bluuebunny/crossref_metadata_2025_split huggingface dataset:
On‐Chip Spiral Waveguides for Ultrasensitive and Rapid Detection of Nanoscale Objects
Authors: Tang Shui‐Jing , Liu Shuai , Yu Xiao‐Chong , Song Qinghai , Gong Qihuang , Xiao Yun‐Feng 
Published: April 2018

AbstractUltrasensitive and rapid detection of nano‐objects is crucial in both fundamental studies and practical applications. Optical sensors using evanescent fields in microcavities, plasmonic resonators, and nanofibers allow label‐free detection down to single molecules, but practical applications are severely hindered by long response time and device reproducibility. Here, an on‐chip dense waveguide sensor to monitor single unlabeled nanoparticles in a strong optical evanescent field is demonstrated. The spiral nanowaveguide design enables two orders of magnitude enhancement in sensing area compared to a straight waveguide, significantly improving the particle capture ability and shortening the target analysis time. In addition, the measurement noise is suppressed to a level of 10−4 in the transmitted power, pushing the detection limit of single particles down to the size of 100 nm. The waveguide sensor on the silicon‐on‐isolator platform can be fabricated reproducibly by the conventional semiconductor processing and compatible with surface functionalization chemistries and microfluidics, which could lead to widespread use for sensing in environmental monitoring and human health.
Der Effekt von Dispersionswechselwirkungen auf die Struktur von Diphenylether‐Aggregaten
Authors: Dietrich Fabian , Bernhard Dominic , Fatima Mariyam , Pérez Cristóbal , Schnell Melanie , Gerhards Markus 
Published: April 2018

AbstractDispersionswechselwirkungen spielen häufig eine wichtige Rolle beim Verständnis ungewöhnlicher Bindungsverhältnisse. Dies wird anhand der systematischen Untersuchung der bevorzugten Strukturen einer Reihe von Diphenylether(DPE)‐Alkohol‐Aggregaten veranschaulicht, bei denen sowohl OH⋅⋅⋅O‐ als auch OH⋅⋅⋅π‐gebundene Isomere gebildet werden können. Dabei wird ein multi‐spektroskopischer Ansatz aus IR/UV‐ und Mikrowellen‐Methoden verfolgt, verbunden mit einer theoretischen Analyse. Der resultierende, von der Solvensgröße abhängige Trend der bevorzugten Strukturen erweist sich als kontraintuitiv: Die OH⋅⋅⋅O‐Struktur wird durch größere Alkohole stabilisiert, von denen jedoch erwartet wird, dass sie stärkere “Dispersionsenergie‐Donoren” sind und somit eigentlich eine OH⋅⋅⋅π‐Koordination bevorzugen sollten. London'sche Dispersionswechselwirkungen in Kombination mit der Verdrillung des DPE‐Rückgrats, bedingt durch die Anlagerung des Lösungsmittelmoleküls, sind wesentlich für die Erklärung dieses Trends.
Palladium‐Catalyzed Enantioselective Arylation of Racemic Ketones to Form Bridged Bicycles via Dynamic Kinetic Resolution
Authors: Huang Xiaolei , Oh William Ray Jun Jie , Zhou Jianrong Steve 
Published: April 2018

AbstractEnantioselective α‐arylation of racemic ketones containing existing α′‐stereocenters is reported for the first time via base‐induced dynamic kinetic resolution. Bridged bicyclic rings are formed in good ee values, which are difficult to obtain otherwise. Furthermore, reactions in DMSO‐d6 resulted in extensive deuteration of both α‐ and α′‐positions in the products, thus supporting a pathway involving rapid, reversible deprotonation of ketones under catalytic conditions.
Emerging Camelina Protein: Extraction, Modification, and Structural/Functional Characterization
Authors: Boyle Claire , Hansen Lucy , Hinnenkamp Chelsey , Ismail Baraem P. 
Published: April 2018

