bluuebunny/crossref_metadata_2025 huggingface dataset:
Content Validity of the Premature Ejaculation Profile, Original and Per-Event Formats, in Men with Lifelong Premature Ejaculation
Authors: Burbridge Claire , Symonds Tara , Osterloh Ian H. , George Katie , Lloyd-Price Lucy
Published: March 2019

Background

The Premature Ejaculation Profile (PEP) is a patient-reported outcome (PRO) measure that is widely used in clinical research in men with premature ejaculation (PE) but has not been fully validated for men meeting the current International Society for Sexual Medicine (ISSM) definition of lifelong PE.

Aim

To explore the content validity of the PEP (original 1-month recall version and new event-driven version) in men meeting current definitions of lifelong PE and to understand the relevance of the concept of ejaculation control.

Methods

In-depth individual interviews were conducted with 24 men in a stable heterosexual relationship, including 15 with lifelong PE, 4 with acquired PE (with intravaginal ejaculation latency time values confirmed during a 4-week period of no treatment), and 5 with no sexual dysfunction. Initial concept elicitation explored individual experiences of having PE (in those with PE), experiences of control, and impact on sexual life. This was followed by a cognitive debriefing of the PEP versions.

Main Outcome Measure

Thematic analysis was used to identify key concepts of PE, understand the experience of control in men with and without PE, and confirm understanding and relevance of questions from original and event-driven versions of the PEP.

Results

The interviews confirmed substantial negative consequences for men with lifelong PE. Men with and without PE could describe ejaculation control (or lack of it). The PEP was shown to cover the key concepts in PE, and the questions were easily understood in both the original or event-driven versions. The items were comprehensive, and the concept of ejaculation control was confirmed. A 1- or 2-category change in each item of the PEP was considered clinically meaningful.

Clinical Implications

The PEP (original and per-event) has strong content validity for use in clinical research studies of men meeting the ISSM definition of lifelong PE.

Strengths & Limitations

This study addressed gaps in previously published research on the development and validation of the PEP and also confirmed that a new event-driven version is also suitable for use in research. However, the study was limited mainly to men meeting a strict definition of lifelong PE; in addition, homosexual men and those not in stable long-term relationships were not studied.

Conclusion

Both the original and per-event PEP versions were shown to have strong content validity and be acceptable for use in men with lifelong PE.
Erectile Dysfunction: An Umbrella Review of Meta-Analyses of Risk-Factors, Treatment, and Prevalence Outcomes
Authors: Allen Mark S. , Walter Emma E.
Published: March 2019

Introduction

Erectile dysfunction (ED) is a major health care problem that has implications for quality of life.

Aim

This umbrella review sought to synthesize all meta-analytic research on risk factors, treatment, and prevalence of ED.

Methods

8 electronic databases were searched for relevant meta-analyses in June 2018. The evidence was graded with 2 measures that use quantitative criteria to establish the quality of report writing and confidence in the effect size reported.

Main Outcome Measures

Lifestyle factors, genetic markers, medical conditions, treatments.

Results

In total, 98 meta-analyses were identified that included 421 meta-analytic effects, 4,188 primary-effects, and 3,971,122 participants. Pooled estimates showed that an unhealthy lifestyle, genetic markers, and medical conditions were associated with an increased risk of ED. Testosterone therapy and phosphodiesterase type 5 inhibitors showed the greatest treatment efficacy, with mild adverse events observed across treatments. Psychological and behavior change interventions produced effect sizes that were comparable to medication but had greater imprecision in effect sizes. There was little evidence that combined treatments were more efficacious than single treatments. Meta-analyses of prevalence estimates showed consistent age trends but were limited to particular regions or clinical samples, meaning that global estimates of ED are difficult to determine.

Clinical Implications

The umbrella review synthesized findings for many treatment options that might aid evidence-based clinical decision-making. Based on prevalence estimates, we recommend that primary care physicians take a proactive approach and enquire about erectile problems in all men over age 40 displaying any health-related issue (eg, overweight, cigarette smoking).

Strengths & Limitations

Strengths include the calculation and comparison of summary estimates across multiple meta-analyses. Limitations include heterogeneity in research quality across research themes limiting effect size comparisons.

Conclusion

The review provides summary estimates for 37 risk factors and 28 treatments. Meta-analyses of risk factors often did not control for important confounders, and meta-analyses of randomized trials were not exclusive to double-blinded trials, active placebo controls, or tests of long-term effects. We recommend further meta-analyses that eliminate lower quality studies and further primary research on behavioral and combined treatments.
Amiloride Relaxes Rat Corpus Cavernosum Relaxation In Vitro and Increases Intracavernous Pressure In Vivo
Authors: Campos Rafael , Claudino Mário A. , de Oliveira Mariana G. , Franco-Penteado Carla F. , Del Grossi Ferraz Carvalho Fernanda , Zaminelli Tiago , Antunes Edson , De Nucci Gilberto
Published: March 2019

Introduction

The antihypertensive effects of thiazide diuretics such as hydrochlorothiazide are commonly associated with erectile dysfunction. The association of hydrochlorothiazide/amiloride is not associated with erectile dysfunction. The hypothesis is that amiloride has beneficial effect in penile erection and, therefore, counterbalances the hydrochlorothiazide-induced disruptive effect.

