bluuebunny/crossref_metadata_2025_split huggingface dataset:
Oriented Nanofibrous Polymer Scaffolds Containing Protein‐Loaded Porous Silicon Generated by Spray Nebulization
Authors: Zuidema Jonathan M. , Kumeria Tushar , Kim Dokyoung , Kang Jinyoung , Wang Joanna , Hollett Geoffrey , Zhang Xuan , Roberts David S. , Chan Nicole , Dowling Cari , Blanco‐Suarez Elena , Allen Nicola J. , Tuszynski Mark H. , Sailor Michael J. 
Published: January 2018

AbstractOriented composite nanofibers consisting of porous silicon nanoparticles (pSiNPs) embedded in a polycaprolactone or poly(lactide‐co‐glycolide) matrix are prepared by spray nebulization from chloroform solutions using an airbrush. The nanofibers can be oriented by an appropriate positioning of the airbrush nozzle, and they can direct growth of neurites from rat dorsal root ganglion neurons. When loaded with the model protein lysozyme, the pSiNPs allow the generation of nanofiber scaffolds that carry and deliver the protein under physiologic conditions (phosphate‐buffered saline (PBS), at 37 °C) for up to 60 d, retaining 75% of the enzymatic activity over this time period. The mass loading of protein in the pSiNPs is 36%, and in the resulting polymer/pSiNP scaffolds it is 3.6%. The use of pSiNPs that display intrinsic photoluminescence (from the quantum‐confined Si nanostructure) allows the polymer/pSiNP composites to be definitively identified and tracked by time‐gated photoluminescence imaging. The remarkable ability of the pSiNPs to protect the protein payload from denaturation, both during processing and for the duration of the long‐term aqueous release study, establishes a model for the generation of biodegradable nanofiber scaffolds that can load and deliver sensitive biologics.
Au/TiO2–gC3N4 Nanocomposites for Enhanced Photocatalytic H2 Production from Water under Visible Light Irradiation with Very Low Quantities of Sacrificial Agents
Authors: Marchal Clément , Cottineau Thomas , Méndez‐Medrano María Guadalupe , Colbeau‐Justin Christophe , Caps Valérie , Keller Valérie 
Published: January 2018

AbstractHere for the first time the design and optimization are presented of a three‐component Au/TiO2–gC3N4 nanocomposite photocatalyst able to efficiently produce H2 from water using very low amounts of sacrificial agents and under visible light irradiation. This enhanced photocatalytic behavior compared to Au/TiO2 and Au/gC3N4 materials is the result of synergetic effects due to high quality assembly and interface between the three components. This optimized nanoscale assembly characterized by simultaneous favorable nanoheterojunction formation between g‐C3N4 and TiO2 semiconductors, as well as AuNPs/gC3N4 and AuNPs/TiO2 junctions, leads to enhanced visible light harvesting, charge separation, and H2 production. This composite photocatalyst yields a high H2 production (350 µmol−1 h−1 gcatalyst−1) under visible light irradiation with minimal amounts of sacrificial agent (≤1 vol%), corresponding to activities much higher than reported so far under comparable conditions.
Simultaneous Improvement of Photovoltaic Performance and Stability by In Situ Formation of 2D Perovskite at (FAPbI3)0.88(CsPbBr3)0.12/CuSCN Interface
Authors: Chen Jiangzhao , Seo Ja‐Young , Park Nam‐Gyu 
Published: January 2018

