bluuebunny/crossref_metadata_2025_split huggingface dataset:
Improved mechanical and flame resistance properties of vinyl ester resin composites by lithium containing polyhedral oligomeric phenyl silsesquioxane
Authors: Zhang Xin , Geng Junming , Zhang Weiwei , Qian Lijun , Qin Zhaolu , Zhang Wenchao 
Published: August 2021

AbstractThe mechanical and flame retardancy properties of vinyl ester resin (VER) composites containing lithium containing polyhedral oligomeric phenyl silsesquioxane (Li‐Ph‐POSS) are investigated. The bending test suggests that Li‐Ph‐POSS improves the mechanical property of the matrix. Compared with the pure VER, the bending strength and flexural modulus are improved by 42.9% and 18.9% with the addition of 3 wt% Li‐Ph‐POSS, respectively. And cone calorimeter test results indicate that Li‐Ph‐POSS endows the matrix good fire resistance. Three weight percent Li‐Ph‐POSS makes the heat release rate (HRR) decline by 32.4% compared with the pure VER. Besides, 3 wt% Li‐Ph‐POSS performs best on smoke suppression and declines the release of CO due to good char‐forming effect of Li‐Ph‐POSS. The improvement of mechanical property and the slightly improved glass transition temperature (Tg) of VER composites confirmed the excellent compatibility between Li‐Ph‐POSS and the matrix. The flame retardant mechanism is revealed by Thermogravimetric coupled with Fourier transform infrared analysis, scanning electron microscopy, and X‐ray photoelectron spectroscopy analysis in detail. The work provides an optional method to prepare flame retarded VER with excellent mechanical properties.
Using multiple random index dates with the reverse waiting time distribution improves precision of estimated prescription durations
Authors: Bødkergaard Katrine , Selmer Randi Marie , Hallas Jesper , Kjerpeseth Lars Jøran , Skovlund Eva , Støvring Henrik 
Published: August 2021

AbstractPurposeTo improve the precision of prescription duration estimates when using the reverse waiting time distribution (rWTD).MethodsFor each patient we uniformly sampled multiple random index dates within a sampling window of length . For each index date, we identified the last preceding prescription redemption, if any, within distance . Based on all pairs of last prescription and index date, we estimated prescription durations using the rWTD with robust variance estimation. In simulation studies with increasing misspecification we investigated bias, root mean square error (RMSE) and coverage probability of the rWTD using multiple index dates (1, 5, 10, and 20). We applied the method to Danish data on warfarin prescriptions from 2013 to 2014 stratifying by and adjusting for sex and age.ResultsIn simulation scenarios without misspecification, the relative bias was negligible (−0.04% to 0.01%) and nominal coverage probabilities almost retained (93.8%–95.4%). RMSE decreased with the number of random index dates (e.g., from 1.3 with 1 index date to 0.6 days with 5). With misspecification, the relative bias was higher irrespective of the number of index dates. Precision increased with the number of index dates, and hence coverage probabilities decreased. When estimating durations of warfarin prescriptions in Denmark, precision increased with number of index dates, in particular in strata with few patients (e.g., men 90+ years: width of 95% confidence interval was 16.2 days with 5 index dates versus 35.4 with 1).ConclusionsIncreasing the number of random index dates used with the rWTD improved precision without affecting bias.
Aryl‐group substituted polysiloxanes with high‐optical transmission, thermal stability, and refractive index
Authors: Meier Dennis , Huch Volker , Kickelbick Guido 
Published: August 2021

AbstractPolysiloxanes are an important class of polymers for optoelectronic applications. Novel polysiloxanes with high‐refractive index (RI) based on phenanthrenyl‐substituted monomers are prepared by a polycondensation reaction starting from various substituted dialkoxysilanes as monomers. The substitution patterns on the Si atom are systematically changed to vary the properties of the linear polymers as well as the final cured material. The two monomers with polycyclic aromatic side groups 9‐phenanthrenylmethyldimethoxysilane and 9‐phenanthrenylphenyldimethoxysilane are synthesized and fully characterized, including their single crystal X‐ray structures. Linear polysiloxanes with variations in hydride, methyl, vinyl, phenyl, and phenanthrenyl side group content are prepared by acid‐ and base‐catalyzed polycondensation reactions. Both SiH and Si vinyl substituted polymers with molecular weights up to 30 kDa and adjustable RI's from 1.52 to 1.63 are obtained and the thermally cured by Pt‐catalyzed hydrosilylation reactions. Polysiloxane resins are obtained with high‐RI's, optical transmittance above 95% and thermal stabilities up to 420°C. Long‐term thermal stability tests show transmittance values above 85% even after 60 days of thermal treatment at 180°C.
Structural basis of bilin binding by the chlorophyll biosynthesis regulator GUN4
Authors: Hu Jiu‐Hui , Chang Jing‐Wen , Xu Tao , Wang Jia , Wang Xiao , Lin Rongcheng , Duanmu Deqiang , Liu Lin 
Published: August 2021

