bluuebunny/crossref_metadata_2025_split huggingface dataset:
Multiple imputation methods for handling incomplete longitudinal and clustered data where the target analysis is a linear mixed effects model
Authors: Huque Md Hamidul , Moreno‐Betancur Margarita , Quartagno Matteo , Simpson Julie A. , Carlin John B. , Lee Katherine J. 
Published: January 2020

AbstractMultiple imputation (MI) is increasingly popular for handling multivariate missing data. Two general approaches are available in standard computer packages: MI based on the posterior distribution of incomplete variables under a multivariate (joint) model, and fully conditional specification (FCS), which imputes missing values using univariate conditional distributions for each incomplete variable given all the others, cycling iteratively through the univariate imputation models. In the context of longitudinal or clustered data, it is not clear whether these approaches result in consistent estimates of regression coefficient and variance component parameters when the analysis model of interest is a linear mixed effects model (LMM) that includes both random intercepts and slopes with either covariates or both covariates and outcome contain missing information. In the current paper, we compared the performance of seven different MI methods for handling missing values in longitudinal and clustered data in the context of fitting LMMs with both random intercepts and slopes. We study the theoretical compatibility between specific imputation models fitted under each of these approaches and the LMM, and also conduct simulation studies in both the longitudinal and clustered data settings. Simulations were motivated by analyses of the association between body mass index (BMI) and quality of life (QoL) in the Longitudinal Study of Australian Children (LSAC). Our findings showed that the relative performance of MI methods vary according to whether the incomplete covariate has fixed or random effects and whether there is missingnesss in the outcome variable. We showed that compatible imputation and analysis models resulted in consistent estimation of both regression parameters and variance components via simulation. We illustrate our findings with the analysis of LSAC data.
Surgeons' posture and muscle strain during laparoscopic and robotic surgery
Authors: Dalager T , Jensen P T , Eriksen J R , Jakobsen H L , Mogensen O , Søgaard K 
Published: January 2020

Abstract

Background
It is assumed that conventional laparoscopy (LAP) and robotic-assisted laparoscopic surgery (RALS) differ in terms of the surgeon's comfort. This study compared muscle workload, work posture and perceived physical exertion of surgeons performing LAP or RALS.

Methods
Colorectal surgeons with experience in advanced LAP and RALS performed one of each operation. Bipolar surface electromyography (EMG) recordings were made from forearm, shoulder and neck muscles, and expressed relative to EMG maximum (%EMGmax). The static, median and peak levels of muscle activity were calculated, and an exposure variation analysis undertaken. Postural observations were carried out every 10 min, and ratings of perceived physical exertion before and after surgery were recorded.

Results
The study included 13 surgeons. Surgeons performing LAP showed higher static, median, and peak forearm muscle activity than those undertaking RALS. Muscle activity at peak level was higher during RALS than LAP. Exposure variation analysis demonstrated long-lasting periods of low-level intensity muscle activity in the shoulders for LAP, in the forearms for RALS, and in the neck for both procedures. Postural observations revealed a greater need for a change in work posture when performing LAP compared with RALS. Perceived physical exertion was no different between the surgical modalities.

Conclusion
Minimally invasive surgery requires long-term static muscle activity with a high physical workload for surgeons. RALS is less demanding on posture.
Pharmacokinetic effects of ginsenoside Rg1 on aconitine, benzoylaconine and aconine by UHPLC–MS/MS
Authors: Xu Yanwen , Yang Liang , Liang Kun , An Rui , Wang Xinhong , Zhang Hai 
Published: January 2020

