bluuebunny/crossref_metadata_2025_split huggingface dataset:
Cross‐linking photopolymerization of monoacrylate initiated by benzophenone
Authors: Sanai Yasuyuki , Kagami Shinobu , Kubota Kouzou 
Published: May 2018

ABSTRACTThe chain‐end structure of the photopolymerized acrylate using benzophenone as an initiator was investigated as well as polymerization behavior. Dodecyl acrylate was used as a monomer in this study. Gelation occurred during ultraviolet (UV) irradiation, whereas a cross‐linker was not employed. Conversion‐time profile below gel point gave a linear first‐order plot suggesting that the steady‐state was held throughout polymerization. Matrix‐assisted laser desorption/ionization time‐of‐flight mass spectra of the resultant polymer indicated that most polymers had an acryloyl group at one of the chain‐ends, while some polymers had an acryloyl group at each chain‐end. The cross‐linking reaction leading to gelation would have been caused by the subsequent copolymerization of the residual monomer with the latter polymer having two acryloyl groups. Dissolved oxygen in the monomer solution influenced the polymer structure giving hydroxyl group at chain‐end. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018, 56, 1545–1553
Hydrogen bond‐reinforced double‐network hydrogels with ultrahigh elastic modulus and shape memory property
Authors: Wang Yan Jie , Li Chen Yu , Wang Zhi Jian , Zhao Yiping , Chen Li , Wu Zi Liang , Zheng Qiang 
Published: May 2018

ABSTRACTDevelopment of tough hydrogels has greatly expanded their applications as load‐bearing materials. However, the elastic modulus of tough hydrogels is usually lower than 1 MPa. It remains a challenge to design tough hydrogels with high modulus. We report here a series of tough double‐network (DN) hydrogels with ultrahigh elastic modulus (up to 200 MPa) by forming robust hydrogen bonds between the first poly(acrylic acid) network and the second poly(N‐isopropyl acrylamide) network. The dense cooperative hydrogen bonds greatly reduce the segmental mobility and thus improve the rigidity of gel matrix. Owing to the dynamic nature of hydrogen bonds, the modulus of hydrogels is strongly influenced by temperature and pH, affording the gels shape memory property. The strategy by forming robust noncovalent bonds between interpenetrating networks should be applicable to other systems for designing tough and versatile hydrogels with diverse promising applications. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2018, 56, 1281–1286
In vitro antiprotozoan activity and mechanisms of action of selected Ghanaian medicinal plants against Trypanosoma, Leishmania, and Plasmodium parasites
Authors: Ohashi Mitsuko , Amoa-Bosompem Michael , Kwofie Kofi Dadzie , Agyapong Jefferey , Adegle Richard , Sakyiamah Maxwell Mamfe , Ayertey Frederick , Owusu Kofi Baffuor‐Awuah , Tuffour Isaac , Atchoglo Philip , Tung Nguyen Huu , Uto Takuhiro , Aboagye Frederick , Appiah Alfred Ampomah , Appiah-Opong Regina , Nyarko Alexander K. , Anyan William Kofi , Ayi Irene , Boakye Daniel Adjei , Koram Kwadwo Ansah , Edoh Dominic , Yamaoka Shoji , Shoyama Yukihiro , Ohta Nobuo 
Published: May 2018

Trypanosomiasis, leishmaniasis, and malaria are protozoan infections of public health importance with thousands of new cases recorded annually. Control of these infection(s) with existing chemotherapy is limited by drug toxicity, lengthy parenteral treatment, affordability, and/or the emergence of resistant strains. Medicinal plants on the other hand are used in the treatment of various infectious diseases although their chemical properties are not fully evaluated. In this study, we screened 112 crude extracts from 72 selected Ghanaian medicinal plants for anti‐Trypanosoma, anti‐Leishmania, and anti‐Plasmodium activities in vitro and investigated their mechanisms of action. Twenty‐three extracts from 20 plants showed significant antiprotozoan activity against at least 1 of 3 protozoan parasites screened with IC50 values less than 20 μg/ml. Eleven extracts showed high anti‐Trypanosoma activity with Bidens pilosa whole plant and Morinda lucida leaf extracts recording the highest activities. Their IC50 (selectivity index [SI]) values were 5.51 μg/ml (35.00) and 5.96 μg/ml (13.09), respectively. Nine extracts had high anti‐Leishmania activity with Annona senegalensis and Cassia alata leaf extracts as the most active. Their IC50 (SI) values were 10.8 μg/ml (1.50) and 10.1 μg/ml (0.37), respectively. Six extracts had high anti‐Plasmodium activity with the leaf and stem‐bark extracts of Terminalia ivorensis recording the highest activity. Their IC50 (SI) values were 7.26 μg/ml (129.36) and 17.45 μg/ml (17.17), respectively. Only M. lucida at 25 μg/ml induced significant apoptosis‐like cell death in Trypanosoma parasites. Anti‐Leishmania active extracts induced varying morphological changes in Leishmania parasites such as multiple nuclei and/or kinetoplast, incomplete flagella division, or nuclear fragmentation. Active extracts may be potential sources for developing new chemotherapy against these infections.
The keto→enol photoisomerization of N‐salicilydenemethylfurylamine: Nonadiabatic ab initio dynamics simulation
Authors: Gao Aihua , Wang Meishan 
Published: May 2018