AbstractThe chlorophyll biosynthesis regulator GENOMES UNCOUPLED 4 (GUN4) is conserved in nearly all oxygenic photosynthetic organisms. Recently, GUN4 has been found to be able to bind the linear tetrapyrroles (bilins) and stimulate the magnesium chelatase activity in the unicellular green alga Chlamydomonas reinhardtii. Here, we characterize GUN4 proteins from Arabidopsis thaliana and the cyanobacterium Synechocystis sp. PCC 6803 for their ability to bind bilins, and present the crystal structures of Synechocystis GUN4 in biliverdin‐bound, phycocyanobilin‐bound, and phytochromobilin‐bound forms at the resolutions of 1.05, 1.10, and 1.70 Å, respectively. These linear molecules adopt a cyclic‐helical conformation, and bind more tightly than planar porphyrins to the tetrapyrrole‐binding pocket of GUN4. Based on structural comparison, we propose a working model of GUN4 in regulation of tetrapyrrole biosynthetic pathway, and address the role of the bilin‐bound GUN4 in retrograde signaling.
Modeling processive motion of kinesin‐13 MCAK and kinesin‐14 Cik1‐Kar3 molecular motors
Authors: Xie Ping 
Published: August 2021

AbstractKinesin‐13 MCAK, which is composed of two identical motor domains, can undergo unbiased one‐dimensional diffusion on microtubules. Kinesin‐14 Cik1‐Kar3, which is composed of a Kar3 motor domain and a Cik1 motor homology domain with no ATPase activity, can move processively toward the minus end of microtubules. Here, we present a model for the diffusion of MCAK homodimer and a model for the processive motion of Cik1‐Kar3 heterodimer. Although the two dimeric motors show different domain composition, in the models it is proposed that the two motors use the similar physical mechanism to move processively. With the models, the dynamics of the two dimers is studied analytically. The theoretical results for MCAK reproduce quantitatively the available experimental data about diffusion constant and lifetime of the motor bound to microtubule in different nucleotide states. The theoretical results for Cik1‐Kar3 reproduce quantitatively the available experimental data about load dependence of velocity and explain consistently the available experimental data about effects of the exchange and mutation of the motor homology domain on the velocity of the heterodimer. Moreover, predicted results for other aspects of the dynamics of the two dimers are provided.
A new catalytic mechanism of bacterial ferredoxin‐NADP+ reductases due to a particular NADP+ binding mode
Authors: Monchietti Paula , López Rivero Arleth S. , Ceccarelli Eduardo A. , Catalano‐Dupuy Daniela L. 
Published: August 2021

AbstractFerredoxin‐NADP+ reductases (FNRs) are ubiquitous flavoenzymes involved in redox metabolisms. FNRs catalyze the reversible electron transfer between NADP(H) and ferredoxin or flavodoxin. They are classified as plant‐ and mitochondrial‐type FNR. Plant‐type FNRs are divided into plastidic and bacterial classes. The plastidic FNRs show turnover numbers between 20 and 100 times higher than bacterial enzymes and these differences have been related to their physiological functions. We demonstrated that purified Escherichia coli FPR (EcFPR) contains tightly bound NADP+, which does not occur in plastidic type FNRs. The three‐dimensional structure of EcFPR evidenced that NADP+ interacts with three arginines (R144, R174, and R184) which could generate a very high affinity and structured site. These arginines are conserved in other bacterial FNRs but not in the plastidic enzymes. We have cross‐substituted EcFPR arginines with residues present in analogous positions in the Pisum sativum FNR (PsFNR) and replaced these amino acids by arginines in PsFNR. We analyzed all proteins by structural, kinetic, and stability studies. We found that EcFPR mutants do not contain bound NADP+ and showed increased Km for this nucleotide. The EcFPR activity was inhibited by NADP+ but this behavior disappeared as arginines were removed. A NADP+ analog of the nicotinamide portion produced an activating effect on EcFPR and promoted the NADP+ release. Our results give evidence for a new model of NADP+ binding and catalysis in bacterial FNRs.We propose that this tight NADP+ binding constitutes an essential catalytic and regulatory mechanism of bacterial FNRs involved in redox homeostasis.
The effect of French maritime pine bark extract supplementation on inflammation, nutritional and clinical status in critically ill patients with traumatic brain injury: A randomized controlled trial
Authors: Malekahmadi Mahsa , Shadnoush Mahdi , Islam Sheikh Mohammed Shariful , Shirvani Armin , Pahlavani Naseh , Gholizadeh Navashenaq Jamshid , Firouzi Safieh , McVicar Jenna , Nematy Mohsen , Zali Mohammad Reza , Moradi Moghaddam Omid , Norouzy Abdolreza 
Published: August 2021