Aim

To investigate the effects of amiloride and its analogues hexamethylamiloride and benzamil on rat isolated corpus cavernosa (CC) and intracavernous pressure (ICP) in anaesthetized rats.

Methods

Rat isolated CC were incubated with amiloride, hexamethylamiloride, and benzamil (10 and 100 μmol/L each), followed by phenylephrine, potassium chloride, and electrical field stimulation (EFS). Their effect on the relaxant responses to EFS and sodium nitroprusside were also determined. Oral (30 mg/kg) and intraperitoneal (3 mg/kg) treatments with amiloride were also investigated on nerve-evoked ICP.

Main Outcome Measures

In vitro functional studies and in vivo ICP measurement on rat CC were performed. Additionally, phosphodiesterase type V isoform A1 activity and the mRNA expressions of Na+/H+ pump, epithelial sodium channel exchangers (ENaC) channels (α-, β- and γ subunits) and Na+/Ca2+ exchangers were evaluated in CC tissues.

Results

Amiloride and its analogues significantly reduced the phenylephrine-, potassium chloride–, and EFS-induced CC contractions, which were not changed by nitro-L-arginine methyl ester (100 μmol/L) or indomethacin (6 μmol/L). In phenylephrine-precontracted CC tissues, amiloride itself caused concentration-dependent relaxation and significantly increased the EFS-induced relaxation. Oral and intraperitoneal treatment with amiloride significantly increased the ICP. Phosphodiesterase type V isoform A1 activity was not affected by amiloride. Na+/H+ pump, ENaC, and Na+/Ca2+ exchanger mRNA expressions were all detected in rat CC tissues.

Clinical Implication

Amiloride analogues may have therapeutic potential for erectile dysfunction.

Strength & Limitations

The interesting effect of amiloride in penile erection was observed in both in vitro and in vivo methods. The evidence at the moment is restricted to rat CC.

Conclusion

Amiloride reduces in vitro CC contractility and enhances erectile function after oral and intraperitoneal administration, possibly via inhibition of ENaC.
Recommending or Rejecting “the Dimple”: WPATH-Affiliated Medical Professionals' Experiences and Attitudes Toward Gender-Confirming Vulvoplasty in Transgender Women
Authors: Milrod Christine , Monto Martin , Karasic Dan H.
Published: March 2019

Introduction

Rising numbers of trans women are undergoing genital surgeries, such as vulvoplasty or vulvovaginoplasty, to create a neovagina. Medical professionals who adhere to the World Professional Association for Transgender Health (WPATH) Standards of Care, Version 7, and who recommend or perform these procedures, are expected to balance best practices with patient preferences, specifically the decision to create or omit the vaginal canal. Due to a paucity of literature on gender-confirming vulvoplasty (GCV) in trans women, there has been no documentation of factors that prompt practitioners to reject or recommend the procedure.

Aim

The aim of the study was to provide descriptive data of WPATH-affiliated medical professionals’ knowledge, experiences, and attitudes toward GCV; surgical risks, benefits, and any considerations when referring transgender women 18–21 years of age for this procedure.

Methods

Purposive sampling of all physicians, surgeons, nurse practitioners, physician assistants, and registered nurses listed in the WPATH membership directory was initiated via invitational e-mails. The 32-item survey focused on demographics, medical practices, surgical techniques, and reasons for recommending or rejecting the procedure. Data analysis included frequencies and Pearson’s χ2 test.

Main Outcome Measures

Key outcome measures included frequency of cases performed; reasons for recommending, rejecting, or performing GCV; and differences in attitudes toward the procedure among various medical professionals.

Results

N = 198 (20.7%) of 956 solicited professionals completed the survey. Surgeons (n = 61) comprised 30.8% of the total sample. 46 surgeons (76.7%) reported having performed vulvovaginoplasty, and 25 (41.7%) had performed GCV. “Patient request” was the most common reason for recommending or performing GCV. Surgeons were more likely to either agree and perform (30.4%), or reject (32.1%) GCV in a patient aged 18–21 than other practitioners, who were more likely to be “unsure” (68.5%). These differences were statistically significant (χ2 = 16.467 [2]; n = 193; P < .001).

Clinical Implications

The data identify a lack of standardized terminology and surgical techniques concerning GCV.

Strength & Limitations

This is the first exploratory study to assess medical practitioner experiences and attitudes toward a seldom documented procedure. A larger, more inclusive sample would increase the statistical strength and representative aspect of the study.

Conclusion

The study shows divergence in attitudes and knowledge among medical practitioners who recommend or perform GCV, and uncertainty when the patient is 18–21 years old. The study contributes to an expanded description and specific indications of performing GCV in the updated WPATH SOC Version 8.
Media corruption and issues of journalistic and institutional integrity in post-communist countries: The case of Bulgaria
Authors: Price Lada Trifonova
Published: March 2019

From a normative standpoint the media are usually seen as one of the pillars of a national integrity system, entrusted with the tasks of exposing and preventing acts of corruption and educating the public of the harm caused by corruption. Nevertheless, corruption continues to be one of the most significant challenges that Europe faces, undermining citizens' trust in democratic institutions and weakening the accountability of political leadership. Evidence suggests that in fragile EU democracies such as Bulgaria, despite more than eight years of full membership and numerous preventive measures, corruption is rife and the press is hardly capable of exposing abuses of power or authority. On the contrary - drawing on in-depth interviews with 35 Bulgarian journalists - this paper argues that since communism collapsed in the late 1980s the media in post-communist societies such as Bulgaria has gradually become an instrument to promote and defend private vested interests, and is plagued by corruption. Senior journalists and editors cast serious doubt over the ability of the post-communist free press and journalism to act as a watchdog for society.
GlobSed: Updated Total Sediment Thickness in the World's Oceans
Authors: Straume E. O. , Gaina C. , Medvedev S. , Hochmuth K. , Gohl K. , Whittaker J. M. , Abdul Fattah R. , Doornenbal J. C. , Hopper J. R.
Published: March 2019

