bluuebunny/crossref_metadata_2025 huggingface dataset:
An Esterase‐like Lyase Catalyzes Acetate Elimination in Spirotetronate/Spirotetramate Biosynthesis
Authors: Lees Nicholas R. , Han Li‐Chen , Byrne Matthew J. , Davies Jonathan A. , Parnell Alice E. , Moreland Pollyanna E. J. , Stach James E. M. , van der Kamp Marc W. , Willis Christine L. , Race Paul R.
Published: January 2019

Spirotetronate and spirotetramate natural products include a multitude of compounds with potent antimicrobial and antitumor activities. Their biosynthesis incorporates many unusual biocatalytic steps, including regio‐ and stereo‐specific modifications, cyclizations promoted by Diels–Alderases, and acetylation‐elimination reactions. Here we focus on the acetate elimination catalyzed by AbyA5, implicated in the formation of the key Diels–Alder substrate to give the spirocyclic system of the antibiotic abyssomicin C. Using synthetic substrate analogues, it is shown that AbyA5 catalyzes stereospecific acetate elimination, establishing the (R)‐tetronate acetate as a biosynthetic intermediate. The X‐ray crystal structure of AbyA5, the first of an acetate‐eliminating enzyme, reveals a deviant acetyl esterase fold. Molecular dynamics simulations and enzyme assays show the use of a His‐Ser dyad to catalyze either elimination or hydrolysis, via disparate mechanisms, under substrate control.
Intracellular Localization of an Osmocenyl‐Tamoxifen Derivative in Breast Cancer Cells Revealed by Synchrotron Radiation X‐ray Fluorescence Nanoimaging
Authors: Fus Florin , Yang Yang , Lee Hui Zhi Shirley , Top Siden , Carriere Marie , Bouron Alexandre , Pacureanu Alexandra , da Silva Julio Cesar , Salmain Michèle , Vessières Anne , Cloetens Peter , Jaouen Gérard , Bohic Sylvain
Published: January 2019

A series of tamoxifen‐like metallocifens of the group‐8 metals (Fe, Ru, and Os) has strong antiproliferative activity on the triple‐negative breast cancer cells (MDA‐MB‐231). To shed light on the mechanism of action of these molecules, synchrotron radiation X‐ray fluorescence nanoimaging studies were performed on cells exposed to osmocenyl‐tamoxifen (Oc‐OH‐Tam) to disclose its intracellular distribution. High‐resolution mapping of the lipophilic Oc‐OH‐Tam in cells revealed its preferential accumulation in the endomembrane system. This is consistent with the ability of the amino nitrogen chain of the compounds to be protonated at physiological pH and responsible for electrostatic interactions between Oc‐OH‐Tam and membranes. A comprehensive scenario is proposed that provides new insight into the cellular behavior and activation of Oc‐OH‐Tam and advances the understanding of its mechanism of action.
Air‐Stable, Lead‐Free Zero‐Dimensional Mixed Bismuth‐Antimony Perovskite Single Crystals with Ultra‐broadband Emission
Authors: Zhang Ruiling , Mao Xin , Yang Yang , Yang Songqiu , Zhao Wenyuan , Wumaier Tuerdi , Wei Donghui , Deng Weiqiao , Han Keli
Published: January 2019

Lead‐free zero‐dimensional (0D) organic‐inorganic metal halide perovskites have recently attracted increasing attention for their excellent photoluminescence properties and chemical stability. Here, we report the synthesis and characterization of an air‐stable 0D mixed metal halide perovskite (C8NH12)4Bi0.57Sb0.43Br7⋅H2O, in which individual [BiBr6]3− and [SbBr6]3− octahedral units are completely isolated and surrounded by the large organic cation C8H12N+. Upon photoexcitation, the bulk crystals exhibit ultra‐broadband emission ranging from 400 to 850 nm, which originates from both free excitons and self‐trapped excitons. This is the first example of 0D perovskites with broadband emission spanning the entire visible spectrum. In addition, (C8NH12)4Bi0.57Sb0.43Br7⋅H2O exhibits excellent humidity and light stability. These findings present a new direction towards the design of environmentally‐friendly, high‐performance 0D perovskite light emitters.
Ruthenium‐Catalyzed ortho C−H Borylation of Arylphosphines
Authors: Fukuda Kazuishi , Iwasawa Nobuharu , Takaya Jun
Published: January 2019

Efficient, phosphine‐directed ortho C−H borylation of arylphosphine derivatives was achieved using Ru catalysts for the first time. The reaction is applicable to various tertiary arylphosphine and arylphosphinite derivatives to give (o‐borylaryl)phosphorus compounds in high yields. This reaction enables easy access to a variety of functionalized phosphine ligands and ambiphilic phosphine boronate compounds, thus realizing a new late‐stage modification of phosphorus compounds.
Copper‐Catalyzed Enantioselective Construction of Tertiary Propargylic Sulfones
Authors: Gómez José Enrique , Cristòfol Àlex , Kleij Arjan W.
Published: January 2019

Tertiary propargylic sulfones are of significant importance in organic synthesis and medicinal chemistry, but to date no general asymmetric synthesis approach has been developed. We disclose a versatile copper‐catalyzed sulfonylation of propargylic cyclic carbonates using sodium sulfinates that allows the construction of propargylic sulfones featuring elusive quaternary stereocenters. This method provides the first successful example of such an enantioselective propargylic sulfonylation, features high asymmetric induction, wide functional group tolerance, and scalability, and enables attractive product diversification.
An Integrated CO2 Electrolyzer and Formate Fuel Cell Enabled by a Reversibly Restructuring Pb–Pd Bimetallic Catalyst
Authors: Lu Xu , Wu Yueshen , Yuan Xiaolei , Wang Hailiang
Published: January 2019

