bluuebunny/crossref_metadata_2025 huggingface dataset:
Performance evaluation of 2 × 2 MIMO–OFDM‐based radio‐over‐fibre system using Alamouti coding and Hammerstein equaliser
Authors: Alizadeh Mohammadreza , Baghersalimi Gholamreza , Nassiri Mahdi
Published: February 2019

Radio‐over‐fibre (RoF) systems consist of two subsystems including optical subsystem and wireless radio frequency subsystem. It is shown that by using multiple‐input multiple‐output (MIMO) and orthogonal frequency‐division multiplexing (OFDM) systems, the RoF transmission can be improved in frequency‐selective channels. In this study, two different configurations of MIMO–OFDM‐based RoF systems are compared for the long‐term evolution standard under different non‐linearity levels, bandwidths, and fading channel conditions. Using the total degradations (TD) criterion, an appropriate quiescent point is determined to decrease the impact of non‐linearity level, and hence the performances of different MIMO detection methods are compared. Bit error rate results demonstrate that by using Hammerstein type equaliser, the system performance is improved under different conditions including different fading channels, Doppler frequencies, bandwidths, and output back off levels. Results demonstrate that with an appropriate structure for MIMO–OFDM–RoF systems, a suitable quiescent point can be found for all scenarios by employing Alamouti coding and Hammerstein equaliser.
Modelling the region‐based VoLTE cell capacity estimation using resource optimisation
Authors: Senapati Rajiv , Pati Hemanta Kumar
Published: February 2019

In this study, the authors introduce analytical models for region‐based Voice over Long Term Evolution (VoLTE) cell capacity estimation. Using the authors' proposed analytical models, they estimate cell capacity in different regions by using several user‐specific voice traffic characteristics such as Voice Activity Factor (VAF) and Silent Insertion Descriptor (SID), and different advanced techniques like Packet bundling and Transmission Time Interval (TTI) bundling. It also incorporates Hybrid automatic repeat request (HARQ) retransmission. In this work, the cell is divided into multiple regions, each corresponding to the area in which user equipment generates a certain level of Channel Quality Indication (CQI) value based on Signal to Interference plus Noise Ratio (SINR). This proposed model for region‐based VoLTE capacity estimation optimises the network resource utilisation and enhances the number of concurrent active VoLTE users within the cell in each region. In this work, they have defined packet bundling and TTI bundling factors for appropriate regions to optimally allocate the radio resources for capacity estimation. Numerical results obtained using their proposed model considering different radio specific parameters are found improving the VoLTE cell capacity significantly. Further, the impact of HARQ on region‐based VoLTE cell capacity is also obtained.
Performance evaluation of a hybrid IP/SDN network in data centre network architectures
Authors: Dhiab Imen , Barouni Yosra , Khalfallah Sofiane , Ben Hadj Slama Jaleleddine
Published: February 2019

The current Internet is facing many challenges to accommodate the growing demands of cloud computing. Software‐defined networking (SDN) is an emerging paradigm, proposed to be used in this context in order to investigate these issues. SDN virtualises network functions, reducing the amount of hardware and allowing to control data centres through software and programs. With SDN, it is possible to build the future Internet and solve the current issues. SDN assures the programmability of the network components and the development of new routing and forwarding approaches without changing the hardware components. However, the transition from traditional Internet protocol (IP) networks to full SDN networks is associated with many challenges in a short term as it requires from network operators a costly investment on new networking equipments. So, fulfilling full SDN architectures must be incrementally introduced in conventional IP networks. This study presents a performance study of a hybrid IP/SDN network, under NS‐3, using Fat Tree, BCube and Three‐tier data centre network (DCN) architectures, compared to conventional IP. Simulation results show that using a hybrid IP/SDN network enhances the performance of DCN architectures by providing an efficient communication and minimising the energy consumption.
Transmit power allocation of energy transmitters for throughput maximisation in wireless powered communication networks
Authors: Yu Zhanwei , Chi Kaikai , Zheng Kechen , Li Yanjun , Cheng Zhen
Published: February 2019

Radio‐frequency (RF) energy harvesting is one promising technology to power the nodes in wireless networks. This study focuses on large‐scale wireless powered communication networks having multiple RF energy transmitters (ETs) and sinks, which almost have not been investigated previously. The authors aim to optimise the throughput via optimizing the transmit power allocation of ETs subject to a total power budget. Specifically, for the sum‐throughput maximisation (STM) problem, they firstly formulate it to be a non‐linear optimisation problem, then prove its convexity and finally propose an efficient dual sub‐gradient algorithm to solve it. Owing to the throughput unfairness among nodes of the STM approach, they further consider the common‐throughput maximisation (CTM; i.e. the worst node's throughput) and propose a very efficient algorithm for it. This algorithm divides the CTM problem into a master problem and a subproblem. The subproblem of determining the feasibility of a given common‐throughput is solved by transforming it to a linear problem whose optimal solution indicates the feasibility. The master problem of determining the maximal common‐throughput is solved by using the bisection search method. Simulation results demonstrate the effectiveness of the CTM approach to mitigate the throughput unfairness problem at the cost of decreased sum‐throughput.
Computer‐aided diagnosis system for ulcer detection in wireless capsule endoscopy images
Authors: Charfi Said , El Ansari Mohamed , Balasingham Ilangko
Published: February 2019

