bluuebunny/crossref_metadata_2025 huggingface dataset:
Transcranial Ultrasonographic Image Analysis System for Decision Support in Parkinson Disease
Authors: Sakalauskas Andrius , Špečkauskienė Vita , Laučkaitė Kristina , Jurkonis Rytis , Rastenytė Daiva , Lukoševičius Arūnas
Published: January 2018

Objectives

Transcranial ultrasonography (US) is a relatively new neuroimaging modality proposed for early diagnostics of Parkinson disease (PD). The main limitation of transcranial US image‐based diagnostics is a high degree of subjectivity caused by low quality of the transcranial images. The article presents a developed image analysis system and evaluates the potential of automated image analysis on transcranial US.

Methods

The system consists of algorithms for the segmentation and assessment of informative brain regions (midbrain and substantia nigra) and a decision support subsystem, which is equipped with 64 classification algorithms. Transcranial US images of 191 participants (118 patients with a clinical PD diagnosis and 73 healthy control participants) were analyzed.

Results

The diagnostic sensitivity and specificity achieved by the proposed system were 85% and 75%, respectively.

Conclusions

Digital transcranial US image analysis is challenging, and the application of a such system as the sole instrument for decisions in clinical practice remains inconclusive. However, the proposed system could be used as a supplementary tool for automated assessment of US parameters for decision support in PD diagnostics and to reduce observer variability.
Clinical value of 4‐hour delayed gadolinium‐Enhanced 3D FLAIR MR Images in Acute Vestibular Neuritis
Authors: Byun Hayoung , Chung Jae Ho , Lee Seung Hwan , Park Chul Won , Park Dong Woo , Kim Tae Yoon
Published: January 2018

Objective

To investigate the clinical significance of 4‐hour delayed‐enhanced 3.0 Tesla three‐dimensional (3D) fluid‐attenuated inversion recovery (FLAIR) magnetic resonance (MR) imaging in acute vestibular neuritis.

Study Design

A prospective observational study.

Methods

Twenty‐nine vestibular neuritis patients were enrolled between January 2017 and June 2017. Vestibular function tests, comprising the caloric and video head impulse tests and vestibular‐evoked myogenic potential measurements, were performed. Precontrast, 10‐minute, and 4‐hour delayed‐enhanced 3D‐FLAIR MR images using double‐dose IV gadolinium were obtained. After laterality and extent of inner ear enhancement were defined, the patients were divided into groups based on the patterns of enhancement, and clinical parameters were analyzed according to the groups.

Results

Twenty patients (20 of 29, 69.0%) had obviously asymmetric enhancement of the affected inner ear structures on 4‐hour delayed images, whereas only three patients (10.3%) had marked enhancement on 10‐minute delayed images. The duration of spontaneous nystagmus (DurSN) was significantly longer in the patients with enhancement, especially with enhancement of the whole inner ear, including the vestibule and semicircular canals (P < 0.033). Spontaneous nystagmus resolved within 12 days in patients without laterality of enhancement, and within 16 days in ipsilesional enhancement confined to the inner auditory canal and fundus. Other results of vestibular function tests did not reveal any significant associations with MR enhancement.

Conclusions

Contrast enhancement of the vestibular nerve and inner ear structures can be identified on 4‐hour delayed‐enhanced 3T 3D‐FLAIR MR images in acute vestibular neuritis. The extent of inner ear enhancement may be associated with the DurSN.

Level of Evidence

4. Laryngoscope, 1946–1951, 2018
Safety of high‐current stimulation for intermittent intraoperative neural monitoring in thyroid surgery: A porcine model
Authors: Lu I‐Cheng , Chang Pi‐Ying , Randolph Gregory W. , Chen Hsiu‐Ya , Tseng Kuang‐Yi , Lin Yi‐Chu , Chiang Feng‐Yu , Wu Che‐Wei
Published: January 2018

Objectives

During monitored thyroidectomy, displacement of the recurrent laryngeal nerve (RLN) or vagus nerve (VN) in some complicated cases can increase the risk of injury. Although increasing the stimulus current can facilitate nerve mapping and localization, the safety of a high‐current stimulus remains unknown. Therefore, this study evaluated the safety of a high‐current stimulus in a porcine model.

Methods

Short‐duration (1 minute), high‐current (3, 5, 10, 15, 20, 25, and 30 mA at 4Hz) stimulus pulses were repeatedly applied to the RLN or VN in six anesthetized piglets. The safety of the high‐current stimulus pulses was assessed in terms of hemodynamic stability during VN stimulation and in terms of nerve function integrity after VN and RLN stimulation.

Results

During VN stimulation with a high‐current stimulus pulse, sinus rhythms in all six piglets showed stable heart rates, and mean arterial pressure was unaffected. High‐current stimulation of the VN and the RLN did not affect electromyography amplitude or latency.

Conclusion

This porcine study showed that applying a short‐duration, high‐current stimulus pulse to the VN or RLN during monitored thyroidectomy has no harmful effects. In clinical practice, a short duration of high‐current stimulus can be applied to facilitate neural mapping, especially in patients with disoriented nerve positions.

Level of Evidence

NA. Laryngoscope, 128:2206–2212, 2018
Hyoepiglottic ligament collagen and elastin fiber composition and changes associated with aging
Authors: Irvine Leslie E. , Yang Zhi , Kezirian Eric J. , Nimni Marcel E. , Han Bo
Published: January 2018

Objective

The epiglottis may contribute to upper airway obstruction in approximately 10% of patients with obstructive sleep apnea. Clinical experience indicates that older patients may be more likely to have epiglottis‐related obstruction. This study was designed to examine tissue characteristics of the hyoepiglottic ligament as a possible factor in epiglottis‐related obstruction based on previous research suggesting that older adults have fewer collagen, elastin, and muscle fibers in the hyoepiglottic ligament.

