bluuebunny/crossref_metadata_2025 huggingface dataset:
Thermal changes in Human Abdomen Exposed to Microwaves: A Model Study
Authors: Kaur J. , Khan S. A.
Published: September 2019

The electromagnetic energy associated with microwave radiation interacts with the biological tissues and consequently, may produce thermo-physiological effects in living beings. Traditionally, Pennes’ bioheat equation (BTE) is employed to analyze the heat transfer in biological medium. Being based on Fourier Law, Pennes’ BTE assumes infinite speed of propagation of heat transfer. However, heat propagates with finite speed within biological tissues, and thermal wave model of bioheat transfer (TWBHT) demonstrates this non-Fourier behavior of heat transfer in biological medium. In present study, we employed Pennes’ BTE and TWMBT to numerically analyze temperature variations in human abdomen model exposed to plane microwaves at 2450 MHz. The numerical scheme comprises coupling of solution of Maxwell's equation of wave propagation within tissue to Pennes’ BTE and TWMBT. Temperatures predicted by both the bioheat models are compared and effect of relaxation time on temperature variations is investigated. Additionally, electric field distribution and specific absorption rate (SAR) distribution is also studied.  Transient temperatures predicted by TWMBT are lower than that by traditional Pennes’ BTE, while temperatures are identical in steady state. The results provide comprehensive understanding of temperature changes in irradiated human body, if microwave exposure duration is short.
Study of Stacked High Tc Superconducting Circular Disk Microstrip Antenna in Multilayered Substrate Containing Isotropic and/or Uniaxial Anisotropic Materials
Authors: Boughrara A. S. , Benkouda S. , Bouraiou A. , Fortaki T.
Published: September 2019

In this paper, we present a rigorous full-wave analysis able to estimate exactly the resonant characteristics of stacked high Tc superconducting circular disk microstrip antenna. The superconducting patches are assumed to be embedded in a multilayered substrate containing isotropic and/or uniaxial anisotropic materials (the analysis is valid for an arbitrary number of layers). London’s equations and the two-fluid model of Gorter and Casimir are used in the calculation of the complex surface impedance of the superconducting circular disks. Numerical results are presented for a single layer structure as well as for two stacked circular disks fabricated on a double-layered substrate.
An Accurate and Compact High Power Monocycle Pulse Transmitter for Microwave Ultra-Wideband Radar Sensors with an enhanced SRD model: Applications for Distance Measurement for lossy materials
Authors: Ahajjam Y. , Aghzout O. , Catala-Civera J. M. , Peñaranda-Foix F. , Driouach A.
Published: September 2019

In This paper, a high power sub-nanosecond pulse transmitter for Ultra-wideband radar sensor is presented. The backbone of the generator is considered as a step recovery diode and unique pulse injected into the circuit, which gives rise to an ultra-wide band Gaussian pulse. The transistor driver and transmission line pulse forming the whole network are investigated in detail.  The main purpose of this work is to transform a square waveform signal to a driving pulse with the timing and the amplitude parameters required by the SRD to form an output Gaussian pulse, and then into high monocycle pulses. In simulation aspect, an improved output response is required, in this way a new model of step recovery diode has been proposed as a sharpener circuit. This proposition was applied to increase the rise-time of the pulses. For a good range radar, a high amplitude pulse is indispensable, especially when it comes to penetrate thick lossy materiel.  In order to overcome this challenge, a simple technique and useful solution is introduced to increase the output amplitude of the transmitter. This technique consists to connect the outputs of two identical pulse generators in parallel respecting the restrictions required. The pulse transmitter circuit is completely fabricated using micro-strip structure technology characteristics. Waveforms of the generated monocycle pulses over 10V in amplitude with 3.5 % in overshoot have been obtained. Good agreement has been achieved between measurement and simulation results.
High Gain Circularly Polarized Pentagonal Microstrip for Massive MIMO Base Station
Authors: Bhadade R. S. , Mahajan S. P.
Published: September 2019

In this paper we propose a circularly polarized pentagonal microstrip antenna on a suspended substrate with coaxial probe feed and five loaded slits for Massive MIMO BS Antenna applications. Massive Multiple-Input Multiple-Output (MIMO) is one of the key component to be incorporated in the 5G cellular systems. The proposed antenna is successfully simulated using HFSS 13.0, fabricated on a FR-4 substrate and measured. The proposed antenna exhibits a much higher gain of 6.17dB, improved impedance bandwidth of 171.9 MHz (Return loss, S11= -10dB) , axial ratio bandwidth (< 3dB) of 135 MHz , patch area of 1775 mm2  , and also yields return loss better than -15 dB around the center frequency of 2.45 GHz (ISM Band). Measured characteristics of the antenna are in good agreement with the simulated results.
A Compact Multi-Band Monopole Antenna using Metamaterial for WLAN/WiMAX Applications
Authors: Mouhouche F. , Azrar A. , Dehmas M. , Djafri K.
Published: September 2019