Wireless capsule endoscopy (WCE) has revolutionised the diagnosis and treatment of gastrointestinal tract, especially the small intestine which is unreachable by traditional endoscopies. The drawback of the WCE is that it produces a large number of images to be inspected by the clinicians. Hence, the design of a computer‐aided diagnosis (CAD) system will have a great potential to help reduce the diagnosis time and improve the detection accuracy. To address this problem, the authors propose a CAD system for automatic detection of ulcer in WCE images. Firstly, they enhance the input images to be better exploited in the main steps of the proposed method. Afterward, segmentation using saliency map‐based texture and colour is applied to the WCE images in order to highlight ulcerous regions. Then, inspired by the existing feature extraction approaches, a new one has been proposed for the recognition of the segmented regions. Finally, a new recognition scheme is proposed based on hidden Markov model using the classification scores of the conventional methods (support vector machine, multilayer perceptron and random forest) as observations. Experimental results with two different datasets show that the proposed method gives promising results.
Hybrid mode control for wide range soft‐switched full‐bridge converter with auxiliary parallel inductor networks
Authors: Tang Yuanhong , Wu Yunfeng , Chen Zhangyong , Zhang Chenyu , Hu Weihao
Published: February 2019

Aiming at the limitations of conventional phase‐shifted full‐bridge (PSFB) converter, such as, narrow zero‐voltage switching (ZVS) range and large duty cycle losses, here, a wide range soft‐switched full‐bridge (FB) converter using hybrid mode control is proposed. Given using of two auxiliary inductors under light load, the energy that required for soft switching is satisfied and thus, ZVS can be achieved, and, therefore, efficiency of converter can be improved significantly under light load. Furthermore, the duty cycle losses of the secondary side are reduced by using a transformer with the small leakage inductor. Based on these merits, the proposed converter has some advantage for the wide range load variation applications without duty cycle losses. This paper presents the circuit configuration of the proposed converter and analyses its operating principles. Experimental results of an 800 W 200/50 V prototype are presented to validate the effectiveness of the proposed converter.
Economic dispatch coordinated with information granule chance constraint goal programming under the manifold uncertainties
Authors: Yin Jiafu , Zhao Dongmei
Published: February 2019

With the increasing integration of wind power and demand response into power system, the complex uncertainties from supply‐side and demand‐side have brought great challenges to daily operation of the power system. It is essential for enabling a comprehensive and adequate consideration of the manifold uncertainties in the grid. In this study, information granule chance constraint goal programming (IGCCGP) is proposed by a combination of chance constraint goal programming and information granule to provide a uniform representation of the multifaceted uncertainties. Leveraging on IGCCGP, the reserve constraints and branch flow constraints for accommodating the complex uncertainties in the grid are developed and the economic dispatch model considering the combined uncertainties from both supply‐side and demand‐side is established. To accelerate model solutions without losing much of model accuracy, the deviation in the IGCCGP is transformed to a deterministic equivalent and the optimal schedule is obtained by a mixed linear integer programming. Finally, a computational study is illustrated in the IEEE 39‐bus system to verify the efficiency of the proposed method.
Distributed, fixed‐time, and bounded control for secondary voltage and frequency restoration in islanded microgrids
Authors: Shrivastava Sonam , Subudhi Bidyadhar
Published: February 2019

Microgrid (MG) technology evolves as a promising solution to deal with the intermittent renewable generations and frequently changing load demand. This paper proposes a fully distributed and bounded secondary control algorithm with flexible convergence time for voltage and frequency restoration. It also enables accurate active power sharing for an islanded MG, compared with the well‐known consensus‐based distributed control approach. The proposed control scheme achieves accelerated fixed‐time convergence. The upper bound on the convergence is established by using the Lyapunov stability theory. The bounded, distributed control approach restores the voltage and frequency in fixed‐time while sharing the active power precisely. Further, the proposed controller is adaptive to the communication topology change and supports the plug and play feature of MG. Extensive simulations have been pursued using MATLAB/SimPowerSyetem toolbox considering frequent load perturbation and communication topology change. The obtained results are analysed to verify the performance of the proposed control algorithm. It is observed that the proposed bounded input controller converges faster than the conventional method.
Accuracy improvement of positioning data in greenhouse for agricultural machinery via optimisation algorithm
Authors: Geng Jing , Wang Xiang , Zhu Saihua , Lin Xiangze
Published: February 2019

Although several indoor positioning systems for greenhouse have been developed in automated agricultural machinery monitoring, the data measured by positioning systems still has large errors. In order to solve the problem, in this study, improved weighted‐centroid algorithm and maximum likelihood estimation (MLE) algorithm were developed to optimise positioning data of agricultural machinery in the greenhouse, which is measured by ultra‐wide band‐based indoor positioning system according to different agricultural machinery working states. Compared with real coordinate data, when agricultural machinery stays still, the average static error of the data was 66.4 mm with the improved weighted‐centroid algorithm; when the machinery is in dynamic state, the average dynamic error of the data was 61 mm and the probability that error <60 mm was 0.848 according to the MLE. Hence, the optimisation algorithms presented in this study improve the positioning accuracy significantly and the position of agricultural machinery is able to be estimated better compared with the raw data.
Gentle Adaboost algorithm based on multi‐feature fusion for face detection
Authors: Yan Chen , Wang Zhengqun , Xu Chunlin
Published: February 2019

