bluuebunny/crossref_metadata_2025_split huggingface dataset:
Electrophoretic separation of multiple chiral center analyte with a three cyclodextrins mixture
Authors: La Zuo , Danel Cécile , Grolaux Gaëlle , Charton Julie , Furman Christophe , Lipka Emmanuelle 
Published: March 2021

AbstractA capillary electrokinetic chromatography method (CEKC) was developed for complete stereoisomeric separation of a neutral, hydrophobic, multiple chiral center dihydropyridone analogue, a drug candidate proposed in type 2 diabetes treatment. A background electrolyte comprising three cyclodextrins was found to successfully separate the eight isomers. First an anionic cyclodextrin, the SBE‐β‐CD, was selected to allow the chiral separation of our neutral compound and partial resolutions of the eight isomers were obtained. Then, the effects of different parameters such as the nature and concentration of the other cyclodextrins added and pH of the buffer were examined. Finally, a triple CD‐system consisted of 15 mM SBE‐β‐CD plus 15 mM γ‐CD and 40 mM HP‐γ‐CD in a 50 mM borate background electrolyte at pH 10, was found to successfully separate the eight isomers. Last, the selectivity and limits of detection and quantification were evaluated for this optimized method.
Clustering Nuclear Magnetic Resonance: Machine learning assistive rapid two‐dimensional relaxometry mapping
Authors: Peng Weng Kung 
Published: March 2021

AbstractLow‐field nuclear magnetic resonance (NMR) relaxometry is an attractive approach from point‐of‐care testing medical diagnosis to in situ oil‐gas exploration. One of the problems, however, is the inherently long relaxation time of the (liquid) samples, (and hence low signal‐to‐noise ratio) which causes unnecessarily long repetition time. In this work, a new class of methodology is presented for rapid and accurate object classification using NMR relaxometry with the aid of machine learning. It is demonstrated that the sensitivity and specificity of the classification is substantially improved with higher order of (pseudo)‐dimensionality (e.g., 2D‐ or multi‐dimensional). This new methodology (termed as ‘Clustering NMR’) may be extremely useful for rapid and accurate object classification (in less than a minute) using low‐field NMR.
The effect of plasma treatment process on the electrical conductivity and coating fastness of silver nanoparticles functionalized aramid fiber paper
Authors: Li Guanglu , Sun Zhenhua , Gao Songwei , Wang Yawen , Chen Shaojuan , Ma Jianwei 
Published: March 2021

AbstractIn this study, electrically conductive meta‐aramid fiber paper (MAFP) was prepared by combining low‐temperature plasma treatment and electroless plating. The influence of various plasma treatment parameters including nozzle speed, plasma cycle time and nozzle height on the electrical conductivity, washing fastness and bending fastness of silver‐coated MAFP was investigated. The results show that low‐temperature plasma treatment etched the surface of meta‐aramid fiber and increased the oxygen content on the MAFP surface. The optimal plasma treatment condition is: nozzle speed of 1 m/min, plasma cycle time of 80%, and nozzle height of 4–5 cm. The electrical resistance of the silver‐plated MAFP pre‐treated under this condition reached as low as 0.15 Ω/sq. In addition, the silver‐plated MAFP maintained high electrical conductivity (sheet resistance below 0.5 Ω/sq) after five washing cycles and 1000 bending cycles.
Accumulation of Insensitive Munition Compounds in the Earthworm Eisenia andrei from Amended Soil: Methodological Considerations for Determination of Bioaccumulation Factors
Authors: Lotufo G.R. , Boyd R.E. , Harmon A.R. , Bednar A.J. , Smith J.C. , Simini M. , Sunahara G.I. , Hawari J. , Kuperman R.G. 
Published: March 2021