In this paper, a tri-band printed monopole antenna with electrically coupled metamaterial units is proposed and investigated. The proposed antenna is designed to cover WLAN/WiMAX applications. The antenna consists of a printed strip line and two double metamaterial unit cells of different size placed near the monopole antenna on opposite sides. Each unit cell exhibits a negative permeability over the resonance frequency at 2.5 GHz and 3.62 GHz, which produces magnetic couplings with the monopole antenna. The proposed antenna structure was fabricated and measured. The measured -10 dB bandwidth for the return loss is from 2.47GHz-2.51GHz, 3.59GHz-3.69GHz, and 5.3GHz - 7.2 GHz, which are suitable for (WLAN: 2.4–2.484,  5.15–5.35,  and  5.725–5.85  GHz) and  (WiMAX: 2.5–2.69, 3.4–3.8, and 5.25–5.85 GHz) band Applications. By using the switches across the gap of proposed-MTM unit cell, the effect of this unit deactivated and its resonance frequency will disappear. Hence, the proposed antenna maintains the omnidirectional radiation pattern.
Characterization of Transmission and Reflection of Ku Band Split Ring Resonator Reflectarray using Waveguide Method
Authors: Naseer N. , Saka B.
Published: September 2019

In this paper, the analysis, design, and measurement of a split ring resonator reflectarray is presented. The 6 different designs of reflectarray are simulated to analyze the effect of splits position on resonance frequency. The SRR reflectarray which covered highest frequency bandwidth at Ku-band is fabricated and tested. In the fabrication, FR4 substrate is used. The S-parameter measurements of the fabricated reflectarray are performed by waveguide method. The obtained results have good reflection characteristics for a wide frequency range from 12 GHz to 16.5 GHz in Ku-band. The maximum value of reflection is achieved approximately at 15.3 GHz frequency
Flattened zero dispersion Photonic crystal fibers with embedded nano holes and ultra low confinement loss for supercontinuum generation
Authors: Fiaboe K. F. , Kumar P. , Roy J. S.
Published: September 2019

In this paper unique photonic crystal fiber (PCF) structure with nanoholes embedded have been studied. Embedded nanoholes have been filled with different materials of alcoholic groups like butanol, ethanol, methanol and propanol. Investigations of these structure shows flattened zero dispersion in visible range to far infrared regions. Simulated PCF structure reports ultra-low confinement loss of the order of 10-8 dB/km. Designed PCF promises to give large nonlinear coefficient of 3000 W-1Km-1 at 1335nm wavelengths. Numerical simulation of the fiber for the generation of supercontinuum generation (SCG) has been performed. Low power pump pulses of 50fs duration have been used. With a fiber of length of 15cm and pulses of 1kW, 2kW, 5kW and 10kW peak power, supercontinuum broadening of about 607nm, 908nm, 1987nm and 2405nm respectively.
Study of Parameter Influence on Quality on the Electromagnetic Imaging Reconstruction from the Spectrum of the Diffracted Field: Application to Reconstruction of the leakage Current of ISM Applicators
Authors: Mejdoub Y. , Ghammaz A. , Rouijaa H. , Senhaji Rhazi K.
Published: September 2019

The ISM applicators generate leakage currents that can disrupt satellite TV transmission, taking into account the effects of the electromagnetic waves and those of the CEM. We are interested in these as a way to reconstitute their leakage currents, using the Micro-waves Imagery. We propose such a method of spectral analysis, which is intended to reconstruct the equivalent current distribution (position and form) to an object starting from the diffracted field spectrum by the Micro-waves Imagery. Our contribution resides in the influence of different parameters (N number of the measurement point, and the distance z0 of the measurement plane) on the reconstitution quality. This method is presented and illustrated; an algorithm of reconstructing the image of an object existing within a surrounding homogenous medium with known dielectric properties, this algorithm is developed with MATLAB. This method leads to more significant results, and quickly permits to get information about the object form.
A new formula for the optimum width of Substrate Integrated Waveguide
Authors: Guellil N. , Djahli F. , Zebiri C.
Published: September 2019

A new formula for calculating the optimum width of a Substrate Integrated Waveguide (SIW) corresponding to the first mode is presented in this paper. Finite Difference Frequency Domain (FDFD) method is applied to analyze the waveguide structure where geometrical parameters of the SIW are iteratively varied in order to minimize the gap between cutoff frequencies of SIW structure and that of an equivalent conventional rectangular waveguide. Adequate parameters are used to derive the new formula. To verify the accuracy of the new formula, several waveguides are designed and analyzed using the commercial software HFSS. The calculated propagation constants are compared with experimental measurements from literature, a very good conformity is obtained.
A Novel Method for Field Analysis and Design of Electromagnet Used in Lifting Applications
Authors: Hashemi A. , Gharaei P. Y.
Published: September 2019

Magnetic crane is one of the industrial applications of magnetic absorption, which uses an electromagnet to create the necessary force for lifting and moving objects. In this paper, the field analysis and design of an electromagnet are discussed. During the electromagnet analysis and design process, with special attention to leakage fluxes and fringing effects, a new magnetic equivalent circuit for an electromagnet is proposed. Also, the nonlinear behavior of the B-H curve of the ferromagnetic core and its saturation point are considered. Due to the various shapes of the ferromagnetic core, the U_I structure is selected with a symmetrical winding to reduce leakage flux and fringing effects. MATLAB software is used for analyzing and designing the electromagnet, and ANSYS Maxwell software is used to simulate its magnetic field. To verify the accuracy of the proposed method, the prototype was made of a magnetic crane with designed electromagnet. The comparison between measurement and simulation results shows that the error is less than 2%, which confirms the accuracy of the proposed method.
Synthesis and Characterization of ZnSe/PVA nanocomposites for optical devices
Authors: Kushwah K. K. , Gupta N. , Khare K. , Singh S. , Aziz F. , Ramrakhiani M.
Published: September 2019