AbstractTo solve the stability issues of perovskite solar cells (PSC), here a novel interface engineering strategy that a versatile ultrathin 2D perovskite (5‐AVA)2PbI4 (5‐AVA = 5‐ammoniumvaleric acid) passivation layer that is in situ incorporated at the interface between (FAPbI3)0.88(CsPbBr3)0.12 and the hole transporting CuSCN is reported. Surface analysis using X‐ray photoelectron spectroscopy confirms the formation of 2D perovskite. Hysteresis is reduced by the interfacial 2D layer, which could be ascribed to improvement of interfacial charge extraction efficiency, associated with suppression of recombination. Moreover, introduction of the interface passivating layer enhances the moisture stability and photostability as compared to the control perovskite film due to hydrophobic nature of 2D perovskite. The unencapsulated device retains 98% of the initial power conversion efficiency (PCE) after 63 d under moisture exposure of about 10% in the dark. A PCE of the control device is boosted from 13.72 to 16.75% as a consequence of enhanced open‐circuit voltage (Voc) and fill factor along with slightly increased short‐circuit current density (Jsc), which results from reduced trap states of (FAPbI3)0.88(CsPbBr3)0.12 as evidenced by enhanced carrier lifetimes and charge extraction. The perovskite/hole transport material interface engineering gives insight into simultaneous improvements of PCE and device stability.
Nucleophile Promiscuity of Engineered Class II Pyruvate Aldolase YfaU from E. Coli
Authors: Hernández Karel , Joglar Jesús , Bujons Jordi , Parella Teodor , Clapés Pere 
Published: January 2018

AbstractPyruvate‐dependent aldolases exhibit a stringent selectivity for pyruvate, limiting application of their synthetic potential, which is a drawback shared with other existing aldolases. Structure‐guided rational protein engineering rendered a 2‐keto‐3‐deoxy‐l‐rhamnonate aldolase variant, fused with a maltose‐binding protein (MBP‐YfaU W23V/L216A), capable of efficiently converting larger pyruvate analogues, for example, those with linear and branched aliphatic chains, in aldol addition reactions. Combination of these nucleophiles with N‐Cbz‐alaninal (Cbz=benzyloxycarbonyl) and N‐Cbz‐prolinal electrophiles gave access to chiral building blocks, for example, derivatives of (2S,3S,4R)‐4‐amino‐3‐hydroxy‐2‐methylpentanoic acid (68 %, d.r. 90:10) and the enantiomer of dolaproine (33 %, d.r. 94:6) as well as a collection of unprecedented α‐amino acid derivatives of the proline and pyrrolizidine type. Conversions varied between 6–93 % and diastereomeric ratios from 50:50 to 95:5 depending on the nucleophilic and electrophilic components.
Direkte Umwandlung von Methan zu protoniertem Formaldehyd bei Raumtemperatur in der Gasphase: Zur Rolle von Quecksilber unter den Oxidkationen der Zinktriade
Authors: Yue Lei , Zhou Shaodong , Sun Xiaoyan , Schlangen Maria , Schwarz Helmut 
Published: January 2018

AbstractIn den thermischen Reaktionen der zweiatomigen Metalloxide [MO].+ der Zinktriade (M=Zn, Cd, Hg) entsteht protonierter Formaldehyd, und zwar als Hauptprodukt, ausschließlich für das [HgO].+/CH4‐Paar. Durch quantenchemische Rechnungen konnten mechanistische Einblicke in diese Reaktion erhalten werden; die unerwartete Bildung von [CH2OH]+ aus [HgO].+/CH4 beruht vermutlich auf relativistischen Effekten.
Stepwise Hydride Transfer in a Biological System: Insights into the Reaction Mechanism of the Light‐Dependent Protochlorophyllide Oxidoreductase
Authors: Archipowa Nataliya , Kutta Roger J. , Heyes Derren J. , Scrutton Nigel S. 
Published: January 2018