AbstractGinseng and aconite are well‐known couplet medicinals. Ginsenoside Rg1 is the main active ingredient in ginseng, and aconitine (AC), benzoylaconine (BAC) and aconine (ACN) are three representative alkaloids in aconite, which belong to the diester alkaloids, monoester alkaloids and alkanolamine alkaloids respectively. The aim of this study was to investigate the pharmacokinetic effects of ginsenoside Rg1 on the three types of alkaloids and to provide evidences for their compatibility mechanism. In this study, the ginsenoside Rg1 was simultaneously intragastrically administered to rats with AC, BAC and ACN, respectively, and the rat plasma was collected at different time points. The plasma drug concentrations of the three types of alkaloids were determined by UHPLC–MS/MS, and the pharmacokinetic parameters were calculated. The results indicated that the peak concentration and area under the concentration–time curve of BAC were significantly increased (P < 0.05), those for AC were decreased (P < 0.05), and the values for ACN did not change after pretreatment with ginsenoside Rg1. It was inferred that ginsenoside Rg1 may affect the absorption and metabolism of AC and BAC and then change their pharmacokinetic parameters. Subsequently, their absorption and metabolism were further investigated using the Caco‐2 cell monolayer and rat liver microsomes in vitro. The Caco‐2 cell monolayer absorption assay indicated that ginsenoside Rg1 could promote the absorption of AC and BAC, and the rat liver microsomes metabolism assay indicated that ginsenoside Rg1 accelerated the metabolism of AC and did not affect the other two alkaloids. All of the results indicated that ginsenoside Rg1 may reduce the toxicity of aconite and improve its efficacy by promoting the absorption of BAC and accelerating the metabolism of AC. These results could provide evidence for the compatibility mechanism of the traditional Chinese herbal formula Shenfu Decoction.
Is the environment‐friendly factor attractive to customers when purchasing electric vehicles? Evidence from South Korea
Authors: Beak Yujin , Kim Kayoung , Maeng Kyuho , Cho Youngsang 
Published: January 2020

AbstractIn a bid to reduce greenhouse gas emissions, several countries worldwide are implementing policies to promote electric vehicles (EVs). However, contrary to expectations, the diffusion speed of EVs has been rather slow in South Korea. This study analyzes consumer preferences for the technological and environmental attributes of EVs and derives policy and environmental implications to promote market diffusion of EVs in South Korea. We conduct a choice‐based conjoint survey of 1,008 consumers in South Korea and estimate the consumer utility function using a mixed logit model considering consumer heterogeneity. Based on the consumer utility function, we analyze consumers' willingness‐to‐pay (WTP) for EV attributes such as driving range, charging method, charging time, autonomous driving function, carbon dioxide (CO2) reduction rate, and purchase price. The results indicate that the current low acceptance of EVs is due to their relatively high price and lack of a battery charging technology that satisfies consumers' expectations of the charging method and time. One interesting finding is that Korean consumers have a relatively higher WTP for the CO2 reduction rate of EVs than consumers in other countries; however, they do not consider CO2 reduction over other technological attributes when choosing EVs. This implies that the rate of CO2 reduction of EVs is not an important factor for South Korean consumers when buying EVs. We also calculate the effect of CO2 reduction with the market penetration of EVs and find that CO2 reduction through the diffusion of EVs depends on the country's electricity generation mix.
A Modified Arrhenius Approach to Thermodynamically Study Regioselectivity in Cytochrome P450‐Catalyzed Substrate Conversion
Authors: Luirink Rosa A. , Verkade‐Vreeker Marlies C. A. , Commandeur Jan N. M. , Geerke Daan P. 
Published: January 2020

AbstractThe regio‐ (and stereo‐)selectivity and specific activity of cytochrome P450s are determined by the accessibility of potential sites of metabolism (SOMs) of the bound substrate relative to the heme, and the activation barrier of the regioselective oxidation reaction(s). The accessibility of potential SOMs depends on the relative binding free energy (ΔΔGbind) of the catalytically active substrate‐binding poses, and the probability of the substrate to adopt a transition‐state geometry. An established experimental method to measure activation energies of enzymatic reactions is the analysis of reaction rate constants at different temperatures and the construction of Arrhenius plots. This is a challenge for multistep P450‐catalyzed processes that involve redox partners. We introduce a modified Arrhenius approach to overcome the limitations in studying P450 selectivity, which can be applied in multiproduct enzyme catalysis. Our approach gives combined information on relative activation energies, ΔΔGbind values, and collision entropies, yielding direct insight into the basis of selectivity in substrate conversion.
Late clinical outcomes of myocardial hybrid revascularization versus coronary artery bypass grafting for complex triple‐vessel disease: Long‐term follow‐up of the randomized MERGING clinical trial
Authors: Esteves Vinicius , Oliveira Marco A. P. , Feitosa Fernanda S. , Mariani José , Campos Carlos M. , Hajjar Ludhmila A. , Lisboa Luiz A. , Jatene Fabio B. , Filho Roberto K. , Lemos Neto Pedro A. 
Published: January 2020