This paper reports in situ preparation of ZnSe-PVA nanocomposite film using ecofriendly, safe, inexpensive, facile and non-organometallic synthetic chemical route, with PVA as the stabilizing agent. The XRD studies showed the formation of cubic ZnSe nanoparticles in PVA matrix with an average size of ~7 nm. Energy band gap determined by absorption edge of UV-VIS absorption spectra revealed increase in band gap with decrease in particle size. The optical properties like Refractive index and Photoluminescence (PL) of ZnSe /PVA with varying concentration of ZnSe content are also reported. The blue shift was found due to size reduction of ZnSe nanoparticles in PVA matrix.
Solution of Axisymmetric Inhomogeneous Problems with the Markov Chain Monte Carlo
Authors: Shadare A. E. , Sadiku M. N. O. , Musa S. M.
Published: September 2019

With increasing complexity of EM problems, 1D and 2D axisymmetric approximations in  p, z plane are sometimes necessary to quickly solve difficult symmetric problems using limited data storage and within shortest possible time. Inhomogeneous EM problems frequently occur in cases where two or more dielectric media, separated by an interface, exist and could pose challenges in complex EM problems. Simple, fast and efficient numerical techniques are constantly desired. This paper presents the application of simple and efficient Markov Chain Monte Carlo (MCMC) to EM inhomogeneous axisymmetric Laplace’s equations. Two cases are considered based on constant and mixed boundary potentials and MCMC solutions are found to be in close agreement with the finite difference solutions.
Scattering from a Buried PEMC Cylinder due to a Line Source Excitation above a Planar Interface Between Two Isorefractive Half Spaces
Authors: Hamid A. K. , Cooray F.
Published: September 2019

A solution to the problem of scattering from a perfect electromagnetic conducting (PEMC) circular cylinder   buried inside a half-space and excited by an infinite electric line source is provided. The line source is parallel to the cylinder axis, and is located in the other half-space. The two half spaces are isorefractive to each other. The source fields when incident at the planar interface separating the two half spaces, generate fields that are transmitted into the half-space where the cylinder is. These fields then become the known basic incident fields for the buried PEMC cylinder. Scattering of these incidents fields by the cylinder will consequently generate fields at the interface that get reflected back into the same half-space and transmitted frontward into the source half-space, all of which are unknown. Imposing appropriate boundary conditions at the surface of the buried cylinder and at a specified point on the interface, enables the evaluation of these unknown fields. The refection coefficient at the specified point is then computed for cylinders of different sizes, to demonstrate how it varies with the PEMC admittance of the buried cylinder, the intrinsic impedance ratio of the two isorefractive half-spaces, and the burial depth of the cylinder.
Sinusoidally Modulated Silicon Leaky Wave Antenna for sub-THz Applications
Authors: Yousef B. M. , Ameen A. M. , Attiya A. M. , Shaalan A. A.
Published: September 2019

A new sub-THz leaky wave antenna based on grounded silicon substrate for chip to chip communication applications is presented. The proposed leaky wave antenna is based on sinusoidally modulated surface reactance. This surface reactance is implemented by using varying width strips on the top of a grounded silicon substrate. Two approaches for developing these strips are studied. These two approaches are based on either highly doped silicon strips or gold strips. Both the doped silicon and the gold are presented by using their corresponding Drude models at the proposed operating frequency. Comparisons between the properties of these two approaches are presented to show the applicability of each one.
Effects of Jigsaw-Puzzle Instructional Strategy on Secondary School Students’ Performance on Growth as a Concept in Biology in Abia State
Authors: Chukwu Joy C. , Arokoyu A. A.
Published: September 2019

The study examined the effects of jigsaw-puzzle instructional strategy on secondary school students’ performance on Growth as a concept in Biology in Ukwa West Local Government Area, Abia State.  Gender effect on Biology students’ performance was also investigated. Two objectives, two research questions and two hypotheses guided the study. Quasi-experimental design was adopted in this study. One hundred and fifteen (115) Biology students from two mixed secondary schools randomly selected formed the sample size. Biology Performance Test on Growth (BPTOG) which contained twenty (20) multiple choice questions was used for gathering data. Test re-test method was to test the instrument. The BPTOG was validated by two experts in Department of Curriculum Studies and Educational Technology, University of Port Harcourt, Nigeria. Reliability index of 0.76 was obtained using Pearson’s Product Moment Correlation. Mean and Standard deviation were used in answering the research questions and Analysis of Covariance (ANCOVA) was used to test the hypotheses at 0.05 level of significance. The findings of the study showed that there was a significant difference between the academic performance of students in experimental group and those in control. More so, gender has no effect on Biology students’ performance in jigsaw-puzzle group. It was recommended that Biology teachers should adopt Jigsaw-Puzzle Instructional Strategy in this 21st century classroom to encourage group learning among students.
A Comparative Study on the Impact of Telecommunication Investment on Economic Growth in EU Vis-à-vis Non-EU OECD Countries: A Dynamic Panel Data Analysis
Authors: Oztunc Hakan , Demirbas Erkan , Orhan Mehmet
Published: September 2019