There are few types of Haar‐like rectangle features, which leads to the problem that the classifier training time is too long due to the large number of feature quantities required in the description of the face. Local binary patterns (LBP) are used to describe the local texture features of the face image. Considering the inadequacy of basic LBP features in face detection, unified MB‐LBP features and unified rotation‐invariant LBP features are used to describe local texture features of faces. Considering the shortcomings of MB‐LBP feature and rotation‐invariant LBP feature on face edge information, the edge azimuth field feature based on Canny operator is combined with the above two features to describe face information. Finally, the Gentle Adaboost classifier was designed to classify all the extracted features. The experimental results show that the unified MB‐LBP feature and the unified rotation invariant LBP feature and the edge azimuth field feature based on Canny operator can not only describe the face information from the local but also the whole, which greatly improves the detection rate and detection speed of the face with multiple poses and different rotation modes.
Robotic spinal surgery system with force feedback for teleoperated drilling
Authors: Rezazadeh Sina , Bai Weibang , Sun Mingjing , Chen Shihang , Lin Yanping , Cao Qixin
Published: February 2019

Drilling into the vertebra is a critical task in spinal surgeries. Traditionally, it is relied upon surgeon's intuition and experience. Robotic‐assisted spinal surgery with fore feedback allows the drilling process to be performed automatically with much higher precision and safety. In this study, a new teleoperated robotic spinal surgery system with a frontend surgical instrument is designed, which is equipped with a force detection and feedback system. The proposed robotic system is manufactured and evaluated via laboratory and in vivo tests. Results prove the effectiveness of the system in precise teleoperation drilling, real‐time force feedback, and achieving less surgical radiation exposure.
PÉGASE.3: A code for modeling the UV-to-IR/submm spectral and chemical evolution of galaxies with dust
Authors: Fioc Michel , Rocca-Volmerange Brigitte
Published: February 2019

A code computing consistently the evolution of stars, gas and dust, as well as the energy they radiate, is required to derive reliably the history of galaxies by fitting synthetic spectral energy distributions (SEDs) to multiwavelength observations. The new code PÉGASE.3 described in this paper extends to the far-infrared/submillimeter the ultraviolet-to-near-infrared modeling provided by previous versions of PÉGASE. It first computes the properties of single stellar populations at various metallicities. It then follows the evolution of the stellar light of a galaxy and the abundances of the main metals in the interstellar medium (ISM), assuming some scenario of mass assembly and star formation. It simultaneously calculates the masses of the various grain families, the optical depth of the galaxy and the attenuation of the SED through the diffuse ISM in spiral and spheroidal galaxies, using grids of radiative transfer precomputed with Monte Carlo simulations taking scattering into account. The code determines the mean radiation field and the temperature probability distribution of stochastically heated individual grains. It then sums up their spectra to yield the overall emission by dust in the diffuse ISM. The nebular emission of the galaxy is also computed, and a simple modeling of the effects of dust on the SED of star-forming regions is implemented. The main outputs are ultraviolet-to-submillimeter SEDs of galaxies from their birth up to 20 Gyr, colors, masses of galactic components, ISM abundances of metallic elements and dust species, supernova rates. The temperatures and spectra of individual grains are also available. The paper discusses several of these outputs for a scenario representative of Milky Way-like spirals. PÉGASE.3 is fully documented and its Fortran 95 source files are public. The code should be especially useful for cosmological simulations and to interpret future mid- and far-infrared data, whether obtained by JWST, LSST, Euclid or e-ELT.
Effect of Aflibercept on Cystoid Macular Edema Associated with Central Retinal Vein Occlusion. Results from a District Hospital in the United Kingdom
Authors: Panos Georgios , Kostakis Vassileios , Porter Grazyna
Published: February 2019

Purpose The purpose of this study was to report the efficiency and safety of intravitreal aflibercept for the treatment of cystoid macular edema (CME) secondary to central retinal vein occlusion (CRVO).

Methods This is a retrospective cohort study. Ten naive eyes of ten patients with CME secondary to CRVO were included. All eyes received a loading dose of 3 monthly aflibercept injections followed by as-needed injections at monthly follow-up visits. Best corrected visual acuity (BCVA) and central retinal thickness (CRT) were evaluated at baseline and at the end of the follow-up period.

Results The median follow-up period was 6 months (range: 6 – 9). The median number of injections was 4 (range: 3 – 5). Median BCVA improved from 1.05 LogMAR units (range: 0.7 – 1.6) at baseline to 0.65 (range: 0.4 – 1.6) at the end of the follow-up period (p = 0.02). Median CRT improved from 690 µm (range: 561 – 1235) at baseline to 243 µm (range: 207 – 531) at the end of the follow-up period (p = 0.002). The power of all statistical tests was greater than 0.8. No adverse effects or complications were documented.

Conclusion Intravitreal aflibercept treatment for CME secondary to CRVO significantly improved both macular anatomy and visual acuity without adverse effects.
Bedeutung der selektiven Lebensqualitätsanalyse nach Sympathikus-Clipping bei Patienten mit lokaler Hyperhidrose
Authors: Schreiner Waldemar , Mykoliuk Iurii , Dudek Wojciech , Sirbu Horia
Published: February 2019

Einleitung Die Hyperhidrose (HH) geht mit einer physischen und psychischen Einschränkung einher. Die Behandlung umfasst sowohl konservative als auch operative Methoden und strebt eine dauerhafte Verbesserung der Lebensqualität (LQ) der Betroffenen an. Die endoskopische Sympathikusblockade (ESB) stellt eine etablierte operative Therapiemethode dar und gilt als ein effektives chirurgisches Verfahren bei Versagen der konservativen Therapieoptionen. Das Ziel unserer Studie war, die LQ-Veränderung und die Patientenzufriedenheit nach ESB durch umfangreiche Analyseverfahren zu untersuchen und entsprechende Einflussfaktoren zu identifizieren.