AbstractObjectivesThis article aimed to compare the outcomes after hybrid revascularization with conventional coronary artery bypass grafting (CABG) surgery.BackgroundThe concept of hybrid coronary revascularization combines the advantages of CABG and percutaneous coronary intervention to improve the treatment of patients with complex multivessel disease.MethodsThe Myocardial hybrid revascularization versus coronary artERy bypass GraftING for complex triple‐vessel disease—MERGING study is a pilot randomized trial that allocated 60 patients with complex triple‐vessel disease to treatment with hybrid revascularization or conventional CABG (2:1 ratio). The primary outcome was the composite of all‐cause death, myocardial infarction, stroke, or unplanned repeat revascularization at 2 years.ResultsClinical and anatomical characteristics were similar between groups. After a mean follow‐up of 802 ± 500 days, the primary endpoint rate was 19.3% in the hybrid arm and 5.9% in the CABG arm (p = NS). The incidence of unplanned revascularization increased over time in both groups, reaching 14.5 versus 5.9% in the hybrid and in the CABG groups, respectively (p = .4). Of note, in the hybrid group, there were no reinterventions driven by the occurrence of stent restenosis.ConclusionsHybrid myocardial was feasible but associated with increasing rates of major adverse cardiovascular events during 2 years of clinical follow‐up, while the control group treated with conventional surgery presented with low rates of complications during the same period. In conclusion, before more definitive data arise, hybrid revascularization should be applied with careful attention in practice, following a selective case‐by‐case indication.
Transcatheter closure of coronary artery fistula: A 21‐year experience
Authors: El‐Sabawi Bassim , Al‐Hijji Mohammed A. , Eleid Mackram F. , Cabalka Allison K. , Ammash Naser M. , Dearani Joseph A. , Bjarnason Haraldur , Holmes David R. , Rihal Charanjit S. 
Published: January 2020

AbstractObjectivesTo evaluate the outcomes of transcatheter coronary artery fistula (CAF) closure and to identify anatomic/procedural factors that may impact outcomes.BackgroundDue to the rarity of CAF, reported experience with transcatheter closure remains limited and anatomic and procedural factors that may lead to unsuccessful closure, complications, or recanalization of CAF are unclear.MethodsAll patients who underwent transcatheter CAF closure at Mayo Clinic from 1997 to 2018 were retrospectively reviewed. CAF anatomic characteristics, procedural techniques, and clinical/angiographic outcomes were assessed.ResultsA total of 45 patients underwent transcatheter closure of 56 CAFs. The most commonly used devices were embolization coils in 40 (71.4%) CAFs, vascular occluders in 10 (17.8%), or covered stent in 2 (3.6%). Acute procedural success with no or trivial residual flow occurred in 50 (89.3%) CAFs. Residual flow was small in three (5.4%) and large in three (5.4%). Eight (17.8%) patients had complications, including device migration in three, intracranial hemorrhage from anticoagulation in one, and myocardial infarction (MI) in four. MI was a result of covered stent thrombosis or stagnation of flow after closure of large distal CAF. Twenty‐two patients with 27 CAFs had follow‐up angiography after successful index procedure at median time of 423 (IQ 97‐1348) days. Of these, 23 (85.2%) had no/trace flow and 4 had large flow from recanalization.ConclusionsTranscatheter CAF closure is associated with a favorable acute procedural success and complication rate in selected patients. Procedural success and risk for complication are highly dependent on CAF anatomy and closure technique.
Electroless Nanoplating of Pd−Pt Alloy Nanotube Networks: Catalysts with Full Compositional Control for the Methanol Oxidation Reaction
Authors: Stohr Tobias , Fischer Angelina , Muench Falk , Antoni Markus , Wollstadt Stephan , Lohaus Christian , Kunz Ulrike , Clemens Oliver , Klein Andreas , Ensinger Wolfgang 
Published: January 2020

AbstractDue to its simplicity, flexibility and conformity, electroless plating presents itself as an attractive route towards functional metal nanostructures. Despite the importance for creating multimetallic materials with enhanced properties, the complex interactions between the components in electroless plating baths make alloy formations a challenging objective. In this work, we outline an electroless plating strategy fabricating Pd−Pt alloy nanomaterials, which is based on arbitrarily miscible plating baths for the individual metals. To demonstrate the excellent nanoscale conformity and homogeneity of our plating system, we apply it to ion track‐etched polymer templates with large inner surfaces as ambitious substrates, resulting in the formation of 3D free‐standing PdxPt100‐x‐nanotube‐networks (NTNWs). Based on the electro‐oxidation of methanol as a model reaction, we utilize the compositional freedom provided by our syntheses for optimizing the catalytic performance of our metal NTNWs, which heavily depends on the Pd−Pt ratio. Within our system, the highest surface normalized activity was found for the Pd20Pt80 NTNW, reaching more than a two‐fold increase of the peak current density in comparison to pure Pt. Overall, our reaction system provides a versatile toolkit for fabricating intricate Pd−Pt nanostructures of arbitrary elemental composition, and constitutes a starting point for designing new electroless alloy plating baths.
Magnetism and Afterglow United: Synthesis of Novel Double Core–Shell Eu2+‐Doped Bifunctional Nanoparticles
Authors: Terraschke Huayna , Franzreb Matthias , Wickleder Claudia 
Published: January 2020

