bluuebunny/crossref_metadata_2025 huggingface dataset:
Hybrid four‐level FC inverter using an internal supercapacitor storage system for a microgrid connected application
Authors: Mansouri Sabri , Tnani Slim , Bachelier Olivier
Published: February 2021

In this study, a new topology of grid‐connected four‐level inverter is introduced. The proposed structure, based on intermediate supercapacitors energy storage, is introduced to ensure two operation modes: to provide power to a microgrid from renewable energy sources and to regulate its voltage during short‐term power disturbances. The main idea is to replace ordinary capacitors of a four‐level flying capacitor (FC) inverter by supercapacitors and operate them under variable voltage conditions. The control strategy applies linear matrix inequalities approach as well as space vector modulation technique to generate the appropriate switching states. The latter part of this study is dedicated to the redundant state selection method for supercapacitors voltages balancing. Through experimental implementation, presented results highlight the efficiency of the proposed hybrid inverter in ensuring microgrid stability.
Multiport bidirectional DC–DC converter for PV powered electric vehicle equipped with battery and supercapacitor
Authors: Savrun Murat Mustafa , Atay Alihan
Published: February 2021

This study presents a novel quasi‐Z‐source converter integrated isolated multiport bidirectional DC–DC converter topology for a photovoltaic (PV) powered and battery/supercapacitor buffered electric vehicle (EV). The proposed topology can provide uninterrupted power to the electric motor of EV and regain the braking energy with the capability of bidirectional power flow. The system integrates quasi‐Z‐source and H‐bridge converters with an existing switch. Thus, a four‐port converter is achieved without any need for individual converters or additional switches. Besides, the high‐gain quasi‐Z‐source converter allows the reduction of the rated voltages of the battery and supercapacitor packs, as well as allows using a high‐frequency transformer (HFT) with a low turn ratio. The isolation between ports is provided by a secondary centre‐tapped HFT. The secondary side of the HFT is equipped with a controlled full‐wave rectifier to provide bidirectional power flow. In addition, a power flow management and corresponding control scheme are suggested. The performance of the proposed system has been evaluated for different operational changes. Results show that it properly performs the power flow between the ports under steady‐state and transient conditions. The power flow capabilities and efficiency values validate the viability and effectiveness of the proposed system.
Investigation of a novel multi‐input‐single‐output DC–DC converter topology with GWO‐based MPPT controller for energy harvesting using Seebeck generators at different thermal gradients
Authors: Thankakan Rakesh , Samuel Nadar Edward Rajan
Published: February 2021

This research work proposes an energy harvesting system using Seebeck generators (SGs) with a novel multi‐input‐single‐output (MISO) DC–DC converter and grey‐wolf optimisation (GWO)‐based maximum power point tracking (MPPT) controller at different thermal gradients. The thermoelectric modules (TEMs) of the SGs convert the thermal energy dissipated by the stator windings of the wind generator (WG) to electrical energy. The proposed MISO power converter topologies have been analysed for two‐inputs, four‐inputs, n‐inputs, and a single‐output for producing higher output power to power a DC micro‐grid. It has the benefit of higher voltage gain and lower voltage stresses on metal–oxide–semiconductor field‐effect transistor switches. The GWO‐based MPPT is employed in this work that overcomes the drawbacks of traditional MPPT methods such as steady‐state oscillation, transients, global convergence capability, and lower MPPT tracking accuracy under non‐uniform temperature conditions. The MPPT controller has effectively tracked a maximum power with a higher tracking accuracy of 98.19%, and the converter has an efficiency of 90.77% corresponding to the wind velocity of 12.9 m/s of the WG. Also, the TEMs are associated in a square series–parallel configuration, and the MISO power converter is analysed with a GWO‐based MPPT controller.
Selected harmonic elimination‐derived multi‐frequency pulse width modulation control strategy for multi‐load MCR WPT system with single transmitting coil
Authors: Chen Xuling , Han Zhengquan , Liu Fuxin
Published: February 2021

Magnetically coupled resonant wireless power transfer (MCR WPT) has become the research focus in recent years because of its safety, simplicity and high efficiency. In multi‐load applications, the ‘one‐to‐one’ charging scenario is difficult to meet the requirement of load diversity, and the development of the ‘one‐to‐many’ charging has become increasingly important. In this study, a multi‐load MCR WPT system with single transmitting coil and multiple receiving coils was investigated. To discriminate the loads for targeted power distribution, each receiving coil cascaded by the load is designed to operate at an individual frequency. For this purpose, a single‐phase full‐bridge inverter and a multi‐frequency pulse width modulation (MFPWM) control strategy were used to generate a multi‐frequency mixed excitation voltage that servers as the input of the single transmitting coil. In view of the different voltage features, two control modes defined as the unipolar and the bipolar modes were presented, and the characteristics of these two modes were analysed. To further reduce the harmonic content in the voltage waveform, a phase‐shifted MFPWM control strategy was proposed, and the design guideline of the phase‐shifted angle was given. Finally, a dual‐load MCR WPT system was taken as an example for the experimental verification, which confirms the correctness and effectiveness of the proposed control strategies.
Lyapunov function‐based improved switching command for a boost converter with an inductor–capacitor input filter
Authors: Gavagsaz‐Ghoachani Roghayeh , Phattanasak Matheepot , Martin Jean‐Philippe , Pierfederici Serge
Published: February 2021