Methods

This is a cross‐sectional study of 25 human cadaver hyoepiglottic ligaments. Specimens were stained using Masson's trichrome and Picrosirius red for collagen fibers and with Verhoeff‐Van Gieson for elastin fibers. Percentage of collagen and elastin fiber staining for each specimen was calculated and averaged over three regions of each ligament section. Regression analysis was used to determine the association between age, smoking history, and collagen and elastin composition of the hyoepiglottic ligament.

Results

The average age of the specimens was 68.4 ± 15.1 years (range 30–90 years). Increasing age was associated with a lower percentage of collagen and elastin fibers. When accounting for tobacco use, each 1‐year increase in age was associated with a 0.53% decrease in Masson's trichrome staining (P = 0.004), a 0.35% decrease in Picrosirius red staining (P = 0.023), and a 0.33% decrease in Verhoeff‐Van Gieson staining (P = 0.008).

Conclusion

Increasing age is associated with decreases in the collagen and elastin content of the hyoepiglottic ligament.

Level of Evidence

NA. Laryngoscope, 128:1245–1248, 2018
3D Micro‐Printing: A new Era for Med‐Tech Applications
Authors: Steimle Alexander
Published: January 2018

In recent years, 3D printing has attracted increasing attention in many industries. From bioprinting of living organs to engine and airplane components, a variety of 3D printing techniques are already in use today, mainly differentiated by the additive or sub‐tractive manufacturing approach. But what's the application potentiality in the med‐tech industry with regards to 3D printing at micro‐scale? And how innovative three‐dimensional thinking can tackle human diseases such as the retinal vein occlusion (RVO) and create transformative products?
Design and Function for Freeform Surfaces
Authors: Mescheder Holger , Hermens Ulrike
Published: January 2018

Anyone who has ever tried to gift‐wrap a ball elegantly will be familiar with the problem: It is not easy to wrap a two‐dimensional structure around a three‐dimensional object without ending up with numerous folds and kinks. The Fraunhofer Institute for Production Technology IPT in Aachen is currently developing a software module which will be capable of transferring functional structures to complex shapes.
Phase Stabilized α‐CsPbI3 Perovskite Nanocrystals for Photodiode Applications
Authors: Sim Kyu Min , Swarnkar Abhishek , Nag Angshuman , Chung Dae Sung
Published: January 2018

High‐performance and high‐reliability photodiodes are demonstrated by using α‐CsPbI3 perovskite nanocrystals (NCs) phase‐stabilized with a low‐temperature solution‐treated active layer. In addition to the high charge mobility, the high absorption coefficient, and IR‐blind characteristics of the perovskite material, the defect‐tolerant nature of α‐CsPbI3 perovskite NCs are combined to realize hysteresis‐free and high detectivity photodiodes. To further minimize interface defects originating from multi‐layer photodiode construction, a poly(3‐hexylthiophene) layer is strategically introduced as a passivation and electron blocking layer, resulting in a low diode ideality factor of 1.5 and a noise equivalent power of 1.6 × 10−13 W Hz−0.5. As a result, high detectivity of 1.8 × 1012 Jones is demonstrated with near‐zero hysteresis. Furthermore, the optimized photodiode exhibits excellent stability under high humidity conditions owing to the intrinsic nature of the defect‐tolerant α‐CsPbI3 perovskite NCs.
A split‐body study evaluating the efficacy of a conformable surface cryolipolysis applicator for the treatment of male pseudogynecomastia
Authors: Jones Isabela T. , Vanaman Wilson Monique J. , Guiha Isabella , Wu Douglas C. , Goldman Mitchel P.
Published: January 2018

Background

Cryolipolysis is a non‐invasive method of body shaping that has been used for male pseudogynecomastia. However, traditional vacuum suction cryolipolysis requires a minimum pinchable fat layer which may not always be present in this area.

Objective

To evaluate the efficacy and safety of a conformable surface cryolipolysis applicator for the reduction of male pseudogynecomastia.

Materials and Methods

Ten male subjects with pseudogynecomastia received two cycles of cryolipolysis to the breast 6 weeks apart. Ultrasound was used to measure the thickness of adipose tissue.

Results

Seven of 10 patients completed the study. Compared to baseline, the mean ± SD change in adipose tissue thickness was 8.12 ± 6.94 mm for the treated versus 1.03 ± 6.03 mm for the control breast at week 6 (p = 0.014), and 8.71 ± 7.04 mm for the treated vs. 2.66 ± 7.04 mm for the control breast at week 12 (P = 0.16). Four (4) of seven (57%) patients were at least slightly satisfied with the treated breast, and although subject satisfaction was higher in the treated breast, this did not reach significance (0.085). Adverse events were mild and transient.