AbstractHydride transfer plays a crucial role in a wide range of biological systems. However, its mode of action (concerted or stepwise) is still under debate. Light‐dependent NADPH: protochlorophyllide oxidoreductase (POR) catalyzes the stereospecific trans addition of a hydride anion and a proton across the C17−C18 double bond of protochlorophyllide. Time‐resolved absorption and emission spectroscopy were used to investigate the hydride transfer mechanism in POR. Apart from excited states of protochlorophyllide, three discrete intermediates were resolved, consistent with a stepwise mechanism that involves an initial electron transfer from NADPH. A subsequent proton‐coupled electron transfer followed by a proton transfer yield distinct different intermediates for wild type and the C226S variant, that is, initial hydride attaches to either C17 or C18, but ends in the same chlorophyllide stereoisomer. This work provides the first evidence of a stepwise hydride transfer in a biological system.
Tailored Organic Electrode Material Compatible with Sulfide Electrolyte for Stable All‐Solid‐State Sodium Batteries
Authors: Chi Xiaowei , Liang Yanliang , Hao Fang , Zhang Ye , Whiteley Justin , Dong Hui , Hu Pu , Lee Sehee , Yao Yan 
Published: January 2018

AbstractAll‐solid‐state sodium batteries (ASSSBs) with nonflammable electrolytes and ubiquitous sodium resource are a promising solution to the safety and cost concerns for lithium‐ion batteries. However, the intrinsic mismatch between low anodic decomposition potential of superionic sulfide electrolytes and high operating potentials of sodium‐ion cathodes leads to a volatile cathode–electrolyte interface and undesirable cell performance. Here we report a high‐capacity organic cathode, Na4C6O6, that is chemically and electrochemically compatible with sulfide electrolytes. A bulk‐type ASSSB shows high specific capacity (184 mAh g−1) and one of the highest specific energies (395 Wh kg−1) among intercalation compound‐based ASSSBs. The capacity retentions of 76 % after 100 cycles at 0.1 C and 70 % after 400 cycles at 0.2 C represent the record stability for ASSSBs. Additionally, Na4C6O6 functions as a capable anode material, enabling a symmetric all‐organic ASSSB with Na4C6O6 as both cathode and anode materials.
Iod(III)‐Verbindungen als Halogenbrückenkatalysatoren
Authors: Heinen Flemming , Engelage Elric , Dreger Alexander , Weiss Robert , Huber Stefan M. 
Published: January 2018

AbstractHypervalente Iod(III)‐Verbindungen sind als vielseitige Reagenzien in der organischen Synthese bekannt. Bisher gibt es allerdings nur einen Bericht über ihren Einsatz als Lewis‐Säuren in der Organokatalyse. Wir berichten hier über erste starke Hinweise auf die entscheidende Bedeutung von Halogenbrücken in dieser Art der Katalyse. Hierbei dienten die Solvolyse von Benzhydrylchlorid und die Diels‐Alder‐Reaktion zwischen Cyclopentadien und Methylvinylketon als Testreaktionen für Halogenidabstraktion sowie die Aktivierung von Neutralverbindungen. Iodoliumsalze (cyclische Diaryliodonium‐Verbindungen) wurden als Aktivatoren und Katalysatoren verwendet, und ihre Aktivität konnte durch Blockieren einer oder beider elektrophiler Achsen signifikant verringert bzw. vollständig ausgeschaltet werden. Im Vergleich zu den zuvor veröffentlichten zweizähnigen kationischen Halogenbrückendonoren zeigen die hier verwendeten einzähnigen Organoiodderivate eine vergleichbare Aktivität (in der Diels‐Alder‐Reaktion) oder sogar eine deutlich höhere (in der Solvolyse von Benzhydrylchlorid).
Single‐Molecule Determination of the Isomers of d‐Glucose and d‐Fructose that Bind to Boronic Acids
Authors: Ramsay William J. , Bayley Hagan 
Published: January 2018