This study presents a control method for DC–DC switching power converters to avoid the instability caused by the interaction between a tightly controlled switching converter and an input low‐pass filter. The proposed method is based on the Lyapunov stability criterion. A non‐linearised model is established, and the instantaneous quantities of the state variables are considered. The switching command is formulated by calculating the stability of the system. The inductor current and voltage across the filter capacitor, along with the state variables in the switching converter, follow the corresponding references. A boost converter is considered to demonstrate the associated effectiveness. The results of several simulations and experiments pertaining to the start‐up, tracking, and regulation stages validate the proposed control approach. Moreover, the robustness of the approach against variations in the parameters of the controlled system is examined experimentally. To demonstrate the superiority of the proposed method, the method is compared with the proportional–integral, fuzzy, and flatness‐based controllers.
Robust current control scheme for single‐phase PWM rectifiers based on improved μ‐synthesis in electric locomotive
Authors: Liu Haoran , Ma Lei , Peng Lin , Song Wensheng , Cheng Shaokun
Published: February 2021

The parameter perturbation of grid‐side equivalent inductance is a significant feature of the uncertainty in the single‐phase pulse‐width modulation rectifiers system for the electric locomotive. This characteristic tends to reduce the robustness of the rectifier system. This study handles these problems in the framework of the structured singular value, which helps to reduce the influence of model parameter perturbation, caused by measurement error and operation condition change, on the robustness. However, the conventional μ‐synthesis robust controls only reflect tracking and anti‐disturbance performance by weighting functions and ignoring the dynamic response performance. Herein, a direct current control (DCC) scheme based on improved μ‐synthesis is proposed. A desired closed‐loop transfer function is introduced to the conventional μ‐synthesis control structure to ameliorate the performance of the dynamic response. Furthermore, considering the external disturbances on the system control output, a suitable weighting function is used to restrict the external disturbance. The input–output relationship of the generalised open‐loop plant can thus be constructed accordingly. The proposed control scheme is compared with the widely applied proportional–integral‐based DCC scheme and the conventional μ‐synthesis DCC scheme. Hardware‐in‐the‐loop experiment results show promising dynamic performance as well as stronger robustness against parameter perturbation and external disturbances.
Interleaved current‐auto‐balance high step‐down converter with coupled inductors
Authors: Nouri Tohid , Shaneh Mahdi
Published: February 2021

This study presents a current‐auto‐balance non‐isolated interleaved high step‐down converter with a coupled inductor. The proposed converter achieves low‐voltage gain by the turns ratio of the coupled inductor and capacitive voltage division which avoids low duty cycles. The voltage stress across the power MOSFETs is decreased and the voltage stress across the diodes is controlled by the turns ratio of the coupled inductors. Therefore, low voltage semiconductors are adopted reducing the switching and conduction losses. Meanwhile, the zero current switching (ZCS) turn‐ON for MOSFETs and ZCS for whole switching transitions of diodes are provided by the leakage inductances that reduces the switching losses and alleviates the reverse recovery problems. Besides, by replacing the inductors with the coupled ones, the power density is improved. Due to the interleaved structure, the output current ripple is minimised and the thermal stress is distributed between the phases. All of these factors improve the conversion efficiency and overall performance of the proposed converter. Moreover, the auto‐current‐sharing performance is realised due to the charge balance of the blocking capacitors. Finally, a 400 W prototype with 400–25 V voltage conversion is fabricated to demonstrate the performance of the proposed converter.
Direct current control strategy of LCL‐type converter for harmonic suppression under distorted grid condition
Authors: Wang Qi , Qin Wenping , Dai Wei , Han Xiaoqing , Wang Lei , Wang Peng
Published: February 2021

The grid voltage distortion represents a significant cause of the grid quality degradation when a renewable energy system is incorporated into the traditional grid. In this paper, a direct harmonic current control strategy is proposed for an LCL converter under distorted grid conditions. The proposed strategy improves the power quality and enhances the converter robustness under the non‐ideal grid conditions. Traditionally, in the harmonic suppression strategy, the capacitor current is commonly used as a harmonic information source to control and suppress harmonics, which not only realises active damping, but also provides harmonic current suppression. Unlike the existing technologies, the proposed strategy realises the closed‐loop control and harmonic current suppression by sampling the converter‐side current. The proposed strategy can achieve a more efficient harmonic suppression than the traditional methods without requiring additional sensors and hidden danger of resonance. The impedance characteristics of multi loops are analysed when a distorted voltage is applied to the LCL converter. Then, the corresponding control strategy is proposed. The similarities and differences in harmonic suppression and stability between the proposed strategy and the traditional strategies are presented and discussed. Finally, the effectiveness and feasibility of the proposed strategy are verified by the simulation and experimental results.
Integrated optimisation model for neutral section location planning and energy‐efficient train control in electrified railways
Authors: Miao Rui , Wu Chaoxian , Zhu Kuan , Xue Fei , Tian Zhongbei , Hillmansen Stuart , Roberts Clive , Lu Shaofeng
Published: February 2021