We present GlobSed, a new global 5‐arc‐minute total sediment thickness grid for the world's oceans and marginal seas. GlobSed covers a larger area than previously published global grids and incorporates updates for the NE Atlantic, Arctic, Southern Ocean, and Mediterranean regions, which results in a 29.7% increase in estimated total oceanic sediment volume. We use this new global grid and a revised global oceanic lithospheric age grid to assess the relationship between the total sediment thickness and age of the underlying oceanic lithosphere and its latitude. An analytical approximation model is used to mathematically describe sedimentation trends in major oceanic basins and to allow paleobathymetric reconstructions at any given geological time. This study provides a much‐needed update of the sediment thickness distribution of the world oceans and delivers a model for sedimentation rates on oceanic crust through time that agrees well with selected drill data used for comparison.
Inflow of Warm Water to the Inner Hornsund Fjord, Svalbard: Exchange Mechanisms and Influence on Local Sea Ice Cover and Glacier Front Melting
Authors: Arntsen Martin , Sundfjord Arild , Skogseth Ragnheid , Błaszczyk Małgorzata , Promińska Agnieszka
Published: March 2019

Observational data covering currents and temperature through two contrasting autumn to spring periods (2010/2011 and 2013/2014) at the constricted entrance to the inner basin of the Hornsund fjord, Svalbard, are investigated. This fjord is presently undergoing significant changes, manifested by reduction of the seasonal sea ice cover and retreating tidewater glacier fronts. The data set presented here shows how local wind, tides, and longer period current fluctuations allow warm water of Atlantic origin to reach the innermost basin of the fjord. While the forcing factors of the exchange mechanisms are not seen to vary much between the two studied seasons, the effect of wind events on exchange is assumed to be modified by local stratification and sea ice concentration. The resulting heat transport depends on availability of heat in the central part of the fjord. The observations indicate that available heat in autumn and winter 2013/2014 effectively hindered formation of a stable sea ice cover. While the present data set does not enable direct quantification of the role of oceanic heat in tidewater glacier melting, we find that the net retreat of glacier fronts was 10 times larger in the warm (ocean) period 2013/2014 compared to the colder 2010/2011.
Summertime Connecticut River Water Pathways and Wind Impacts
Authors: Jia Yan , Whitney Michael M.
Published: March 2019

Long Island Sound is a large macrotidal estuary. Connecticut River as the primary freshwater source enters near the sound's mouth. The summertime pathways of river water under low discharge and mild wind conditions are studied through both numerical simulations with a passive dye pulse and field surface drifter observations. Within the 19‐day modeling analysis period a third of the river dye pulse remains in the eastern sound; another third of the pulse moves up‐estuary with the near‐bottom dense inflow into the central and western sound with a spring‐neap tidal modulation; and another third leaves the sound with the near‐surface outflow toward the continental shelf through Block Island Sound. The latter pathway is confirmed by field surface drifter tracks. Three scenarios of wind forcing are tested: a WRF‐ROMS Coupled case, a NARR data forcing case, and a No‐Wind case. The results show though that the sound is tidal mixing dominated, mild winds still alter the position and strength of the estuarine exchange flow, and either enhances by the cross‐estuary winds or lateral straining. On the shelf, winds play a more important role on the fresher estuarine water distribution. The sensitivities of circulation, salinity, and numerical drifter tracks to different atmospheric forcings also are studied. The results suggest that the coupled model has better performance to simulate surface drifter tracks.
Upwelling in the Ocean Basins North of the ACC: 2. How Cool Subantarctic Water Reaches the Surface in the Tropics
Authors: Toggweiler J. R. , Druffel Ellen R. M. , Key Robert M. , Galbraith Eric D.
Published: March 2019

Large volumes of cool water are drawn up to the surface in the tropical oceans. A companion paper shows that the cool water reaches the surface in or near the upwelling zones off northern and southern Africa and Peru. The cool water has a subantarctic origin and spreads extensively across the Atlantic and Pacific basins after it reaches the surface. Here, we look at the spreading in two low‐resolution ocean general circulation models and find that the spreading in the models is much less extensive than observed. The problem seems to be the way the upwelling and the spreading are connected (or not connected) to the ocean's large‐scale overturning. As proposed here, the cool upwelling develops when warm buoyant water in the western tropics is drawn away to become deep water in the North Atlantic. The “drawing away” shoals the tropical thermocline in a way that allows cool subantarctic water to be drawn up to the surface along the eastern margins. The amounts of upwelling produced this way exceed the amounts generated by the winds in the upwelling zones by as much as 4 times. Flow restrictions make it difficult for the warm buoyant water in our models to be drawn away.
Production of Secondary Organic Aerosol During Aging of Biomass Burning Smoke From Fresh Fuels and Its Relationship to VOC Precursors
Authors: Ahern A. T. , Robinson E. S. , Tkacik D. S. , Saleh R. , Hatch L. E. , Barsanti K. C. , Stockwell C. E. , Yokelson R. J. , Presto A. A. , Robinson A. L. , Sullivan R. C. , Donahue N. M.
Published: March 2019