AbstractMonosaccharides, such as d‐glucose and d‐fructose, exist in aqueous solution as an equilibrium mixture of cyclic isomers and can be detected with boronic acids by the reversible formation of boronate esters. The engineering of accurate, discriminating and continuous monitoring devices relies on knowledge of which cyclic isomer of a sugar binds to a boronic acid receptor. Herein, by monitoring fluctuations in ionic current, we show that an engineered α‐hemolysin (αHL) nanopore modified with a boronic acid reacts reversibly with d‐glucose as the pyranose isomer (α‐d‐glucopyranose) and d‐fructose as either the furanose (β‐d‐fructofuranose) or the pyranose (β‐d‐fructopyranose). Both of these binding modes contradict current binding models. With this knowledge, we distinguished the individual sugars in a mixture of d‐maltose, d‐glucose, and d‐fructose.
Using landing statistics and fishers’ traditional ecological knowledge to assess conservation threats to Pacific goliath grouper in Colombia
Authors: Castellanos‐Galindo Gustavo A. , Chong‐Montenegro Carolina , Baos E Rodrigo A. , Zapata Luis A. , Tompkins Paul , Graham Rachel T. , Craig Matthew 
Published: January 2018

Abstract

Groupers are vulnerable to fishing pressure largely because of their life‐history traits. The Pacific goliath grouper (PGG; Epinephelus quinquefasciatus), the largest reef fish inhabiting the tropical Eastern Pacific region, is suspected to be subject to high levels of exploitation, but scarce information exists on their population status and the species remains classed as Data Deficient according to the International Union for Conservation of Nature (IUCN) Red List.
This study documents for the first time the threats to the PGG along the Colombian Pacific coast, where one of the few active fisheries for this species persists. Reconstructed landings of groupers and traditional ecological knowledge, gathered throughout several coastal villages, were used to obtain a historical and contemporary overview of the PGG status in Colombia.
Over the past 20 years grouper landings in the Colombian Pacific have been around 200 tons per year. Landings of PGG have averaged ~35 tons per year and are now close to matching those of the historically most landed grouper on this coast, the rooster hind (Hyporthodus acanthistius). The current small‐scale fishery for PGG focuses on immature small individuals, with most taken from the extensive southern mangroves. Until recently fishers have captured PGG exclusively with handlines, but new fishing practices (spearfishing) and markets commanding higher prices for small individuals are increasing the extinction risk for the PGG.
The exploitation of PGG in the Colombian Pacific may not be as severe as in other countries where severe population declines are suspected (e.g. Mexico). Low coastal human population density and the presence of relatively intact mangroves, essential habitat for juvenile fishes, contribute to the persistence of PGG populations throughout the Colombian Pacific.
National and regional conservation and management measures should identify and protect mangrove nurseries and offshore spawning aggregation sites. Well‐enforced protected nurseries and spawning aggregation sites will then protect juvenile and adult PGG, improving the sustainability of this fishery.
Rheological Behavior of Mixtures of Ionic Liquids with Water
Authors: Kliemann Christian , Kleiber Michael , Müller Karsten 
Published: January 2018

AbstractThe changes in viscosity exhibited upon mixing remain one of the major challenges for substance property prediction. Viscosity often drastically changes after even small changes in concentration of one of the compounds in the mixture. The viscosity behavior of mixtures of ionic liquids with water has been studied. First, a generalized evaluation of the shape of the viscosity‐concentration curves has been done. About one‐tenth of the investigated systems exhibited maxima or inflection points of the curve. The simple logarithmic mixing rule turns out to be applicable as a first approximation for many systems. However, it tends to underestimate mixture viscosity. Following these results, parameters for a group contribution method were fitted and evaluated. This method is based on the Grunberg and Nissan extension of the logarithmic mixing rule.
Achieving Skeletal Diversity in Peptide Macrocycles through The Use of Heterocyclic Grafts
Authors: Kaldas Sherif J. , Yudin Andrei K. 
Published: January 2018

AbstractDespite their therapeutic potential, peptide macrocycles often suffer from drawbacks such as low membrane permeability, proteolytic instability, and conformational lability. As a result, there have been significant efforts to “depeptidize” amino acid‐rich macrocycles through the incorporation of heterocyclic grafts into their backbones. In this concept article, we summarize selected recent methodologies that can be used to introduce heterocycles into cyclic peptides.
From a Metastable Layer to a Stable Ring: A Kinetic Study for Transformation Reactions of Li2Mo3TeO12 to Polyoxometalates
Authors: Oh Seung‐Jin , Lim Seong‐Ji , You Tae‐Soo , Ok Kang Min 
Published: January 2018