Methoden Von Juli 2008 bis April 2016 wurden 105 Patienten wegen therapierefraktärer HH operiert. In allen Fällen wurde ein ESB entsprechend vorliegenden Hyperhidroseform und dem STS-Expertenkonsens (STS: Society of Thoracic Surgeons) durchgeführt. Die LQ und das Hyperhidrosestatus wurden anhand von detaillierten Fragebogen (ein selbst entwickelter Fragebogen, SF36, DLQI, Hyperhidrose LQ (HidroQoL)) selektiv prä- und postoperativ analysiert und bewertet. Die statistische Bearbeitung erfolgte anhand SPSS Statistics Version 21.0.0.2 für Windows (Armonk, NY: IBM Corp.). Die statistische Analyse erfolgte anhand deskriptiver Analyse und nicht parametrischer Tests.

Ergebnisse 105 Patienten zwischen Juli 2008 bis April 2016 wurden mittels bilateralem ESB operiert und evaluiert: 73 Frauen (69,5%) und 31 Männer (29,5%) im Medianalter von 26 Jahren (16 – 64), mit fokaler palmarer und axillarer (HPA) 13 (12,4%), palmoplantarer (PPH) 20 (19%), palmoplantarer und axillarer (PPAH) 47 (44,8%), axillarer Hyperhidrose (HA) 11 (10,5%) und Gesichtshyperhidrose (HF) 14 (13,3%). HydroQoL-Score zeigte eine Verbesserung in allen HH-Formen. Das DLQI wies eine Verbesserung in allen Patientengruppen auf, während die LQ-Analyse mittels SF36 eine Verbesserung in sozialer Funktionsfähigkeit und dem psychischen Wohlbefinden in allen HH-Formen außer HA aufzeigte. Mit postoperativem Ergebnis waren 86,7% (91) Patienten zufrieden. Das kompensatorische Schwitzen (KS) wurde in 76,2% (80) der Fälle beobachtet ohne einen eindeutigen LQ-Einfluss. Keine signifikante Korrelation zwischen KS und der Hyperhidroseform war feststellbar.

Schlussfolgerungen Die ESB geht mit einer dauerhaften LQ-Verbesserung in der sozialen Funktionsfähigkeit, dem psychologischen Wohlbefinden und der hohen Patientenzufriedenheit einher. Das Auftreten vom KS hat keine eindeutige Korrelation zu LQ und Patientenzufriedenheit.
Occult Urinary Incontinence Treatment: Systematic Review and Meta-analysis—Brazilian Guidelines
Authors: Matsuoka Priscila Katsumi , Castro Rodrigo Aquino , Baracat Edmund Chada , Haddad Jorge Milhem
Published: February 2019

Objective To evaluate if performing anti-incontinence procedures during surgical anterior and/or apical prolapse correction in women with asymptomatic urinary incontinence (UI) may prevent stress urinary incontinence (SUI) postoperatively.

Methods We have performed a systematic review of articles published in the PubMed, Cochrane Library, and Lilacs databases until March 31, 2016. Two reviewers performed the data collection and analysis, independently. All of the selected studies were methodologically analyzed. The results are presented as relative risk (RR), with a 95% confidence interval (CI).

Results After performing the selection of the studies, only nine trials fulfilled the necessary prerequisites. In the present review, 1,146 patients were included. Altogether, the review included trials of three different types of anti-incontinence procedures. We found that performing any anti-incontinence procedure at the same time of prolapse repair reduced the incidence of SUI postoperatively (RR = 0.50; 95% CI: 0.28–0.91). However, when we performed the analysis separately by the type of anti-incontinence procedure, we found different results. In the subgroup analysis with midurethral slings, it is beneficial to perform it to reduce the incidence of SUI (RR = 0.08; 95% CI: 0.02–0.28). On the other hand, in the subgroup analysis with Burch colposuspension, there was no significant difference with the control group (RR = 1.47; 95% CI: 0.28–7.79]).

Conclusion Performing any prophylactic anti-incontinence procedure at the same time as prolapse repair reduced the incidence of SUI postoperatively. The Burch colposuspension did not show any decrease in the incidence of SUI postoperatively.
Three-Dimensional Surface Reconstruction of the Human Cochlear Nucleus: Implications for Auditory Brain Stem Implant Design
Authors: Tarabichi Osama , Kanumuri Vivek V. , Klug Julian , Vachicouras Nicolas , Duarte Maria J. , Epprecht Lorenz , Kozin Elliott D. , Reinshagen Katherine , Lacour Stéphanie P. , Brown M Christian , Lee Daniel J.
Published: February 2019

Objective The auditory brain stem implant (ABI) is a neuroprosthesis placed on the surface of the cochlear nucleus (CN) to provide hearing sensations in children and adults who are not candidates for cochlear implantation. Contemporary ABI arrays are stiff and do not conform to the curved brain stem surface. Recent advancements in microfabrication techniques have enabled the development of flexible surface arrays, but these have only been applied in animal models. Herein, we measure the surface curvature of the human CN and adjoining regions to assist in the design and placement of next-generation conformable clinical ABI arrays. Three-dimensional (3D) reconstructions from ultrahigh T1-weighted brain magnetic resonance imaging (MRI) sequences and histologic reconstructions based on postmortem adult human brain stem specimens were used.