AbstractAfterglow–magnetic nanoparticles (NPs) offer enormous potential for bioimaging applications, as they can be manipulated by a magnetic field, as well as emitting light after irradiation with an excitation source, thus distinguishing themselves from fluorescent living cells. In this work, a novel double core–shell strategy is presented, uniting co‐precipitation with combustion synthesis routes to combine an Fe3O4 magnetic core (≈15 nm) with an afterglow SrAl2O4:Eu2+,Dy3+ outer coat (≈10 nm), and applying a SiO2 protective middle layer (≈16 nm) to reduce the luminescence quenching caused by the Fe core ions. The resulting Fe3O4@SiO2@SrAl2O4:Eu2+,Dy3+ NPs emit green light attributed to the 4f65d1→4f7(8S7/2) transition of Eu2+ under UV radiation and for a few seconds afterwards. This bifunctional nanocomposite can potentially be applied for the detection and separation of cells or diagnostically relevant molecules.
pH‐Dependent Hydration Change in a Gd‐Based MRI Contrast Agent with a Phosphonated Ligand
Authors: Charpentier Cyrille , Salaam Jérémy , Nonat Aline , Carniato Fabio , Jeannin Olivier , Brandariz Isabel , Esteban‐Gomez David , Platas‐Iglesias Carlos , Charbonnière Loïc J. , Botta Mauro 
Published: January 2020

AbstractThe heptadentate ligand L was shown to form an extremely stable Gd complex at neutral pH with a pGd value of 18.4 at pH 7.4. The X‐ray crystal structures of the complexes formed with Gd and Tb displayed two very different coordination behaviors being, respectively, octa‐ and nonacoordinated. The relaxometric properties of the Gd complex were studied by field‐dependent relaxivity measurements at various temperatures and by 17O NMR spectroscopy. The pH‐dependence of the longitudinal relaxivity profile indicated large changes around neutral pH leading to a very large value of 10.1 mm−1⋅s−1 (60 MHz, 298 K) at pH 4.7. The changes were attributed to an increase of the hydration number from one water molecule in basic conditions to two at acidic pH. A similar trend was observed for the luminescence of the Eu complex, confirming the change in hydration state. DOSY experiments were performed on the Lu analogue, pointing to the absence of dimers in solution in the considered pH range. A breathing mode of the complex was postulated, which was further supported by 1H and 31P NMR spectroscopy of the Yb complex at varying pH and was finally modeled by DFT calculations.
Sodium Bicyclo[1.1.1]pentanesulfinate: A Bench‐Stable Precursor for Bicyclo[1.1.1]pentylsulfones and Bicyclo‐ [1.1.1]pentanesulfonamides
Authors: Bär Robin M. , Gross Patrick J. , Nieger Martin , Bräse Stefan 
Published: January 2020

AbstractHerein, we present the synthesis of the bench‐stable sodium bicyclo[1.1.1]pentanesulfinate (BCP‐SO2Na) and its application in the synthesis of bicyclo[1.1.1]pentyl (BCP) sulfones and sulfonamides. The salt can be obtained in a four‐step procedure from commercially available precursors in multigram scale without the need for column chromatography or crystallization. Sulfinates are known to be useful precursors in radical and nucleophilic reactions and are widely used in medicinal chemistry. This building block enables access to BCP sulfones and sulfonamides avoiding the volatile [1.1.1]propellane which is favorable for the extension of SAR studies. Further, BCP‐SO2Na enables the synthesis of products that were not available with previous methods. A chlorination of BCP‐SO2Na and subsequent reaction with a Grignard reagent provides a new route to BCP sulfoxides. Several products were analyzed by single‐crystal X‐ray diffraction.
Experimental study on the influence of the orifice size on hydrodynamic characteristics and bubble size distribution of an external loop airlift reactor
Authors: Lu Xia , Zheng Xiaotao , Ding Yigang , Lin Wei , Wang Wei , Yu Jiuyang 
Published: January 2020