A single device combining the functions of a CO2 electrolyzer and a formate fuel cell is a new option for carbon‐neutral energy storage but entails rapid, reversible and stable interconversion between CO2 and formate over a single catalyst electrode. We report a new catalyst with such functionalities based on a Pb–Pd alloy system that reversibly restructures its phase, composition, and morphology and thus alters its catalytic properties under controlled electrochemical conditions. Under cathodic conditions, the catalyst is relatively Pb‐rich and is active for CO2‐to‐formate conversion over a wide potential range; under anodic conditions, it becomes relatively Pd‐rich and gains stable catalytic activity for formate‐to‐CO2 conversion. The bifunctional activity and superior durability of our Pb–Pd catalyst leads to the first proof‐of‐concept demonstration of an electrochemical cell that can switch between the CO2 electrolyzer/formate fuel cell modes and can stably operate for 12 days.
Chromium complexes based on thiophene–imine ligands for ethylene oligomerization
Authors: Ferreira Jorge , Zilz Raquel , Boeira Igor S. , da Silva Sabrina M. , Casagrande Adriana C.A. , Casagrande Osvaldo L.
Published: January 2019

A new set of Cr(III) complexes, {L}CrCl3(THF), based on thiophene–imine (2a, L = PhOC6H4(N═CH)‐2‐SC4H3; 2b, L = PhOC2H4(N═CH)‐2‐SC4H3; 2c, L = Ph(NH)C2H4(N═CH)‐2‐SC4H3; 2d, L = PhOC6H4(N═CH)‐2‐SC4H2‐5‐Ph; 2e, L = Ph(NH)C2H4(N═CH)‐2‐SC4H2‐5‐Ph) have been prepared and characterized using elemental analysis and infrared spectroscopy. Upon activation with methylaluminoxane, all the chromium complexes generated active systems affording a nonselective distribution of α‐olefins with turnover frequencies in the range 9500–93 500 (mol ethylene) (mol Cr)−1 h−1, and producing mostly oligomers (95.0–99.3 wt% of total products). Small amounts of polymer were produced in these oligomerization reactions (0.8–8.2 wt%). The catalytic activities were quite sensitive to the ligand environment. Moreover, the effects of oligomerization parameters (temperature, [Al]/[Cr] molar ratio, time) on the activity and on the product distribution were examined.
Palladacycles bearing COOH‐/ester‐functionalized N‐heterocyclic carbenes: Divergent syntheses and catalytic applications
Authors: Hu Yanyan , Guo Shuai
Published: January 2019

Two new [C^N]‐type palladacyclic dinuclear complexes bearing carboxylate‐containing N‐heterocyclic carbenes (NHCs) were synthesized, and in both cases the carboxylato‐NHC ligand adopts a bridging mode. Both complexes proved to be suitable precursors, which can be used to divergently access palladacycles bearing ester‐ or COOH‐functionalized NHCs upon esterification or acidolysis. In the esterification reactions, alkyl halides are found to selectively react with the carboxylato moieties, and the palladacycle scaffold is retained even when excess haloalkane is employed. In the acidolysis reactions, the desired COOH‐tethered complexes can only be obtained when stoichiometric acid (with respect to Pd) is used, while excess acid destroys the metallacycle scaffold. Finally, a preliminary catalytic study reveals the good performances of all newly synthesized complexes in direct aromatic C─H functionalization reactions with alkynes. Poisoning experiments indicate that these hydroarylation reactions are likely to be homogeneously catalyzed.
Oxidation of sulfides including DBT using a new vanadyl complex of a non‐innocent o‐aminophenol benzoxazole based ligand
Authors: Saeedi Roonak , Safaei Elham , Lee Yong‐Ill , Lužnik Janez
Published: January 2019

Reaction of a non‐innocent o‐aminophenol benzoxazole based ligand HLBAP with VOCl3 afforded a vanadyl complex, VOLBIS (SQ), in which SQ is a 2,4‐di‐tert‐butylsemiquinone produced from hydrolysis of HLBAP. The crystal structure of VOLBIS (SQ) exhibits an octahedral geometry with the VO2+ center coordinated by two nitrogen and one oxygen atoms of LBAP and two oxygen atoms of SQ. Electrochemical studies showed quasi‐reversible metal‐centered reduction and ligand‐centered oxidation of complex. The magnetic moment of VOLBIS (SQ) is consistent with the spin‐only value expected for S = 1/2 system. The neutral species of VOLBIS (SQ) is EPR active, which is consistent with a paramagnetic electronic ground state (S = 1/2). This result is in accordance with the vanadyl (IV) moiety surrounded by tridentate iminobenzosemiquinonate anion radical (HLBIS)•‐ and benzosemiquinone ligand (SQ)•. The theoretical calculations confirm the experimental results. Furthermore, we present the optimal conditions for maximum efficiency of sulfide oxidation for oxidative desulfurization with hydrogen peroxide and 6 times reusability of catalyst for sulfoxidation of dibenzothiophene.
Impact of thermal processing or solvent casting upon crystallization of PLA nanocellulose and/or nanoclay composites
Authors: Trifol J. , van Drongelen M. , Clegg F. , Plackett D. , Szabo P. , Daugaard A. E.
Published: January 2019