Design This is a retrospective review of radiologic data and postmortem histologic axial sections.

Setting This is set at the tertiary referral center.

Participants Data were acquired from healthy adults.

Main Outcome Measures The main outcome measures are principal curvature values (Kmin and Kmax) and global radius of curvature.

Results The CN was successfully extracted and rendered as a 3D surface in all cases. Significant curvatures of the CN in both histologic and radiographic reconstructions were found with global radius of curvature ranging from 2.08 to 8.5 mm. In addition, local curvature analysis revealed that the surface is highly complex.

Conclusion Detailed rendering of the human CN is feasible using histology and 3D MRI reconstruction and highlights complex surface topography that is not recapitulated by contemporary stiff ABI arrays.
Thymic Epithelial Tumors: Prognostic Significance and Relationship between Histology and the New TNM Staging System
Authors: Tamburini Nicola , Maniscalco Pio , Migliorelli Andrea , Nigim Fares , Quarantotto Francesco , Maietti Elisa , Cavallesco Giorgio
Published: February 2019

Background This study aims to describe the relationship between the new tumor nodes metastasis (TNM) staging and World Health Organization (WHO) classification and to identify how these two variables relate to each other and whether they possess a prognostic value in predicting survival and recurrence of disease.

Methods Medical records of 54 patients who underwent surgery for thymic epithelial tumors between 1996 and 2015 were reviewed.

The histologic type of neoplasm was classified according to the criteria of WHO and staging was evaluated using the new TNM classification system.

Results A significant correlation between the TNM stages and the histological classification was found (p < 0.001). Complete resection is related to both TNM stage and histological grading (p < 0.001). Evaluation of the 5- and 10-year survival curves shows how these are significantly correlated only at the stage (p = 0.03 and = 0.04, respectively). The risk of death at 5 and 10 years for stages III to IV is six and three times higher than in stages I to II, respectively. Regarding the disease-free survival, there is significant correlation with both staging and histology (p = 0.001 and = 0.02, respectively).

Conclusions There is a significant correlation between the new TNM staging and the histological grade WHO. The ability to implement a complete resection, the overall and disease-free survival is closely related to the thymoma stage. Furthermore, both histotype and stage correlate with disease-free survival. In fact, the least aggressive stages, both WHO and TNM, have a free time out of disease superior to advanced stages.
The Role of Stroke as a Trigger for Incident Venous Thromboembolism: Results from a Population-based Case-Crossover Study
Authors: Morelli Vânia , Sejrup Joakim , Småbrekke Birgit , Rinde Ludvig , Grimnes Gro , Isaksen Trond , Hansen John-Bjarne , Hindberg Kristian , Brækkan Sigrid
Published: February 2019

Stroke is associated with a short-term increased risk of subsequent venous thromboembolism (VTE). It is unclear to what extent this association is mediated by stroke-related complications that are potential triggers for VTE, such as immobilization and infection. We aimed to investigate the role of acute stroke as a trigger for incident VTE while taking other concomitant VTE triggers into account. We conducted a population-based case-crossover study with 707 VTE patients. Triggers were registered during the 90 days before a VTE event (hazard period) and in four preceding 90-day control periods. Conditional logistic regression was used to estimate odds ratios with 95% confidence intervals (CIs) for VTE according to triggers. Stroke was registered in 30 of the 707 (4.2%) hazard periods and in 6 of the 2,828 (0.2%) control periods, resulting in a high risk of VTE, with odds ratios of 20.0 (95% CI: 8.3–48.1). After adjustments for immobilization and infection, odds ratios for VTE conferred by stroke were attenuated to 6.0 (95% CI: 1.6–22.1), and further to 4.0 (95% CI: 1.1–14.2) when other triggers (major surgery, red blood cell transfusion, trauma, and central venous catheter) were added to the regression model. A mediation analysis revealed that 67.8% of the total effect of stroke on VTE risk could be mediated through immobilization and infection. Analyses restricted to ischemic stroke yielded similar results. In conclusion, acute stroke was a trigger for VTE, and the association between stroke and VTE risk appeared to be largely mediated by immobilization and infection.
Major histocompatibility complex class I diversity limits the repertoire of T cell receptors
Authors: Migalska Magdalena , Sebastian Alvaro , Radwan Jacek
Published: February 2019