Inflammation plays an important role in the pathophysiology of traumatic brain injury (TBI). Based on the anti‐inflammatory properties of French maritime pine bark extract and the neuroprotective effects, we aimed to evaluate the effects of its supplementation on TBI. Sixty‐seven TBI patients admitted to the intensive care units (ICUs) were enrolled. After stabilizing the hemodynamic status, the intervention group received 150 mg of French maritime pine bark extract supplementation (Oligopin) with enteral nutrition for 10 days. The control group received a placebo. Inflammatory status and oxidative stress markers were measured three times. Also, clinical and nutritional statuses were assessed. Supplementation, significantly decreased IL‐6 (β = −53.43 pg/ml, 95% confidence interval [CI] = −91.74, −15.13, p = .006), IL‐1β (β = −111.66 pg/ml, 95% CI = −183.79, −39.5402, p = .002) and C‐reactive protein (β = −19.99 mg/L, 95% CI = −27.23, −12.76, p ˃ .001) in the intervention group compared to control group after 10 days. Clinical scores including acute physiology and chronic health evaluation II and sequential organ failure assessment were reduced (β = −3.72, 95% CI = −5.96, −1.49, p = .001and β = −2.07, 95% CI = −3.23, −0.90, p < .001, respectively), and Nutric score was reduced compared to control group (β = −.60, 95% CI = −1.08, −0.12, p = .01). The survival rate was higher by 15% in the intervention group compared to control group. Oligopin supplementation in TBI patients in ICU reduced inflammation and improved the clinical status and malnutrition score and thereby reducing the mortality rate.
Guidance for characterization of in‐house reference materials for light element stable isotope analysis
Authors: Dunn Philip J. H. , Malinovsky Dmitry , Holcombe Gill , Cowen Simon , Goenaga‐Infante Heidi 
Published: August 2021

RationalePreparation of in‐house reference materials (RMs) is an important aspect of light element stable isotope analysis. While some relevant information is available, there is as yet no clear set of guidelines available covering all aspects of in‐house production and characterization of RMs.MethodsTo address this need, the experience of production of certified reference materials under accreditation to ISO 17034:2016 and ISO/IEC 17025:2017 has been distilled into guidance for production of in‐house RMs that are fit‐for‐purpose.ResultsThe guidance provided covers five areas: (i) planning; (ii) material considerations including preparation, packaging, and storage; (iii) measurements and assessments; (iv) value and uncertainty assignment; and (v) monitoring and use.ConclusionsIn‐house RMs prepared by following this guidance can be used to provide traceability to measurement results when used for normalization or for quality control and/or assurance purposes.
Developing an innovative method to control the probability density function shape of the state response for nonlinear stochastic systems
Authors: Wang Lingzhi , Xie Guo , Qian Fucai , Shangguan Anqi 
Published: August 2021