Conclusion

A conformable surface cryolipolysis applicator was effective in reducing the mean adipose tissue thickness in subjects with male pseudogynecomastia. Lasers Surg. Med. 50:608–612, 2018. © 2018 Wiley Periodicals, Inc.
Effect of low‐level laser therapy on the healing of sites grafted with coagulum, deproteinized bovine bone, and biphasic ceramic made of hydroxyapatite and β‐tricalcium phosphate. In vivo study in rats
Authors: de Oliveira Guilherme J.P.L. , Aroni Maurício A.T. , Medeiros Marcell C. , Marcantonio Elcio , Marcantonio Rosemary A.C.
Published: January 2018

Objective

The aim of this study was to evaluate the effect of low‐level laser therapy (LLLT) on the healing of biomaterial graft areas (i.e., coagulum, deproteinized bovine bone, and biphasic ceramics comprising hydroxyapatite and β‐tricalcium phosphate).

Material and Methods

Ninety rats were divided into two groups according to laser irradiation use (λ 808 nm, 100 mW, φ ∼600 μm, seven sessions with 28 J of irradiation dose in total): a laser group and a control group. Each of these groups was divided into three subgroups of 15 animals each according to the type of biomaterial used: Coagulum (COA), deproteinized bovine bone (DBB), and hydroxyapatite/β‐tricalcium phosphate (HA/βTCP). Biomaterials were inserted into Teflon domes, and these domes were grafted to the lateral aspect of the mandibular branch of the rats. The animals were sacrificed after 30, 60, and 90 days. Scarring patterns were evaluated by microtomography and histometry. The expression levels of BMP2, osteocalcin (OCN), and alkaline phosphatase (ALP) were evaluated by immunohistochemistry. The mRNA expression levels of ALP, BMP2, Jagged1, Osterix, Runx2, and TGFβ1 were determined by RT‐qPCR.

Results

The animals treated with LLLT exhibited increased mineralized tissues and bone, particularly after 90 days. These increases were associated with increased BMP2, OCN, and ALP protein expression and ALP, BMP2, and Jagged1 mRNA expression.

Conclusion

LLLT improved the osteoconductive potential of DBB and HA/βTCP grafts and bone formation in ungrafted areas. Lasers Surg. Med. 50:651–660, 2018. © 2018 Wiley Periodicals, Inc.
Commercialization of eHealth innovations in the market of the UK healthcare sector: A framework for a sustainable business model
Authors: Oderanti Festus Oluseyi , Li Feng
Published: January 2018

Demographic trends with extended life expectancy are placing increasing pressures on the UK state‐funded healthcare budgets. eHealth innovations are expected to facilitate new avenues for cost‐effective and safe methods of care, for enabling elderly people to live independently at their own homes and for assisting governments to cope with the demographic challenges. However, despite heavy investment in these innovations, large‐scale deployment of eHealth continues to face significant obstacles, and lack of sustainable business models (BMs) is widely regarded as part of the greatest barriers. Through various empirical methods that include facilitated workshops, case studies of relevant organizations, and user groups, this paper investigates the reasons the private market of eHealth innovations has proved difficult to establish, and therefore it develops a framework for sustainable BMs that could elimiesnate barriers of eHealth innovation commercialization. Results of the study suggest that to achieve sustainable commercialization, BM frameworks and innovation diffusion characteristics should be considered complements but not substitutes.
Customers’ judgments and misjudgments of corporate responsibility communication: A cross‐country investigation of the effects on confidence and trust within the banking sector
Authors: Civera Chiara , Casalegno Cecilia , Mosca Fabrizio , Maple Peter
Published: January 2018

Customers’ judgment of corporate responsibility (CR) communication and the effect on confidence and trust as interlinked paradigms are intriguing areas of investigation from both theoretical and empirical perspectives. This research aims to clarify the nature of effective CR communication toward customers by identifying situations of over‐ and undercommunication of CR that might cause misjudgments and therefore lower the level of confidence among customers. The study also provides insights to better explain the link between confidence and trust related to customers’ perceptions of CR communication and compares different judgments and misjudgments regarding the banking industries in Italy and the United Kingdom. The study adopts real and fictitious bank case studies to conduct focus groups investigations of 160 millennial customers’ perceptions of CR communication and how it affects their level of confidence. The findings highlight the role of trust in making independent judgments on CR communications. Some similarities and slight differences in the impact of CR communication on confidence emerge between the countries and greatly depend on the customers’ level of trust in real banks and the influence of the industry effect characterizing the banking sector. This study provides fertile ground for future research into the implementation of a more effective and balanced CR communication strategy to increase customers’ confidence and into the understanding of which communication drivers, apparently independent of CR, affect trust in the long term.
The opportunity to improve psychological competences of project managers in international businesses
Authors: Rodríguez‐Rivero Rocío , Ortiz‐Marcos Isabel , Ballesteros‐Sánchez Luis , Romero Javier
Published: January 2018

Many projects are currently conducted in international businesses in which cultural issues play an important role. In‐depth analysis of the risks associated with the unknown of this type of issues offers companies a better understanding of how to focus their marketing tools to be more effective, and provides project managers with strategies to improve customer relationships. Hofstede's Cultural Dimensions and Meyer's Culture Map have demonstrated that every society possesses distinguishing features. These cultural theories serve as foundation for including the category of culture in a proposed Cultural Risk Breakdown Structure. Through a literature review, risks associated with cultural differences are identified in projects executed in Africa, China, and the Middle East. By linking these risks to cultural dimensions, it is possible to identify the psychological competences framework in international businesses. Therefore, the aim of this paper is to create not only a comprehensive record of these risks but also a list of the new skills and competences that project managers must possess to improve client satisfaction and make decisions in a cross‐cultural environment. By considering the association between psychological aspects and cultural issues, this analysis will be of considerable benefit for improving relationships in international contexts.
Numerical investigation of droplet impact on the welding pool in gas metal arc welding
Authors: Mokrov O. , Lysnyi O. , Simon M. , Reisgen U. , Laschet G. , Apel M.
Published: January 2018

