaction parameters like effect of catalyst quantity, effect of time and effect of temperature was deeply studied. The catalyst was characterized by SEM, HR‐TEM, EDX, XRD, ICP‐AES and IR.
Virtual Screening, Molecular Docking, and DFT Studies of Some Thiazolidine‐2,4‐diones as Potential PIM‐1 Kinase Inhibitors
Authors: Asati Vivek , Thakur Santosh S. , Upmanyu Neeraj , Bharti Sanjay K.
Published: January 2018

In the present study, ZINC database has been used for virtual screening of thousand of compounds based on previously reported pharmacophore against PIM‐1 kinase. These compounds were further screened by Glide docking methodologies such as high throughput virtual screening (HTVS), standard precision (SP) and extra precision (XP), against PIM‐1 kinase (PDB ID: 4DTK). Eight top‐ranked compounds ZINC22066185, ZINC05678245, ZINC16431468, ZINC05773728, ZINC36633741, ZINC16779084, ZINC19909862 and ZINC15056464, were selected by virtual screening and docking studies. These compounds were showed better binding affinities towards PIM‐1 kinase by using amino acid residues such as LYS67, GLU171, ASP128, and ASP186. The top‐ranked compounds were showed their predicted binding energies with PIM‐1 kinase in the range of −9.06, −8.45, −8.96, −8.78, −8.63, −8.56, −8.56 and −8.30 kcal/mol, respectively. Various reference ligands of PDB ID: 4DTK, 3VBQ and 3VC4, were also taken for docking study on protein kinase (PDB ID: 4DTK) to find out the comparative Glide score of receptor ligand complexes. To confirm the inhibitors potencies, the orbital energies, such as HOMO and LUMO, of the hit compounds were calculated. The results of the study showed that ZINC22066185 and ZINC16779084, may be considered as prototype compounds for further development of potential PIM‐1 inhibitors.
Band Engineering via Sn‐doping of Zinc Oxide Electron Transport Materials for Perovskite Solar Cells
Authors: Su Tongyu , Zheng Yuanhui , Ma Zongwei , Cheng Long , Xu Xueli , Zhang Fapei , Yu Gui , Sheng Zhigao
Published: January 2018

The performance of planar perovskite solar cells (PSCs) is quite dependent on the interfacial conditions and then the interfacial band engineering is very important not only for the effective improvement of power conversion efficiency (PCE) but also for the better understanding of the charge transfer in the cells. In this report, the band engineering of the ZnO based electron transport layer (ETL) in PSCs was studied by modulating Sn‐doping level (0 ≤ x ≤ 0.2). A V‐like variation of work function (Wf) as function of Sn‐doping level in Zn1‐xSnxO1+x films was realized from 4.23 to 4.39 eV. As a result, the photovoltaic performance of PSCs with the Zn1‐xSnxO1+x ETLs was adjusted and the V‐like tendencies of photovoltaic parameters of devices, such as open‐circuit voltage (VOC) and the short‐circuit current (JSC), were found. The maximum values of VOC and JSC were achieved as 1.04 V and 20.68 mA cm−2 with an ETL of Zn1‐xSnxO1+x, respectively, which corresponds to a highest PCE of 14.12% for ZnO‐based pervoskite solar cells with a large fill factor of 65.62.