Here, we present how processing (solvent casting or isothermal crystallization) impacts crystallinity of poly(lactic acid) (PLA) and its nanocomposites (PLA/1 wt % cellulose nanofibers (CNFs), PLA/1 wt % nanoclay (C30B) or PLA/1 wt % CNF/1 wt % C30B. Polarized optical microscopy demonstrated a heterogeneous nucleation process during isothermal crystallization leading to smaller homogeneously distributed spherulites. With solvent casting, no effect on morphology was observed with respect to the nanoparticles, but an increased spherulite size was observed at higher temperatures. This fact raises significant concerns regarding the suitability of solvent casting as a lab‐scale procedure to investigate materials. Additionally, combining the reinforcing agents, CNF, and C30B, did not increase nucleation rate, in contrast with the general tendency, where the incorporation of both particles led to improved properties (e.g., thermomechanical and barrier properties). However, a combination of C30B and CNF did lead to an overall increase in the rigid amorphous fraction and a reduced mobile amorphous fraction. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47486.
Polyurethane‐based poly (ionic liquid)s for CO2 removal from natural gas
Authors: Bernard Franciele L. , dos Santos Leonardo M. , Schwab Marina B. , Polesso Barbara B. , do Nascimento Jailton F. , Einloft Sandra
Published: January 2019

Carbon dioxide separation from CH4 is important to the environment and natural gas processing. Poly (ionic liquid)s (PILs) based on polyurethane structures are considered as potential materials for CO2 capture. Thus, a series of anionic PILs based on polyurethane were synthesized. The effects of polyol chemical structure and counter‐cations (imidazolium, phosphonium, ammonium, and pyridinium) in CO2 sorption capacity and CO2/CH4 separation performance were evaluated. The synthesized PILs were characterized by NMR, DSC, TGA, dinamical mechanical thermo analysis (DMTA), SEM, and AFM. CO2 sorption, reusability, and CO2/CH4 selectivity were assessed by the pressure‐decay technique. The counter‐cation and polyol chemical structure play an important role in CO2 sorption and CO2/CH4 selectivity. PILs exhibited competitive thermal mechanical properties. Results showed that PILPC‐TBP was the best poly (ionic liquid) for CO2/CH4 separation. Moreover, poly (liquid ionic) base polyol (polycarbonate) with phosphonium (PILPC‐TBP) demonstrated higher CO2 sorption capacity (21.4 mgCO2/g at 303.15 K and 0.08 MPa) as compared to other reported poly (ionic liquids). © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47536.
Associations of Symptomatic Knee Osteoarthritis With Histopathologic Features in Subchondral Bone
Authors: Aso Koji , Shahtaheri S. Mohsen , Hill Roger , Wilson Deborah , McWilliams Daniel F. , Walsh David A.
Published: January 2019

Objective

Subchondral bone and the osteochondral junction are thought to contribute to osteoarthritis (OA) knee pain. We undertook this study to identify osteochondral pathologies specifically associated with symptomatic human knee OA.

Methods

Medial tibial plateau samples from 2 groups of subjects (n = 31 per group) were matched for macroscopic chondropathy scores. The symptomatic chondropathy group had undergone total knee replacement for OA knee pain, at which time specimens of the medial tibial plateau were obtained. The asymptomatic chondropathy group included subjects who died of unrelated illness (specimens were obtained at postmortem examination) and who had not previously sought help for knee pain. OA histopathology, immunoreactivity for nerve growth factor (NGF) and CD68 (macrophages), tartrate‐resistant acid phosphatase–positive subchondral osteoclasts, and synovitis were compared between groups.

Results

Mankin scores, subchondral bone density, and subchondral CD68‐immunoreactive macrophage infiltration were similar between the 2 groups. NGF‐like immunoreactivity was found in subchondral mononuclear cells and osteoclasts, as well as in chondrocytes. NGF in osteochondral channels and osteoclast densities in subchondral bone were higher in the symptomatic chondropathy group than in the asymptomatic chondropathy group (P < 0.01 and P = 0.02, respectively), as were synovitis scores (P < 0.01). Osteochondral pathology was not significantly associated with synovitis score. The differences in NGF expression and in osteoclast density remained significant after adjustment for age and synovitis score (P = 0.01 and P = 0.04, respectively). Osteochondral NGF and osteoclast densities, together with synovitis scores, explained ~28% of sample allocation to symptomatic or asymptomatic groups.

Conclusion

Subchondral pathology was associated with symptomatic knee OA, independent of chondropathy and synovitis. Increased NGF expression in osteochondral channels and increased osteoclast density appear to be key features associated with bone pain in knee OA.
No Association of Discontinuing Tumor Necrosis Factor Inhibitors Before Gestational Week Twenty in Well‐Controlled Rheumatoid Arthritis and Juvenile Idiopathic Arthritis With a Disease Worsening in Late Pregnancy
Authors: Förger Frauke , Bandoli Gretchen , Luo Yunjun , Robinson Loan , Johnson Diana L. , Chambers Christina D.
Published: January 2019

Objective

To investigate whether the discontinuation of tumor necrosis factor inhibitors (TNFi) during pregnancy is associated with any changes of the disease course in women with rheumatoid arthritis (RA) and juvenile idiopathic arthritis (JIA).

Methods

Pregnant women with RA and JIA from the US and Canada were enrolled in the Organization of Teratology Information Specialists (OTIS) Autoimmune Diseases in Pregnancy Project, a prospective cohort study. Information about medication and disease activity (patient‐reported outcome measures) was collected prior to gestational week 20 and at gestational week 32. Associations between patterns of TNFi continuation or discontinuation and disease activity changes were tested in unadjusted and multivariate analyses.

