bluuebunny/crossref_metadata_2025_split huggingface dataset:
Encapsulation of hydrophobic or hydrophilic iron oxide nanoparticles into poly(lactic acid) micro/nanoparticles via adaptable emulsion setup
Authors: Song Anna , Ji Shaowen , Sook Hong Joung , Ji Yi , Gokhale Ankush A. , Lee Ilsoon 
Published: April 2016

ABSTRACTIn this study, a one‐step water‐in‐oil‐in‐water (W/O/W) emulsion process was employed to encapsulate either hydrophilic (∼10 nm) or hydrophobic (∼5 nm) iron oxide nanoparticles (IONPs) into poly(lactic acid) (PLA). Via the simple adjustment of emulsification temperature to high temperature (HT, 60 °C) or room temperature (RT, 25 °C), a transformation of PLA‐IONPs composite particles from hollow microparticles to solid nanospheres can be achieved. At RT, PLA nanocomposite particles (30–200 nm) encapsulating IONPs were generated regardless of the hydrophobicity of IONPs. On the other hand, at HT, our method resulted in the hollow microparticles (2–5 µm). This study presents a fast and easily adaptable process to encapsulate either hydrophobic or hydrophilic IONPs into the hydrophobic polymeric particles, with different shapes and sizes, by simply adjusting the emulsification temperature through the one‐step W/O/W emulsion. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43749.
Green Tea and Glycine Modulate the Activity of Metalloproteinases and Collagen in the Tendinitis of the Myotendinous Junction of the Achilles Tendon
Authors: Vieira Cristiano Pedrozo , De Oliveira LetÍCia Prado , Da Ré Guerra Flávia , Marcondes Maria Cristina Cintra , Pimentel Edson Rosa 
Published: April 2016

ABSTRACTThe myotendinous junction (MTJ) is the weakest element in the muscle‐tendon unit of the heel, and thus the most susceptible to injuries. The scarcity of adequate treatments means that tendinitis is a major concern to athletes and other groups who depend on their physical fitness, although green tea and glycine have both been shown to have beneficial effects on the inflammation. The present study investigated the remodeling effects of green tea and glycine in the MTJ of rats with tendinitis. For this, male Wistar rats were divided into five groups: animals without tendinitis and animals with tendinitis; animals with tendinitis supplied with green tea; animals with tendinitis supplied with a glycine diet; animals with tendinitis supplied with a green tea and glycine diet. Tendinitis was induced and the treatment with green tea (700 mg/kg/day) and a 5% glycine diet lasted 7 days. The treatments regulated the activity of metalloproteinases (MMP)‐2, ‐8, and ‐9, and induced the synthesis of type I collagen, glycosaminoglycans, and non‐collagenous proteins. Changes were also noted in the compaction of the collagen molecules and the amount of tenocytes. When combined, green tea and glycine modulated the inflammatory process and induced the synthesis of the elements involved in the post‐lesion recovery of the tissue. The data from the MTJ were different when compared with results already published using the whole Achilles tendon. These data indicate that each region of the inflamed tendon can exhibit different responses during the treatment and therefore, modify its extracellular matrix components to facilitate recovery and repair. Anat Rec, 299:918–928, 2016. © 2016 Wiley Periodicals, Inc.
Risk factors for recurrence in patients with papillary thyroid carcinoma undergoing modified radical neck dissection
Authors: Lee Y M , Sung T Y , Kim W B , Chung K W , Yoon J H , Hong S J 
Published: April 2016

Abstract

Background
This study evaluated the impact of lymph node-related factors on the risk of and site of recurrence in patients who had papillary thyroid carcinoma with lymph node metastasis in the lateral compartment (classified as pN1b).

Methods
Patients underwent total thyroidectomy with unilateral modified radical neck dissection for classical papillary thyroid carcinoma. Risk factors for recurrence were evaluated according to the pattern of recurrence.