This study aims to comparatively investigate the effects of telecommunication infrastructure on the economical growth in OECD countries. For this purpose, OECD countries were divided into two groups i.e. European Union (EU) and non-EU OECD countries for the period of 1993-2013. Findings of dynamic panel data model showed that investment on the telecommunication infrastructure has more positive effect on EU OECD countries than non-EU OECD countries. Since telecom appears as the key sector to fuel growth because it is associated with information technology and all ramifications of computer based applications and mobile communication, all countries at all development levels are proposed to focus on investing in these sectors the opposite of which hinders growth.
Modelling Nigeria Naria Exchange Rate against Some Selected Country’s Currencies Volatility: Application of GARCH Model
Authors: Abdulhakeem Ajayi , Adams Samuel Olorunfemi , Akano Rafiu Olayinka
Published: September 2019

This paper examines the exchange rate volatility with GARCH-type model of the daily exchange rate return series from January 2012 – August 2016 for Naira/Chinese Yuan, Naira/India Rupees, Naira/Spain Euro, Naira/UK Pounds and Naira/US Dollar returns. The studies compare estimates of variants of GARCH (1, 1), EGARCH (1, 1), TGARCH (1,1) and GJR-GARCH (1,1) models. The result from all models indict presence of volatility in the five currencies and equally indicate that most of the asymmetric models rejected the existence of a leverage effect except for models with volatility break. For GARCH (1, 1), GJR-GARCH (1, 1,) EGARCH (1,1) and TGARCH (1, 1), it was observed that India have the best exchange rate with the highest log-likelihood (Log L) and the lowest AIC and BIC followed by USA, China, Spain and United Kingdom respectively. The four models was later compared for the exchange rates of the five countries under consideration i.e. China, India, Spain, UK and USA  to select the best fitted model for each country and it was discovered that GJR-GARCH (1,1) is the best fitted model for all the countries followed by GARCH (1,1), TGARCH (1,1) and EGARCH (1,1) in that order.
A Comparative Study of the Daily Activity Patterns of Dog Faced Baboon (Papio anubis) in Captivity at the Kano University Zoo and Kano Zoological Garden
Authors: Dutse Isah Suleiman , Yahaya Mohammed Musa , Oshibanjo D. O. , Daya Dan`azumi Danboyi
Published: September 2019

Aim: This study seeks to observed the daily activity patterns of dog faced baboon (Papio anubis) in Kano University of Science and Technology Wudil Zoo and Kano Zoological Garden.

Materials and Methods: The study was carried out daily between 6:00am to 6:00pm from December 2016 to January 2017. Digital camera was also attached to cages at the two sites. The observation in the activity patterns were recorded on recording sheet, observation is done three times a week at 20 minutes intervals.

Results: The findings on activity pattern of dog faced baboon (Papio anubis) in captivity shows that the day time activities decrease from morning to evening. Resting activities was 47.5%, movement and feeding were carried out in the morning, followed by afternoon and evening with 33.3% and 19.1% activities respectively. The results from the  Kano Zoological Garden, indicated that 42.7% of the activities perform by dog faced baboon in captivity are resting, this is followed by movement which accounted for 34.9% of the activities, while feeding activities account for the least with 22.4%. Similarly, about 43.2% of the recorded activities carried out by dog faced baboon in Kano University of Science and Technology Wudil, Zoo was resting, followed by movement which constituted 34.8% of the activities and feeding activity which accounted for 22%.

Conclusion: Due to the fact that majority of the baboons activities usually take place between morning and afternoon, it is recommended that visitors interested in baboons should plan their visitation to the Zoo pen during that time. It is also recommended that feeding and harassing of animals by the visitors should be discouraged in order to ensure consistency in their behaviour.
Assessment of Genetic Variability and Character Association of Myanmar Local Rice (Oryza sativa L.) Germplasm
Authors: Htwe Nyo Mar , Phyu Su Latt , Thu Chan Nyein
Published: September 2019

Forty-two Myanmar local rice genotypes were evaluated to estimate the magnitude of genetic variability and relationship of some agronomic traits. Randomized Complete Block (RCB) design with three replications was used to design this experiment at the Department of Plant Breeding, Physiology and Ecology, Yezin Agricultural University in Myanmar, 2017 (dry season). STAR (Statistical Tool for Agricultural Research, version 2.0.1) statistical software for analysis of variance and genetic parameter, and SPAR 2 software for path analysis were used to obtain the optimal result in the collected data: plant height, effective tillers hill-1, panicle/straw weight ratio, panicle length, filled grain percent, spikelet panicle-1, 1000 grain weight, harvest index, yield plant-1. Genotypes showed highly significant difference for all the traits studied, meaning that the genotypes constitute a pool of germplasm with adequate genetic variability. Genetic variance was higher than environmental variance and heritability were above 80 % in all characters, which ensures the predominance of the genetic components among genotypes. The slight difference between genotypic coefficient variation (GCV) and phenotypic coefficient of variation (PCV) in all characters indicated there is enough genetic variability for the traits to be facilitated selection. High heritability with high genetic advance for spikelet panicle-1 and filled grain percent, their strong and positive correlation and the positive direct effect on yield plant-1 indicated that these are important indicator characters and their manipulation through selection. These characters can be utilized as selection criteria for further breeding programs related to high yielding rice varieties.
Iranian Elderly in Sydney, Australia: A Reflection on Life
Authors: Khavarpour Freidoon A. , Hafshajani Atena , Clapham Kathleen , Clapham Kathleen
Published: September 2019