AbstractInvited for the cover of this issue is the group of Kang Ming Ok at the Chung An University in Seoul. The image depicts stacked Jenga blocks with unstable structures and highly organized structures, depicting the metastable tellurites and the thermodynamically stable polyoxometalates, respectively. Read the full text of the article at 10.1002/chem.201704755.
A survey of techniques for architecting SLC/MLC/TLC hybrid Flash memory–based SSDs
Authors: Alsalibi Ahmed Izzat , Mittal Sparsh , Al‐Betar Mohammed Azmi , Sumari Putra Bin 
Published: January 2018

SummaryFlash memory–based solid‐state drives (SSDs) offer several attractive features and benefits compared to hard disk drive (HDD), such as shock resistance and better performance especially for random data access. Depending on the number of bits in each cell, Flash memory can be designed as single/multi/triple level cell (SLC/MLC/TLC), which have different performance, density, cost and write endurance characteristics. To bring the best of these together, several researchers have proposed designing SSD using hybrid SLC/MLC/TLC Flash memory. However, these SSDs also present several challenges such as buffer management, placement of hot/cold data in suitable portion, and intelligent garbage collection. Several recent techniques aim to address these challenges. In this paper, we present a survey of techniques for managing SSDs designed with SLC/MLC/TLC Flash memory. We classify the works on several axes to bring out their similarities and differences. We aim to synthesize the state‐of‐art progress in hybrid SSD management and also spark further research in this area.
Reducing distributed JR program start‐up time via extending JR's operation abstraction
Authors: Olsson Ronald A. , Keen Aaron W. , Williamson Todd 
Published: January 2018

SummaryThis paper shows how to simplify and speed up distributed JR program start‐up. We accomplish this goal by extending JR's operation abstraction so that it includes the creation of virtual machines and remote objects, the key components in distributed JR programs. This extension is conceptually simple, fits well with the rest of the JR language, and provides additional flexibility. Extending JR's operation abstraction yields a considerably less complex solution and a simpler implementation than other approaches, which would have led to redundant or ad‐hoc language mechanisms. The extension also allows for reduced distributed JR program start‐up costs because the creation of virtual machines and remote objects can now be done in parallel. This paper also describes how we have simulated this extension and have implemented a prototype that provides this extension. These reflect closely what we would need to do to actually include the extension within the standard JR implementation. Using the simulation and prototype, we obtained performance data on a few typical distributed applications written to use the extension. The data show large reductions, ranging from about 50% to 95%, in distributed JR program start‐up times. Our experiments also explored a few strategies to further reduce start‐up times, but, among our strategies, the straightforward strategies seem the best. This paper also discusses design alternatives for creating virtual machines and remote objects. Our experience suggests that the proposed extension to JR's operation abstraction is actually worthwhile to add to the standard JR language and implementation.
A faster phase frequency detector using transmission gate–based latch for the reduced response time of the PLL
Authors: Koithyar Aravinda , Ramesh T.K. 
Published: January 2018