After smoke from burning biomass is emitted into the atmosphere, chemical and physical processes change the composition and amount of organic aerosol present in the aged, diluted plume. During the fourth Fire Lab at Missoula Experiment, we performed smog‐chamber experiments to investigate formation of secondary organic aerosol (SOA) and multiphase oxidation of primary organic aerosol (POA). We simulated atmospheric aging of diluted smoke from a variety of biomass fuels while measuring particle composition using high‐resolution aerosol mass spectrometry. We quantified SOA formation using a tracer ion for low‐volatility POA as a reference standard (akin to a naturally occurring internal standard). These smoke aging experiments revealed variable organic aerosol (OA) enhancements, even for smoke from similar fuels and aging mechanisms. This variable OA enhancement correlated well with measured differences in the amounts of emitted volatile organic compounds (VOCs) that could subsequently be oxidized to form SOA. For some aging experiments, we were able to predict the SOA production to within a factor of 2 using a fuel‐specific VOC emission inventory that was scaled by burn‐specific toluene measurements. For fires of coniferous fuels that were dominated by needle burning, volatile biogenic compounds were the dominant precursor class. For wiregrass fires, furans were the dominant SOA precursors. We used a POA tracer ion to calculate the amount of mass lost due to gas‐phase oxidation and subsequent volatilization of semivolatile POA. Less than 5% of the POA mass was lost via multiphase oxidation‐driven evaporation during up to 2 hr of equivalent atmospheric oxidation.
The Dangers of Glacial Lake Floods: Pioneering and Capitulation
Authors: Palmer Jane
Published: March 2019

During the past 70 years, Peruvian engineers virtually eliminated the risks posed by glacial lake floods. But climate change and a political blind eye are increasing the dangers once again.
Is the Recent Drought on the Colorado River the New Normal?
Authors: Barsugli Joseph , Hoerling Martin , Livneh Ben
Published: March 2019

Understanding Historical Changes in the Flow of the Colorado River; Boulder, Colorado, 24–25 September 2018
Pluto’s and Charon’s Craters Reveal a Solar System Deficit
Authors: Kornei Katherine
Published: March 2019

The New Horizons spacecraft recorded images of craters that imply an unexpected dearth of small objects in the Kuiper Belt.
Investigation of chemical composition of meat using spatially off-set Raman spectroscopy
Authors: Ostovar pour Saeideh , Fowler Stephanie M. , Hopkins David L. , Torley Peter J. , Gill Harsharn , Blanch Ewan W.
Published: March 2019

Spatially off-set Raman spectroscopy (SORS) offers non-invasive chemical characterisation of the sub-surface of various biological tissues as it permits the assessment of diffusely scattering samples at depths of several orders of magnitude deeper than conventional Raman spectroscopy.
Aptamer biorecognition-triggered DNAzyme liberation and Exo III-assisted target recycling for ultrasensitive homogeneous colorimetric bioassay of kanamycin antibiotic
Authors: Chen Zhichao , Xiong Feng , Yu Aimin , Lai Guosong
Published: March 2019

Aptamer biorecognition-triggered DNAzyme liberation and Exo III-assisted target recycling enable the ultrasensitive homogeneous colorimetric bioassay of kanamycin antibiotic.
Role of polysaccharide conjugation in physicochemical and emulsifying properties of egg phosvitin and the calcium binding capacity of its phosphopeptides
Authors: Cui Yanchun , Li Xiang , Lu Mei , Liu Xuebo , Duan Xiang
Published: March 2019

Glycosylation with pectin simultaneously improved the emulsifying properties of egg phosvitin and the calcium binding capacity of its phosphopeptides.
Magnetic silica aerogels with high efficiency for selective adsorption of pyrethroid insecticides in juices and tea beverages
Authors: Feng Tiantian , Ye Xiu , Zhao Yongna , Zhao Zexin , Hou Shanshan , Liang Ning , Zhao Longshan
Published: March 2019

A new magnetic adsorbent silica aerogel was synthesized for concentration of organic compounds and to determine trace insecticides.
Ln(OTf)3-catalysed highly regioselective alcoholysis of 2,3-epoxy alcohols
Authors: Nakamura Daichi , Sasano Yusuke , Iwabuchi Yoshiharu
Published: March 2019

The C3-selective alcoholysis of 2,3-epoxy alcohols has been realized by judicious choice of Ln(OTf)3 catalyst.
The multiple effects of polyaniline additive to improve the efficiency and stability of perovskite solar cells
Authors: Zheng Haiying , Xu Xiaoxiao , Xu Shendong , Liu Guozhen , Chen Shuanghong , Zhang Xianxi , Chen Tingwei , Pan Xu
Published: March 2019

By introducing polyaniline as an additive, the perovskite solar cells exhibit a high PCE of 19.09% with improved humidity and heat stability.
A single-atom catalyst of cobalt supported on a defective two-dimensional boron nitride material as a promising electrocatalyst for the oxygen reduction reaction: a DFT study
Authors: Deng Chaofang , He Rongxing , Shen Wei , Li Ming , Zhang Tao
Published: March 2019