The growth in the number and proportion of older adults is unprecedented in the history of Australia.  Two factors, longer life spans and ageing baby boomers, have combined to increase this portion of population of Australian aged in recent decades.  Using qualitative approach, 20 Iranian migrants, aged 65 and over, were selected and interviewed through a 10 months period, in 2016 and 2017.  Conducted in various locations, participants were asked to reflect upon their social and economic experience in Australia.  Most were positive about their lives in Australia, considered themselves as Australian citizen, believed Australians have ‘great deal of respect’ for the elderly, are very “warm” and “respectful” towards their elder generation, utilised various government services, and aimed to facilitate the process of “Australisation” of their children.  The result indicates that the life of these elderlies can be enhanced by supporting various social and economic services and, by providing ongoing English language classes, a better quality of life for this segment of the population will be ranched.
The effects of training managers on management competencies to improve their management practices and work engagement of their subordinates: A single group pre- and post-test study
Authors: Adachi Hidehiko , Sekiya Yuki , Imamura Kotaro , Watanabe Kazuhiro , Kawakami Norito
Published: September 2019

Objectives

The aim of this study was to investigate the effect of a training program for managers on their management competencies and work engagement of their subordinate workers and to investigate the mediating effect of management competencies on the subordinate work environment.

Methods

A training program, developed based on the UK Health and Safety Executive management competencies framework, was offered to managers in a finance company in Japan. Management competency was assessed at baseline and 1 month after the intervention. Work engagement was assessed at baseline and at a 1-year follow-up. Multilevel correlations between changes in components of management competency and changes in subordinate work engagement were analyzed.

Results

Although 6 of 12 components of management competency increased significantly following the intervention, significant intervention effect on subordinate work engagement was not found. Among 12 components of management competency, the integrity of managers showed significant multilevel correlation with work engagement of their subordinates. Subgroup analyses revealed that this multilevel correlation increased when a manager and a subordinate differed in gender.

Conclusions

The results of this study indicated that the training program developed in this study effectively improved the management competency of managers and that integrity of managers may facilitate work engagement of subordinate workers, especially when a manager and a subordinate are of different genders. Thus, a training program focused on improving the integrity of managers could enhance the work engagement of employees.
Enantioselective Kinetic Resolution/Desymmetrization of Para‐Quinols: A Case Study in Boronic‐Acid‐Directed Phosphoric Acid Catalysis
Authors: Huang Banruo , He Ying , Levin Mark D. , Coelho Jaime A. S. , Bergman Robert G. , Toste F. Dean
Published: September 2019

A chiral phosphoric acid‐catalyzed kinetic resolution and desymmetrization of para‐quinols operating via oxa‐Michael addition was developed and subsequently subjected to mechanistic study. Good to excellent s‐factors/enantioselectivities were obtained over a broad range of substrates. Kinetic studies were performed, and DFT studies favor a hydrogen bonding activation mode. The mechanistic studies provide insights to previously reported chiral anion phase transfer reactions involving chiral phosphate catalysts in combination with boronic acids.

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Palladium‐Catalyzed Domino Heck/Phosphorylation towards 3,3‐Disubstituted Phosphinonyloxindoles
Authors: Lu Guozhang , Huangfu Xinlei , Wu Zi'ang , Tang Guo , Zhao Yufen
Published: September 2019

The first Pd‐catalyzed domino Heck/phosphorylation of N‐(2‐iodophenyl)acrylamides with secondary phosphine oxides has been developed. The use of PdCl2 as a catalyst, 1,4‐bis(diphenylphosphino)butane as a ligand, K2CO3 as a base, various N‐(2‐iodophenyl)acrylamide derivatives are tolerant in this transformation, affording 3‐phosphinomethyl 3,3‐disubstituted oxindole products in good to excellent yields. This transformation offers a straightforward route to the formation of the new C−C and P−C bonds, oxindole ring in one step. Moreover, this method can be easily adapted to large‐scale preparation.

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Template‐Assisted Formation of High‐Quality α‐Phase HC(NH2)2PbI3 Perovskite Solar Cells
Authors: Shi Pengju , Ding Yong , Ren Yingke , Shi Xiaoqiang , Arain Zulqarnain , Liu Cheng , Liu Xuepeng , Cai Molang , Cao Guozhong , Nazeeruddin Mohammad Khaja , Dai Songyuan
Published: September 2019

Formamidinium (FA) lead halide (α‐FAPbI3) perovskites are promising materials for photovoltaic applications because of their excellent light harvesting capability (absorption edge 840 nm) and long carrier diffusion length. However, it is extremely difficult to prepare a pure α‐FAPbI3 phase because of its easy transformation into a nondesirable δ‐FAPbI3 phase. In the present study, a “perovskite” template (MAPbI3‐FAI‐PbI2‐DMSO) structure is used to avoid and suppress the formation of δ‐FAPbI3 phases. The perovskite structure is formed via postdeposition involving the treatment of colloidal MAI‐PbI2‐DMSO film with FAI before annealing. In situ X‐ray diffraction in vacuum shows no detectable δ‐FAPbI3 phase during the whole synthesis process when the sample is annealed from 100 to 180 °C. This method is found to reduce defects at grain boundaries and enhance the film quality as determined by means of photoluminescence mapping and Kelvin probe force microscopy. The perovskite solar cells (PSCs) fabricated by this method demonstrate a much‐enhanced short‐circuit current density (  Jsc) of 24.99 mA cm−2 and a power conversion efficiency (PCE) of 21.24%, which is the highest efficiency reported for pure FAPbI3, with great stability under 800 h of thermal ageing and 500 h of light soaking in nitrogen.
Development of Murine Systemic Lupus Erythematosus in the Absence of BAFF
Authors: Stohl William , Yu Ning , Chalmers Samantha , Putterman Chaim , Jacob Chaim O.
Published: September 2019

Objective

To determine whether systemic lupus erythematosus (SLE) can develop in the absence of BAFF in an SLE‐prone host.