AbstractCamelina sativa, a sustainable oilseed crop, is a novel source of plant protein. The aim of this work was to evaluate two protein extraction approaches, alkaline and salt extraction, and determine their impact on the structural and functional properties of camelina protein. Protein yield, content, structural characteristics, and functional properties of the produced camelina protein concentrates (CPC, 70–80% protein) and camelina protein hydrolysates were assessed and compared to reference proteins, whey protein isolate and soy protein isolate (SPI). Compared to alkaline pH extraction, data showed that salt extraction produces less denatured and more functional CPC, composed mainly of cruciferin and napin proteins. The functionality of the salt‐extracted CPC was comparable and sometimes better than that of SPI. Specifically, the solubility (~70%) of the salt‐extracted CPC at pH 3.4 was significantly (P < 0.05) higher than that (~50%) of SPI. Additionally, salt‐extracted CPC had significantly higher emulsification capacity and foaming capacity than SPI. On the other hand, the gelation property of CPC was inferior to that of SPI, an observation attributed to the molecular size of camelina protein compared to soy protein. Upon hydrolysis of CPC with Aspergillus oryzae protease, a limited benefit to solubility was noted at pH 7 postthermal treatment. Overall, results revealed the potential of camelina as a novel source of functional plant protein that might gain a position in the protein market place, and possibly compete with soy protein for several applications targeting the use of plant proteins.
Chemical Composition, Physical Properties, and the Oxidative Stability of Oil Bodies Extracted From Argania spinosa
Authors: Zaaboul Farah , Raza Husnain , Lazraq Abderrahim , Deng Boxin , Cao Chen , Liu Yuan F. 
Published: April 2018

AbstractOil bodies (OB) were extracted from argan kernels using an aqueous extraction method. The composition of OB revealed its lipid profile, which had a high content of stearic and palmitic acid. Besides, evidence suggested an association between OB and tocopherols. The physical properties of argan OB (AOB) showed that their size was around 1.9 μm and the ζ‐potential went from +17.7 mV at pH 2.0 to −32.25 mV at pH 8, with an isoelectric point around pH 5.1. OB were stable and small at pH 2.0, 7.0, and 8.0 but large near the pI. Additionally, AOB were stable against aggregation/coalescence even in high salt concentrations, and also against thermal processing (95 °C) with only a change in their interfacial properties. AOB emulsion showed interesting oxidative stability at different storage temperatures and heat treatment. Heat treatment and storage at low temperature preserved oleosins from degradation by the endogenous enzyme, and H‐oleosin 15 kDa resisted hydrolyzation even at a high storage temperature for 2 weeks.
Poly(2‐hydroxyethyl methacrylate)/boric acid composite hydrogel as soft contact lens material: Thermal, optical, rheological, and enhanced antibacterial properties
Authors: Ulu Ahmet , Balcioglu Sevgi , Birhanli Emre , Sarimeseli Ayse , Keskin Rukiye , Koytepe Suleyman , Ates Burhan 
Published: April 2018

ABSTRACTThe present work proposes to fabricate a composite hydrogel material that well characterized, transparent, biocompatible, and self‐antibacterial as potential soft contact lens material. For this purpose, poly(2‐hydroxyethyl methacrylate) (PHEMA)/boric acid (BA) composite hydrogels were successfully prepared by chemical crosslinking with BA through in situ polymerization using different BA ratios between 1 and 10% w/w. Afterward, the compositions, thermal stability, transparence, oxygen permeability, water uptake capacity, swelling ratio as well as morphological and rheological properties, in vitro degradability, in vitro cytotoxicity, and antibacterial properties of the all prepared materials were analyzed using a series of different techniques. The thermal stability, hydrophilicity, water uptake, oxygen permeability gradually increased depending ratio of BA, which is desirable for biomaterial. While the transparence and refractive index decreased, the composite hydrogels, except for BA content of 10 wt %, maintained enough transparency to be used for contact lens. In addition, PHEMA/BA composite hydrogels exhibited good cytocompatibility (PHEMA‐1%BA and PHEMA‐3%BA) and excellent antibacterial activity against Gram‐positive (Staphylococcus aureus and Enterococcus faecium) and Gram‐negative (Escherichia coli and Pseudomonas aeruginosa) bacteria. Overall, the results demonstrated that the obtained PHEMA/BA composite hydrogels could be considered as self‐antibacterial contact lens and a potential composite biomaterial for other applications. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46575.
Interfacial compatibility of super‐tough poly(lactic acid)/polyurethane blends investigated by positron annihilation lifetime spectroscopy
Authors: Zhao Xipo , Yu Xiaolei , Chen Hao , Zhou Weiyi , Fang Pengfei , Peng Shaoxian 
Published: April 2018