Single cobalt atoms supported by a defective two-dimensional boron nitride material catalyze the ORR via a direct 4e− pathway with a largest activation barrier of 0.3 eV.
Visible-light-induced radical trifluoromethylthiolation of N-(o-cyanobiaryl)acrylamides
Authors: Zhu Mei , Fu Weijun , Guo Weisi , Tian Yunfei , Wang Zhiqiang , Ji Baoming
Published: March 2019

Visible-light-mediated trifluoromethylthiolation of N-(o-cyanobiaryl)acrylamides with N-trifluoromethylthiosaccharin as the source of SCF3 radicals provided an efficient route to SCF3-containing ring-fused phenanthridine derivatives.
Facile synthesis of 2-(2-aminobenzoyl)benzoic acids via a base-promoted aerobic cascade reaction
Authors: Shen Jinhai , Chen Yangxin , Chen Ting , Zou Zhongai , Feng Yadong , You Qihua
Published: March 2019

A novel base-promoted aerobic cascade reaction for the regiospecific synthesis of 2-(2-aminobenzoyl)benzoic acids under metal-free conditions is developed.
A flexible solid-state zinc ion hybrid supercapacitor based on co-polymer derived hollow carbon spheres
Authors: Chen Shengmei , Ma Longtao , Zhang Kui , Kamruzzaman M. , Zhi Chunyi , Zapien Juan Antonio
Published: March 2019

For the first time solid-state zinc ion hybrid supercapacitors based on co-polymer derived hollow carbon spheres with good flexibility have been developed.
Nano-modified indium tin oxide incorporated with ideal microlens array for light extraction of OLED
Authors: Zhou Jun-Gui , Hua Xiao-Chen , Chen Yang-Kai , Ma Yu-Yang , Huang Chen-Chao , Wang Yan-Dong , Fung Man-Keung
Published: March 2019

Nano-modified ITO anode with low haze incorporated with ideal microlens arrays is achieved for high-efficiency OLED.
Energy efficient SBSs sleep mode analysis for successive user association and resource scheduling algorithms in two‐tier heterogeneous network
Authors: Peng Xuefei , Li Jiandong , Zhang Hao
Published: March 2019

This study analyses and compares the downlink energy efficiency (EE) of user association and resource scheduling algorithms considering sleep mode of small cell base stations (SBSs) in two‐tier heterogeneous cellular networks. Owing to the NP‐hardness of joint user association and resource scheduling algorithms, the authors successively perform user association and resource scheduling algorithms. Firstly, in the user association algorithms, sleep mode for the SBSs without associated users is considered to improve EE, where they associate users with the macrocell base station (MBS) or SBSs according to three signal strength strategies, namely, unbiased user association, biased user association and signal to interference plus noise ratio‐based user association. Then, in the resource scheduling algorithms, they schedule the MBS and SBSs resource blocks to users based on three scheduling criteria, i.e. maximum received signal strength, round robin and proportional fairness, respectively. Fairness among users is also analysed. In the simulation, numerical results for different successive user association and resource scheduling algorithms are compared. The optimum algorithms are found in the different network environments. These results are significant for the heterogeneous network operation to get high EE.
LILAC: computable capabilities based high performance protocol for CRFID
Authors: Zhao Jumin , Wu Hao , Li Deng‐ao , Li Yanxia , Zhu Biaokai
Published: March 2019

Compared with traditional radio frequency identification (RFID), computational RFID (CRFID) tag has more powerful computing capability, but it shows poor performance when it follows EPC Class‐1 Generation‐2 protocol especially transmitting large amounts of data. In fact, the operation of the CRFID tag entirely depends on the state of energy. For this point, this study proposes an optimised protocol called LILAC. LILAC allows tags to select the communication time slot according to their current voltage value measured by using an analogue‐to‐digital converter rather than randomly selecting, the authors proposed a more reasonable time slot mapping algorithm for LILAC that increases the success rate of tag responding. In addition, they design a data transmission format that can be retransmitted to improve the uplink throughput. Finally, they implemented LILAC on a CRFID platform and practically measured several parameters to compare with the existing well‐known protocol. The results of experiments show that LILAC increases the maximum communication distance by more than half in the access phase and doubles the goodput of the backscatter link in both the inventory and access phase.
Improved LAS detector for MIMO systems with imperfect channel state information
Authors: Chihaoui Issa , Ammari Mohamed Lassaad , Fortier Paul
Published: March 2019

Likelihood ascent search (LAS) detector is a neighbourhood search algorithm and one of the simplest schemes for low‐complexity near‐optimal detection in massive multiple‐input multiple‐output systems. LAS detector design under the assumption of perfect channel state information has been an area of research for decades. However, channel estimation errors have never been taken into account by conventional LAS detectors when calculating the maximum‐likelihood decoding metric. As a result, the bit error rate performance of LAS detectors can be significantly degraded. This study proposes robust LAS detectors which take channel estimation errors into account in the computation of the ML decoding metric. The proposed approach involves the computation of the equivalent noise covariance matrix inverse, which may increases the computational complexity. Therefore, the authors also propose a low complexity method to inverse the covariance matrix. Simulation results show that the proposed schemes outperform the conventional LAS detector.
Adaptive location‐based millimetre wave beamforming using compressive sensing based channel estimation
Authors: Abdelreheem Ahmed , Mohamed Ehab Mahmoud , Esmaiel Hamada
Published: March 2019