A transient three‐dimensional model that describes physical phenomena inside a welding pool during gas–metal arc welding process is presented. The model considers such phenomena as heat‐mass transfer, electromagnetics, hydrodynamic processes and deformation of the weld pool free surface. The fluid flow in the weld pool is induced due to the presence of the mechanical impact of the droplets, thermo‐capillary surface tension, thermal buoyancy and electromagnetic forces. The weld pool surface deformation is calculated by considering arc pressure and droplet impact force. A comparative analysis of the impact of the electric current of the welding arc and different force factors causing the motion of liquid metal in the weld pool on the shape of the welded seam was carried out and discussed.
Investigation on the transferability of algorithms for the numerical optimization of cooling channel design in injection molding on metal gravity die casting
Authors: Hopmann C. , Schneppe T. , Theunissen M. , Bührig‐Polaczek A. , Wolff N.
Published: January 2018

The thermal mold design and the identification of a proper cooling channel design are primordial steps in the development of complex molds for injection molding. In order to find a suitable cooling channel system, a lot of effort is needed to avoid part warpage after solidification. In current research, a simulative procedure to optimize the cooling channel layout iteratively is being developed at the Institute of Plastics Processing. These algorithms are transferred to the metal gravity die casting process, which has several similar requirements to the mold. Effectively, the simulation is simplified to a heat conduction problem. Instead of water, high temperature resistant oil is deployed and the casted material is a A356 aluminum alloy instead of semi‐crystalline plastics. The algorithm is adapted to these changed boundary conditions and the calculation of the optimized heat distribution is performed. Aim of this procedure is the construction of a mold producing parts with less warpage than a conventional mold.
Influence on martensite‐start‐temperature and volume expansion of low‐transformation‐temperature materials used for residual stress relief in beam welding
Authors: Reisgen U. , Olschok S. , Sharma R. , Gach S.
Published: January 2018

Low‐transformation‐temperature materials (LTT) are used as high‐alloy welding filler material for high‐strength steels in order to minimize the tensile stresses and resulting distortion of the component during the welding process. The increase in the volume of the structure produced during martensitic transformation is utilized in order to counteract the volume shrinkage due to the cooling process. As stated in the field of study various elements influence the starting temperature of the martensite transformation, the influence on the volume expansion during the martensite formation is unknown. The influence of alloying elements nickel and chromium on the conversion behavior of low‐transformation‐temperature materials is to be investigated in detail. In particular, the effect of the variation of the mentioned elements on the starting temperature of the martensitic phase transformation and the extent of the volume expansion associated with that is investigated. In addition, the change in the hardness of the different low‐transformation‐temperature alloys is recorded and compared.
Characterisation of quasi‐stationary temperature fields in laser welding by infrared thermography
Authors: Francis J.A. , Gach S. , Olscho S. , Reisgen U. , Haeusler A. , Gillner A. , Poprawe R.
Published: January 2018

In this work, high‐speed thermography is shown to effectively capture quasi‐stationary temperature fields during the laser welding of steel plates. This capability is demonstrated for two cases, with one involving the addition of a ferritic‐bainitic filler wire, and the other involving the addition of a low‐transformation‐temperature (LTT) filler wire. The same welding parameters are used in each case, but the temperature fields differ, with the spacing between isotherms being greater in the case where the low‐transformation‐temperature filler material is added. This observation is consistent with the differences in the extent of the heat‐affected zone in each sample, and the shape of the weld pool ripples on the weld bead surfaces. The characterization of temperature fields in this way can greatly assist in the development of novel methods for reducing residual stresses, such as the application of low‐transformation‐temperature filler materials through partial‐metallurgical injection (PMI). This technique reduces or eliminates tensile residual stresses by controlling the temperature fields so that phase transformations take place at the optimum times, and success can only be guaranteed through precise knowledge of the temperature fields in the vicinity of the welding heat source in real time.
Influence of process strategy on distortion and residual stresses for the powder based laser metal deposition process
Authors: Pirch N. , Schleifenbaum H. , Linnenbrink S. , Gasser A. , Poprawe R. , Niessen M.
Published: January 2018

Laser metal deposition (LMD) induces a complex 3‐axis residual stress state, which superimposes the external service stresses and can cause unpredicted in‐service failures. To optimize the process it is important to know the mechanisms and the opportunities to influence the occurrence of residual stresses. From the mathematical point of view, laser metal deposition represents a free boundary value problem. The track geometry is part of the solution. Previously the authors developed a thermal model that is used to calculate the time‐ and space resolved temperature distribution and the track geometry. The thermal model encompasses the powder stream, its interaction with the laser radiation, the shadowing of the laser radiation by the particles, the heating of the particles and the melt pool computation. In this publication, the evolution of residual stresses for overlapping tracks for single and multilayer processing for different powder mass rates is described.
Dietary Factors Modulate Colonic Tumorigenesis Through the Interaction of Gut Microbiota and Host Chloride Channels
Authors: Zhang Yong , Kang Chao , Wang Xiao‐lan , Zhou Min , Chen Meng‐ting , Zhu Xiao‐hui , Liu Kai , Wang Bin , Zhang Qian‐yong , Zhu Jun‐dong , Mi Man‐tian
Published: January 2018

Scope

In recent decades, the association among diet, gut microbiota, and the risk of colorectal cancer (CRC) has been established. Gut microbiota and associated metabolites, such as bile acids and butyrate, are now known to play a key role in CRC development. The aim of this study is to identify that the progression to CRC is influenced by cholic acid, sodium butyrate, a high‐fat diet, or different dose of dihydromyricetin (DMY) interacted with gut microbiota.