Discontinuously electrified sections, such as neutral sections (NSs) widely exist in modern electrified railways. As a special arrangement of insulator, NSs with no electricity supplies are set up to ensure the two sections are kept electrically separate. This paper proposes a distance‐based mixed‐integer linear programming (MILP) model to incorporate both NS location planning and energy‐efficient train control (EETC) problem and concurrently optimise the NS location and train speed trajectory. The main contribution of this study is that based on the proposed integrated model, a number of case studies are conducted to investigate on the impact mechanism of NS locations on the total energy consumption of train operations. The optimisation results show that the energy saving rate in comparison with the worst cases is ranging from 1.9% to 6.1%% in various scenarios and significant saving rate can be achieved via planning the NS to be located in coasting areas as determined by EETC. In conclusion, the energy‐saving effect of the optimal NS location planning on the total energy consumption largely depends on how the NS‐triggered forced coasting is located in the journey and NS locations near stations and switching areas of speed limit lead to significant energy increase for bi‐directional journeys.
Systematic literature review of photovoltaic output power forecasting
Authors: Başaran Kıvanç , Bozyiğit Fatma , Siano Pierluigi , Yıldırım Taşer Pelin , Kılınç Deniz
Published: February 2021

Since the harmful effects of climate warming on our planet were first observed, the use of renewable energy resources has been significantly increasing. Among the potential renewable energy sources, photovoltaic (PV) system installations keep continuously increasing world‐wide due to its economic and environmental contributions. Despite its significant benefits, the inherent variability of PV power generation due to meteorological parameters can cause power management/planning problems. Thus, forecasting of PV output data (directly or indirectly) in an accurate manner is a critical task to provide stability, reliability, and optimisation of the grid systems. In considering the literature reviewed, there are various research items utilizing PV output power forecasting. In this study, a systematic literature review based on the search of primary studies (published between 2010 and 2020), which forecast PV power generation using machine learning and deep learning methods, is reported. The studies are evaluated based on the PV material used, their approaches, generated outputs, data set used, and the performance evaluation methods. As a result, gaps and improvable points in the existing literature are revealed, and suggestions which include novelties are offered for future works.
Dynamic modelling and control for assessment of large‐scale wind and solar integration in power systems
Authors: Kyesswa Michael , Çakmak Hüseyin , Kühnapfel Uwe , Hagenmeyer Veit
Published: February 2021

The integration of variable and unpredictable renewable energy sources into the current power networks introduces considerable changes in system operations. This poses enormous threats to the stability of the power system. Hence, it is essential to analyse the necessary adjustments in operation strategies in preparation for increased amounts of variable generation in existing power systems. The present study describes the dynamic modelling and integration of solar photovoltaic and wind power generation systems into a transient stability analysis toolbox. In view of the inherent connection of renewable energy generators to the electrical network through converter systems, the main contribution in the present study is the development of high‐level control functions to model converter interfaces with reference to standard grid operation codes. The dynamic models and corresponding control functions are tested using a network representing the transmission grid of the Baden‐Württemberg state in Germany as part of the assessment process to analyse the capability of the control functions for grid stability support. The simulation results show that the proposed converter control functions can equip renewable energy generators with equivalent features from a functional point of view to those of synchronous generators.
Escherichia coli DH5α functionalised magnetite nanoparticles applied for the magnetic extraction of bacteriophages
Authors: Pacios‐Michelena Sandra , Rodríguez‐Herrera Raúl , Rincón‐Enríquez Gabriel , Ramos‐González Rodolfo , Flores‐Gallegos Adriana C. , Chávez‐González Mónica L. , Segura‐Ceniceros Elda P. , Ilyina Anna
Published: February 2021

The study presents the design of a magnetic nanosystem functionalised with Escherichia coli for bacteriophage isolation. The chitosan‐coated nanoparticles (C‐MNP) were synthesised by coprecipitation, then functionalised with E. coli cells. Different concentrations of C‐MNP and incubation times were tested. The immobilisation kinetics and adsorption isotherm were studied. The kinetics was described with the pseudo‐stationary state after 30 min. The isotherm was linearized in the Freundlich model. Thermogravimetric analysis verified the functionalisation of C‐MNP with E. coli. The complex was used for the extraction of coliphage, for the analysis of the effect of time and salt concentration on phage desorption, and phage extractions with the reuse of the magnetic nanosystem. Compared with traditional methods, an increase in the phage titre collected with the nanocomplex was achieved. The obtained results suggest that C‐MNP/E. coli nanosystem can be used at least three cycles for the phage extraction. The release of the phages from the nanosystem was sensitive to the salt concentration. The use of a designed nano‐bio complex allowed a rapid and efficient separation of the phages from the water sample under the application of an external magnetic field, and with the possibility of reusing the magnetic complex.
Solvothermal synthesis and characterisation of doped TiO2 nanocrystals for light scattering applications
Authors: Dubey Raghvendra S. , Pathan Habib.M. , Kale Bharat B. , Ambekar Jalindar D.
Published: February 2021

Mesoporous nanoparticles have a larger surface area and therefore, suitable for dye‐sensitised solar cells and photocatalytic applications. This Letter presents the analysis of solvothermal derived as‐prepared TiO2 and doped TiO2 nanocrystals by utilising acetone as the solvent. The as‐prepared and doped TiO2 nanoparticles endorsed the presence of anatase phase along with the slightly deviated diffraction peaks with the reduced crystallite size as a result of doping. Surface morphology analyses evidenced the mesoporous microspheres of nanoparticles, whereas the stoichiometry study exhibited the elementary peaks in the as‐prepared and doped samples. The estimated optical bandgaps are found to be 2.68, 2.92, 2.48 and 2.88 eV in accordance with the doped TiO2 with copper, tin, barium and zinc–magnesium as compared to 3.16 eV of TiO2. Doped samples evidenced the enhanced scattering capability, whereas tin and zinc–magnesium co‐doped samples demonstrated the highest diffuse reflectance in a broad wavelength range from 550 to 800 nm.
Study on preparation and structure of chrysanthemum‐shaped micron calcium carbonate based on inverse microemulsion
Authors: Zhao Tiaobin , Xu Chao , Ma Yitong , Zeng Yiwen , Wang Nong
Published: February 2021