Major histocompatibility complex (MHC) genes encode proteins that initiate adaptive immune responses through the presentation of foreign antigens to T cells. The high polymorphism found at these genes, thought to be promoted and maintained by pathogen-mediated selection, contrasts with the limited number of MHC loci found in most vertebrates. Although expressing many diverse MHC genes should broaden the range of detectable pathogens, it has been hypothesized to also cause deletion of larger fractions of self-reactive T cells, leading to a detrimental reduction of the T cell receptor (TCR) repertoire. However, a key prediction of this TCR depletion hypothesis, that the TCR repertoire should be inversely related to the individual MHC diversity, has never been tested. Here, using high-throughput sequencing and advanced sequencing error correction, we provide evidence of such an association in a rodent species with high interindividual variation in the number of expressed MHC molecules, the bank vole (
Myodes glareolus
). Higher individual diversity of MHC class I, but not class II, was associated with smaller TCR repertoires. Our results thus provide partial support for the TCR depletion model, while also highlighting the complex, potentially MHC class-specific mechanisms by which autoreactivity may trade off against evolutionary expansion of the MHC gene family.
Neuromelanin-sensitive MRI as a noninvasive proxy measure of dopamine function in the human brain
Authors: Cassidy Clifford M. , Zucca Fabio A. , Girgis Ragy R. , Baker Seth C. , Weinstein Jodi J. , Sharp Madeleine E. , Bellei Chiara , Valmadre Alice , Vanegas Nora , Kegeles Lawrence S. , Brucato Gary , Kang Un Jung , Sulzer David , Zecca Luigi , Abi-Dargham Anissa , Horga Guillermo
Published: February 2019

Significance

Neuromelanin-sensitive MRI (NM-MRI) purports to detect the content of neuromelanin (NM), a product of dopamine metabolism that accumulates in the substantia nigra (SN). Prior work has shown that NM-MRI provides a marker of SN integrity in Parkinson’s disease. Here, we show that it may additionally provide a marker of dopamine function in the human nigrostriatal pathway. Supporting this, we found that NM-MRI signal correlated with NM concentration, dopamine levels in the striatum, SN blood flow, and severity of psychosis in schizophrenia, all in the absence of neurodegeneration. Thus, noninvasive NM-MRI is a promising tool that could have diverse research and clinical applications to investigate in vivo the role of dopamine in neuropsychiatric illness.
Antidepressant-relevant concentrations of the ketamine metabolite (2
R
,6
R
)-hydroxynorketamine do not block NMDA receptor function
Authors: Lumsden Eric W. , Troppoli Timothy A. , Myers Scott J. , Zanos Panos , Aracava Yasco , Kehr Jan , Lovett Jacqueline , Kim Sukhan , Wang Fu-Hua , Schmidt Staffan , Jenne Carleigh E. , Yuan Peixiong , Morris Patrick J. , Thomas Craig J. , Zarate Carlos A. , Moaddel Ruin , Traynelis Stephen F. , Pereira Edna F. R. , Thompson Scott M. , Albuquerque Edson X. , Gould Todd D.
Published: February 2019

Significance

Standard antidepressant treatments require weeks to show effectiveness. A single subanesthetic dose of ketamine rapidly attenuates many clinical signs and symptoms of depression; however, ketamine treatment also has many adverse effects, including dissociation and potential for abuse, which are mediated by NMDA glutamate receptor (NMDAR) inhibition. Previous work has revealed that the ketamine metabolite (2
R
,6
R
)-hydroxynorketamine (HNK) induces antidepressant-like responses in rodents while minimizing the adverse effects observed with ketamine. The results of this study, using a multitude of experimental approaches, confirm that antidepressant-relevant concentrations of (2
R
,6
R
)-HNK are not sufficient to block NMDARs. This provides a basis for work directed at alternative molecular targets and toward novel drugs that exert rapid antidepressant effects independent of NMDAR inhibition and NMDAR-mediated adverse effects.
Elementary response triggered by transducin in retinal rods
Authors: Yue Wendy W. S. , Silverman Daniel , Ren Xiaozhi , Frederiksen Rikard , Sakai Kazumi , Yamashita Takahiro , Shichida Yoshinori , Cornwall M. Carter , Chen Jeannie , Yau King-Wai
Published: February 2019

Significance

For decades, amplification at the step of rhodopsin–G protein (transducin) interaction in rod phototransduction has been believed to be ∼500, a high value often generalized to other G protein-coupled receptor pathways. Recently, there have been indications that this amplification may be considerably lower. Nonetheless, disputes persist because of the large variation in estimates obtained by different groups, plus the drawback that some key measurements used in such estimates came from experiments on nonintact rods. As such, the dogma continues in textbooks. Here, we report experiments entirely on intact rods to measure the effect of a single transducin molecule via the transducin–phosphodiesterase (PDE) complex, and conclude that a photoexcited rhodopsin activates effectively only ∼12–14 transducin–PDE effector complexes.
Calpain drives pyroptotic vimentin cleavage, intermediate filament loss, and cell rupture that mediates immunostimulation
Authors: Davis Michael A. , Fairgrieve Marian R. , Den Hartigh Andreas , Yakovenko Olga , Duvvuri Bhargavi , Lood Christian , Thomas Wendy E. , Fink Susan L. , Gale Michael
Published: February 2019

Significance

Pyroptosis is a form of inflammatory cell death. It is driven by plasma membrane pore formation that is thought to rupture cells through osmotic influx, thereby releasing intracellular content that initiates an inflammatory response to fight acute infection and tissue damage. However, when chronic or unregulated, this process can drive autoimmune disease and cancer. Here, we show that pyroptotic cells do not undergo rupture in culture. Instead, the calcium-dependent protease calpain destroys intermediate filaments, which provide mechanical resilience to cells. As a result, cells are susceptible to rupture by mechanical disruption from shear stress or compression as occurs in the blood stream or within tissues. Thus, our data reveal potential targets for the therapeutic intervention of autoimmune diseases and cancer.
Photoexcitation-controlled self-recoverable molecular aggregation for flicker phosphorescence
Authors: Jia Xiaoyong , Shao Cancan , Bai Xin , Zhou Qiaohui , Wu Bin , Wang Linjun , Yue Bingbing , Zhu Haiming , Zhu Liangliang
Published: February 2019