Methods and results

An AOM/DSS (azoxymethan/dextran sodium sulfate) model is established to study the gut microbiota compsition before and after tumor formation during colitis‐induced tumorigenesis. All above dietary factors profoundly influence the composition of gut microbiota and host colonic tumorigenesis. In addition, mice with DMY‐modified initial microbiota display different degrees of chemically induced tumorigenesis. Mechanism analysis reveals that gut microbiota‐associated chloride channels participated in colon tumorigenesis.

Conclusion

Gut microbiota changes occur in the hyperproliferative stage before tumor formation. Gut microbiota and host chloride channels, both of which are regulated by dietary factors, are associated with CRC development.
Ultrawideband dipole receiving antenna for measuring short pulses with extended bandwidth
Authors: Balzovsky Evgeny , Buyanov Yury , Koshelev Vladimir , Nekrasov Eduard
Published: January 2018

This article presents the design of an ultrawideband active integrated antenna based on an electric dipole and the results of its testing. The antenna is intended to perform low‐distortion measurements of the instantaneous electric field strength of short pulses whose spectra lie within the frequency range from 0.05 to 3 GHz. The antenna is fabricated using the technology of printed circuit boards on a 1‐mm thick FR4 plate of dimensions 60 × 28 mm. It has a built‐in balancing‐to‐unbalancing unit and an unbalanced output. The difference in output voltage pulse waveform between the proposed antenna and a reference TEM‐antenna is insignificant.
Low‐profile tilted‐beam waveguide slot antenna using corrugations for UAV applications
Authors: Jin Yunnan , Lee Hojoo , Woo Daewoong , Choi Jaehoon
Published: January 2018

We propose a low‐profile tilted‐beam waveguide slot antenna using corrugations for unmanned aerial vehicle (UAV) applications. The proposed antenna consists of a WR‐90 rectangular waveguide with a central slot on top and two asymmetric corrugations. The antenna satisfies a 10‐dB return loss from 9.82 to 10.18 GHz. To realize the low‐profile characteristic, the proposed antenna is fed from the flank instead of the bottom of the waveguide. In addition, the proposed antenna attains a tilted beam pointing 45 degrees from the broadside direction due to the asymmetric corrugations on the conducting plate. The antenna has a measured peak gain of 6.95 dBi at the center frequency of the operation band, which satisfies the gain requirement for UAV applications. The experimental and simulated results of the proposed antenna are in good agreement.
A compact four‐element MIMO antenna for WLAN applications
Authors: Pandit Soumen , Mohan Akhilesh , Ray Priyadip
Published: January 2018

This article presents a compact four‐element multiple‐input multiple‐output (MIMO) antenna for wireless local area network applications. The overall volume of the proposed MIMO antenna is 26 mm × 26 mm × 0.8 mm and the edge‐to‐edge distance is 4 mm. The MIMO antenna operates at 5.6 to 5.8 GHz frequency band with isolation greater than 15.4 dB. The envelope correlation coefficient and the channel capacity loss for the proposed MIMO antenna are within the acceptable limits in the operating frequency band. The simulated results are verified with fabrication and measurements.
Linear CMOS power amplifier using continuous gate voltage control
Authors: Kim Joonhyung
Published: January 2018

In this article, an linearization technique using a gate voltage adaptation of a common gate stage for a cascode CMOS power amplifier (PA) is presented. The tracking of minimum in‐band third‐order intermodulation distortion by controlling with respect to instantaneous power level enhances the linearity of CMOS PA over a wide range of operation level. The experimental results show that the CMOS PA with proposed scheme has an overall efficiency of 34.6% and a gain of 25.8 dB at an average output power of 27 dBm. Under this condition, the adjacent channel leakage ratio is <–34.8 and 5.4 dBc lower when compared with the use of no linearization technique.
A novel two‐step flare wide band horn antenna
Authors: Manshari Saeed , Kashani Farokh , Moradi Gholamreza , Sarijlo Mohamad
Published: January 2018

In this letter, a novel dual section or two step flare horn antenna for working at 1.5–8 GHz is presented. Novelty of this design is through utilizing of double flare section in horn so that the adverse effects of diffractions caused by ridges on radiation are decreased. The proficiency of new design is indicated in terms of location of the phase center, radiation pattern, and VSWR. Similarity of pattern for the two main polarizations over 10 dB beamwidth at 45° slant rotation is a feature of this antenna for applications that need similar amplitude patterns for two horizontal and vertical polarizations in the main beam. One prototype of antenna has been fabricated and tested with excellent agreement between measured and simulated results. Amplitude radiation patterns of this antenna for vertical and horizontal polarizations and also distance of the phase center from aperture versus frequency are illustrated.
4 × 4 MIMO antenna design with folded ground plane for 2.4 GHz WLAN applications
Authors: Ahmad Muhammad Sajjad , Mohyuddin Wahab , Choi Hyun Chul , Kim Kang Wook
Published: January 2018