AbstractThe photoinduced isomerization of cis‐keto and trans‐keto isomers in N‐salicilydenemethylfurylamine has been studied using the surface‐hopping approach at the CASSCF level of theory. After the cis‐keto or trans‐keto isomer is excited to S1 state, the molecule initially moves to a excited‐state local minimum. The torsional motion around relative bonds in the chain drives the molecule to approach a keto‐form conical intersection and then nonadiabatic transition occurs. According to our full‐dimensional dynamics simulations, the trans‐keto and enol photoproducts are responsible for the photochromic effect of cis‐keto isomer excited to S1 state, while no enol isomer was obtained in the photoisomerization of trans keto on excitation. The cis keto to enol and cis keto to trans keto isomerizations are reversible photochemical reactions. It is confirmed that this aromatic Schiff base is a potential molecular switch. Furthermore, the torsion of CN bond occurs in the radiationless decay of trans‐keto isomer, while it is completely suppressed by an intramolecular hydrogen bonding interaction in the dynamics of cis‐keto form. Moreover, the excited‐state lifetime of cis keto is longer than that of trans‐keto form due to the O···HN hydrogen bond.
(TMT)n clusters as dilute debris‐free tin source for generation of multiply charged tin ions of relevance in extreme ultraviolet (EUV) lithography, under intense laser irradiation
Authors: Sharma Pramod , Das Soumitra , Vatsa Rajesh K. 
Published: May 2018

RationaleMultiply charged tin ions ([Sn]8+ to [Sn]13+) are considered as ideal‐emitters at extreme ultraviolet (EUV) wavelength ~13.5 nm, pertinent to the fabrication of advanced micro‐electronic devices. Solid tin targets have been widely explored for the generation of these ions, but debris generation has restricted their utilization. Tin‐containing molecular clusters have the potential to act as dilute and debris‐free sources for the generation of tin ions, as investigated in the present study.MethodsEfficient coupling of laser energy with clusters has been utilized for the generation of multiply charged tin ions. The ions generated have been characterized using time‐of‐flight mass spectrometry. By varying experimental parameters, the yield of multiply charged tin ions has been manipulated, for tetramethyltin (TMT) clusters. In addition, the energetic electrons and photons liberated upon laser‐cluster interaction have been probed utilizing an in‐house developed retarding field analyzer.ResultsInteraction of TMT clusters with 1064 nm picosecond laser pulses of intensity ~1013 W/cm2 leads to the generation of multiply charged tin ions (up to [Sn]14+) and carbon ions (up to [C]4+). Efficient laser‐cluster interaction is evident from the generation of multiply charged tin ions with ionization energy ~282 eV ([Sn]14+). By varying the experimental conditions, the distribution of multiply charged tin ions can be influenced to obtain significant relative ion yields of multiply charged tin ions from [Sn]8+ to [Sn]13+.ConclusionsTetramethyltin clusters have the potential to act as dilute and debris‐free sources for EUV lithographic applications, in contrast to bulk tin targets. The inherent properties of clusters, such as higher local density and the pulsed nature of the cluster source, are appropriate for EUV lithographic applications.
Supporting teachers to negotiate uncertainty for science, students, and teaching
Authors: Manz Eve , Suárez Enrique 
Published: May 2018