Significance

We employed photoexcitation as a unique control method to manipulate molecular aggregation and emission to advance luminescent probe techniques. This study harnesses dynamical and rhythmical photoluminescence to strengthen visualization in bioimaging. These advantages are based on the merit of a type of photocontrollable material, which can undergo fast and self-recoverable aggregation-induced phosphorescence while mostly avoiding possible side reactions and fatigue accumulation, compared with traditional bidirectional manipulations.
Ultrasonic Tomography of Brick Columns Based on FEM Calculations
Authors: Zielinska Monika , Rucka Magdalena
Published: February 2019

Ultrasonic tomography is one of the most developed method of non-destructive testing. Despite being used mainly in medicine, it is becoming more and more popular as a method for monitoring of structural elements. It allows to examine the internal structure and technical condition of the tested element. This paper investigates the influence of crosssectional geometry on an obtained tomographic image. Wave propagation signals were obtained using finite element method (FEM). The analysis was conducted on six models of solid brick columns with a square section. The first one constituting a reference model was made in the form of a full column. The other models contained internal inclusions affecting propagating waves such as: a hole or a steel plate, circular bar and square pipe adhesively bonded with mortar. The obtained results of the analysis presented in the study allowed to assess the ultrasonic tomography usability for masonry structures.

A post-publication change was made to this article on 12 Mar 2020 to add acknowledgement of funding.
Atorvastatin: A hydroxymethylglutaryl-coenzyme A reductase inhibitor
Authors: Malinowski Jennifer M.
Published: February 2019

The pharmacology, pharmacokinetics, clinical efficacy, adverse effects, interactions, and formulary considerations of atorvastatin relative to other hydroxymethylglutaryl-coenzyme A (HMG-CoA) reductase inhibitors (statins) are discussed.

Atorvastatin calcium, a synthetic stereoisomer of a pentasubstituted pyrrole, prevents the conversion of HMG-CoA by competitive and selective inhibition of HMG-CoA reductase. This limits cholesterol formation. Atorvastatin undergoes extensive first-pass metabolism; the first-pass effect is saturable at higher doses. Time to maximum plasma concentration ranges from one to four hours. The plasma elimination half-life is considerably longer than for other statins. Like other statins, atorvastatin reduces low-density-lipoprotein cholesterol (LDL-C) and total cholesterol in patients with hypercholesterolemia. However, the reductions achieved with atorvastatin exceed those for other statins. Atorvastatin recipients are more likely to achieve LDL-C goals and to do so more quickly. Atorvastatin also moderately reduces triglyceride levels in patients with hypertriglyceridemia and may play a role in the management of familial hypercholesterolemia. Adequate lipid control with atorvastatin monotherapy may preclude the need for combination drug therapy in some patients. The adverse effects of atorvastatin include mild gastrointestinal disturbances, increased liver enzyme levels, and myalgia. Drug interactions involving atorvastatin can be expected to parallel those of other statins metabolized via CYP3A4. Atorvastatin has become a popular addition to hospital formularies, even though formal pharmacoeconomic analyses are lacking.

Atorvastatin effectively reduces blood lipids and may offer some advantages over other statins, but more studies are needed to clarify its optimal role in pharmacotherapy.
Urokinase activity after freezing: implications for thrombolysis in intraventricular hemorrhage
Authors: Rhoney Denise H. , Coplin William M. , Zaran Frank K. , Brish Linda K. , Weingarten Cindy M.
Published: February 2019

The retention of urokinase activity after frozen storage was studied.

Urokinase powder was reconstituted aseptically in sterile water for injection or preservative-free 0.9% sodium chloride injection to a final concentration of 5000 IU/mL. Samples were stored in 5-mL plastic syringes at -20 or -70 degrees C for up to six months. Samples containing urokinase 25,000 IU/mL were similarly prepared by using sodium chloride injection as the diluent and were stored frozen at the same temperatures for up to 93 days. Urokinase activity was measured with a chromogenic assay at each test interval. Samples were also cultured after thawing to evaluate their potential to support microbial growth.

The activity of urokinase at either concentration did not change appreciably during the study period. The method of thawing-at room temperature or in a refrigerator-had no effect on urokinase activity. No microbial growth was observed.

Urokinase 5000 IU/mL did not show any changes in activity when reconstituted with sterile water for injection or 0.9% sodium chloride injection and frozen for up to six months. Urokinase 25,000 IU/mL in sodium chloride injection was also stable after 93 days of frozen storage.
Concussion History and Career Status Influence Performance on Baseline Assessments in Elite Football Players
Authors: Cookinham Brittani , Swank Chad
Published: February 2019

Objective

To determine if concussion history and career status is associated with neurocognitive performance in elite football players.

Methods

The study design was a cross-sectional single assessment. Fifty-seven elite football players (age 29.39 ± 7.49 years) categorized as draft prospects, active professional players, and retired professional players were assessed on the Sport Concussion Assessment Tool – third edition (SCAT-3), in an outpatient therapy setting.