A 4 × 4 MIMO antenna design for packed conditions is presented for WLAN applications. The proposed antenna consists of a radiating patch, a parasitic patch, and a folded ground plane to achieve the desired resonant frequency, return loss, bandwidth, and isolation for the worst case scenario. The antennas are fed individually by 50 Ohm coaxial feedings. The proposed antenna design has measured 73 MHz bandwidth >10 dB, and exhibits isolation better than 10 dB over the desired band, when there is no physical separation between antennas. The prototype for the 4 × 4 MIMO is constructed and the results are compared. The simulation and measurement results are well in agreement.
Study and design of wristband RFID antenna for healthcare applications
Authors: Marouf F. Z. , Ziani Kerarti D.
Published: January 2018

The RFID technology is widely improved in the last decade. It offers different applications touching different areas. Tags could be modeled under several shapes serving the desired application; it can take a wristband form in the case of human body identification. In this paper, we present a design of an antenna implemented on the tag, with the aim to sense different physiological human parameters (temperature, blood pressure, O2 saturation, etc.). This antenna has a bent form, suitable for the medical application. It was put on flexible substrate to be conformal to the wrist. It presents good characteristics in terms of impedance matching.
Study on the estimation of the LED‐package life using a statistical approach
Authors: Park Seil , Kim Gun So , Kim Chung Hyeok
Published: January 2018

Since the LED has been popularly used in the lighting field, many of the standards for LED lights such as those regarding LED modules, LED luminaries, and LED lamps have been renewed or newly published. In the development of the relevant standards, many other standards for LED appurtenances have also been developed to measure the LED packages and to produce the luminous flux, color chromaticity, color rendering index, and luminous‐intensity distribution. Although many standards has been developed for different purposes, a standard for the projection of the lumen maintenance of the LED packages and luminaires is nonexistent. LED products are widely known for their long lifetimes, but the formation of accurate definitions of their life periods and the lumen maintenance regarding the LED products are not possible due to the LED‐package components such as the phosper material and the soldering techniques. The method in the IES LM‐80‐08 had been mainly used as an alternative for the projection of the lumen maintenance, but an active discussion of the Border Function and Temperature Acceleration methods in terms of their use as current international standards has occurred. In this study, a new equation for the lumen‐maintenance projection is proposed for the accurate measurement of the lumen maintenance for which a set of 12 LED packages is used. By using the equation, the real value of the LED‐product life can be easily estimated, and it can be compared with the manufacturer claim regarding the value of the LED‐product life.
Mitigation of common mode noise in bent differential transmission line using curved PBG unit cell
Authors: Ranade S. R. , Shevgaonkar R. K. , Sidhique A. , Rao P. H.
Published: January 2018

A curved photonic band gap (PBG) unit cell loaded bent differential line is proposed to suppress the differential‐to‐common mode conversion noise. The PBG unit cell, loaded at the bend is designed and optimized to provide the required delay characteristic on the inner transmission line of a differential line. An LC equivalent circuit of curved PBG unit cell is proposed and constituent lumped element parameters are calculated. The realized PBG loaded bent differential line exhibits a measured mode conversion noise below −20 dB from DC to 6 GHz demonstrating a common mode noise suppression of around 9 dB.
Conceptual design and implementation of a four‐element MIMO antenna system packaged within a metallic handset
Authors: Gao Chen , Li Xiao‐Qian , Lu Wen‐Jun , Wong Kin‐Lu
Published: January 2018

The conceptual design of a multiple input multiple output (MIMO) antenna system packaged within a metallic handset for future wireless communications is proposed, simulated, and implemented. The presented MIMO antenna system is composed of four‐identical slotted microstrip magnetic dipoles. The whole antenna system is installed within an emulated handset with a metallic back cavity and frames. A few antenna prototypes are fabricated and measured to validate the conceptual design. Owning to the inherent microstrip magnetic dipole configuration, the packaged MIMO antenna system exhibits a good impedance matching, a high element isolation, an acceptable average radiation efficiency of about 40%, and a wide beam coverage performance at 3.5 GHz‐band. Compared to conventional single input single output (SISO) wireless communication systems, the channel capacity can be nearly tripled by employing the designed MIMO handset.
Optically transparent microstripline with micro‐ and wired‐metal mesh
Authors: Lee Hoon Hee , Kang Seok Hyon , Jung Chang Won
Published: January 2018

Optically transparent microstriplines designed using a conductive micro‐metal mesh film (µ‐MMF) and a conductive wired‐metal mesh (WMM) are presented. The transparent microstriplines are fabricated on a transparent acryl substrate with thickness (hs) of 1.25 mm, relative permittivity (ɛr) of 2.6, and loss tangent (tan δ) of 0.009. The average optical transmittance of µ‐MMF and WMM is 62% and 71%, respectively, in the visible band (400–750 nm). The sheet resistance of µ‐MMF and WMM is 0.08 and 0.01 Ω/sq, respectively. In addition, two types of copper microstriplines are fabricated for performance comparison. Insertion losses (S21) and return losses (S11) of transparent microstriplines of lengths 1, 3, and 5 cm are measured to be under 2 dB and higher than 15 dB up to 6 GHz, respectively.
Multiband reconfigurable Bowtie slot antenna using switchable slot extensions for WiFi, WiMAX, and WLAN applications
Authors: Mansoul Ali , Seddiki Mohamed Lamine
Published: January 2018