AbstractThis study addresses how to help elementary science teachers explore the uncertainty inherent in scientific activity and support elementary students to engage in more complex and authentic investigations. We describe a district partnership focused on understanding how to support elementary teachers to adapt curricula to promote science practices. We then present a close analysis of how teachers navigated ideas about uncertainty during their work exploring tools to adapt their curriculum. We argue that an essential aspect of the teachers’ work was developing a more nuanced view of scientific uncertainty, including more precise goals for students’ engagement in scientific activity and a repertoire of strategies for supporting students to engage with scientific uncertainty without unduly increasing uncertainty for teachers. We trace three strategies that appeared to help teachers negotiate and develop this more nuanced view: beginning with complex phenomena, iterating on investigations, and leveraging variability in students’ ways of conducting investigations. The findings have implications for the design of professional development programs for elementary teachers, particularly the support that teachers might need to negotiate a nuanced set of teacher and student roles when seeking to engage students more authentically in science practices.
Single‐Step Synthesis of Novel Polyionic Liquids Having Antibacterial Activity and Showing π‐Electron Mediated Selectivity in Separation of Aromatics
Authors: Ethirajan Sudheesh Kumar , Sengupta Arijit , Jebur Mahmood , Kamaz Mohanad , Qian Xianghong , Wickramasinghe Ranil 
Published: May 2018

AbstractOne‐pot synthesis of polyionic liquids (PILs) from pyridinium and phosphonium family was reported in the present investigation. The size exclusion chromatographic (SEC) method was employed for the determination of the molecular weight of the polymer and the dispersity during synthesis. The aggregation behavior of these PILs was investigated in polar‐ protic, polar‐ aprotic and apolar‐aprotic solvents. The FTIR spectroscopic analysis was utilized for the characterization of the functional groups in PILs, whereas 1H‐NMR analysis was employed for structural characterization of the PILs in terms of the existence of magnetically non‐equivalent protons. UV‐Vis spectroscopic characterization was also employed for these PILs. The anti‐bacterial activity of these PILs were investigated using two gram positive bacteria staphylococcus aureus and pseudomonas aeruginosa. Plate reader method was used to determine the ratio of live to dead bacterial cell in presence of PILs as a function of time by monitoring the fluorescence wave length of the corresponding cells after tagging them suitably with the appropriate dye. The plate counting method was also employed for the direct counting of the number of colony of the bacteria as a function of time in presence of the synthesized PILs. A π‐electron mediated separation was found to bring the selectivity in sorption of aromatics on these PILs.
Pd‐Catalyzed Chemoselective Suzuki‐Miyaura Reactions of 1‐Bromo‐4‐(halomethyl)naphthalene
Authors: Pei Mingming , Liu Ping , Ma Xiaowei , Liu Yan , Dai Bin 
Published: May 2018

AbstractA Pd‐catalyzed chemoselective Suzuki‐Miyaura reaction of 1‐bromo‐4‐(halomethyl)naphthalene and arylboronic acids for the formation of C(sp3)–C(sp2) bond via highly selective C(sp3)‐X bond cleavage is disclosed, which enables the general synthesis of functionalized 1‐benzyl‐4‐bromonaphthalene compounds in good yields under mild conditions. Moreover, the 1‐benzyl‐4‐bromonaphthalene was also obtained on a multi‐gram scale, and further to prepare more complex target molecules through the related chemical transformation.
Children's stress‐related reports and stress biomarkers interact in their association with metabolic syndrome risk
Authors: Michels Nathalie , Matthys Dante , Thumann Barbara , Marild Staffan , De Henauw Stefaan 
Published: May 2018

AbstractThe purpose was to examine the cross‐sectional associations of stress‐related reports and stress biomarkers with metabolic syndrome (MetS) risk in children while also testing the interaction between stress biomarkers and stress reports. In 353 children (5–10 years old, 7.9% overweight/obese), MetS risk was measured by blood pressure, waist circumference, glucose homeostasis, triglycerides, and high‐density cholesterol. Stress was measured by stress‐related reports (events, emotions, and internalizing/externalizing problems) and two biomarkers: salivary cortisol (total‐day and morning output) and heart rate variability (percentage of consecutive normal RR intervals differing more than 50 ms and low‐to‐high‐frequency ratio). Cross‐sectional regression analyses with z scored total MetS risk as outcome were adjusted for age, sex, and socio‐economic status. Only internalizing problems were directly related to a higher MetS risk score (β = 0.236). Cortisol and heart rate variability were significant moderators: High cortisol morning output resulted in a positive (unfavourable) report–MetS relationship (β = 0.259–0.552), whereas low percentage of consecutive normal RR intervals differing more than 50 ms resulted in a negative (favourable) report–MetS relationship (β = −0.298) and low low‐to‐high‐frequency ratio in a positive (unfavourable) report–MetS relationship (β = 0.478). In conclusion, stress can sometimes be a disadvantageous factor in metabolic health of otherwise healthy children. The cortisol biomarker seems relevant because metabolic risk was highest when stress‐related reports were accompanied by high morning cortisol output.
Untersuchungen zum Tragverhalten randnaher Verbunddübelleisten
Authors: Broschart Yannick , Gajda Joanna , Kurz Wolfgang 
Published: May 2018