Results

Among 490 women (397 with RA, 93 with JIA) enrolled between 2005 and 2017, 122 (24.9%) discontinued a TNFi before gestational week 20, 201 (41.0%) received a TNFi beyond week 20, and 167 (34.1%) did not receive a TNFi during pregnancy. At the time of enrollment, disease activity was low to minimal in 72.9% of women. TNFi discontinuation was not associated with a clinically important worsening of patient reported outcome measures at the third trimester. Univariate but not multivariate analysis showed that women receiving TNFi beyond week 20 were more likely to experience improved disease activity scores at the third trimester.

Conclusion

Discontinuing TNFi before gestational week 20 seems feasible in women with RA and JIA who enter pregnancy with well‐controlled disease.
Characterisation of N‐(Octadecyl)‐1,8‐naphthalimide Monolayer Compression Using Molecular Dynamics and Experimental Approaches
Authors: Welsh Ivan D. , Draper Daria , Kim Jaehwan , Kitchen Jonathan A. , Allison Jane R.
Published: January 2019

The development of luminescent surfaces is an active area of supramolecular chemistry, particularly for the development of new sensing platforms. One particularly useful surface deposition method is the Langmuir–Blodgett technique where organic amphiphilic fluorophores (e.g. 1,8‐naphthalimides) can form ordered monolayers at an air–water interface before being deposited onto solid supports. The ability to simulate monolayer formation and consequently develop predictability over film formation would allow for significant advances in the luminescent materials field where synthesis might be directed by simulation data. Here, we compare pressure‐area isotherms of N‐(octadecyl)‐1,8‐naphthalimide determined experimentally, using the Langmuir–Blodgett technique, and computationally, using three different simulation techniques. We find that all three simulation techniques are able to describe the liquid‐condensed/liquid‐expanded region of the isotherm, and that the isotherms are highly similar in this region, although the NγT ensemble performs best. Experimental isotherms showed film formation properties that align with the simulation data, suggesting that simulations are a viable means to direct synthesis. Investigation of the underlying structural details disclosed by the simulations reveals the compression‐induced ordering at atomic‐level detail, which will allow prediction of how functionalisation of the naphthalimides will alter the monolayer compression and mounting process.
An undergraduate laboratory experience using CRISPR‐cas9 technology to deactivate green fluorescent protein expression in Escherichia coli
Authors: Pieczynski Jay N. , Deets Amber , McDuffee Alexis , Lynn Kee H.
Published: January 2019

Undergraduates learn that gene editing in diverse organisms is now possible. How targeted manipulation of genes and genomes is utilized in basic science and biomedicine to address biological questions is challenging for undergraduates to conceptualize. Thus, we developed a lab experience that would allow students to be actively engaged in the full process of design, implementation of a gene editing strategy, and interpretation of results within an 8‐week lab period of a Genetics course. The laboratory experience combines two transformative biotechnology tools; the utilization of green fluorescent protein (GFP) as a diagnostic marker of gene expression and the fundamentals and specificity of Clustered Regularly Interspaced Short Palindromic Repeats‐cas9 (CRISPR‐cas9) gene editing in bacterial cells. The students designed and constructed plasmids that express single guide RNA targeted to GFP, expressed the sgRNA and cas9 in bacteria cells, and successfully deactivated GFP gene expression in the bacterial cells with their designed CRISPR‐cas9 tools. Student assessment revealed most students achieved student learning objectives. We conclude this lab experience is an effective and accessible method for engaging students in the scientific practices, knowledge and challenges revolving targeted CRISPR‐cas9 gene manipulation. © 2019 International Union of Biochemistry and Molecular Biology, 47(2): 145–155, 2019.
An improved ultra‐high‐performance liquid chromatography–tandem mass spectrometric method for the quantitation of dexmedetomidine in small volume of pediatric plasma
Authors: Moorthy Ganesh S. , Vedar Christina , Moorthy Ahila S. , Prodell Janice L. , Zuppa Athena F.
Published: January 2019

Dexmedetomidine (Dex), a highly selective α2‐adrenergic agonist, is used primarily for the sedation and anxiolysis of adults and children in the intensive care setting. A sensitive and selective assay for Dex in pediatric plasma was developed by employing ultra‐high‐performance liquid chromatography–tandem mass spectrometry with d4‐Dex as an internal standard. Dex was extracted from 0.1 mL of plasma by micro‐elution solid‐phase extraction. Separation was achieved with a Waters XBridge C18 column with a flow rate of 0.3 mL/min using a mobile phase comprising 5 mm ammonium acetate buffer with 0.03% formic acid in water and methanol–acetonitrile (50:50, v/v). The intra‐day precision (coefficient of variation) and accuracy for quality control samples ranged from 1.32 to 8.91% and from 92.8 to 108%, respectively. The inter‐day precision and accuracy ranged from 2.13 to 8.45% and from 97.0 to 104%, respectively. The analytical method showed excellent sensitivity using a small sample volume (0.1 mL) with a lower limit of quantitation of 5 pg/mL. This method is robust and has been successfully employed in a pharmacokinetic study of Dex in neonates and infants postoperative from cardiac surgery.
Quantitative analysis of enasidenib in dried blood spots of mouse blood using an increased‐sensitivity LC–MS/MS method: Application to a pharmacokinetic study
Authors: Dittakavi Sreekanth , Jat Rakesh Kumar , Mullangi Ramesh
Published: January 2019