Methods

Starting with C57BL/6 mice that express a human BCL2 transgene (Tg) in their B cells (thereby rendering B cell survival largely independent of BAFF‐triggered signals), we introgressed this Tg into NZM 2328 mice genetically deficient in BAFF (NZM.Baff−/−) to generate NZM.Baff−/−.Bcl2Tg mice. Expression of human Bcl‐2 and lymphocyte profiles were assessed by fluorescence‐activated cell sorting, and serologic profiles were determined by enzyme‐linked immunosorbent assay. Immunofluorescence and histologic analyses were performed to assess renal immunopathologic features in the mice, and clinical disease was assessed according to the outcomes of severe proteinuria and death.

Results

In comparison to their non‐Tg NZM.Baff−/− littermates (n ≥ 7), NZM.Baff−/−.Bcl2Tg mice (n ≥ 8) overexpressed Bcl‐2 in their B cells and developed significantly increased percentages and numbers of B cells and plasma cells, serum levels of IgG autoantibodies, glomerular deposition of IgG and C3, and severity of glomerular and tubulointerstitial inflammation, culminating in severe proteinuria and death (all P < 0.05 versus NZM.Baff−/− littermates). The time course for development of SLE‐like features in NZM.Baff−/−.Bcl2Tg mice was more rapid than has been previously observed in NZM 2328 wild‐type mice (median age at death 4.5 months versus 7.5 months). NZM.Baff−/−.Bcl2Tg mice remained responsive to BAFF, since reintroduction of the Baff gene into these mice further accelerated the course of disease (median age at death 3 months).

Conclusion

The role of BAFF in the development of SLE‐like disease may be dispensable as long as B cell survival is preserved via a BAFF‐independent pathway. This may help explain the limited and variable clinical success with BAFF antagonists in human SLE. Thus, NZM.Baff−/−.Bcl2Tg mice may serve as a powerful murine model for the study of BAFF‐independent SLE.
Predicting survival in cancer patients with and without 30‐day readmission of an unplanned hospitalization using a deficit accumulation approach
Authors: Hembree Timothy N. , Thirlwell Sarah , Reich Richard R. , Pabbathi Smitha , Extermann Martine , Ramsakal Asha
Published: September 2019

Background

For cancer patients with an unplanned hospitalization, estimating survival has been limited. We examined factors predicting survival and investigated the concept of using a deficit‐accumulation survival index (DASI) in this population.

Methods

Data were abstracted from medical records of 145 patients who had an unplanned 30‐day readmission between 01/01/16 and 09/30/16. Comparison data were obtained for patients who were admitted as close in time to the date of index admission of a study patient, but who did not experience a readmission within 30 days of their discharge date. Our survival analysis compared those readmitted within 30 days versus those who were not. Scores from 23 medical record elements used in our DASI system categorized patients into low‐, moderate‐, and high‐score groups.

Results

Thirty‐day readmission was strongly associated with the survival (adjusted hazard ratio [HR] 2.39; 95% confidence interval [CI], 1.46‐3.92). Patients readmitted within 30 days of discharge from index admission had a median survival of 147 days (95% CI, 85‐207) versus patients not readmitted who had not reached median survival by the end of the study (P < .0001). DASI was useful in predicting the survival; median survival time was 78 days (95% CI, 61‐131) for the high score, 318 days (95% CI, 207‐426) for the moderate score, and not reached as of 426 days (95% CI, 251 to undetermined) for the low‐score DASI group (P < .0001).

Conclusions

Patients readmitted within 30 days of an unplanned hospitalization are at higher risk of mortality than those not readmitted. A novel DASI developed from clinical documentation may help to predict survival in this population.
Detection of SRY‐positive46,XX male syndrome by the analysis of cell‐free fetal DNA via non‐invasive prenatal testing
Authors: De Falco Luigia , Savarese Giovanni , Suero Teresa , Amabile Sonia , Ruggiero Raffaella , Savarese Pasquale , Fico Antonio
Published: September 2019

We report a new case of 46,XX male syndrome that was detected following an anomalous result by non‐invasive prenatal testing (NIPT) and a discrepancy between the fetal karyotype and the ultrasonographic investigation. With the increasing use of NIPT, more gender discordances can be identified prenatally and be amenable to early therapy.
Characterisation of the endocrine pancreas in type 1 diabetes: islet size is maintained but islet number is markedly reduced
Authors: Seiron Peter , Wiberg Anna , Kuric Enida , Krogvold Lars , Jahnsen Frode L , Dahl‐Jørgensen Knut , Skog Oskar , Korsgren Olle
Published: September 2019