In this Letter, new chrysanthemum‐shaped micrometre calcium carbonate was prepared by using CaCl2 aqueous solution + NH3H2O + CTAB + n‐butanol + n‐hexane inverse microemulsion system. Scanning electron microscope, X‐ray powder diffraction, and Fourier transform infrared spectroscopy were used to characterise the morphology and structure of the micron calcium carbonate. Further, the formation mechanism of chrysanthemum‐shaped micron calcium carbonate was discussed.
Friction measurement and motion state determination of a single polystyrene nanoparticle during manipulation
Authors: Ma Xiao , Wang Weiqi , Xie Guoxin , Guo Dan , Wen Shizhu
Published: February 2021

Over the past two decades, the manipulation of nanoparticles has attracted increasing attention. This process provides essential information about tribology, which is of great significance for the exploration of the origin of friction. However, the motion state of the nanoparticles during this process must first be determined. Furthermore, since the nanoparticles could slide, roll, or spin when manipulated by the probe of the atomic force microscope, it was difficult to distinguish whether the force measured in the experiments denoted sliding or rolling friction. In this Letter, considerable manipulation and friction measurement experiments were performed, while the theoretical rolling and sliding friction were calculated using the Double‐Hertz model. Furthermore, by comparing the theoretical calculations and experimental results, the motion state of the nanoparticle could be determined. Additionally, it was found that the critical rolling distance, which is essential for calculating rolling friction, decreases as the particle size increases.
Hybrid game approach‐based channel congestion control for the Internet of Vehicles
Authors: Amer Hayder M. , Al‐Kashoash Hayder , Ma Shuang , Khami Mohammed J. , Mihaylova Lyudmila
Published: February 2021

Communications between the Internet of Vehicles in smart cities helps increase the awareness and safety among drivers. However, the channel congestion problem is considered as a key challenge for the communication networks due to continuing collection and exchange of traffic information in dense environments. The channel congestion problem degrades the efficiency and reliability of the ad hoc network. Therefore, the adaptation of the data rate and power control is considered as one of the effective solutions to mitigate channel congestion. A new hybrid game transmission rate and power channel congestion control approach on the Internet of Vehicle networks where the nodes play as greedy opponents demanding high information rates with the maximum power level are developed. Furthermore, the existence of a Nash equilibrium, which is the optimal information rate and power transmission for every vehicle, is established. Simulation results demonstrate that the proposed approach enhances the network performance by an overall percentage of 42.27%, 43.94% and 47.66% regarding channel busy time, messages loss and data collision as compared with others. This increases the awareness and performance of the vehicular communication network.
Halo shapes constrained from a pure sample of central galaxies in KiDS-1000
Authors: Georgiou Christos , Hoekstra Henk , Kuijken Konrad , Bilicki Maciej , Dvornik Andrej , Erben Thomas , Giblin Benjamin , Heymans Catherine , Hildebrandt Hendrik , de Jong Jelte T. A. , Kannawadi Arun , Schneider Peter , Schrabback Tim , Shan Huan Yuan , Wright Angus H.
Published: February 2021

We present measurements of fh, the ratio of the aligned components of the projected halo and galaxy ellipticities, for a sample of central galaxies using weak gravitational lensing data from the Kilo-Degree Survey (KiDS). Using a lens galaxy shape estimation that is more sensitive to outer galaxy regions, we find fh = 0.50 ± 0.20 for our full sample and fh = 0.55 ± 0.19 for an intrinsically red sub-sample (that therefore has a higher stellar mass), rejecting the hypothesis that round halos and/or galaxies are not aligned with their parent halo at 2.5σ and 2.9σ, respectively. We quantify the 93.4% purity of our central galaxy sample using numerical simulations and overlapping spectroscopy from the Galaxy and Mass Assembly survey. This purity ensures that the interpretation of our measurements is not complicated by the presence of a significant fraction of satellite galaxies. Restricting our central galaxy ellipticity measurement to the inner isophotes, we find fh = 0.34 ± 0.17 for our red sub-sample, suggesting that the outer galaxy regions are more aligned with their dark matter halos than the inner regions. Our results are in agreement with previous studies and suggest that lower mass halos are rounder and/or less aligned with their host galaxy than samples of more massive galaxies, studied in galaxy groups and clusters.
Brandverletzungen auf Schiffen und Booten
Authors: Striepling Enno , Rudolf Klaus
Published: February 2021