A simple, sensitive and rapid assay method has been developed and validated as per regulatory guidelines for the estimation of enasidenib on mouse dried blood spots (DBS) using liquid chromatography coupled to tandem mass spectrometry with electrospray ionization in the positive‐ion mode. The method employs liquid extraction of enasidenib from DBS disks of mouse whole blood followed by chromatographic separation using 0.2% formic acid–acetonitrile (25:75, v/v) at a flow rate of 1.0 mL/min on an Atlantis dC18 column with a total run time of 2.0 min. The MS/MS ion transitions monitored were m/z 474.0 → 267.1 for enasidenib and m/z 309.2 → 251.3 for the internal standard (warfarin). The assay was linear in the range of 1.01–3044 ng/mL. The within‐run and between‐run precisions were in the range of 3.18–9.06 and 4.66–8.69%, respectively. Stability studies showed that enasidenib was stable on DBS cards for 1 month. This novel method has been applied to analyze the DBS samples of enasidenib obtained from a pharmacokinetic study in mice.
Microbial transformation of ambrisentan to its glycosides by Cunninghamella elegans
Authors: Sponchiado Rafaela , Sorrentino Julia Medeiros , Olegário Natália , Oliveira Sendy Sales , Cordenonsi Leticia Malgarim , Silveira Gustavo Pozza , Fuentefria Alexandre M. , Mendez Andreas S. L. , Steppe Martin , Garcia Cássia V.
Published: January 2019

The purpose of this paper is to describe the glycosylation of ambrisentan (AMB) by cultures of Cunninghamella elegans ATCC 9245. AMB is an endothelin receptor antagonist, which is used to treat pulmonary arterial hypertension. Filamentous fungi are morphologically complex and may exhibit different forms depending on the species and the nature of the culture medium. A biotransformation study was conducted to investigate the ability of C. elegans to metabolize AMB. Parameters were optimized by testing on different culture media and concentrations, pH, drug concentration, static and shaking conditions. Ambrisentan's metabolite, obtained after 240 h of incubation as a result of glycosylation pathway, was separated by HPLC and determined by high‐resolution mass spectrometry. The method showed linearity over 300–1000 μg mL−1 (r = 0.998). Accuracy, precision, robustness and stability studies agree with international guidelines. Results are consistent in accordance with the principles of green chemistry as the experimental conditions had a low environmental impact, and used little solvent.
Board structures, liberal countries, and developed market economies. Do they matter in environmental reporting? An international outlook
Authors: Pucheta‐Martínez María Consuelo , Gallego‐Álvarez Isabel , Bel‐Oms Inmaculada
Published: January 2019

Previous empirical evidence has shown the effect of most corporate governance mechanisms on corporate social responsibility and environmental disclosure. However, there is scant empirical evidence that examines the influence of liberal countries, developed market economies, and board structures on environmental disclosure. Thus, this research aims to explore how liberal and developed countries and board structures affect environmental reporting. We hypothesise a linear and positive association between companies located in countries with liberal and developed market economies and environmental reporting. Moreover, we hypothesise that one‐tier board structures negatively affect environmental disclosure. Focusing on 13,100 companies domiciled in 39 different countries from 2005 to 2015, it is established that those companies located in liberal and developed economies are more likely to disclose environmental information, whereas one‐tier boards have a negative effect.
Anatomical study of the zygomatic and buccal branches of the facial nerve: Application to facial reanimation procedures
Authors: Kehrer Andreas , Engelmann Simon , Ruewe Marc , Geis Sebastian , Taeger Christian , Kehrer Michael , Prantl Lukas , Tamm Ernst , Bleys Ronald R.L.A.W. , Mandlik Veronika
Published: January 2019

The facial nerve is responsible for any facial expression channeling human emotions. Facial paralysis causes asymmetry, lagophthalmus, oral incontinence, and social limitations. Facial dynamics may be re‐established with cross‐face‐nerve‐grafts (CFNG). Our aim was to reappraise the zygomaticobuccal branch system relevant for facial reanimation surgery with respect to anastomoses and crossings. Dissection was performed on 106 facial halves of 53 fresh frozen cadavers. Study endpoints were quantity and relative thickness of branches, correlation to “Zuker's point”, interconnection patterns and crossings. Level I and level II branches were classified as relevant for CFNG. Anastomoses and fusion patterns were assessed in both levels. The zygomatic branch showed 2.98 ± 0.86 (range 2–5) twigs at level II and the buccal branch 3.45 ± 0.96 (range 2–5), respectively. In the zygomatic system a single dominant branch was present in 50%, two co‐dominant branches in 9% and three in 1%. In 66% of cases a single dominant buccal twig, two co‐dominant in 12.6%, and three in 1% of cases were detected. The most inferior zygomatic branch was the most dominant branch (P = 0.003). Using Zuker's point, a facial nerve branch was found within 5 mm in all facial halves. Fusions were detected in 80% of specimens. Two different types of fusion patterns could be identified. Undercrossing of branches was found in 24% at levels I and II. Our study describes facial nerve branch systems relevant for facial reanimation surgery in a three‐dimensional relationship of branches to each other. Clin. Anat. 32:480–488, 2019. © 2019 Wiley Periodicals, Inc.
The effect of scanning distance on the accuracy of intra‐oral scanners used in dentistry
Authors: Kim Min‐Kyoung , Kim Ji‐Min , Lee Yoo‐Mee , Lim Young‐Jun , Lee Seung‐Pyo
Published: January 2019