ABSTRACTSupertough polylactide (PLA)/polyurethane (PU) blends were prepared by reactive blending of PLA with polyester polyol and toluene‐2,4‐diisocyanate. The free volume and interfacial compatibility between the two polymers were investigated by positron annihilation lifetime spectroscopy. The PU particles dispersed homogeneously in the PLA matrix and self‐assembled into a subinclusion microstructure, resulting in fibrils and significant plastic deformation occurs during impact process. More phase interface and free volume cavities formed between PLA and PU boundary because of a good interfacial compatibility between the two polymers, leading to smaller sizes of free volume cavities, and the increasing of the number of these cavities. Therefore, the toughness of PLA was greatly improved by blending PU. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci.2018,135, 46596.
Effect of glucose fouling on the dissolved gases permeation through maximum‐crystallized poly(lactic acid) films
Authors: Hsiao Mingyin , Nara Suguru , Kitagawa Takeharu , Nagai Kazukiyo 
Published: April 2018

ABSTRACTIn this study, we investigated the effect of fouling on the dissolved oxygen and carbon dioxide permeation in water through maximum‐crystallized poly(lactic acid) (PLA) films by using proton nuclear magnetic resonance, attenuated total reflection‐Fourier transform infrared spectroscopy, wide‐angle X‐ray diffraction, and ultraviolet–visible spectroscopy, contact angle, water content ratio, and dissolved gas permeation. Fouling means the adhesion of contents on a container's internal surface, where content adhesion can directly influence the barrier property of the container. Glucose, a beverage ingredient, was used as a foulant. The permeation of dissolved gases in amorphous PLA film, maximum‐crystallized PLA film, and fouled maximum‐crystallized PLA film was determined. The decreased interstices in the polymer chains during crystallization resulted in the inhibition of the diffusion and decrease in the permeability coefficient of the gases. Moreover, the slope of the permeability coefficient for carbon dioxide in the Arrhenius plot was found smaller than that of oxygen's. This result indicated that the gas barrier property of dissolved carbon dioxide was considerably influenced by solubility and readily decreases during glucose fouling. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46604.
Design, synthesis, and molecular docking study of 3H‐imidazole[4,5‐c]pyridine derivatives as CDK2 inhibitors
Authors: Wu Yi‐Zhe , Ying Hua‐Zhou , Xu Lei , Cheng Gang , Chen Jing , Hu Yong‐Zhou , Liu Tao , Dong Xiao‐Wu 
Published: April 2018

AbstractA novel series of imidazo[4,5‐c]pyridine‐based CDK2 inhibitors were designed from the structure of CYC202 via scaffold hopping strategy. These compounds were synthesized and biologically evaluated for their CDK2 inhibitory and in vitro anti‐proliferation potential against cancer cell lines. Several compounds exhibited potent CDK2 inhibition with IC50 values of less than 1 µM. The most potent compound 5b showed excellent CDK2 inhibitory (IC50 = 21 nM) and in vitro anti‐proliferation activity against three different cell lines (HL60, A549, and HCT116). The molecular docking and dynamic studies portrayed the potential binding mechanism between 5b and CDK2, and several key interactions between them were observed, which would be the reason for its potent CDK2 inhibitory and anti‐proliferation activities. Therefore, the pyridin‐3‐ylmethyl moiety would serve as an excellent pharmacophore for the development of novel CDK2 inhibitors for targeted anti‐cancer therapy.
Enhanced chemiluminescence of the fluorescein–KIO4 system by CdTe quantum dots for determination of catechol
Authors: Cai Na , Yang DongQin , He YanYan , Chen FuNan 
Published: April 2018