Abstract
The present study investigates the bioaccumulation of the insensitive munition compounds 2,4-dinitroanisole (DNAN) and 3-nitro-1,2,4-triazol-5-one (NTO), developed for future weapons systems to replace current munitions containing sensitive explosives. The earthworm Eisenia andrei was exposed to sublethal concentrations of DNAN or NTO amended in Sassafras sandy loam. Chemical analysis indicated that 2- and 4-amino-nitroanisole (2-ANAN and 4-ANAN, respectively) were formed in DNAN-amended soils. The SumDNAN (sum of DNAN, 2-ANAN, and 4-ANAN concentrations) in soil decreased by 40% during the 14-d exposure period. The SumDNAN in the earthworm body residue increased until day 3 and decreased thereafter. Between days 3 and 14, there was a 73% decrease in tissue uptake that was greater than the 23% decrease in the soil concentration, suggesting that the bioavailable fraction may have decreased over time. By day 14, the DNAN concentration accounted for only 45% of the SumDNAN soil concentration, indicating substantial DNAN transformation in the presence of earthworms. The highest bioaccumulation factor (BAF; the tissue-to-soil concentration ratio) was 6.2 ± 1.0 kg/kg (dry wt) on day 3 and decreased to 3.8 ± 0.8 kg/kg by day 14. Kinetic studies indicated a BAF of 2.3 kg/kg, based on the earthworm DNAN uptake rate of 2.0 ± 0.24 kg/kg/d, compared with the SumDNAN elimination rate of 0.87 d–1 (half-life = 0.79 d). The compound DNAN has a similar potential to bioaccumulate from soil compared with trinitrotoluene. The NTO concentration in amended soil decreased by 57% from the initial concentration (837 mg NTO/kg dry soil) during 14 d, likely due to the formation of unknown transformation products. The bioaccumulation of NTO was negligible (BAF ≤ 0.018 kg/kg dry wt). Environ Toxicol Chem 2021;40:1713–1725. © 2021 SETAC. This article has been contributed to by US Government employees and their work is in the public domain in the USA.
Tolerability of lithium: A naturalistic discontinuation study in older inpatients (≥60 years)
Authors: Flapper Marinke , van Melick Els , van Campen Jos , Schutter Natasja , Kok Rob 
Published: March 2021

AbstractObjectivesLithium is one of the most effective treatment options in both bipolar disorder and treatment‐resistant depression. The use of lithium in older patients declined during the last decades, probably resulting in undertreatment of older patients. To investigate how well lithium is tolerated in old age, we aimed to determine the frequency, reasons, and possible predictors of discontinuation due to adverse effects in a cohort of inpatients ≥60 years who had started with lithium.MethodsWe performed a retrospective cohort study based on chart reviews. Participants were in treatment at Parnassia Group at The Hague, The Netherlands. After inclusion (between January 2010 and December 2016), participants were followed until April 2017, when we performed data extraction and analysis.ResultsIn our sample of 135 patients (median age 69 years, median follow‐up duration 18 months), 49 (36.3%) participants discontinued lithium. Only a minority (11 [8.1%]) of the participants discontinued solely due to adverse effects. The majority discontinued lithium due to psychiatric (18, 5%) reasons (most commonly mentioned within this subgroup: lack of effectiveness and noncompliance) or a combination of reasons (7.4%). None of the factors we studied (age, gender, Charlson Comorbidity Index, polypharmacy, renal function, and neurological history) were significantly associated with discontinuation due to adverse effects.ConclusionsThe frequency of lithium discontinuation in our cohort was in range with frequencies reported in younger patients. Older age itself should not be a reason to withhold lithium treatment.
Global health and innovation: A panoramic view on health human resources in the COVID‐19 pandemic context
Authors: Denis Jean Louis , Côté Nancy , Fleury Charles , Currie Graeme , Spyridonidis Dimitrios 
Published: March 2021

AbstractWhile policy‐makers in many jurisdictions are paying increasing attention to health workforce issues, human resources remain at best only partially aligned with population health needs. This paper explores the governance of human resources during the pandemic, looking at the Quebec health system as a revelatory case. We identify three issues related to health human resource (HHR) policies: working conditions, recognition at work and scope of practice. We empirically probe these issues based on an analysis of popular media, policy reports and participant observation by the lead authors in various forums and research projects. Using an integrated model of HHR, we identify major vulnerabilities in this domain. Persistent labour shortages, endemic deficiencies in working environments and inequity across occupational categories limit the ability to address critical HHR issues. We propose three ways to eliminate HHR vulnerabilities: reorganize work through participatory initiatives, implement joint policy making to rebalance power across the health workforce, and invest in the development of capacities at all system levels.
The effect of combined exposure of zinc and nickel on the development of zebrafish
Authors: Yang Yongmeng , Yu Yue , Zhou Rong , Yang Yan , Bu Yuanqing 
Published: March 2021