In this letter, a compact multi‐band reconfigurable CPW fed bowtie slot antenna is presented and these performances are discussed. The known properties of the bowtie antenna, namely a high gain and a fairly large bandwidth have been used in order to design a reconfigurable multiband antenna which makes it possible to switch between a single band (initial mode) and dual band or triple band modes, making it more agile in frequency. The proposed approach is based on the integration of two pairs of slots on the two sides of the antenna to create new bands optimized to operate in the two bands of WiFi and WiMAX at 2.4 GHz and 3.5 GHz, respectively. The results of measurements and simulations are presented and compared and a good agreement is established. The antenna is intended for multiservices and cognitive radios applications.
An efficient and reliable small signal intrinsic parameters extraction for HEMT GaN devices
Authors: Maafri Djabar , Saadi Abdelhalim , Slimane Abdelhalim , Yagoub Mustapha C. E
Published: January 2018

To efficiently design GaN HEMT devices, a robust extraction of their intrinsic electrical equivalent circuit element values is critical. Aiming to accurately determine all intrinsic element values, a new elements‐based small‐signal equivalent circuit technique is introduced in this paper. Compared to the conventional GaAs‐based HEMT small‐signal model composed of 16 elements, the proposed equivalent circuit consists of two parasitic distributed interelectrode extrinsic capacitances and two additional feedback intrinsic resistances. The circuit element values were obtained starting from measured S‐parameters and using Y‐matrix transformations. The efficiency of the proposed methodology was demonstrated through excellent agreement between simulated and measured data up to 60 GHz.
A ku‐band distributed SPDT switch in 0.5 μm AlGaN/GaN HEMT technology
Authors: Zaibet Imane , Hettak Khelifa , Yagoub Mustapha C. E.
Published: January 2018

In this paper, a wideband single‐pole double‐throw (SPDT) switch using the traveling‐wave concept was demonstrated. Realized in 0.5 μm AlGaN/GaN HEMT process, it achieves good performance at Ku‐band despite the process being intended for low‐frequency applications. This type of switch combined the off‐state shunt transistors and series coplanar waveguide (CPW) lines to form an artificial transmission line. CPW is also used to eliminate parasitics associated with through‐substrate microstrip vias and coupling of adjacent transmission lines. An accurate switch HEMT model was extracted and used in the design. A 9–25 GHz single‐pole double‐throw (SPDT) switch in conjunction with quarter‐wavelength impedance transformers demonstrates an insertion loss of less than 6 dB, return loss better than 10 dB and an isolation of better than 25 dB.
A novel ultra‐wideband antipodal Vivaldi antenna with trapezoidal dielectric substrate
Authors: Wan Fayu , Chen Jun , Li Binhong
Published: January 2018

An ultra‐wideband Vivaldi antenna is designed in this article, its frequency band is 3.3–40 GHz. Based on the traditional antipodal Vivaldi antenna, a trapezoidal dielectric substrate is loaded in the direction of major axis, which not only eliminates the antenna gain peak shifting problem, but also improves the directional radiation performance. The dimension of the antenna is 57.5 mm × 60.7 mm. The substrate of the antenna is Rogers RO4003C with relative dielectric constant (ɛr) of 3.38, loss tangent of 0.0027, and thickness of 0.508 mm. The simulation and measured results show that bandwidth of the antenna is 3.3–40 GHz, and it also has many advantages such as good radiation direction, high gain, narrow main lobe width, and low cross‐polarization ratio.
High isolation 4‐port diplexer based on double‐sided parallel‐strip lines
Authors: Lu Yun‐Long , Wang Yi , Hua Changzhou , Liu Taijun
Published: January 2018

A high isolation 4‐port diplexer implemented using double‐sided parallel‐strip lines (DSPSLs) is presented in this letter. Two back‐to‐back 3‐port diplexers and a 180° phase shifter are employed to construct the proposed device. The DSPSL structure enables a compact phase shifter without incurring any extra circuit footprint. The 4‐port circuit topology suppresses the leakage between the 2 channels by signal cancellation, resulting in significantly improved channel isolation. For demonstration, a 4‐port diplexer with operating frequencies of 1.85 and 2.1 GHz is designed, fabricated and measured. The experimental results show that the 4‐port diplexer has good in‐band performance and high isolation of 50 and 51 dB. This is an improvement of over 23 dB compared with the conventional 3‐port diplexer.
Filtering Gysel power divider with arbitrary power splitting ratio
Authors: Dong Gaoya , Wang Weimin , Zhang Bo , Liu Yuanan
Published: January 2018

A novel filtering Gysel power divider (PD) structure based on coupled lines is presented to realize arbitrary power splitting ratio and filtering response. The proposed filtering PD consists of three parallel‐coupled lines, two short‐circuited stubs, two stepped impedance stubs and two grounded isolation resistors. Two transmission zeros (TZs) are introduced by the stepped impedance stubs, which can greatly improve the passband selectivity and out‐of‐band rejection performances. Theoretically, closed‐form equations for the proposed structure are derived based on even‐odd mode method. For verification, two filtering Gysel PDs with equal and unequal power splitting ratios (
) are designed and experimentally demonstrated in this paper.
Asymmetric double QW superluminescent diodes for broadband and high‐power use
Authors: Kwon Oh‐Kee , Lee Chul Wook
Published: January 2018