AbstractIn this paper, a novel chemiluminescence (CL) system was introduced based on the use of CdTe quantum dots (QDs) with the mixture solutions of fluorescein and potassium periodate (KIO4) in alkaline medium. The CL signal of an ultra‐weak system was strongly enhanced in the presence of QDs. The application of CdTe QDs–fluorescein–KIO4 system is reported for the first time. It was found that catechol had a diminishing effect on the CL reaction. Under optimal experimental conditions, CL intensity decreased linearly in a 1 to 100 μM catechol concentration range, with a 0.18 μM detection limit. A possible reaction mechanism was proposed according to the results of kinetic analyses, CL spectra, ultraviolet–visible and fluorescence spectra. The results pointed to an efficient energy transfer between the CL energy donor CdTe QDs and acceptor fluorescein. Finally, the CL method was successfully applied to the determination of catechol in environmental water samples.
Utility of Von Pechman synthesis of coumarin reaction for development of spectrofluorimetric method for quantitation of salmeterol xinafoate in pharmaceutical preparations and human plasma
Authors: Awad Mohamed , Hammad Mohamed A. , Abdel‐Megied Ahmed M. , Omar Mahmoud A. 
Published: April 2018

AbstractSimple, precise and selective spectrofluorimetric technique was evolved for quantitation of selective β2 agonist drug namely salmeterol xinafoate (SAL). Utilizing its phenolic nature, a method was described based on the reaction of the studied drug with ethyl acetoacetate (EAA) to yield extremely fluorescent coumarin product which can be detected at 480 nm (λex = 420 nm). The procedure obeys Beer's law with a correlation coefficient of r = 0.9999 in the concentration range between 500 and 5000 ng ml−1 with and 177 ng ml−1 for limit of detection (LOD) and limit of quantification (LOQ), respectively. Diverse reaction variables influencing the firmness and formation of the coumarin product were accurately examined and modified to ensure greatest sensitivity of the procedure. The proposed technique was performed and examined according to the US Food and Drug Administration (FDA) guidelines for bio‐analytical methods and was efficiently applied for quantitation of SAL in both pharmaceutical preparations (% recovery = 100.06 ± 1.07) and spiked human plasma (% recovery = 96.64–97.14 ± 1.01–1.52).
Clinical translation of microbe‐based therapies: Current clinical landscape and preclinical outlook
Authors: Vargason Ava M. , Anselmo Aaron C. 
Published: April 2018

AbstractNext generation microbe‐based therapeutics, inspired by the success of fecal microbiota transplants, are being actively investigated in clinical trials to displace or eliminate pathogenic microbes to treat various diseases in the gastrointestinal tract, skin, and vagina. Genetically engineered microbes are also being investigated in the clinic as drug producing factories for biologic delivery, which can provide a constant local source of drugs. In either case, microbe‐therapeutics have the opportunity to address unmet clinical needs and open new areas of research by reducing clinical side effects associated with current treatment modalities or by facilitating the delivery of biologics. This review will discuss examples of past and current clinical trials that are investigating microbe‐therapeutics, both microbiome‐modulating and drug‐producing, for the treatment of a range of diseases. We then offer a perspective on how preclinical approaches, both those focused on developing advanced delivery systems and those that use in vitro microbiome model systems to inform formulation design, will lead to the realization of next‐generation microbe‐therapeutics.
Enzymatic synthesis of ethyl esters from waste oil using mixtures of lipases in a plug‐flow packed‐bed continuous reactor
Authors: Poppe Jakeline Kathiele , Matte Carla Roberta , de Freitas Vitória Olave , Fernandez‐Lafuente Roberto , Rodrigues Rafael C. , Záchia Ayub Marco Antônio 
Published: April 2018