Analogue beamforming is normally used in conjunction with millimetre wave (mmWave) communications to overcome the high propagation and penetration losses inherent in mmWave transmissions. Thus, producing a high‐efficient mmWave beamforming using low beamforming training (BT) complexity turns to be a big challenge towards ubiquitous mmWave communications. In this study, low‐complex and high‐efficient adaptive mmWave BT using compressive sensing (CS) based channel estimation is introduced utilising mobile station (MS) localisation. In which, MS positioning is used to estimate the ranges of angle of departures and angle of arrivals of the mmWave channel considering the statistics of its angular spread. Then, an adaptive multi‐level beam search using CS‐based channel estimation is used to estimate the best transmit/receive beam for establishing the mmWave link. Thus, the antenna weight vectors of each beam searching level, i.e. the beamwidth and the number of beams, used for constructing the sensing matrix are adaptively adjusted. The high potency of the proposed mmWave BT scheme over the conventional ones in both BT complexity and performance is proved by the means of mathematical and simulation analysis.
Hybrid beamforming for multi‐user MIMO with partially‐connected RF architecture
Authors: Hu Chen , Liu Yingzhuang , Liao Limin , Zhang Ruijie
Published: March 2019

The traditional fully‐digital beamforming is realised by the full radio‐frequency (RF) chain configuration, which will be impracticable in massive multiple‐input multiple‐output (MIMO) systems because of the overburden energy consumption of RF chains at millimetre wave frequencies. To address this issue, a series of hybrid beamforming schemes have been proposed to reduce the number of RF chains. Although the hybrid beamforming schemes for single‐user MIMO (SU‐MIMO) have been studied extensively, the performance of hybrid beamforming for multi‐user MIMO (MU‐MIMO), especially for partially‐connected hybrid architecture, still has room for improvement. In this study, the authors propose a hybrid beamforming scheme for MU‐MIMO systems. Specifically, they focus on the design of analogue beamforming and optimise the analogue RF precoders and combiners jointly. The simulation results show that the proposed hybrid beamforming in fully‐connected structure can achieve a better performance compared with the existing hybrid beamforming schemes in both SU‐MIMO and MU‐MIMO systems. It is also observed that the proposed hybrid beamforming can achieve significant performance advantages compared with the existing hybrid beamforming schemes in partially‐connected structures.
Memory‐efficient recursive scheme for multi‐field packet classification
Authors: Li Wenjun , Li Dagang , Bai Yongjie , Le Wenxia , Li Hui
Published: March 2019

Multi‐field packet classification is not only an indispensable and challenging functionality of existing network devices, but it also appears as flow tables lying at the heart of the forwarding plane of software defined networking age. Despite almost two decades of research, algorithmic solutions still fall short of meeting the line‐speed of high‐performance network devices. Although decomposition‐based approaches, such as cross‐producting and recursive flow classification (RFC), can achieve high lookup rate by performing a parallel search on chunks of the packet header, both of them suffer from memory explosion problem during aggregation. In this study, the authors propose an HybridRFC, a memory‐efficient recursive scheme for multi‐field packet classification. By addressing the embedded problem of the RFC caused by uncontrollably expanded cross‐product tables, HybridRFC can not only reduce the memory consumption to a practical level but also improve pre‐processing performance significantly. Experimental results show that the memory requirement of HybridRFC is two orders of magnitude less than RFC, as well as three orders of speed‐up on the performance of table building on average.
Efficient thrust generation in robotic fish caudal fins using policy search
Authors: Shan Yixi , Bayiz Yagiz E. , Cheng Bo
Published: March 2019

Thrust generation is a crucial aspect of fish locomotion that depends on a variety of morphological and kinematic parameters. In this work, the kinematics of caudal fin motion of a robotic fish are optimised experimentally. The robotic fish actuates its caudal fin with flapping and rotation motion, and also measures the fin hydrodynamic force and torque. Total nine designs of the caudal fins are investigated, with three different shapes (or inclination angles) and three stiffness. The optimisation is based on a policy search (PS) algorithm, which is used to maximise the thrust‐generation efficiency of the caudal fins. The authors first parametrise fin spanwise‐rotation as a sinusoidal function using rotation amplitude and phase delay and test whether it is beneficial to thrust‐generation efficiency. The result shows that the rotation does not contribute to the efficiency, as the efficiency is maximised at zero amplitude. Next, the authors optimise flapping amplitude and trajectory profile without fin rotation. Results show that smaller flapping amplitude results in higher efficiency and linear flapping trajectories are preferred over sinusoidal ones. Fins that have the highest flexibility are more efficient in thrust generation although they generate less thrust, while an inclination angle of 30° yields the most efficient fin shape.
Adaptive soft starter for a three‐phase induction‐motor driving device using a multifunctional series compensator
Authors: Jiang Fei , Tu Chunming , Guo Qi , Wu Zhengyu , Li Yinyi
Published: March 2019