The aim of this study was to evaluate the factors affecting intra‐oral scanner accuracy by analyzing variation in measurements of a dental model according to scanning distance. A dental cast, including a prepared left mandibular first molar, was used. Rectangular frames measuring 20 × 30 mm with heights of 2.5, 5.0, and 7.5 mm were made. The model was scanned 10 times with a reference scanner to obtain the true value. Scanning was performed 10 times at four distances of 0, 2.5, 5.0, and 7.5 mm with the frame of each height using the following intra‐oral scanners: TRIOS; CS 3500; and PlanScan. In the linear distance measurement method (2D), measurements were taken at five parameters using the Rapidform software. In the best‐fit alignment method (3D), using the Geomagic Control X, the root mean square values of the two scan images were calculated. In the 2D comparison, the different from the reference value was the smallest at 2.5 and 5.0 mm. In the 3D comparison, 2.5 and 5.0 mm were the most accurate, and 0 mm was the least accurate among the four distances. To the best of our knowledge, this study was the first to evaluate the accuracy of scanning distances, and found a difference between the accuracy of the scanning distance and the accuracy of the scanner. Moreover, the results of this study indicated that the scanning distance was a variable affecting accuracy. Clin. Anat. 32:430–438, 2019. © 2019 Wiley Periodicals, Inc.
Fabrication of Tubular g‐C3N4 with N‐Defects and Extended π‐Conjugated System for Promoted Photocatalytic Hydrogen Production
Authors: Shan Xin , Ge Guifang , Zhao Zhongkui
Published: January 2019

Semiconductor photocatalytic hydrogen evolution from water splitting using solar energy is one of the most potential strategies for settling the energy crisis, but a bottleneck is occurred in developing a highly efficient photocatalyst. Herein, we successfully fabricated a tubular g‐C3N4 with nitrogen defects (including both nitrogen vacancies and cyano groups) and extended π‐conjugated system, wherein the nitrogen defects and extended π‐conjugated system were conveniently introduced during thermal polymerization of the pyridinium alkaline ionic liquid‐modified hydrogen‐bonding melamine‐cyanuric acid supramolecular (PHMCS) pre‐aggregates towards carbon nitride with hexagonal cylinder morphology formed by the pyridinium alkaline ionic liquid‐assisted hydrothermal process of low‐cost melamine, in which the added trace pyridinium alkaline ionic liquid serves as an all‐rounder with three roles including the promoting agent towards the transformation of melamine to cyanuric acid for constructing PHMCS, nitrogen defects making agent, and the electronic‐tuning agent regarding of the as‐formed carbon nitride. The tubular structure enhances the light scattering and improves the accessibility of active sites. Meanwhile, the high charge transfer efficiency, broad optical absorption region, and suitable energy band positions are related to both the introduction of nitrogen defects by alkali of ionic liquid and the extended π‐electron delocalization in the conjunction carbon nitride networks. As a consequence, the resulted carbon nitride using optimized amount of pyridinium alkaline ionic liquid (AIL‐2.0‐CN) photocatalyst exhibited a high hydrogen evolution rate of 1284 μmol h−1 g−1 (λ>420 nm) with an apparent quantum efficiency of 4.2 % at 420 nm, which is 13.6 times higher than that of bulk g‐C3N4 (B−CN), and even 3.5 folds much higher than the one (SHPY−CN) prepared by the similar process to that for AIL‐2.0‐CN except for the replacement of pyridinium alkaline ionic liquid by a mixture containing a corresponding amount of pyridine and sodium hydroxide, suggesting the promoting effect resulting from the unique characteristic of pyridinium alkaline ionic liquid. Based on the unique physicochemical properties and the molecules‐ adjustability, the developed alkaline ionic liquid assisted strategy can open an avenue for designing and preparing excellent g‐C3N4 based photocatalysts with tunable geometric and electronic structures for solar hydrogen production.
Rapid Models for Predicting the Low‐Temperature Behavior of Diesel
Authors: Vráblík Aleš , Velvarská Romana , Štěpánek Kamil , Pšenička Martin , Hidalgo José Miguel , Černý Radek
Published: January 2019

The cold filtration plugging point (CFPP) is the method most commonly applied to characterize the low‐temperature behavior of diesel and its components. However, this method is time‐consuming and does not have good repeatability, especially for samples with very low CFPP values like kerosene, light cycle oil, etc. Three new models for CFPP prediction were developed and compared: a combined density and distillation curve, differential scanning calorimetry, and near‐infrared. A set of 133 samples of diesel components were used to create the models, containing streams from different sources and levels of treatment. A further 28 diesel samples were used to validate and compare the models. All three models not only were faster than the standard method but also were found to be in good agreement with CFPP values. Each model has its own particular advantages suiting it to a particular type of diesel sample and stage of the diesel production process.
Life Cycle of Wash Oil for Benzol Absorption from Coke Oven Gas
Authors: Večeř Marek , Koutník Ivan , Wichterle Kamil
Published: January 2019

An important source of benzol is coke oven gas, which is a by‐product of metallurgical coke production. A cycle of absorption into the washing oil and reverse desorption is a crucial step in this technology. The wash oil itself is a complex mixture of hydrocarbons with higher boiling point. Its washing property is changing during time of use. The concentration of unabsorbed benzene in the coke oven gas leaving the absorption is monitored as an indicator of the washing oil condition. A secondary parameter is the viscosity of the washing oil. The optimal operating conditions of the absorption unit of benzol and the ranges of physical properties, which mainly influence the benzol absorption, were identified. Beside the increasing absorption efficiency, it is significant to prolong the life cycle of wash oil.
Enantiomeric assay of escitalopramS(+)‐enantiomer and its “in‐process impurities” using two different techniques
Authors: Soliman Suzan Mahmoud
Published: January 2019