We report the use of broadband and high‐power InGaAs/GaAs asymmetric double quantum‐well (ADQW) superluminescent diodes (SLDs), which consist of a tilted, bent, and straight waveguide. To examine the effects of the arrangement of the ADQW and the gain provided by a straight waveguide on the output performances, we fabricated SLDs with different lengths for two types of ADQW, that is, a wide QW at the p‐side for Sample 1, and a narrow QW at the p‐side for Sample 2, and tested their spectral width and output power. The fabricated SLDs with a straight length (L3) of 80 μm show −3 dB spectral widths of 122 and 116 nm and output powers of 20 and 16 mW at an injection current of 250 mA for Samples 1 and 2, respectively. For both samples, it appears that, as the L3 increases, the spectral width decreases and the output power increases. From this result, we confirmed that both the spectral width and the output power can be adjusted and optimized at a given structure for various applications.
RF phase noise filtering properties of an actively mode‐locked laser
Authors: Mbonde Hamidu , Ozharar Sarper , Ozdur Ibrahim
Published: January 2018

In this article, we are presenting the experimental results and theoretical analysis of radio frequency (RF) phase noise filtering properties of a high Q cavity actively driven mode‐locked laser. The experimental results show that, the phase noise of a 10 GHz RF tone can be filtered by at least 10 dB at 200 kHz offset frequency. A theoretical analysis on the limits of phase noise filtering due to the spontaneous emission and the frequency mismatch between the laser cavity modes and the synthesizer frequency is also included.
Reconfigurable and stable frequency selective surfaces on nonuniform and finite arrays
Authors: Silva Neto V. P. , D'Assunção A. G.
Published: January 2018

A reconfigurable frequency selective surface (FSS) is presented based on a nonuniform and finite array of square loop conducting patches printed on a dielectric substrate. The reconfigurability is performed changing the polarization of PIN diodes in the patch elements of the FSS array, from OFF to ON state and vice versa. Simulation is performed by the wave concept iterative procedure (WCIP) formulation and Ansoft HFSS package. Remarkably, a generalization of the WCIP method is proposed to solve scattering problems on FSS structures composed of nonuniform and finite arrays. Prototypes are fabricated for comparison purpose. Simulations and measurements show that the nonuniform and finite FSS has dual band behavior and stable frequency response for different angles of the incident plane wave. A very good agreement between HFSS simulation, WCIP formulation, and experimental results is verified.
Identification of tentative marker in Corvina and Primitivo wines with CMC‐se
Authors: Kessler Pavel , Godejohann Markus
Published: January 2018

This paper introduces CMC‐se—a program for computer‐assisted structure elucidation. In the experimental part, the combination of modern analytical methods (LC‐SPE‐NMR/MS) and structure elucidation software is used for the identification of tentative markers in red wines.
Fecal incontinence knowledge, attitudes, and help‐seeking behaviors among community‐dwelling adults in Korea
Authors: Joh Hee‐Kyung , Seong Moo‐Kyung , Ahn Hyun‐Jun
Published: January 2018

Objectives

Fecal incontinence (FI) is a common debilitating disorder that tends to be underreported. Although low health literacy likely contributes to the underreporting, studies on FI knowledge among the general population remain scarce. We investigated how FI knowledge is associated with attitudes and help‐seeking behaviors.

Methods

We conducted a cross‐sectional survey among community‐dwelling adults undergoing national health screening in Korea. A structured, self‐administered questionnaire was used to assess FI knowledge, attitudes, and help‐seeking behaviors. Odds ratios (ORs; 95% confidence intervals, CIs) were estimated using logistic regression with adjustment for covariables.

Results

Of the 601 participants completing the survey, only 29.8% were aware of the term FI, and their knowledge levels were insufficient. As for FI‐related attitudes, 24.6% considered FI to be very rare, and 22.3% considered it to be moderately or less distressing. Individuals who knew the term FI tended to consider FI more common (OR: 2.45; 95%CI: 1.49‐4.02) and distressing (OR: 1.68; 95%CI: 1.07‐2.63) than those without knowledge. Assuming future FI occurrence, those considering FI to be distressing were less willing to ignore or self‐manage the condition (OR: 0.25; 95%CI: 0.11‐0.58). Among patients with FI (n = 83), only 30.1% had sought help and 8.4% had consulted doctors. Knowing the term FI was significantly associated with overall help‐seeking behavior (OR: 9.23; 95%CI: 2.09‐40.77).

Conclusions

FI knowledge levels and help‐seeking rates were low among community‐dwelling adults. FI knowledge was significantly associated with attitudes and help‐seeking behaviors. Future public education programs are warranted to improve FI knowledge, attitudes, and help‐seeking behaviors.
Reactive toughening of urea–formaldehyde resin with poly(vinyl alcohol) by formation of interpenetrating networks
Authors: Liu Yalong , Yuan Junling , Zhao Xiaowen , Ye Lin
Published: January 2018

A series of urea–formaldehyde/poly(vinyl alcohol) (UF/PVA) blends were prepared via in situ polymerization. During the synthesis process, intra‐ and intermolecular acetalization of PVA occurred, along with the addition and condensation reactions between urea and formaldehyde, resulting in the formation of UF/PVA interpenetrating networks. With the increase of PVA content, the curing temperature shifted to higher temperatures and the activation energy (E) increased, suggesting that it was more difficult for the blends to cure. UF/PVA blends showed high storage modulus and only one broad tan δ peak, indicating that the stiffness was enhanced and the phase separation was limited at the chain segmental level. By the introduction of PVA, the elongation at break, impact strength, KIC value, and roughness of the fracture surface increased obviously, while the tensile strength can still maintain at a high level. Due to the forced compatibilization of the two components, homogeneous interpenetrating UF/PVA networks can form and thus the toughness of the blends was enhanced. POLYM. ENG. SCI., 58:2031–2038, 2018. © 2018 Society of Plastics Engineers