SummaryIn this paper, we present a new design of phase frequency detector (PFD) without reset, such that the blind zone and dead zone issues in the phase locked loop are annihilated. The PFD is designed using transmission gate–based latches, which produce UP and DOWN pulses only when there is a distinct phase difference between the reference and divided frequencies. Thus, the continuous pulses that get produced by the conventional NAND gate–based latches are avoided, leading to reduced power consumption of the PFD. The charge pump makes use of an op‐amp used as a buffer, to reduce the current mismatch. The loop filter used is of second order, and the voltage‐controlled oscillator is of conventional current–starved type. The divider makes use of true single‐phase clock latches. It was found that the phase locked loop with new design of PFD, compared with the conventional design, consumes 27% lesser power, and the lock time is decreased by 79%. In addition, it was found that the control voltage swing is reduced by 71%, which leads to much lesser spur content at the output of the voltage‐controlled oscillator.
NKX6.1 hypermethylation predicts the outcome of stage II colorectal cancer patients undergoing chemotherapy
Authors: Chang Sou‐Yi , Kuo Chih‐Chi , Wu Chang‐Chieh , Hsiao Cheng‐Wen , Hu Je‐Ming , Hsu Chih‐Hsiung , Chou Yu‐Ching , Shih Yu‐Lueng , Lin Ya‐Wen 
Published: January 2018

AbstractColorectal cancer (CRC) is a common malignancy worldwide. CRC patients in the same stage often present with dramatically different clinical scenarios. Thus, robust prognostic biomarkers are urgently needed to guide therapies and improve treatment outcomes. The NKX6.1 gene has been identified as a hypermethylation marker in cervical cancer, functioning as a metastasis suppressor by regulating epithelial–mesenchymal transition. Here, we investigated whether hypermethylation of NKX6.1 might be a prognostic biomarker for CRC. By analyzing the methylation and expression of NKX6.1 in CRC tissues and CRC cell lines. We quantitatively examined the NKX6.1 methylation levels in 151 pairs of CRC tissues by using methylation‐specific polymerase chain reaction analysis and found that NKX6.1 was hypermethylated in 35 of 151 CRC tissues (23%). NKX6.1 gene expression was inversely correlated with the DNA methylation level in CRC cell lines in vitro. Then, we analyzed the association of NKX6.1 methylation with clinical characteristics of these CRC patients. Our data demonstrated that patients with NKX6.1 methylation presented poorer 5‐year overall survival (P = 0.0167) and disease‐free survival (P = 0.0083) than patients without NKX6.1 methylation after receiving adjuvant chemotherapy. Most importantly, these data revealed that stage II CRC patients with NKX6.1 methylation had poorer 5‐year disease‐free survival (P = 0.0322) than patients without NKX6.1 methylation after adjuvant chemotherapy. Our results demonstrate that methylation of NKX6.1 is a novel prognostic biomarker in CRC and that it may be used as a predictor of the response to chemotherapy.
A longitudinal study of cognitive trajectories and its factors for Koreans aged 60 and over: A latent growth mixture model
Authors: Min Jong Won 
Published: January 2018

ObjectiveThe purpose of this study is twofold: first, to identify cognitive trajectories of older Koreans in a population‐based longitudinal panel survey and, second, to investigate the main characteristics of the identified heterogeneous classes of cognitive trajectories.MethodsData came from 2445 cognitively healthy persons aged 60 or older in the 2006 to 2012 Korean Longitudinal Study of Aging. Using Korean–mini mental status examination (K‐MMSE) as a measure of global cognitive function, the latent growth mixture modeling approach examined potential heterogeneity of longitudinal changes over the 6 years.ResultsThis study found that older Koreans reported an average K‐MMSE score of 27 at baseline and experienced a cognitive decline every 2 years by −1.6 (2006‐2008) and −1.2 (2008‐2010), followed by a slight increase of 0.7 in 2012. Results from the latent growth mixture modeling analysis indicated that there were 2 heterogeneous classes of longitudinal changes in the K‐MMSE over a period of 6 years: class 1 with stable cognitive function and class 2 with sharp cognitive decline over time. The sharp decline was found among those older in age and with higher level of depression at baseline. On the contrary, being male, higher education, active social engagement, and regular exercise were main characteristics of stable cognitive function.ConclusionAs the first to examine cognitive trajectories among older Koreans, this study highlighted heterogeneity of cognitive trajectories in the population that should be considered for developing differential intervention strategies aimed at both promoting healthy brain and delaying/preventing cognitive decline.