AbstractHerrn Univ.‐Prof. Dr.‐Ing. Jörg Lange zur Vollendung seines 60. Lebensjahres gewidmetVerbunddübelleisten stellen im Stahlverbundbau eine wirtschaftliche Alternative zu den klassischen Verbundmitteln, den Kopfbolzendübeln, dar. Ihr Einsatz birgt vielerlei Vorteile. Moderne Verbunddecken werden in zunehmendem Maße filigraner ausgeführt und darüber hinaus werden oftmals haustechnische Funktionen darin integriert, wie beispielsweise Lüftungsanlagen oder eine thermische Aktivierung der Betonflächen [1]. Um derart geringe Deckendicken zu realisieren, können Verbunddübelleisten horizontal innerhalb der Betonplatte positioniert werden, wodurch eine nahe Position zum freien Betonplattenrand resultiert. Bisherige Untersuchungen beschreiben unterschiedliche Versagensbilder von Konstruktionen mit Verbunddübelleisten, beispielsweise Spalten der Betonplatte, Ausstanzen eines Betonkegels oder Plastizieren der Stahlzähne.An der TU Kaiserslautern wurden Verbunddübelleisten mit einer Puzzle‐Geometrie und Positionen nahe zum freien Betonplattenrand experimentell sowie mithilfe von numerischen Simulationen untersucht. Zusätzlich wurde der positive Einfluss einer Wendelbewehrung zwischen den Stahlzähnen analysiert. Speziell bei diesen randnahen Positionen der Verbunddübelleisten wurden zusätzliche primäre und sekundäre Versagensmechanismen beobachtet. Die Ergebnisse dieser Untersuchungen sowie ein erster Ansatz für ein Bemessungsmodell werden in diesem Artikel vorgestellt.
Ersatzneubau zweier Fachwerkverbundbrücken im Zuge der B 54 über die BAB 45
Authors: Mank Harald , Dieter Alwin 
Published: May 2018

AbstractHerrn Prof. Dr.‐Ing. Jörg Lange zur Vollendung seines 60. Lebensjahres gewidmetDie zwei geplanten Fachwerkverbundbrücken mit Längen von 120 und 96 m Spannweite sollen die BAB 45 als Einfeldträger im schleifenden Schnitt queren. Da als statische Systeme Einfeldträger zum Zuge kamen, konnte auf den problematischen Bau von Mittelstützen zwischen den Richtungsfahrbahnen der BAB verzichtet werden. Im folgenden Beitrag wird die Wahl der Ausführungsvariante erläutert, insbesondere im Hinblick auf naturschutzrechtliche und bauzeitliche Belange, den Entwurf, den spezifischen Bauablauf und die Verkehrsführung. Besonderes Augenmerk wurde auch auf die Arbeitssicherheit beim Ersatzneubau und bei den zukünftigen Instandsetzungsarbeiten gerichtet.
3,4‐Dihydroxybenzaldehyde lowers ROS generation and protects human red blood cells from arsenic(III) induced oxidative damage
Authors: Maheshwari Nikhil , Khan Fahim Halim , Mahmood Riaz 
Published: May 2018

AbstractArsenic (As) is a potent environmental toxicant and chronic exposure to it results in various malignancies in humans. Oxidative stress has been implicated in the etiopathogenesis of As‐induced toxicity. This investigated the protective effect of plant antioxidant 3,4‐dihydroxybenzaldehyde (DHB) on sodium meta‐arsenite (SA), an As‐(III) compound, induced oxidative damage in human red blood cells (RBC). The RBC were first incubated with different concentrations of DHB and then treated with SA at 37°C. Hemolysates were prepared and assayed for various biochemical parameters. Treatment of RBC with SA alone enhanced the generation of reactive oxygen species and increased lipid and protein oxidation. Reduced glutathione levels, total sulfhydryl content and cellular antioxidant power were significantly decreased in SA alone treated RBC, compared to the untreated control cells. This was accompanied by membrane damage, alterations in activities of antioxidant enzymes and deranged glucose metabolism. Incubation of RBC with DHB, prior to treatment with SA, significantly and dose‐dependently attenuated the SA‐induced changes in all these parameters. Scanning electron microscopy of RBC confirmed these biochemical results. Treatment of RBC with SA alone converted the biconcave discoids to echinocytes but the presence of DHB inhibited this conversion and the RBC retained their normal shape. These results show that DHB protects human RBC from SA‐induced oxidative damage, most probably due to its antioxidant character.
The relationship between masticatory ability, age, and dental and prosthodontic status in an institutionalized elderly dentate population in Qingdao, China
Authors: Zhang Qian , Witter Dick J. , Bronkhorst Ewald M. , Creugers Nico H. J. 
Published: May 2018

Abstract
Objectives
To identify relationships between masticatory ability and age, and dental and prosthodontic status amongst an institutionalized elderly dentate population in China.