AbstractExcessive accumulation of Zn2+ or Ni2+ can cause various problems to aquatic animals. In this study, the developmental toxicity induced by individual or combined exposure of Zn2+ and Ni2+ to zebrafish embryos and larvae were evaluated to better understand the interaction between Zn2+ and Ni2+. Both of individual and combined exposure of Zn2+ and Ni2+ could cause obvious developmental toxicity, which mainly occurred after hatching, at a concentration‐dependent manner. The calculated 168‐h LC50 were 2.79 mg/L for Zn2+ and 7.44 mg/L for Ni2+. The interaction of Zn2+ and Ni2+ based on mortality was found to be an antagonism. Various malformations, including tail curving, spinal curvature, pericardial edema, and yolk sac edema, were observed with significant effects on body length and heartbeat rates after exposure of Zn2+ and Ni2+. Meanwhile, some genes related to cardiovascular development and bone formation were mainly down‐regulated by the individual and combined exposure of Zn2+ and Ni2+. The individual exposure was more toxic than combined exposure because the interaction of Zn2+ and Ni2+ was determined to be an antagonism. The down‐regulation of genes related to cardiovascular development and bone formation may contribute to the observed malformation and decreases of body length and heartbeat rates.
The impact of free returns on online purchase behavior: Evidence from an intervention at an online retailer
Authors: Patel Pankaj C. , Baldauf Christoph , Karlsson Stefan , Oghazi Pejvak 
Published: March 2021

AbstractWhether free returns create economic value for online retailers is a question of increasing importance. Using order‐level data from an online fashion retailer in Sweden, we investigate the introduction of free returns for customers in Denmark starting November 1, 2017, but not for customers in Sweden, Norway, Finland, France, Germany, and the rest of Europe (the control group). Using difference‐in‐differences, with and without sample matching, the introduction of free returns increased the order bill by 54.95 Swedish Krona (SEK) (9.15%), product variety per order by 0.057 (8.74%), gross margin per order by 29.90 SEK (9.71%), and returns by 0.195 items per order (7.86%). This likelihood of increased returns was generally similar across different product categories. The findings are robust to parallel trends, event studies, placebo effects, alternative control groups (with Scandinavian countries, Sweden and Norway), country‐time trends, and correlations between outcome variables. Based on back‐of‐the‐envelope calculations, the cost of offering free returns is greater than the increase in gross profit driven by free returns. Though our results show that free returns may not be of short‐term benefit, retailers must also consider the long‐term strategic implications of free returns.
Nanoencapsulation in low‐molecular‐weight chitosan improves in vivo antioxidant potential of black carrot anthocyanin
Authors: Chatterjee Niladri Sekhar , Dara Pavan Kumar , Perumcherry Raman Sreerekha , Vijayan Divya K , Sadasivam Jayashree , Mathew Suseela , Ravishankar Chandragiri Nagarajarao , Anandan Rangasamy 
Published: March 2021

AbstractBACKGROUNDAnthocyanins are flavonoids that are potential antioxidant, anti‐inflammatory, anti‐obesity, and anti‐carcinogenic nutraceutical ingredients. However, low chemical stability and low bioavailability limit the use of anthocyanins in food. Nanoencapsulation using biopolymers is a recent successful strategy for stabilization of anthocyanins. This study reports the development, characterization, and antioxidant activity of black carrot anthocyanin‐loaded chitosan nanoparticles (ACNPs).RESULTSThe ionic gelation technique yielded the ACNPs. The mean hydrodynamic diameter d and polydispersity index PDI of chitosan nanoparticles and ACNPs were found to be d = 455 nm and PDI = 0.542 respectively for chitosan nanoparticles and d = 274 nm and PDI = 0.376 respectively for ACNPs. The size distribution was bimodal. The surface topography revealed that the ACNPs are spherical and display a coacervate structure. Fourier transform infrared analysis revealed physicochemical interactions of anthocyanins with chitosan. The loading process could achieve an encapsulation efficiency of 70%. The flow behavior index η of encapsulated ACNPs samples revealed Newtonian and shear thickening characteristics. There was a marginal reduction in the in vitro antioxidant potential of anthocyanins after nanoencapsulation, as evidenced from 2,2‐diphenyl‐1‐picrylhydrazyl, ferric reducing antioxidant power, and 2,2′‐azino‐bis(3‐ethylbenzothiazoline‐6‐sulfonic acid) assays. Interestingly, the in vivo antioxidant potential of anthocyanins improved following nanoencapsulation, as observed in the serum antioxidant assays.CONCLUSIONThe optimized nanoencapsulation process resulted in spherical nanoparticles with appreciable encapsulation efficiency. The nanoencapsulation process improved the in vivo antioxidant activity of anthocyanins, indicating enhanced stability and bioavailability. The promising antioxidant activity of the ACNPs suggests a potential for utilization as a nutraceutical supplement. © 2021 Society of Chemical Industry.
Verification of data in a nationwide transanal total mesorectal excision registry in China
Authors: An Yong‐Bo , Yao Hong‐Wei , Yang Xuan‐Hua , Zhang Xiao , Zhang Zhong‐Tao 
Published: March 2021