Die Arbeitsunfälle an Bord von Seeschiffen wiesen mit durchschnittlich 28 % verbrannter Körperoberfläche im Vergleich zu den Freizeitunfällen mit 9 % die ausgedehnteren Verletzungen auf. Alle 19 Verletzten befanden sich im erwerbsfähigen Alter. Die Brandverletzungen ereigneten sich überwiegend im Maschinenraum bzw. bei Tätigkeiten am Motor. Der Rettungsweg vom Unfallort an Bord bis zum definitiv versorgenden Brandverletztenzentrum erforderte den Einsatz verschiedener Rettungsmittel, wie z. B. Rettungshubschrauber, Rettungskreuzer sowie landgestützter Rettungsmittel. Achtzehn Patienten haben die Brandverletzung mit einem guten funktionellen Ergebnis überlebt, ein Verletzter ist bei infauster Prognose verstorben. Voraussetzung für ein gutes Outcome ist eine suffiziente Erstversorgung an Bord, eine technisch gut ausgestattete Rettungskette und das Zusammenwirken von erstbehandelndem Krankenhaus und dem aufnehmenden Brandverletztenzentrum.
Kompressionsfraktur als Ursache für anhaltende Beschwerden im Bereich des thorakolumbalen Übergangs
Authors: Lackenbauer Wolfgang
Published: February 2021

Eine 79-jährige Patientin wird mit Schmerzen in der Lendenwirbelsäule zur Physiotherapie überwiesen. Die Patientin hat seit Jahren intermittierende Schmerzen in der Lendenwirbelsäule. Vor 6 Wochen stürzte die Patientin auf der Treppe direkt auf das Gesäß und mit dem Rücken gegen die Stufen. Im Unfallkrankenhaus werden 2 gebrochene Rippen diagnostiziert. Seit dem Unfall klagt die Patientin über ungewöhnlich starke und anhaltende Schmerzen in der Lendenwirbelsäule, die vom Hausarzt 6 Wochen lang mit Infusionen und Interferenzstrom therapiert werden. Zusätzlich wird eine Überweisung zur Physiotherapie ausgestellt. Bei der Untersuchung durch den Physiotherapeuten gibt die Patientin starke Schmerzen in der Lendenwirbelsäule, vor allem bei langem Gehen, Bücken und Sitzen, an. Bei der körperlichen Untersuchung fällt besonders die markante Druckempfindlichkeit im Bereich des 1. Lendenwirbels (LWK 1) auf. Laut Patientin wurde bis dato kein bildgebendes Verfahren an der Lendenwirbelsäule durchgeführt (nur vom Brustkorb im Unfallkrankenhaus). Auf Grund vorhandener Risikofaktoren für eine mögliche osteoporotische Fraktur der Wirbelsäule (Geschlecht weiblich, hohes Alter, signifikantes Trauma) wird die Patientin mit der Bitte um radiologische Abklärung zum Hausarzt zurückgeschickt. Eine anschließend durchgeführte Röntgenuntersuchung bestätigt den Verdacht des Therapeuten – eine Impressionsfraktur des LWK 1 wird diagnostiziert.
Reverse Anterolateral Drawer Test schneidet am besten ab
Authors: Vielitz Arne
Published: February 2021

Li Q, Tu Y, Chen J et al. Reverse Anterolateral Drawer Test Is More Sensitive and Accurate for Diagnosing Chronic Anterior Talofibular Ligament Injury. Knee Surg Sports Traumatol Arthrosc 2020; 28: 55–62. doi: 10.1007/s00167-019-05705-x
Keine Empfehlung für VBI Tests
Authors: Vielitz Arne
Published: February 2021

Hutting N, Kranenburg HAR, Kerry R. Yes, We Should Abandon Pre-Treatment Positional Testing of the Cervical Spine. Musculoskelet Sci Pract 2020; 49: 102181.
Alkylzirconocenes in Organic Synthesis: An Overview
Authors: Jiang Chao , Qi Xiangbing , Yang Chao
Published: February 2021

Organozirconium chemistry has found extensive applications in organic synthesis since its discovery in the last century. Alkyl­zirconocenes, which are easily generated by the hydrozirconation of alkenes with the Schwartz reagent, are widely utilized for carbon–carbon­ and carbon–heteroatom bond formation. This short review summarizes the progress to date on the applications alkylzirconocenes in organic synthesis.

1 Introduction

2 General Methods for Generating Alkylzirconocenes

3 Transformations of Alkylzirconocenes by Heteroatoms

4 Insertion of Unsaturated Groups into Alkylzirconocenes

5 Transmetalations

6 Cross-Coupling Reactions of Alkylzirconocenes

7 Photochemistry of Alkylzirconocenes

8 Bimetallic Reagents of Zirconium

9 Asymmetric Transformations

10 Applications of Alkylzirconocenes Generated from the Negishi Reagent

11 Conclusions and Outlook
The Value of OpenNotes for Pediatric Patients, Their Families and Impact on the Patient–Physician Relationship
Authors: Sarabu Chethan , Lee Tzielan , Hogan Adam , Pageler Natalie
Published: February 2021

Background OpenNotes, the sharing of medical notes via a patient portal, has been extensively studied in adults but not in pediatric populations. This has been a contributing factor in the slower adoption of OpenNotes by children's hospitals. The 21st Century Cures Act Final Rule has mandated the sharing of clinical notes electronically to all patients and as health systems prepare to comply, some concerns remain particularly with OpenNotes for pediatric populations.

Objectives After a gradual implementation of OpenNotes at an academic pediatric center, we sought to better understand how pediatric patients and families perceived OpenNotes. This article presents the detailed steps of this informatics-led rollout and patient survey results with a focus on pediatric-specific concerns.

Methods We adapted a previous OpenNotes survey used for adult populations to a pediatric outpatient setting (with parents of children <12 years old). The survey was sent to patients and families via a notification email sent as a standard practice after a clinic visit, in English or Spanish.