AbstractFor nonlinear stochastic systems, controlling low‐order moment indexes, such as mean and variance, may not effectively achieve actual control requirements since they do not reflect the complete statistical characteristics of random variables. Instead, the probability density function (PDF), which provides complete characterization of statistical properties, can be used to control each order moment more efficiently. Existing PDF shape control methods are mainly suited for nonlinear systems with polynomial forms, which leads to limitations in their applications. In this article, we propose a PDF shape control method using the Fokker–Planck–Kolmogorov (FPK) equation for nonlinear stochastic systems with arbitrary expression. In the proposed method, the exact stationary solution of the FPK equation is derived first. If the nonlinear function of the stochastic system is not polynomial, it is first converted into a polynomial form using the approximation method. The controller is then devised for PDF shape control, and the parameters of the controller are optimized to obtain the optimal controller. We conducted simulation experiments to validate the effectiveness of the proposed method. The results show that the proposed method can effectively control the PDF shape of the state response for nonlinear stochastic systems, regardless of whether the target PDF is unimodal, symmetric bimodal, or asymmetric bimodal. Compared with the Fourier transform method, the control effect of the proposed method is much better. The results suggest that the proposed method provides a scientific basis for wider applications of the PDF shape control method.
Stressors associated with the COVID‐19 pandemic, disability, and mental health: Considerations from the Intermountain West
Authors: Ciciurkaite Gabriele , Marquez‐Velarde Guadalupe , Brown Robyn Lewis 
Published: August 2021

AbstractThe deleterious mental health effects associated with the COVID‐19 pandemic are increasingly apparent, however, questions remain about the extent to which pandemic‐related stressor exposure has contributed to increased psychological distress among an already disadvantaged group, individuals with disabilities. The first aim of the study was to examine the distribution of pandemic‐related stressors across multiple dimensions—employment, personal and family finances, personal relationships, and quality of social life—among individuals with and without disabilities. The second aim of the study was to examine the association between a composite COVID‐19 stressor score and two mental health outcomes—depressive and anxiety symptoms—among the two subsamples. The study used quota‐based online survey data (N = 2043) collected in the summer of 2020 from adults (18 and older) residing in the Intermountain West, half of whom had a self‐reported disability. Study results demonstrated that individuals with disabilities experienced pandemic‐related stressors at significantly higher rates relative to their non‐disabled counterparts. Further, pandemic stressor exposure was associated with greater negative effects on their psychological well‐being. We argue that the COVID‐19 pandemic is generating a secondary mental illness pandemic, and that individuals with disabilities are affected by it at significantly higher proportions.
Simultaneously Enhancing Efficiency and Stability of Perovskite Solar Cells Through Crystal Cross‐Linking Using Fluorophenylboronic Acid
Authors: Li Mingguang , Gao Huan , Yu Longsheng , Tang Senlin , Peng Ying , Zheng Chao , Xu Ligang , Tao Ye , Chen Runfeng , Huang Wei 
Published: August 2021

AbstractOrganic‐inorganic metal halide perovskites are regarded as one of the most promising candidates in the photovoltaic field, but simultaneous realization of high efficiency and long‐term stability is still challenging. Here, a one‐step solution‐processing strategy is demonstrated for preparing efficient and stable inverted methylammonium lead iodide (MAPbI3) perovskite solar cells (PSCs) by incorporating a series of organic molecule dopants of fluorophenylboronic acids (F‐PBAs) into perovskite films. Studies have shown that the F‐PBA dopant acts as a cross‐linker between neighboring perovskite grains through hydrogen bonds and coordination bonds between F‐PBA and perovskite structures, yielding high‐quality perovskite crystalline films with both improved crystallinity and reduced defect densities. Benefiting from the repaired grain boundaries of MAPbI3 with the organic cross‐linker, the inverted PSCs exhibit a remarkably enhanced performance from 16.4% to approximately 20%. Meanwhile, the F‐PBA doped devices exhibit enhanced moisture/thermal/light stability, and specially retain 80% of their initial power conversion efficiencies after more than two weeks under AM 1.5G one‐sun illumination. This work highlights the impressive advantages of the perovskite crystal cross‐linking strategy using organic molecules with strong intermolecular interactions, providing an efficient route to prepare high‐performance and stable planar PSCs.
Weak Anchoring Sites of Thiolate‐Protected Luminescent Gold Nanoparticles
Authors: He Kui , Tan Yue , Zhao Zhipeng , Chen Huarui , Liu Jinbin 
Published: August 2021