This study proposes an adaptive soft starter control for induction motors using a multifunctional series compensator (MFSC). The proposed MFSC can operate in two modes: (i) the compensation mode for voltage sags and (ii) the virtual impedance mode for soft starting. Various MFSC functions are obtained by controlling the output characteristics of the series inverter. In the voltage sag compensation mode, a voltage is injected in series with the fault phase; as a result, the terminal voltage of the motor remains constant. In the soft‐starter mode, the proposed converter injects adjustable virtual impedance in each phase; as a result, the starting current can be limited to the desired value. A novel control scheme and the optimal parameter selection of the MFSC are also presented. The design methodology of the proposed MFSC is verified using simulations conducted in MATLAB/Simulink software. Experimental results prove the capability and effectiveness of the proposed MFSC.
Effect of the oil‐paper insulation aging on partial discharge characteristics in a hemispherical surface model
Authors: Wang Yongqiang , Zhang Xia , Jiang Xiaolei , Wang Yunjia
Published: March 2019

To investigate the effect of aging on surface discharge of the pressboard on the shielding electrode at the end of bushing, a thermal aging preparation methods of different aging degrees of pressboard samples, surface defect model, and the associated hemisphere are designed and the step‐up method is used for subsequent experimental work. Finally, the partial discharges (PDs) under different degrees of aging are compared and combined with Fourier Transform Infrared spectra and electric field simulation. Results show that the pre‐discharge occurs mainly in the oil gap between the hemispherical electrode edge and the pressboard. The aging of the pressboard exerts no obvious effect on the discharge characteristics in the initial stage of PD; with the development of the discharge, the development of aging of pressboard leads to a higher electric field intensity acting over a greater area, the more intense the discharge, the faster the relative discharge increases and the larger its amplitude. This discharge will cause decomposition of the oil in the pores of the aging pressboard thus generating gas bubbles which will move as discharge develops. When the bubbles reach the surface of the pressboard, the local electric field intensity will increase and the discharge will become more intense.
Breakdown performance of transformer oil in the presence of single‐phase nanocrystalline ZnO and nano‐partial substitution
Authors: Sabiha Nehmdoh A. , Ghoneim Sherif S M. , Hessien Mahmoud M.
Published: March 2019

In this study, newly structured nanoparticles are synthesised and incorporated in the transformer oil for enhancing the dielectric properties. A new nanocrystalline series of zinc oxide (ZnO) and ZnO partially substituted by lanthanum oxide is presented for the first time, where the precursor technique is utilised to create the nano‐powders. Different partial substitutions facilitate to manipulate nanocrystalline sizes, and therefore the effect on nanofluid dielectric characteristics is attained. Another factor during the laboratory nanoparticles preparation is considered that the precursor is annealed at different temperatures. The nanocrystalline phase compositions are experimentally examined and evaluated using X‐ray diffraction and transmission electron microscope. Accordingly, single‐phase and multi‐phase nanocrystalline powders are ascertained. The transformer oil incorporated with nanoparticles is prepared and its dielectric strength is measured using an oil breakdown voltage tester. The measured dielectric strength of transformer oil with and without nanoparticles is statistically evaluated using Weibull distribution. The most appropriate nanofluid and concentration are estimated experimentally. Toward interpreting the nanofluid dielectric enhancement, their electric field distribution is numerically evaluated at different nanoparticle concentrations using COMSOL multiphysics. This study supports the analysis and optimisation of transformer oil dielectric performance.
Enhanced photocatalytic activity of ternary multilayered Ag/TiO2/CNT composites for methylene blue degradation
Authors: Ye Xiaoyun , Wang Zhaopeng , Wang Qianting , Chen Dinggui , Lin Yan , Liu Shuying
Published: March 2019

The TiO2 modified carbon nanotube composites (TiO2/CNT) and Ag deposited ternary multilayered composites (Ag/TiO2/CNT) were prepared by chemical deposition and sonochemical reaction, respectively. The composites were characterised by transmission electron microscopy, scanning electron microscopy, X‐ray diffraction, Fourier‐transform infrared spectroscopy, and ultraviolet–visible (UV–vis). The results showed that anatase TiO2 layers were wrapped on the surfaces of the CNTs. The face‐centred‐cubic structure of Ag nanoparticles (NPs) was dispersedly formed on the surfaces of the Ag/TiO2/CNT composites. The expected formation and good dispersion of Ag was obtained by high‐intensity ultrasound irradiation assistance. All the resulted TiO2/CNT and Ag/TiO2/CNT composites exhibited a higher photocatalytic performance than that of TiO2 for the degradation of methylene blue. The novel nanocomposite photocatalysts were developed through structural changes and double effects of carbon materials and noble metals as electron acceptors. Inhibited recombination of electron‐hole pairs allows effective electron transfer and active redox reaction on the surfaces of the composites. The novel composite combines the CNTs with excellent electronic nature and nobel metallic NPs with the special semiconductor‐metal junction. It can provide new guidance for the application of carbon nanotube‐based photocatalytic materials in photocatalysis field from UV–vis spectrum.
Electrodeposited and then acetate‐processed Ni(OH)2/NiOOH composites for enhanced electrocatalytic oxidation of urea
Authors: Qian Li Hong , Liang Xiao Cai , lan Zhou Hua
Published: March 2019