Materials and methods
A sample of 512 elders living in eight nursing homes in Qingdao was categorized based on a hierarchical dental functional classification system with and without tooth replacements. Masticatory disability scores (MDSs) were analyzed using multiple regression models with only age, and age and dentition variables for participants having ≥ 10 natural and those having < 10 natural teeth in each jaw.

Results
Overall, associations between MDS and age, number of teeth, and number of teeth replaced by dental prostheses were identified. For participants having ≥ 10 natural teeth in each jaw, no significant associations between MDS and age and dental and prosthodontic status were found. Participants having < 10 natural teeth in each jaw had higher MDS (increasing chewing difficulties) at higher ages. However, when “premolar region sufficient” and “molar region sufficient” were included, MDS was not associated with age, but with these dentition variables. For participants having ≥ 10 teeth including prosthodontically replaced teeth in each jaw, age was the only variable associated with MDS. For participants having < 10 teeth including teeth replaced in each jaw, the significant factor was “premolar region sufficient.” Overall, lower MDS was associated with increasing number of teeth, as well as with increasing number of teeth replaced by dental prostheses.

Conclusions
In this population of institutionalized dentate elderly, masticatory ability was significantly associated with dental and prosthodontic status.

Clinical relevance
For institutionalized elderly, having less than ten natural teeth in each jaw is associated with chewing problems. Most important dentition factor is the presence of three to four premolar pairs. Teeth added by partial removable dental prostheses compensate impaired masticatory ability due to tooth loss for 50% compared to natural teeth.
Minority stress, perceived burdensomeness, and depressive symptoms among sexual minority youth
Authors: Baams Laura , Dubas Judith Semon , Russell Stephen T. , Buikema Rosemarie L. , van Aken Marcel A.G. 
Published: May 2018

ABSTRACTAlthough studies have shown links between minority stress and mental health (e.g., Meyer, 2003), there is little research explaining this association. Research has suggested that adequate coping skills might protect youth from the negative impact of stress (Compas et al., 2017). Thus, we aimed to examine: 1) whether associations between minority stress and depressive symptoms occurred through mechanisms of perceived burdensomeness and thwarted belongingness, and 2) whether these associations were dependent on level of problem‐solving coping (moderated mediation). Using an online survey of 267 sexual minority youth from the Netherlands (16–22 years; 28.8% male), the results show an indirect relationship of sexual orientation victimization and internalized homophobia with depressive symptoms occurring through perceived burdensomeness; for both males and females. Problem‐solving coping skills did not significantly moderate the aforementioned indirect relationships. These results have implications for prevention and intervention work that currently focuses on social isolation rather than perceived burdensomeness.
Effect of vertical profile inefficiency during descent on fuel burn, emissions and flight time
Authors: Aksoy H. , Usanmaz O. , Turgut E. T. 
Published: May 2018

ABSTRACTVertical profile inefficiency caused by low-level flight segments during arrival and departure operations has a great impact on the financial cost of operators as well as negative environmental effects. In this regard, continuous descent and climb operations for arrival and departure phases are mostly preferred as one of the methods that reduce or eliminate vertical profile inefficiencies. In this study, focus is put on the arrival phase and the purpose is: (i) to analyse the vertical profiles of arrival traffic at Mugla Milas-Bodrum Airport (BJV), Antalya Airport (AYT) and Ankara Esenboga Airport (ESB) and to characterise the level-offs that occur in the arrival phase and (ii) to quantify the potential time, fuel and emission savings in the event of a shift of inefficient low-level flight segments to the cruise segment of equal distance. For the purpose of this paper, real-time flight data is used for the analysis of the vertical profiles of flights. Flight parameters, such as latitude, longitude, altitude, speed and so on are used to determine, visualise and characterise level-off segments. The Boeing Fuel Flow Method 2 is used to calculate emissions at any altitude. Analyses of the results show that 80%, 74% and 69% of arrival traffic at BJV, AYT and ESB, respectively. were exposed to at least one level-off lasting longer than 20 seconds and significant potential for time, fuel and emissions savings exist for three airports.