Insulin deficiency in type 1 diabetes (T1D) is generally considered a consequence of immune‐mediated specific beta‐cell loss. Since healthy pancreatic islets consist of ~65% beta cells, this would lead to reduced islet size, while the number of islets per pancreas volume (islet density) would not be affected. In this study, we compared the islet density, size, and size distribution in biopsies from subjects with recent‐onset or long‐standing T1D, with that in matched non‐diabetic subjects. The results presented show preserved islet size and islet size distribution, but a marked reduction in islet density in subjects with recent onset T1D compared with non‐diabetic subjects. No further reduction in islet density occurred with increased disease duration. Insulin‐negative islets in T1D subjects were dominated by glucagon‐positive cells that often had lost the alpha‐cell transcription factor ARX while instead expressing PDX1, normally only expressed in beta cells within the islets. Based on our findings, we propose that failure to establish a sufficient islet number to reach the beta‐cell mass needed to cope with episodes of increased insulin demand contributes to T1D susceptibility. Exhaustion induced by relative lack of beta cells could then potentially drive beta‐cell dedifferentiation to alpha‐cells, explaining the preserved islet size observed in T1D compared to controls.
Adolescent but not adult Sprague‐Dawley rats display goal‐directed responding after reward devaluation
Authors: Towner Trevor Theodore , Fager Michael , Spear Linda Patia
Published: September 2019

Alcohol drinking is typically initiated in adolescence, with use sometimes escalating to problematic levels. Escalation of drinking is often associated with a shift in drinking motives, with goal‐directed initial use later transitioning to more habitual behavior. This study assessed whether adolescents are more sensitive than adults to habit formation when indexed via insensitivity to reward devaluation in an operant task for food reward. Adolescent and adult Sprague‐Dawley rats were trained on either a random ratio (RR) or random interval (RI) schedule before undergoing devaluation. Adolescent animals on both schedules increased the number of lever presses across all training days. In contrast, adults in the RR group increased the number of lever presses across days whereas RI adults remained relatively stable. In response to pellet devaluation, only adolescents exhibited reduced responding, suggestive of goal‐directed behavior, whereas no age differences were evident following control (home cage chow) devaluation. Contrary to our hypothesis, adolescents (but not adults) displayed goal‐directed responding indexed via sensitivity to reward devaluation. These findings suggest that adolescents are not necessarily more likely to develop habits than adults, and hence other factors may contribute to the greater propensity of adolescents to engage in and escalate alcohol use.
Large local reaction to Hymenoptera stings: Sound studies are needed to change a shared concept
Authors: Pucci Stefano , Incorvaia Cristoforo , Romano Antonino
Published: September 2019

The natural history of large local reactions to Hymenoptera stings allowed to estimate the risk to develop a systemic reaction after an initial large local reaction in about 4% of patients. A recently published study claimed that such risk concerns instead around one‐fourth of patients. However, such study is flawed by serious imprecision, particularly the unreliable identification by patients of the culprit insect, as well as the dubious identification of the causative venom in multisensitized patients. Also, the authors criticized previous studied because of the limited number of patients, while they included in the study 662 patients. Indeed, when only patients clearly restung by the same insect according to their history data were considered, the number of patients fell to 35. These data are unable to change the current shared concept on the low risk of systemic reactions in patients with initial large local reaction.
A systematic review of the effectiveness, safety, and acceptability of medical management of intrauterine fetal death at 14–28 weeks of gestation
Authors: Cleeve Amanda , Fønhus Marita Sporstøl , Lavelanet Antonella
Published: September 2019

Background

Optimal dose, interval, and administration route of misoprostol with added benefit of mifepristone for management of second trimester intrauterine fetal death (IUFD) are not established.

Objectives

To assess effectiveness, safety, and acceptability of medical management of second trimester IUFD.

Search strategy

Research databases from January 2006 to October 2018.

Selection criteria

Randomized controlled trials with IUFD cases at 14–28 weeks of gestation.

Data collection and analysis

We screened and extracted data, assessed risk of bias, conducted analyses, and assessed overall certainty of the evidence.

Main results

Sixteen trials from 1695 citations. When misoprostol is used alone, 400 μg is more effective than 200 μg (RR 0.78; 95% CI, 0.66–0.92, moderate certainty evidence); the sublingual route is more effective than the oral route (RR 0.88; 95% CI, 0.70–1.11, low certainty evidence). There may be little to no difference between the sublingual and vaginal route (RR 0.93; 95% CI, 0.85–1.03, low certainty evidence). Certainty of evidence related to mifepristone–misoprostol regimens and safety and acceptability is very low.

Conclusions

Misoprostol 400 μg every 4 hours, sublingually or vaginally, may be effective. We cannot draw conclusions about safety and acceptability, or about the added benefits of mifepristone.
Photobiomodulation Increases Viability in Full‐Thickness Grafts in Rats Submitted to Nicotine
Authors: de Souza Thamires R. , de Souza Ana Karina , Garcia Sérgio B. , das Neves Lais M. S. , Barbosa Rafael I. , de Jesus Guirro Rinaldo R. , de Oliveira Guirro Elaine C.
Published: September 2019

Background and Objectives

Photobiomodulation (PBM) therapy with 830 nm wavelength or 660 wavelength to compare the effects with parameters of 30 mW, 0.028 cm2, 9.34 seconds, and 3.64 J on the total integration of total skin grafts in rats submitted to nicotine.