Results Approximately 7% of patients/families with access to OpenNotes read the note during the study period, and 159 (20%) of those patients responded to the survey. Of the survey respondents, 141 (89%) of patients and families understood their notes; 126 (80%) found the notes always or usually accurate; 24 (15%) contacted their clinicians after reading a note; and 153 (97%) patients/families felt the same or better about their doctor after reading the note.

Conclusion Although limited by relatively low survey response rate, OpenNotes was well-received by parents of pediatric patients without untoward consequences. The main concerns pediatricians raise about OpenNotes proved to not be issues in the pediatric population. Our results demonstrate clear benefits to adoption of OpenNotes. This provides reassurance that the transition to sharing notes with pediatric patients can be successful and value additive.
Apolipoprotein-E Gene Polymorphism and Lipid Composition among IUGR and AGA Neonates
Authors: Elangovan Bharathi , N.T Rajesh , Subrahmanian Meenu
Published: February 2021

Objective The objective of this study is to study the profile of apolipoprotein E (APOE) gene polymorphism and lipid profile among intrauterine growth restriction (IUGR) and appropriate for gestational age (AGA) neonates. This is an observational study. This study was done at the neonatal unit of a teaching hospital in South India. All consecutively born IUGR neonates (cases) of more than 32 weeks' gestational age and AGA neonates (controls) were enrolled for the study. Genomic DNA extraction was done from a total of 102 peripheral venous blood samples. Genotyping of the APOE rs429358 and rs7412 defining the ε2, ε3, and ε4 alleles was done by polymerase chain reaction–restriction fragment length polymorphism method. Prefeed venous blood was collected and analyzed for lipid profile estimation. The allelic frequencies of cases versus control were ε2—9 (8.7%) versus 3 (2.9%); ε3—88 (84.6%) versus 81 (79.4%); and ε4–7 (6.7%) versus 18 (17.6%). The frequency of ε4 isoform allele, associated with adult onset of metabolic diseases was less among the IUGR group. The mean total cholesterol (TC), Low-Density Lipoprotein (LDL), High-Density Lipoprotein, and triglyceride (TG) were 107.59 ± 35.99, 51.69 ± 24.68, 21.75 ± 9.58, and 151.22 ± 61.84 mg/dL, respectively, in the IUGR group. The mean TC and LDL levels in IUGR group were marginally higher than AGA neonates (107 ± 35.99 vs. 100.37 ± 22.69 mg/dL and 51.69 ± 24.68 versus 46.9 ± 19.51 mg/dL, p > 0.05). In both groups, the mean TC and TGL levels were elevated in the ε4 isoform subgroup (p > 0.05). In our study, the ε2 allele was the second most predominant APOE isoform and the ε4 allele of the APOE gene associated with adult-onset diseases was not increased among IUGR neonates. Neonates with ε4 allele showed an abnormal lipid profile in both study groups suggesting a possible association.
Validation of the Role of Thrombin Generation Potential by a Fully Automated System in the Identification of Breast Cancer Patients at High Risk of Disease Recurrence
Authors: Marchetti Marina , Gomez-Rosas Patricia , Pesenti Marina , Verzeroli Cristina , Giaccherini Cinzia , Russo Laura , Sarmiento Roberta , Masci Giovanna , Celio Luigi , Minelli Mauro , Gamba Sara , Tartari Carmen Julia , Tondini Carlo , Giuliani Francesco , Petrelli Fausto , D'Alessio Andrea , Gasparini Giampietro , Labianca Roberto , Santoro Armando , De Braud Filippo , Falanga Anna ,   on behalf of the HYPERCAN Investigators
Published: February 2021

Background The measurement of thrombin generation (TG) potential by the calibrated automated thrombogram (CAT) assay provides a strong contribution in identifying patients at high risk of early disease recurrence (E-DR). However, CAT assay still needs standardization and clinical validation.

Objective In this study, we aimed to validate the role of TG for E-DR prediction by means of the fully automated ST Genesia system.

Methods A prospective cohort of 522 patients from the HYPERCAN study with newly diagnosed resected high-risk breast cancer was included. Fifty-two healthy women acted as controls. Plasma samples were tested for protein C, free-protein S, and TG by ST Genesia by using the STG-ThromboScreen reagent with and without thrombomodulin (TM).

Results In the absence of TM, patients showed significantly higher peak and ETP compared with controls. In the presence of TM, significantly lower inhibition of ETP and Peak were observed in patients compared with controls. E-DR occurred in 28 patients; these patients had significantly higher peak and endogenous thrombin potential (ETP) in the absence of TM compared with disease-free patients. Multivariable analysis identified mastectomy, luminal B HER2-neg, triple negative subtypes, and ETP as independent risk factors for E-DR. These variables were combined to generate a risk assessment score, able to stratify patients in three-risk categories. The E-DR rates were 0, 4.7, and 13.5% in the low-, intermediate-, and high-risk categories (hazard ratio = 8.7; p < 0.05, low vs. high risk).