The Ni(OH)2/NiOOH nanoparticles (NPs) electrodeposited on a glassy carbon electrode (GCE) in Ni(NO3)2 and NH3 ·H2 O aqueous solution for the electrode materials. Then the nickel hydroxide/oxyhydroxide acetate was formed in acetate solution. The effects of deposition conditions such as the concentration of Ni(NO3)2 solution, the number of sedimentary cycles, the concentration of acetate in the soaking liquid and the soaking time are discussed in detail. The electrochemical properties of the material have been investigated by cyclic voltammetry, Tafel curve, EIS and amperometric i–t curve techniques. The result displays excellent electrocatalytic activity towards the electrocatalytic oxidation of urea in alkaline solution. Furthermore, the modified electrode for oxidation reaction has the advantages of simple preparation, good electrochemical properties and stabilisation.
Inductively coupled CH4/H2 plasma etching process for mesa delineation of InAs/GaSb type‐II superlattice pixels
Authors: Das Sona , Das Utpal
Published: March 2019

An inductively coupled plasma etching process for delineation of InAs/GaSb type‐II superlattice pixels is presented. An optimised etch recipe without alternate plasma cleaning step showed an etch rate as high as 0.11 μm/min that results in smooth vertical sidewalls for the type‐II superlattice pixel arrays with 10 μm pitch size and 2.4 μm deep trenches. At 70 K, the dark current density for the mesa etched + SU‐8 polymer passivated type‐II superlattice photodiodes was found to be 0.11 A/cm2 at an applied reverse bias voltage of 0.2 V. The activation energy of 13 meV obtained from the Arrhenius plot and a variable area diode array technique showed that the measured dark current is mainly attributed to bulk tunnelling current. This technique of mesa delineation for the type‐II superlattice pixel arrays with small pitch size is a viable option in realising next‐generation infrared focal plane arrays.
Preparation and characterisation of Ag modified rutile titanium dioxide and its photocatalytic activity under simulated solar light
Authors: Zhu Xiaodong , Han Shihu , Zhu Dongzhi , Chen Shanhua , Feng Wei , Kong Qingquan
Published: March 2019

Generally, anatase titanium dioxide (TiO2) exhibit better photocatalytic activity than rutile TiO2. In the present work, Ag modified TiO2 were prepared by a simple sol–gel method and the photocatalytic activity of pure TiO2 was enhanced via adding Ag. Moreover, Ag modified rutile TiO2 shows the best photocatalytic activity compared to Ag modified anatase TiO2 and pure TiO2 owing to the lowest recombination rate of photogenerated pairs and the most surface hydroxyl groups.
Controllable synthesis of CdSe QDs@NPC composite improving electron–hole separation and enhancing visible‐light photocatalytic activities toward RhB degradation
Authors: Zhu Jiayu , Wang Ze , Li Yafeng , Wang Yuanrui
Published: March 2019

In this work, NPC (nanoporous carbon) is purposely employed to accommodate the semiconductor CdSe QDs (quantum dots) in the absence of any capping agent to facilitate the visible‐light photocatalyst CdSe QDs@NPC composite. CdSe QDs@NPC composite has been achieved by the facile method of the incipient‐wetness deposition, and furthermore characterised by powder X‐ray diffraction, inductively coupled plasma atomic emission spectroscopy, X‐ray photoelectron spectroscopy, Brunauer–Emmett–Teller, transmission electron microscopy (TEM) and high‐resolution TEM (HRTEM). The results of TEM and HRTEM show that CdSe QDs are implanted into NPC and bound to several nanometres. Both X‐ray diffraction and HRTEM indicate that the as‐synthesised CdSe QDs belong to the cubic phase. The photocatalytic performance of CdSe QDs@NPC composite has been evaluated by degrading the RhB under visible‐light irradiation. NPC as electron acceptor and transport channel can enhance the synergism of CdSe and NPC by improving the electron–hole separation. Furthermore, the photocatalytic mechanism exhibits that h+ and O2 −• species are the decisive, active species in the degradation process of RhB.
Controllable synthesis and enhanced photocatalytic activity of B‐TiO2 nanospheres
Authors: Wang Shumin , Yan Xiaoxia , Deng Dongmei , He Haibo , Lei Yunyi , Shen Xia , Luo Liqiang
Published: March 2019

A series of boron‐doped‐titanium dioxide (B‐TiO2) nanospheres were synthesised via a mild and facile spray‐drying process. The obtained nanospheres were relatively uniform with a size of about 100 nm. A strong absorption in the visible‐light range was observed due to the formation of Ti–O–B bonds, by narrowing the bandgap of B‐TiO2 from 3.1 to 2.8 eV. The as‐synthesised 3 wt% B‐TiO2 exhibited the greatest photocatalytic activity in the degradation of p‐nitrophenol. The photocatalytic performance was improved, which could be attributed to high absorption of the visible‐light region and efficient separation of photogenerated electron–hole pairs.
Recent development of samples’ surface properties using scanning ion conductance microscopy
Authors: Li Zhenhui , Xu Ke , Wei Fanan
Published: March 2019

Scanning ion conductance microscopy has a widespread application in imaging non‐conductive substrates, especially biological samples due to its high‐resolution and non‐contact imaging. In this work, state‐of‐the‐art achievements on exploring samples’ surface properties including surface morphology, sample conductivity and dynamics using scanning ion conductance microscopy are firstly introduced, which confirm that scanning ion conductance microscopy is such a mature technology that realises non‐invasive and high‐resolution imaging. Then, combinations with scanning electrochemical microscopy and atomic force microscopy are demonstrated, which realise the multifunction of scanning ion conductance microscopy. Furthermore, improvements that can help enhance the imaging rate are presented. Finally, the future direction of scanning ion conductance microscopy is discussed.