The enantiomeric purity of escitalopram oxalate ESC and its “in‐process impurities,” namely, ESC‐N‐oxide, ESC‐citadiol, andR(−)‐enantiomer were studied in drug substance and products using high‐performance liquid chromatography (HPLC)‐UV (Method I), synchronous fluorescence spectroscopy (SFS) (Method IIA), and first derivative SFS (Method IIB). Method I describes as an isocratic HPLC‐UV for the direct resolution and determination of enantiomeric purity of ESC and its “in‐process impurities.” The proposed method involved the use of αl‐acid glycoprotein (AGP) chiral stationary phase. The regression plots revealed good linear relationships of concentration range of 0.25 to 100 and 0.25 to 10 μg mL−1for ESC and its impurities. The limits of detection and quantifications for ESC were 0.075 and 0.235 μg mL−1, respectively. Method II involves the significant enhancement of the fluorescence intensities of ESC and its impurities through inclusion complexes formation with hydroxyl propyl‐β‐cyclodextrin as a chiral selector in Micliavain buffer. Method IIA describes SFS technique for assay of ESC at 225 nm in presence of its impurities:R(−)‐enantiomer, citadiol, and N‐oxide at ∆λ of 100 nm. This method was extended to (Method IIB) to apply first derivative SFS for the simultaneous determination of ESC at 236 nm and its impurities: theR(−)‐enantiomer, citadiol, and N‐oxide at 308, 275, and 280 nm, respectively. Linearity ranges were found to be 0.01 to 1.0 μg mL−1for ESC and its impurities with lower detection and quantification limits of 0.033/0.011 and 0.038/0.013 μg mL−1for SFS and first derivative synchronous fluorescence spectra (FDSFS), respectively. The methods were used to investigate the enantiomeric purity of escitalopram.
A Simple Way for Implementing Extraction Columns of Infinite Height in Flowsheet Simulators
Authors: Kaul Martin , Hasse Hans , Burger Jakob
Published: January 2019

A surrogate model to implement an extraction column of infinite height in process simulation software is presented. The model consists of three decanters and a few specifications which are easy to implement in commercial process simulators. Using the model, the minimum solvent flow rate and the limiting product compositions are determined. In an example, the surrogate model for the extraction column is combined with standard unit operation models for describing an extraction process with a distillative solvent recycle.
MS‐Based Screening of 5‐Substituted Nipecotic Acid Derived Hydrazone Libraries as Ligands of the GABA Transporter 1
Authors: Hauke Tobias J. , Höfner Georg , Wanner Klaus T.
Published: January 2019

A screening of compound libraries based on nipecotic acid derivatives with lipophilic residues attached to the scarcely explored 5‐position of the core structure was used for the search of new inhibitors of the γ‐aminobutyric acid (GABA) transporter 1 (mGAT1). The generated compound libraries, which were based on hydrazone chemistry commonly used in dynamic combinatorial chemistry but rendered pseudostatic, were screened for their binding affinities toward mGAT1 by means of MS Binding Assays. With nipecotic acid derived hydrazone rac‐16 h [rac‐(3R,5S)‐{5‐[(E)‐2‐{[5‐(2‐phenylethynyl)thiophen‐2‐yl]methylidene}hydrazin‐1‐yl]piperidine‐3‐carboxylic acid}‐sodium chloride (1/2)], one hit was found and evaluated displaying sub‐micromolar potency (pKi=6.62±0.04) and a noncompetitive interaction mode at mGAT1. By bearing a 5‐(2‐phenylethynyl)thiophen‐2‐yl residue attached to the 5‐position of nipecotic acid via a three‐atom spacer, compound rac‐16 h contains a structural moiety so far unprecedented for these kinds of bioactive molecules, and complements novel 5‐substituted nipecotic acid derived ligands of mGAT1 revealed in a recently published screening campaign. This new class of ligands, with an inhibition mode distinct from that of benchmark mGAT1 inhibitors, could serve as research tools for investigations of mGAT1‐mediated GABA transport.
Magnetic Recovery of Cellulase from Cellulose Substrates with Bare Iron Oxide Nanoparticles
Authors: Schnell Florian , Kube Massimo , Berensmeier Sonja , Schwaminger Sebastian P.
Published: January 2019

Cellulase is an enzyme used to hydrolyze a wide range of cellulose based materials and thus facilitates the production of glucose. In order to provide a greener chemistry, cellulase has been immobilized on magnetic nanoparticles, which allow for simple magnetic separation and recovery. The nanoparticles have been characterized thoroughly and the binding parameters of cellulase on the magnetic iron oxides were investigated. The so produced nano‐biocatalysts were subjected to enzymatic tests in different temperature and pH media. Reusability and influence of the storage time was also examined. The stability of the enzyme increased by immobilization to the particles compared to free cellulase. We were able to recover immobilized cellulase from the degraded substrate in the milliliter with a handmagnet as well as in the liter scale with a high gradient magnetic separator. The continuous process for the degradation of cellulose and the recovery of the nano‐biocatalysts paves the way for industrial applications.
Research on improved text classification method based on combined weighted model
Authors: Wang Yongchang , Zhu Ligu
Published: January 2019

Text classification is very important in information retrieval, but the traditional text classification model has many problems, such as the feature dimension disaster, the lack of semantic features, etc. Aiming at the problems, this paper proposes an improved TFIDF model combined with the Word2vec model for weighing word vectors. In view of the inability of the Word2vec model to distinguish the importance of words with the text, TFIDF is further introduced to weighing Word2vec word vectors to achieve a weighted Word2vec classification model. For data preprocessing, we optimized the traditional StringToWordVector algorithm. The main improvement of StringToWordVector is the introduction to a new algorithm of stem extraction. First, this paper gives a simple description of the basic steps and algorithms of traditional text classification, and then, the ideas and steps of the improved StringToWordVector algorithm are proposed. Finally, experimental results using our improved algorithm are tested for four different data sets (WEBO_SINA and three standard UCI data sets). The experimental results show that the improved StringToWordVector algorithm combined with the combined weighted model has higher classification accuracy, recall, and F1 values than the traditional text classification model only using the Word2vec model or using TFIDF. The experimental results are satisfactory.
Efficient Photodegradation of Organic Pollutants By Using a Bi2CuO4/BiPO4 Heterojunction Photocatalyst
Authors: Praveen Athma E , Samanta Tuhin , Ganguli Sagar , Mahalingam Venkataramanan
Published: January 2019