AbstractBackground and ObjectivesTransanal total mesorectal excision is a surgical procedure for mid‐ and low rectal cancer. The Chinese TaTME Registry Collaborative is a nationwide database collecting information on patients who have undergone this procedure.MethodsCenters were invited by the registry committee to participate in a three‐part data audit project: remote audits for data completeness and deviation values, onsite source verification of data accuracy, and an online survey of the characteristics of data managers.ResultsTwenty‐three tertiary centers participated in this project. The median case volume registered by the centers was 51 (interquartile range, 25–89). The overall data completeness for 30 verified variables was 89.1%. Eight centers achieved a high data completeness rate (>95%). The source data of eight centers were verified onsite. The overall accuracy rate was 90.4% (85.3%–97.6% across centers). Postoperative complications, mortality, and proximal/distal resection margin involvement were accurately reported in >95% of cases. The data completeness rate was higher if the data manager was a surgeon/surgical resident (94.2% vs. 84.8%, p = 0.045).ConclusionsThe completeness and accuracy of the data in the Chinese TaTME Registry Collaborative are acceptable. The quality of the data is highest when entered by colorectal surgeons and residents.
Vestibular Impairments on Objective Diagnostic Tests in HIV+ Women and Control Men and Women
Authors: Cohen Helen S. , Plankey Michael W. , Sangi‐Haghpeykar Haleh 
Published: March 2021

ObjectiveTo describe the value of two vestibular test batteries across ages in healthy men and women for detecting vestibular disorders and to compare the occurrence of vestibular disorders in the healthy adult population and women with human immunodeficiency virus (HIV) disease.Study DesignTwo groups were tested on the battery of objective diagnostic tests of the vestibular system.SettingTwo tertiary care centers.SubjectsHealthy controls (284 women and 105 men) and women (63) with HIV/AIDS (HIV+) who are being followed up in a longitudinal study of HIV. They were tested on objective diagnostic tests of the vestibular system.ResultsIn all age decades, healthy controls had evidence of vestibular impairment, significantly more in older adults. HIV+ subjects, all females, did not differ from healthy control females.ConclusionThese data suggest that at all ages, people do have decreased vestibular function, even young, asymptomatic, and apparently healthy adults. HIV disease, itself, does not cause an increased prevalence of peripheral vestibular disorders when HIV is controlled on antiretroviral medication.Level of Evidence2 Laryngoscope, 131:E2318–E2322, 2021
Moisture‐Resistant and Mechanically Strong Polyimide‐Polymethylsilsesquioxane Hybrid Aerogels with Tunable Microstructure
Authors: Xi Shuang , Wang Xiaodong , Liu Ting , Zhang Ze , Zhang Xiaoxue , Shen Jun 
Published: March 2021

AbstractMoisture‐resistant and mechanically strong polyimide (PI)‐polymethylsilsesquioxane hybrid aerogels with doubly cross‐linked structures are synthesized through sol–gel technology and supercritical CO2 fluid drying. By using bis(trimethoxysilylpropyl) amine as a cross‐linker, the end‐capped polyamide acid derived from biphenyl‐3,3′,4,4′‐tetracarboxylic dianhydride and 4,4′‐oxydianiline is cross‐linked with a silica network using methyltrimethoxysilane as the silica source precursor. The resultant hybrid aerogels show low density (0.12–0.15 g cm−3), low thermal conductivity (0.032–0.049 W m−1 K−1), high hydrophobicity (125–140°) and good thermal stability (above 435 °C) with tunable microstructure. With the increase of silica sol volume, the microstructure of hybrid aerogels transforms from fibrous network to hierarchical microstructure. Aerogels with high content of silica sol exhibit good moisture resistance, high Young's modulus (Max. 19.6 MPa), and high specific modulus (Max. 131 kN m kg−1), which are attributed to their unique hierarchical microstructure with a sheet skeleton. These hybrid aerogels are promising in the fields of thermal insulation, aerospace applications and so on.
A Practical and Efficient Synthesis of Uniform Conjugated Rod‐Like Oligomers
Authors: Hahn Daniel , Schneider Rebekka V. , Foitzik Elena , Meier Michael A. R. 
Published: March 2021