Conclusion Our data validate the ETP parameter with a fully automated standardized system and confirm its significant contribution in identifying high-risk early breast cancer at risk for E-DR during chemotherapy.
Selective Intra-Arterial Calcium Stimulation Venous Sampling Test for Preoperative Localization of Occult Neuroendocrine Tumors: Recall for an Old Technique
Authors: Patil Mangaladevi S. , Nezami Nariman , Bercu Zachary L. , Martin Louis G. , Dariushnia Sean R. , Xing Minzhi , Newsome Janice , Kokabi Nima
Published: February 2021

Background Surgical resection is the curative treatment for neuroendocrine tumors (NETs). Noninvasive imaging is unreliable in localizing NETs measuring less than 2 cm. This study investigates the safety and efficacy of the selective intra-arterial calcium stimulation venous sampling test (SACST) for preoperative localization of functional NETs within the pancreas.

Methods This retrospective analysis of the patients referred for localization of radiologically occult functional NETs from 2004 to 2019 was performed at a single institution. The technical success, diagnostic accuracy, and complications of the test were evaluated.

Results Twenty-three patients underwent SACST. The SACST was technically successful in 100% of the patients. Lesions were successfully localized in 19 (83%) patients. Tumor blush was seen in one patient. The mean ± standard deviation of maximal dimension of the resected tumor was 2.0 ± 1.9 cm. Sensitivity, specificity, positive predictive value, and negative predictive value of the SACST for localization of all lesions were 1.0, 0.57, 0.84, and 1.0, as well as 1.0, 0.57, 0.80, and 1.0 for insulinomas, respectively.

Conclusion SACST is a feasible, safe, well-tolerated, and effective procedure to preoperatively localize radiologically occult NETs within the pancreas.
Livestock indirectly decrease nest abundance of two shrub-nesting species in Patagonian Monte Desert
Authors: Tadey Mariana
Published: February 2021

Domestic livestock may indirectly affect bird species through changes in vegetation structure (e.g. cover), reducing the availability of food, nesting sites, refugia and, therefore, reproduction in many ecosystems worldwide. However, it remains unclear how the effect of livestock on vegetation structure can influence insectivorous birds that use shrubs for nest construction and placement rather than for feeding. Several species from the Furnariidae family inhabit Monte Desert, Argentina, exhibiting an extraordinary diversity in nest placement and structure that allows them to survive habitat aridity. Nest abundance and size of two common furnariid species, Pseudoseisura gutturalis and Leptasthenura aegithaloides, were studied across a cumulative livestock impact gradient (livestock impact by years grazed). These bird species use large, closed-nests (~40cm and ~100cm length, respectively) built with thorny branches placed on thorny shrubs. The study encompassed nine independent rangelands within the same habitat, but with increasing livestock density, establishing a gradient in grazing intensity. In each rangeland, nest abundance, nest and supporting plant characteristics, vegetation structure and the percentage of browsing were assessed. Plant cover was lower in rangelands with higher livestock impact, and this was associated with lower nest abundance and nest size. Nest abundance of L. aegithaloides was halved, whereas P. gutturalis was decreased 10-fold comparing the extremes of the livestock impact gradient (0.06 vs 1.63 cattle ha−1×years). Nests tended to be smaller and more spherical with increasing livestock impact. The significant and positive association between nest abundance and vegetation structure together with the importance of mating and reproduction for bird lifecycles suggests that the nest abundance of these species could be used as an indicator of habitat degradation. Therefore, furnariid nest abundance could be used as a first step for diagnosing ecosystem health and designing ecologically sustainable management practices in Monte Desert. Changes in vegetation structure (e.g. cover) such as those imposed by livestock may unpredictably affect plant-associated species affecting their reproduction, demography and ecosystem biodiversity.
Pest, weed and disease management.
Authors: Rees Paul A.
Published: February 2021

This chapter contains questions about pests and weeds and their control, invasive species, parasites, and animal and plant diseases. The questions are arranged by topic and divided into three levels: foundation, intermediate and advanced.
Global environmental change and biodiversity loss.
Authors: Rees Paul A.
Published: February 2021

This chapter contains questions about global warming, other aspects of environmental change and global biodiversity loss. The questions are arranged by topic and divided into three levels: foundation, intermediate and advanced.
cMyBP-C phosphorylation modulates the time-dependent slowing of unloaded shortening in murine skinned myocardium
Authors: Giles Jasmine , Fitzsimons Daniel P. , Patel Jitandrakumar R. , Knudtsen Chloe , Neuville Alexander J. , Moss Richard L.
Published: February 2021

In myocardium, phosphorylation of cardiac myosin-binding protein-C (cMyBP-C) is thought to modulate the cooperative activation of the thin filament by binding to myosin and/or actin, thereby regulating the probability of cross-bridge binding to actin. At low levels of Ca2+ activation, unloaded shortening velocity (Vo) in permeabilized cardiac muscle is comprised of an initial high-velocity phase and a subsequent low-velocity phase. The velocities in these phases scale with the level of activation, culminating in a single high-velocity phase (Vmax) at saturating Ca2+. To test the idea that cMyBP-C phosphorylation contributes to the activation dependence of Vo, we measured Vo before and following treatment with protein kinase A (PKA) in skinned trabecula isolated from mice expressing either wild-type cMyBP-C (tWT), nonphosphorylatable cMyBP-C (t3SA), or phosphomimetic cMyBP-C (t3SD). During maximal Ca2+ activation, Vmax was monophasic and not significantly different between the three groups. Although biphasic shortening was observed in all three groups at half-maximal activation under control conditions, the high- and low-velocity phases were faster in the t3SD myocardium compared with values obtained in either tWT or t3SA myocardium. Treatment with PKA significantly accelerated both the high- and low-velocity phases in tWT myocardium but had no effect on Vo in either the t3SD or t3SA myocardium. These results can be explained in terms of a model in which the level of cMyBP-C phosphorylation modulates the extent and rate of cooperative spread of myosin binding to actin.
A radiative type-II seesaw model with broken symmetry ansatz
Authors: Datta Satyabrata , Ghosal Ambar
Published: February 2021