Photocatalysis is the most promising and cheap route for water purification. In this work, we demonstrate the degradation of organic pollutants, such as picric acid and methylene blue, by an efficient, reusable Bi2CuO4/BiPO4 heterojunction photocatalyst. The Bi2CuO4/BiPO4 heterojunction was fabricated using a solvothermal method followed by sonication. The Bi2CuO4/BiPO4 heterojunction shows enhanced photocatalytic degradation of picric acid and methylene blue dye under ultraviolet‐visible (UV/Vis) light compared to its individual constituents as well as compared to the previously reported Bi2CuO4‐based photocatalyst. The high photocatalytic activity of the Bi2CuO4/BiPO4 heterojunction can be attributed to the enhanced separation efficiency of the photogenerated electron and hole pairs. The photocatalytic activity of the Bi2CuO4 nanostructures, which is generally weak due to faster recombination of the electron and hole, is enhanced by means of heterojunction formation with BiPO4 nanocrystals. Interestingly, the hydroxyl radical, which was found to be the primary active species, is not generated at the valence band due to thermodynamic constraints. In contrast, experiments carried out under controlled conditions unequivocally confirm that their generation is related to oxygen reduction at the conduction band.
Tuning the Crystal Structure and Luminescence of Pyrrolidinium Manganese Halides via Halide Ions
Authors: Jiang Chunli , Fu Hanmei , Han Ying , Li Dong , Lin Hechun , Li Bo , Meng Xiangjian , Peng Hui , Chu Junhao
Published: January 2019

Luminescent and lead‐free organic‐transition metal halides (OTMHs) are greatly interesting for optical applications. In this work, six single crystals of pyrrolidinium manganese halides are prepared (C4H10N)MnCl3 (1), (C4H10N)8(Mn2Cl10)(MnCl4) (2), (C4H10N)MnBr3 (3), (C4H10N)2MnBr4 (4), and (C4H10N)2MnI4 (5 and 6 with two different crystal configurations). The analysis of crystal structures illustrates that halide ions play an important role in the crystal structure and further affect the luminescent properties of pyrrolidinium manganese halides. It is only for Cl− and Br− that produce perovskite‐type crystals which exhibit red emission. Other crystals with MnX42− tetrahedron unit emit green or yellow lights. It is interesting that the obtained crystals only contain one kind of halide ion with higher atomic number if there are two kinds of halide ions existing in the crystal growth solution. This study illustrates that the luminescent properties of OTMHs can be tuned by halide ions through deliberately designing experiments.
Self‐Templating Synthesis of 3D Hollow Tubular Porous Carbon Derived from Straw Cellulose Waste with Excellent Performance for Supercapacitors
Authors: Chen Zhimin , Wang Xiaofeng , Xue Beichen , Wei Qingling , Hu Lianghai , Wang Zichen , Yang Xiaomin , Qiu Jieshan
Published: January 2019

A three‐dimensional hollow tubular porous carbon (SCPC) was prepared from straw cellulose waste through a self‐templating method combined with NaOH activation. Straw cellulose acts both as carbon source and structural template. The obtained SCPC exhibits a 3D hierarchical porous network structure. SCPC has a high specific surface area, a high mesoporosity ratio, and a low resistivity, which make it display excellent electrochemical performance for supercapacitors. SCPC showed a high specific capacitance of 312.57 F g−1 in 6 m KOH at 0.5 A g−1, an excellent rate performance of 281.32 F g−1 even at 15 A g−1, and an outstanding cyclic stability of 92.93 % capacitance retention after 20 000 cycles at 1 A g−1. SCPC‐based supercapacitors can deliver an energy density of 8.67 Wh kg−1 at a power density of 3.50 kW kg−1 in 6 m KOH and an energy density of 28.56 Wh kg−1 at a power density of 14.09 kW kg−1 in 1 m Et4NBF4/PC, which demonstrates the possibility of applying SCPC in supercapacitors. This research not only offers a facile and sustainable method for the preparation of hierarchical porous carbon for electrochemical energy storage devices but also provides a highly efficient method for the utilization of biomass waste.
Dynamic wildlife occupancy models using automated acoustic monitoring data
Authors: Balantic Cathleen , Donovan Therese
Published: January 2019

Automated acoustic monitoring of wildlife has been used to characterize populations of sound‐producing species across large spatial scales. However, false negatives and false positives produced by automated detection systems can compromise the utility of these data for researchers and land managers, particularly for research programs endeavoring to describe colonization and extinction dynamics that inform land use decision‐making. To investigate the suitability of automated acoustic monitoring for dynamic occurrence models, we simulated underlying occurrence dynamics, calling patterns, and the automated acoustic detection process for a hypothetical species under a range of scenarios. We investigated an automated species detection aggregation method that considered a suite of options for creating encounter histories. From these encounter histories, we generated parameter estimates and computed bias for occurrence, colonization, and extinction rates using a dynamic occupancy modeling framework that accounts for false positives via small amounts of manual confirmation. We were able to achieve relatively unbiased estimates for all three state parameters under all scenarios, even when the automated detection system was simulated to be poor, given particular encounter history aggregation choices. However, some encounter history aggregation choices resulted in unreliable estimates; we provide caveats for avoiding these scenarios. Given specific choices during the detection aggregation process, automated acoustic monitoring data may provide an effective means for tracking species occurrence, colonization, and extinction patterns through time, with the potential to inform adaptive management at multiple spatial scales.