AbstractHerein, a more practical and efficient synthesis protocol for the preparation of uniform rod‐like oligo(1,4‐phenylene ethynylene)s (OPE)s is presented. Applying an iterative reaction cycle consisting of a decarboxylative coupling reaction and a saponification of an alkynyl carboxylic ester, a uniform pentamer is obtained in ten steps with 14% overall yield. The copper‐free conditions prevent homocoupling until the trimer stage, resulting in a significantly easier work‐up of the products. Homocoupling is observed from the tetramer stage on, but a simple variation of the work‐up procedure also yields the uniform tetramer and pentamer. A thorough comparison with the commonly used and described Sonogashira approach reveals that with the new presented strategy, OPEs can be built in similar overall yield, but easier purification and in a quarter of the time. All oligomers are fully characterized by proton and carbon nuclear magnetic resonance spectroscopy (NMR), mass spectrometry (MS), size‐exclusion chromatography (SEC), and infrared spectroscopy (IR).
A Highly Selective Polymer Material using Benzo‐9‐Crown‐3 for the Extraction of Lithium in Presence of Other Interfering Alkali Metal Ions
Authors: Oral Iklima , Abetz Volker 
Published: March 2021

AbstractThe recovery of lithium from global water resources continues to be challenging due to interfering metal ions with similar solution properties. Hence, a lithium‐selective diblock copolymer system containing crown ethers (CEs) is developed. A polystyrene‐block‐poly(methacrylic acid) diblock copolymer is synthesized first via a one‐pot solution–emulsion reversible addition–fragmentation chain transfer polymerization. A subsequent Steglich esterification yields the CE functionalized polymer. The complexation properties with different alkali metals are first investigated by liquid−liquid extraction (LLE) in dichloromethane (DCM) − water systems using free benzo‐9‐crown (B9C3), benzo‐12‐crown‐4 (B12C4), and benzo‐15‐crown‐5 (B15C5) CEs as reference components, followed by the correspondingly CE‐functionalized polymers. Extraction complexation constants in the aqueous phase are determined and the impact of the complexation constants on the extractability is estimated. The B9C3 CE is especially appealing since it has the smallest cavity size among all CEs. It is too small to complex sodium or potassium ions; however, it forms sandwich complexes with a lithium‐ion resulting in extraordinary complexation constants in polymer systems avoiding other interfering alkali metal ions. On this basis, a new material for the efficient extraction of lithium ion traces in global water resources is established.
Ring‐Opening Metathesis Polymerization of Norbornene‐Based Monomers Obtained via the Passerini Three Component Reaction
Authors: Barther Dennis , Moatsou Dafni 
Published: March 2021

AbstractRing‐opening metathesis polymerization is a robust method to synthesize a variety of polymers by using ring‐strained molecules as monomers, e.g., norbornenes. However, the synthesis of monomers with multiple functional groups remains a challenge, albeit peptide functional norbornenes have previously been used. Here, the Passerini three component reaction is exploited to synthesize norbornenes with two variable functional groups varying in bulkiness and distance from the polymerizable alkene. The results indicate that the functional groups do not affect the kinetics of the polymerization, whereas the length of the linker has a minor effect. Furthermore, a diblock‐type copolymer is synthesized in a one‐pot fashion, also indicating good control of the polymerization process. The thermal properties of all polymers are evaluated, highlighting the effect of monomer composition. This synthetic approach can be transferred to a variety of compounds, thus promising highly diverse polymers with complex compositions and architectures.
Synthesis of Polymers Bearing a Chiral Backbone via Stereospecific Ionic Ring‐Opening Polymerization of Chiral Donor‐Acceptor Cyclopropanes
Authors: Emmerich Alexis , Daniliuc Constantin G. , Studer Armido 
Published: March 2021

AbstractThe stereospecific ionic ring‐opening polymerization of various donor‐acceptor cyclopropanes is reported. The chiral cyclopropane monomers are readily prepared with established methodology and stereospecific polymerization is best conducted with a catalytic amount of MgBr2 serving as a Lewis acid and as an initiator. Polymers with molecular masses of up to 7800 g mol−1 containing a stereocenter in every repeating unit are obtained and the substituents of the monomers can be readily varied to access a novel class of chiral polymers.