This work describes the continuous synthesis of ethyl esters via enzymatic catalysis on a packed‐bed continuous reactor, using mixtures of immobilized lipases (combi‐lipases) of Candida antarctica (CALB), Thermomyces lanuginosus (TLL), and Rhizomucor miehei (RML). The influence of the addition of glass beads to the reactor bed, evaluation of the use of different solvents, and flow rate on reaction conditions was studied. All experiments were conducted using the best combination of lipases according to the fatty acid composition of the waste oil (combi‐lipase composition: 40% of TLL, 35% of CALB, and 25% of RML) and soybean oil (combi‐lipase composition: 22.5% of TLL, 50% of CALB, and 27.5% of RML). The best general reaction conditions were found to be using tert‐butanol as solvent, and the flow rate of 0.08 mL min−1. The combi‐lipase reactors operating at steady state for over 30 days (720 h), kept conversion yields of ∼50%, with average productivity of 1.94 gethyl esters
h−1, regardless of the type of oil in use. © 2018 American Institute of Chemical Engineers Biotechnol. Prog., 34:952–959, 2018
A Comparative Reengineering Study of cpADH5 through Iterative and Simultaneous Multisite Saturation Mutagenesis
Authors: Ensari Yunus , Dhoke Gaurao V. , Davari Mehdi D. , Ruff Anna Joëlle , Schwaneberg Ulrich 
Published: April 2018

AbstractPositions identified in directed evolution campaigns or by (semi)rational design can be recombined iteratively or simultaneously. Iterative recombination has yielded many success stories and is beneficially used if screening capabilities are limited (four iterative SSMs generate 20×4=80 different enzyme variants). Simultaneous site saturation mutagenesis offers significantly higher diversity (204=160 000 variants) and enables greater improvements to be found, especially if the selected positions are in close proximity to each other (cooperative effects). Here we report a first comprehensive comparison of iterative and simultaneous saturation of four residues in Candida parapsilosis alcohol dehydrogenase 5 (cpADH5) with methyl 3‐hydroxyhexanoate as substrate. Screening of 7200 clones from 33 site saturation mutagenesis libraries (exploring 17 recombination paths) yielded the cpADH5 W286A variant, with a 82‐fold improved initial activity toward methyl 3‐hydroxyhexanoate. Screening 3500 clones from a single OmniChange library with four positions (C57, W116, L119, and W286; 1.8 % of the generated sequence space) yielded the cpADH5 C57V/W286S variant, with a 108‐fold improvement in initial activity toward methyl 3‐hydroxyhexanoate. A 1.8 % coverage of the sequence space of the simultaneous multisite saturation library was, in comparison to the investigated 17 recombination paths, sufficient to identify a cpADH5 variant with improved activity.
Palladium‐Catalyzed Cross‐Dehydrogenative Coupling of o‐Xylene: Evidence of a New Rate‐Limiting Step in the Search for Industrially Relevant Conditions
Authors: Álvarez‐Casao Yolanda , van Slagmaat Christian A. M. R. , Verzijl Gerard K. M. , Lefort Laurent , Alsters Paul L. , Fernández‐Ibáñez M. Ángeles 
Published: April 2018

AbstractAn efficient cross‐dehydrogenative coupling of o‐xylene under neat conditions, which brings important industrial benefits towards the synthesis of a monomer used in polyimide resins, is reported. The catalyst based on the combination of Pd/N ligand/carboxylate=1:1:2 does not require a Cu cocatalyst and proceeds at 11 bar of O2 pressure. Evaluation of the deuterium kinetic isotope effect (KIE) provides evidence for three different rate‐determining steps, which depend on the reaction conditions (medium, temperature). Under the reported neat conditions, the dissociation of a carboxylate‐bridged dimer to generate a more reactive monometallic Pd species is proposed to be the rate‐limiting step.
Strong Preference of the Redox‐Neutral Mechanism over the Redox Mechanism for the TiIV Catalysis Involved in the Carboamination of Alkyne with Alkene and Diazene
Authors: Guo Jiandong , Lu Yu , Zhao Ruihua , Liu Zheyuan , Menberu Wasihun , Wang Zhi‐Xiang 
Published: April 2018