AbstractThe orifice size has a significant influence on hydrodynamic characteristics and bubble size distribution (BSD) in gas‐liquid flow. However, the mechanism of the influence of orifice size on BSD and hydrodynamic characteristics in an external loop airlift reactor (EL‐ALR) has not been fully revealed. In this work, the effects of the orifice size on hydrodynamic characteristics and BSD in a laboratory scale EL‐ALR were investigated using the particle image velocimetry (PIV) technique and digital image analysis (DIA). The results show that the transition superficial gas velocity becomes greater when the orifice size is reduced. The time‐averaged bubble velocity profiles along the riser radius are parabolic, and the shape of the time‐averaged bubble velocity curve is strongly dependent on the orifice diameter. The larger the orifice diameter, the steeper the parabolas. For sparger with lager orifice diameters, the BSD curve is bimodal even at low superficial gas velocity, and its peaks shift to a larger equivalent bubble diameter. The bubble aspect ratio appears to be related only to the equivalent diameter of the bubbles, regardless of the diameter of the orifice. It has a defined relationship between the bubble aspect ratio and the bubble equivalent diameter, and a new correlation is obtained based on the experimental data. This study will help to gain an understanding of the influence of sparger orifice size on the hydrodynamic characteristics and BSD and provide a basis for numerical simulation.
Metal‐Organic Sheets for Efficient Drug Delivery and Bioimaging
Authors: Song Yucong , Yang Jingjie , Wang Lei , Xie Zhigang 
Published: January 2020

AbstractMetal‐organic frameworks (MOFs) formed by coordination between metal ions or clusters and organic bridging ligands possess great potential for biomedicine applications, given their high biocompatibility and biodegradability. Compared with the traditional three‐dimensional (3D) MOFs, two‐dimensional (2D) MOFs with sheet‐like morphologies exhibit unique properties. In this study, a nanoscale 2D leaf‐shaped MOF (NZIF−L) was synthesized via coordination self‐assembly between 2‐methylimidazole (Hmim) and Zn2+ with subsequent morphology and size control. The fabricated NZIF−L is cytocompatible and can be quickly endocytosed, which makes it an excellent cargo carrier. Subsequent to loading with either doxorubicin (DOX) or 4,4′‐(1,2‐diphenylvinyl)‐1,2‐di‐(phenylcarboxylic acid) (TCPE), the respectively obtained DOX@NZIF−L and TCPE@NZIF−L showed promise for killing and imaging cancer cells.
Study of MHD dynamo effect at the outlet from plasma accelerator in the presence of longitudinal magnetic field
Authors: Kozlov Andrei N. 
Published: January 2020

AbstractProperties of compressible flows in the quasi‐stationary plasma accelerator have been studied in the presence of an additional longitudinal magnetic field and the arising rotation of plasma flow. Numerical study was carried out within the framework of two‐dimensional magnetic hydrodynamics (MHD) model of the axisymmetric plasma flows taking into account the finite conductivity of medium and radiation transport. Dynamics of compressible plasma flows is accompanied by the MHD dynamo effect or generation of magnetic field on a conical shock wave forming at the outlet from the accelerator.
Enhanced redesigned spatial modulation: Design and performance evaluation under correlated fading channels
Authors: Gudla Vishnu Vardhan , Kumaravelu Vinoth Babu 
Published: January 2020

SummarySpatial modulation techniques (SMTs) have emerged as promising multiple‐input and multiple‐output (MIMO) technology for fifth generation (5G) networks, which can achieve an appealing trade‐off between conflicting design objectives such as reliability, hardware cost, complexity, spectral efficiency, and energy efficiency. Most of the SMTs suffer from significant performance deterioration under correlated fading channels. In this paper, a novel spectral efficient SMT referred as enhanced redesigned spatial modulation (EReSM) is proposed, which is robust against adverse channel correlation effects. At any time instant, EReSM activates either one or two transmit antennas and employs a robust bits to antenna index mapping that ensures the selection of antenna subsets with maximum spatial separation to mitigate the effect of spatial correlation. EReSM also exploits phase rotation of transmitted symbols as an additional dimension to convey an extra information bit. The rotation angles used for bit mapping are optimized for various modulation schemes to maximize the minimum euclidean distance between the symbols. To analyze the performance, analytical upper bound expression for average bit error probability (ABEP) is derived for both uncorrelated and spatially correlated channel conditions. Monte Carlo simulation results substantiate the accuracy of the analytical results and also demonstrate that the proposed EReSM outperform conventional redesigned spatial modulation (ReSM) by at least 4 dB.