Results

Common symptoms were the following: fatigue (45.6%), trouble falling asleep (35.1%), difficulty remembering (33.3%) and irritability (22.8%); 36.8% reported no symptoms. The low concussion (0–1) group reported fewer symptoms (U = 608.50, p < .001), less symptom severity (U = 598.00, p = −.001), and produced greater scores on the Standardized Assessment of Concussion (SAC) total scores compared to the multiple concussion (2+) group (U = 253.00, p = .024), but no differences were observed on modified Balance Error Scoring System (m-BESS) scores (U = 501.50, p = .066) on the Mann–Whitney U test. The Kruskal–Wallis test and post-hoc analysis indicated retired players were significantly different from draft prospects and current professional players for total symptom scores (p < .001), total symptom severity (p < .001), SAC total scores (p = .030), and m-BESS (p < .001).

Conclusions

Concussion history and career status appear associated with total symptoms, symptom severity, performance on the SAC, and the m-BESS in elite football players. With this in mind, future research is recommended to determine longitudinal impact for elite football players.
Benefits of dimension reduction in penalized regression methods for high-dimensional grouped data: a case study in low sample size
Authors: Ajana Soufiane , Acar Niyazi , Bretillon Lionel , Hejblum Boris P , Jacqmin-Gadda Hélène , Delcourt Cécile ,   for the BLISAR Study Group, Acar Niyazi , Ajana Soufiane , Berdeaux Olivier , Bouton Sylvain , Bretillon Lionel , Bron Alain , Buaud Benjamin , Cabaret Stéphanie , Cougnard-Grégoire Audrey , Creuzot-Garcher Catherine , Delcourt Cécile , Delyfer Marie-Noelle , Féart-Couret Catherine , Febvret Valérie , Grégoire Stéphane , He Zhiguo , Korobelnik Jean-François , Martine Lucy , Merle Bénédicte , Vaysse Carole
Published: February 2019

Motivation

In some prediction analyses, predictors have a natural grouping structure and selecting predictors accounting for this additional information could be more effective for predicting the outcome accurately. Moreover, in a high dimension low sample size framework, obtaining a good predictive model becomes very challenging. The objective of this work was to investigate the benefits of dimension reduction in penalized regression methods, in terms of prediction performance and variable selection consistency, in high dimension low sample size data. Using two real datasets, we compared the performances of lasso, elastic net, group lasso, sparse group lasso, sparse partial least squares (PLS), group PLS and sparse group PLS.

Results

Considering dimension reduction in penalized regression methods improved the prediction accuracy. The sparse group PLS reached the lowest prediction error while consistently selecting a few predictors from a single group.

Availability and implementation

R codes for the prediction methods are freely available at https://github.com/SoufianeAjana/Blisar.

Supplementary information

Supplementary data are available at Bioinformatics online.
Ghana’s Child Panels: Effective Child Protection and Juvenile Justice System or Superfluous Creation?
Authors: Adu-Gyamfi Jones
Published: February 2019

In accordance with the United Nations’ requirements for dealing with juvenile offenders, Ghana’s Children Act 1998 mandated local authorities to establish child panels to mediate minor offences committed by children. However, to date there has not been any research that has examined the functioning and effectiveness of the child panels. This research examined the operationalisation and effectiveness of child panels in Ghana. The study involved the use of semi-structured interviews and focus group discussions with panel members of four local authorities. Findings showed that the child panels are not functioning effectively in Ghana. The relevance of the child panels has been questioned since it was found to be duplicating the roles of some other child welfare agencies. This article discusses the challenges impeding the effectiveness of the child panels and outlines recommendations to improve their effectiveness.
Simplified frozen elephant trunk technique for combined open and endovascular treatment of extensive aortic diseases
Authors: Detter Christian , Demal Till Joscha , Bax Lennart , Tsilimparis Nikolaos , Kölbel Tilo , von Kodolitsch Yskert , Vettorazzi Eik , Reichenspurner Hermann , Brickwedel Jens
Published: February 2019

OBJECTIVES:

This study aims to analyse the impact of a simplified frozen elephant trunk (FET) technique on early outcome.

METHODS:

Between October 2010 and August 2018, 92 consecutive patients (mean age 64.4 ± 12.2 years) underwent FET surgery. Underlying pathologies were thoracic aneurysm in 35 patients, acute aortic dissection in 25 patients and chronic dissection in 32 patients. Thirty patients underwent a simplified FET technique with deployment of the stent graft in arch zone 2 with an extra-anatomic bypass to the distal left subclavian artery using the third branch of the Thoraflex™ Hybrid Plexus prosthesis via a supraclavicular access during reperfusion. These patients were compared to 62 patients who received the conventional FET procedure, in which a distal anastomosis is performed in arch zone 3.

RESULTS:

Circulatory arrest (41.7 ± 10.5 vs 76.5 ± 33.0 min; P < 0.001) and antegrade cerebral perfusion times (60.9 ± 13.5 vs 92.1 ± 33.1 min; P < 0.001) were significantly reduced in zone 2 vs zone 3 patients, respectively. The 30-day mortality rate was 3.3% (n = 1) in zone 2 patients vs 17.7% (n = 11) in zone 3 patients (P = 0.75). Stent deployment in zone 2 was associated with significantly reduced rates of postoperative stroke [zone 2: n = 0 (0.0%); zone 3: n = 11 (17.7%), P = 0.046] and recurrent nerve palsy [zone 2: n = 1 (3.3%); zone 3: n = 14 (22.6%), P = 0.020).

CONCLUSIONS:

Simplifying the FET procedure leads to reduced circulatory arrest and cerebral perfusion times and improves early outcome.