AbstractTitanium catalysis generally prefers redox‐neutral mechanisms. Yet it has been reported that titanium could promote bond formations in a way similar to reductive elimination. Accordingly, redox catalytic cycles involving TiIV/TiII cycling have been considered. By studying, as an example, the carboamination of alkynes with alkenes and azobenzene catalyzed by the [TiIV]=NPh imido complex, we performed DFT computations to gain an understanding of how the “abnormal” catalysis takes place, thereby allowing us to clarify whether the catalysis really follows TiIV/TiII redox mechanisms. The reaction first forms an azatitanacyclohexene by alkyne addition to the [TiIV]=NPh bond, followed by alkene insertion. The azatitanacyclohexene can either undergo Cα−Cγ coupling, to afford bicyclo[3.1.0]imine, or β‐H elimination, to yield a [TiIV]−H hydride, which then undergoes Cα=Cβ or Cγ=Cδ insertion to give an α,β‐ or β,γ‐unsaturated imine, respectively. Both the geometric and electronic structures indicate that the catalytic cycles proceed through redox‐neutral mechanisms. The alternative redox mechanisms (e.g., by N−H or C−H reductive elimination) are substantially less favorable. We concluded that electronically, the TiIV catalysis intrinsically favors the redox‐neutral mechanism, because a redox pathway would involve TiII structures either in the triplet ground state or in the high‐lying open‐shell singlet state, but the involvement of triplet TiII structures is spin‐forbidden and that of singlet TiII structures is energetically disadvantageous.
Kinetics of Ethylene Epoxidation on a Promoted Ag/α‐Al2O3 Catalyst—The Effects of Product and Chloride Co‐Feeds on Rates and Selectivity
Authors: Chen Cha‐Jung , Harris James W. , Bhan Aditya 
Published: April 2018

AbstractThe overall chloriding effectiveness factor (Z*), defined as the ratio of ethyl chloride concentration in parts per million to the sum of ethylene and ethane concentration in mole percent multiplied by a weighting factor to account for their efficacy in removing chlorine‐adatoms from the surface, was used as a parameter to account for the effects of chlorine on the kinetics of ethylene epoxidation on a highly promoted 35 wt % Ag/α‐Al2O3 catalyst. An increase in O2 order (≈0.7 to 1) and a decrease in C2H4 order (≈0.5 to <0) with increasing Z* (Z*=2.1, 3.4, 5.2, and 8.9) was observed implicating kinetic relevance of O2 activation on chloride‐promoted silver catalysts. Carbon dioxide co‐feed (1–5 mol %) was found to promote ethylene oxide selectivity as CO2 co‐feed reversibly inhibits CO2 synthesis rates (−0.6 order) more than ethylene oxide synthesis rates (−0.49 order) at all Z* values. Ethylene oxide and CO2 rates were found to be invariant with ethylene oxide (0–0.5 mol %) and acetaldehyde (0–1.7 ppm) co‐feeds, suggesting that there is minimal product inhibition under reaction conditions. A model involving a common reaction intermediate for ethylene oxide and carbon dioxide synthesis and two types of atomically adsorbed oxygen species—nucleophilic and electrophilic oxygen—is proposed to plausibly describe the observed reaction rate dependencies and selectivity trends as a function of the chloriding effectiveness.
A snapshot of the evolving epidemiology of oropharynx cancers
Authors: Chaturvedi Anil K. , Zumsteg Zachary S. 
Published: April 2018

The trajectory of the human papillomavirus–positive oropharyngeal cancer epidemic in the United States reveals that “what's past is prologue” (William Shakespeare, The Tempest): birth cohorts that previously experienced rises in incidence at younger ages do so now at older ages. Trials to determine the optimal clinical management of this increasingly older patient population are needed.See also pages 2993‐9.