AbstractSurface functionalization of gold nanoparticles (AuNPs) with thiolate ligands is a successful strategy for controlling their stability, nanotoxicity, circulation, and interaction with biological environments as leading nanomedicines. However, the effects of the weak anchoring groups of NH2 and COOH have been long‐term ignored because of the well‐recognized strong anchoring site of S–Au. Herein, the authors achieve controllable weak anchoring sites of the luminescent AuNPs using a typical thiolate peptide such as glutathione with anchoring groups of SH, COOH, and NH2. Additionally, they establish that not only the strong anchoring site of S–Au, but also the weak anchoring sites from N‐Au and COO–Au are critical to the behavior of AuNPs at both in vitro and in vivo levels. These results open up new possibilities for the fundamental understanding of the significance of the weak anchoring sites in the future surface functionalization of nanomedicines toward advanced theranostics.
Towards a data‐driven framework for optimizing security‐efficiency tradeoff in QUIC
Authors: Murthy Amith , Asghar Muhammad Rizwan , Tu Wanqing 
Published: August 2021

AbstractAdvances in computing and compression technology, coupled with high‐speed networks, has beaconed an era of video streaming on the Internet. This has led to a need to enhance the security of communications transporting data without degrading its performance. The transport layer security (TLS) protocol negotiates configurations for securing communication channels. Such conversations adversely impact latency, thereby presenting a fundamental tradeoff between security and efficiency. In this work, we present a conceptual framework, called SEC‐QUIC (Secure and Efficient Configurations for QUIC), that focuses on optimizing this tradeoff specifically for video transmissions by investigating various factors in Quick UDP Internet Connections (QUIC). Transport‐layer‐related elements, such as maximum transmission unit (MTU) sizes, cipher suites, and ACK timer, are examined to evaluate the impact on the security‐efficiency tradeoff in QUIC‐based video transmissions using platform‐based experiments. Subsequently, we develop a conceptual framework to leverage QUIC's dynamics based on the context of a connection to optimize the security‐efficiency tradeoff. Our findings demonstrate the need to alter default configurations based on the contextual factors of a connection (eg, resource constraints and network conditions) in QUIC‐based video transmissions to balance the tradeoff. Experiments reveal an MTU of 1400 bytes is found to have 60% better throughput compared to an MTU of 1200 bytes while also 4% less CPU usage on average for the transmission of 100 MB video files. Overall, our experiments suggest that fine‐tuning performance and security related configurations is an effective approach to optimizing the security‐efficiency tradeoff in video transmissions.
Residual mechanical properties of concrete containing lightweight expanded clay aggregate (LECA) after exposure to elevated temperatures
Authors: Dabbaghi Farshad , Dehestani Mehdi , Yousefpour Hossein 
Published: August 2021

AbstractThe mechanical properties of light‐weight concrete (LWC) in fire are known to be better than those of normal‐strength concrete (NSC), both at high temperature (hot properties) and after cooling (residual properties). The objective of this paper is to increase the knowledge of LWC's residual properties by testing a number of mixes containing expanded clay as light‐weight coarse aggregate. An experimental program was carried out, in which one normal‐weight concrete mix and two lightweight aggregate mixes containing different amounts of LECA were used to fabricate 72 concrete cylinders and 36 concrete prisms. All mixes contained silica fume as a supplementary cementitious material. The specimens were tested at the ambient temperature and after exposure to temperatures of 250, 500, and 750°C to obtain their compressive and tensile strength, modulus of elasticity, and stress–strain response. Results indicate that exposure to temperatures up to 250°C has no significant effect on the mechanical properties of concrete containing LECA just as in normal weight concrete. However, with increasing the temperature, increasing the lightweight aggregate content of the mix resulted in better strength retention after exposure to elevated temperatures. The experimental data are also used to develop equations to evaluate the residual mechanical properties of concrete.
Centering Language and Student Voice in Multilingual Literacy Instruction
Authors: Proctor C. Patrick , Silverman Rebecca D. , Jones Renata Love 
Published: August 2021

AbstractThe authors describe a 3‐year project to design and test a multilingual literacy curriculum that centers language and student voice in the service of literacy development for multilingual learners. In the first 2 years, researchers, teachers, and students worked together to develop the curriculum using design‐based, case study methods. In the third year, teachers participated in a quasi‐experimental implementation of the curriculum that showed positive effects on students’ language, reading, and writing outcomes. This longitudinal work reflects four broad principles for multilingual literacy instruction: (1) focus on language and metalinguistic awareness; (2) enact dialogic approaches to engage students; (3) use multimodal texts and scaffolds to support comprehension and expression; and (4) take a multilingual perspective. The authors provide an overview of the curriculum design process and the quasi‐experimental field trial. Then, each principle is theoretically and empirically unpacked, and instructionally described using qualitative data collected over the full 3 years.