Study Design/Materials and Methods

Sixty male Wistar rats were divided in six groups: Sham—skin‐grafting surgery; 830 nm—skin‐grafting followed by 830 nm irradiation; 660 nm—skin grafting followed by 660 nm irradiation; Nicotine—subjected to subcutaneous nicotine injection (2 mg/kg twice a day for 4 weeks), followed by skin grafting; Group Nicotine/830 nm—similar to Group Nicotine, followed by 830 nm irradiation; Group Nicotine/660 nm—similar to Group Nicotine, followed by 660 nm irradiation. The percentage contraction of the grafting tissue was evaluated through ImageJ®. The thickness of the epidermis, inflammatory infiltrates, and the space between the implanted tissue and receptor bed were determined by histology; and the expression of vascular growth factor and blood vessel density (factor VIII) were evaluated by immunohistochemistry.

Results

The PBM at both wavelengths promoted a facilitating effect on the integration of the skin graft under nicotine and had a more significant effect on the thickness of the epidermis and expression of angiogenesis without nicotine at a wavelength of 830 nm. Different wavelengths influence responses related to the viability of cutaneous grafts in rats submitted to nicotine.

Conclusions

The PBM with 830 nm and 660 nm promoted beneficial results in skin grafts submitted to the deleterious action of nicotine. Lasers Surg. Med. © 2019 Wiley Periodicals, Inc.
Application of Ultrasound Thermal Imaging for Monitoring Laser Ablation in Ex Vivo Cardiac Tissue
Authors: Park Suhyun , Hwang Jieun , Park Jung‐Eun , Ahn Yeh‐Chan , Kang Hyun Wook
Published: September 2019

Background and Objective

Laser ablation can be used to treat atrial fibrillation by thermally isolating pulmonary veins. In this study, we evaluated the feasibility of high‐resolution (<1 mm) ultrasound thermal imaging to monitor spatial temperature distribution during laser ablation on ex vivo cardiac tissue.

Study Design/Materials and Methods

Laser ablation (808 nm) was performed on five porcine cardiac tissue samples. A thermocouple was used to measure the interstitial tissue temperature during the laser ablation process. Tissue‐strain‐based ultrasound thermal imaging was conducted to monitor the spatial distribution of the temperature in the cardiac tissue. The tissue temperature was estimated from the time shifts of ultrasound signals owing to the changes in the speed of sound and was compared with the measured temperature. The temperature estimation coefficient k of porcine cardiac tissue was calculated from the estimated thermal strain and the measured temperature. The degree of tissue coagulation (temperatures > 50°C) was derived from the estimated temperature and was compared with that of the tested cardiac tissue.

Results

The estimated tissue temperature using strain‐based ultrasound thermal imaging at a depth of 1 mm agreed with thermocouple measurements. During the 30‐second period of the laser ablation process, the estimated tissue temperature increased from 25 to 70°C at a depth of 0.1 mm, while the estimated temperature at a depth of 1 mm increased up to 46°C. Owing to the uncertainty of the coefficient k, the k value of the porcine cardiac tissue varied from 160 to 220°C with temperature changes of up to 20°C. The estimated coagulation region in the ultrasound thermal imaging was 20% wider (+0.6 mm) but 9% shallower (−0.1 mm) than the measured region of the ablated porcine cardiac tissue.

Conclusions

The current study demonstrated the feasibility of temperature monitoring with the use of ultrasound thermal imaging during the laser ablation on ex vivo porcine cardiac tissue. The high‐resolution ultrasound thermal imaging could map the spatial distribution of the tissue temperature. The proposed method can be used to monitor the temperature and thermal coagulation to achieve effective laser ablation for atrial fibrillation. Lasers Surg. Med. © 2019 Wiley Periodicals, Inc.
Mosaic complete tetrasomy 21 in a fetus with complete atrioventricular septal defect and minor morphological variations
Authors: Gatinois Vincent , Bigi Nicole , Mousty Eve , Chiesa Jean , Musizzano Yuri , Schneider Anouck , Lefort Geneviève , Pinson Lucile , Gaillard Jean‐Baptiste , Ragon Clémence , Perez Marie‐Josée , Tournaire Magali , Blanchet Patricia , Corsini Carole , Haquet Emmanuelle , Callier Patrick , Geneviève David , Pellestor Franck , Puechberty Jacques
Published: September 2019

Background

Tetrasomy 21 is a very rare aneuploidy which could clinically resemble a Down syndrome. It was most often described in its partial form than complete. We report the prenatal, pathological and genetic characteristics of a fetus with mosaic complete tetrasomy 21. This is the second well‐documented description of a complete tetrasomy 21 in the literature.

Methods

Prenatal and fetal pathological examinations, cytogenetic and molecular analyses were performed to characterize fetal features with tetrasomy 21.

Results

Prenatal ultrasound examination revealed an isolated complete atrioventricular septal defect with normal karyotype on amniotic fluid. After termination of pregnancy, clinical examination of the fetus evoked trisomy 21 or Down syndrome. Chromosomal microarray analysis and FISH on lung tissue showed a mosaicism with four copies of chromosome 21 (tetrasomy 21).

Conclusion

Our observation and the review of the literature reported the possibility of very weak mosaicism and disease‐causing confined tissue‐specific mosaicism in fetus or alive patients with chromosome 21 aneuploidy, mainly Down syndrome. In case of clinical diagnosis suggestive of Down syndrome, attention must be paid to the risk of false‐negative test due to chromosomal mosaicism (very weak percentage, different tissue distribution). To overcome this risk, it is necessary to privilege the diagnostic techniques without culture step and to increase the number of cells and tissues analyzed, if possible. This study highlights the limits of microarray as the unique diagnostic approach in case of weak mosaic and French cytogenetics guidelines recommend to check anomalies seen in microarray by another technique on the same tissue.