Parametrization of the neutrino mass matrix in terms of well-known measured quantities is an attractive way to obtain a phenomenologically viable form. We propose a model of neutrino mass matrix based on type-II seesaw mechanism adhering the concept of badly broken symmetry. Two of the mixing angles are coming out as θ
23 ∼ 46.08°, θ
13 ∼ 8.69°. However, to accommodate the other oscillation parameters, we further add an extra doublet and the neutrino masses are generated through the Zee mechanism at the one loop level, and the modified model can admit all the extant data for a suitable choice of model parameters.
The use of dose quantities in radiological protection: ICRP publication 147 Ann ICRP 50(1) 2021
Authors: Harrison J D , Balonov M , Bochud F , Martin C J , Menzel H-G , Smith-Bindman R , Ortiz-López P , Simmonds J R , Wakeford R
Published: February 2021

The International Commission on Radiological Protection has recently published a report (ICRP Publication 147; Ann. ICRP
50, 2021) on the use of dose quantities in radiological protection, under the same authorship as this Memorandum. Here, we present a brief summary of the main elements of the report. ICRP Publication 147 consolidates and clarifies the explanations provided in the 2007 ICRP Recommendations (Publication 103) but reaches conclusions that go beyond those presented in Publication 103. Further guidance is provided on the scientific basis for the control of radiation risks using dose quantities in occupational, public and medical applications. It is emphasised that best estimates of risk to individuals will use organ/tissue absorbed doses, appropriate relative biological effectiveness factors and dose–risk models for specific health effects. However, bearing in mind uncertainties including those associated with risk projection to low doses or low dose rates, it is concluded that in the context of radiological protection, effective dose may be considered as an approximate indicator of possible risk of stochastic health effects following low-level exposure to ionising radiation. In this respect, it should also be recognised that lifetime cancer risks vary with age at exposure, sex and population group. The ICRP report also concludes that equivalent dose is not needed as a protection quantity. Dose limits for the avoidance of tissue reactions for the skin, hands and feet, and lens of the eye will be more appropriately set in terms of absorbed dose rather than equivalent dose.
One-dimensional heat-flow simulations using simple digital and analogue models
Authors: Atkin Keith
Published: February 2021

This paper shows how two distinct but related models can be used to bring out the essential physics of heat flow in one dimension. The first is a simple step-wise procedure using SMath Studio, while the second is an electric analogue using a basic RC ladder connected to an Arduino microcontroller. Both models can be demonstrated in real time within a lecture or teaching-laboratory environment. Differences and similarities of the two approaches are discussed.
Dynamic of the system in a periodic potential, submitted to an electromagnetic wave: Path integral approach
Authors: Issofa N , Kuetche C P F , Ateuafack M E , Fai L C
Published: February 2021

We introduced the formalism of path integrals to describe the dynamics of a system consisting of two particles. One is located in a periodic potential well (first subsystem), while the other particle is outside the well and subjected to a circular electromagnetic field (second subsystem). Thanks to this formalism, we are able to describe the dynamics of our system by a propagator which is the product of two subsystems of propagators. The propagator of the first subsystem is put in the standard form exp[Action] as a result of the coherent spin states. This form of propagator is possible by replacing the spin with a unit vector aligned along the polar and azimuthal directions. The second subsystem propagator come with the use of the Feynman-Vernon functional on the subsystem. Thanks to its two propagators, we have succeeded in explicitly and analytically evaluating the dynamics of our dissipative quantum system by a single propagator. Using this fundamental result, we evaluated the special case where the second subsystem bathed in a super-ohmic environment.
Insight into kerosene conveying CNTs and Fe3O4 nanoparticles through a porous medium: significance of Coriolis force and entropy generation
Authors: Ullah Ikram , Ali Rashid , Khan Ilyas , S. Nisar K.
Published: February 2021

Nanomaterials have advanced features due which it is more efficient in different areas like refrigerator, hybrid-power engine, engine cooling, pharmaceutical processes etc. Hybrid nanomaterials are significant for the improvement of heat transfer in the fluid. The aim of this study is to communicate irreversibility analysis in Dracy-Forchheimer flow of nanomaterials with hybrid nanoparticles/kerosene oil mixture. Xue’s and Hamilton-Crosser models are converted for hybrid empirical relations. Analysis of entropy is performed to estimate the disorder within the thermo-physical frame. The governing flow expressions have been converted to ODEs by dimensionless variables. The obtained system have been computed through NDSolve based Shooting scheme. Behavior of various parameters on different distributions are provided via tables and graphs. Further detailed assessment at the surface (skin friction and Nusselt number) is provided across various parameters. Our findings designates that temperature upgraded for both hybrid and nano phases against heat source parameter and Eckert number while a contrary trend is seen for temperature gradient. There is remarkable increase for hybrid nanofluid when compared with common nanoliquid. As a whole hybrid nanomaterials have great influence through out our analysis when compared with regular nanomaterials.