Results
A total of 324 patients were included in the study. The median follow-up was 63 (range 14–181) months. Recurrence was detected in 47 patients (14·5 per cent). In the multivariable analysis, a maximum diameter of metastatic lymph nodes larger than 2·0 cm (hazard ratio (HR) 1·15, 95 per cent c.i. 1·06 to 1·25; P = 0·033) and a central compartment metastatic lymph node ratio of more than 0·42 (HR 3·35, 1·65 to 6·79; P &lt; 0·001) were identified as independent risk factors for locoregional recurrence. Age 45 years or older (HR 5·69, 1·24 to 26·12; P = 0·025) and extranodal extension of metastasis (HR 12·71, 1·64 to 98·25; P = 0·015) were risk factors for distant metastasis. In subgroup analysis of locoregional recurrence, several lymph node-related factors affected the risk of recurrence according to the specific site of metastasis.

Conclusion
Lymph node-related factors are of importance for the risk of recurrence in patients with classical papillary thyroid carcinoma classified as pN1b.
Development of a structured undergraduate research experience: Framework and implications
Authors: Brown Anne M. , Lewis Stephanie N. , Bevan David R. 
Published: April 2016

AbstractParticipating in undergraduate research can be a pivotal experience for students in life science disciplines. Development of critical thinking skills, in addition to conveying scientific ideas in oral and written formats, is essential to ensuring that students develop a greater understanding of basic scientific knowledge and the research process. Modernizing the current life sciences research environment to accommodate the growing demand by students for experiential learning is needed. By developing and implementing a structured, theory‐based approach to undergraduate research in the life sciences, specifically biochemistry, it has been successfully shown that more students can be provided with a high‐quality, high‐impact research experience. The structure of this approach allowed students to develop novel, independent projects in a computational molecular modeling lab. Students engaged in an experience in which career goals, problem‐solving skills, time management skills, and independence in a research lab were developed. After experiencing this approach to undergraduate research, students reported feeling challenged to think critically and prepared for future career paths. The approach allowed for a progressive learning environment where more undergraduate students could participate in publishable research. Future areas for development include implementation in a bench‐top lab and extension to disciplines beyond biochemistry. In this study, it has been shown that utilizing the structured approach to undergraduate research could allow for more students to experience undergraduate research and develop into more confident, independent life scientists well prepared for graduate schools and professional research environments. © 2016 by The International Union of Biochemistry and Molecular Biology, 44(5):463–474, 2016.
Reversible Gel–Sol Transition of a Photo‐Responsive DNA Gel
Authors: Kandatsu Daisuke , Cervantes‐Salguero Keitel , Kawamata Ibuki , Hamada Shogo , Nomura Shin‐ichiro M. , Fujimoto Kenzo , Murata Satoshi 
Published: April 2016

AbstractStimuli‐responsive DNA gels that can undergo a sol‐gel transition in response to photo‐irradiation provide a way to engineer functional gel material with fully designed DNA base sequences. We propose an X‐shaped DNA motif that turns into a gel by hybridization of self‐complementary sticky ends. By embedding a photo‐crosslinking artificial base in the sticky‐end sequence, repetitive gel–sol transitions are achieved through UV irradiation at different wavelengths. The concentration of the DNA motif necessary for gelation is as low as 40 μm after modification of the geometrical properties of the motif. The physical properties, such as swelling degree and diffusion coefficient, were assessed experimentally.
Screening, Molecular Cloning, and Biochemical Characterization of an Alcohol Dehydrogenase from Pichia pastoris Useful for the Kinetic Resolution of a Racemic β‐Hydroxy‐β‐trifluoromethyl Ketone
Authors: Bulut Dalia , Duangdee Nongnaphat , Gröger Harald , Berkessel Albrecht , Hummel Werner 
Published: April 2016

AbstractThe stereoselective synthesis of chiral 1,3‐diols with the aid of biocatalysts is an attractive tool in organic chemistry. Besides the reduction of diketones, an alternative approach consists of the stereoselective reduction of β‐hydroxy ketones (aldols). Thus, we screened for an alcohol dehydrogenase (ADH) that would selectively reduce a β‐hydroxy‐β‐trifluoromethyl ketone. One potential starting material for this process is readily available by aldol addition of acetone to 2,2,2‐trifluoroacetophenone. Over 200 strains were screened, and only a few yeast strains showed stereoselective reduction activities. The enzyme responsible for the reduction of the β‐hydroxy‐β‐trifluoromethyl ketone was identified after purification and subsequent MALDI‐TOF mass spectrometric analysis. As a result, a new NADP+‐dependent ADH from Pichia pastoris (PPADH) was identified and confirmed to be capable of stereospecific and diastereoselective reduction of the β‐hydroxy‐β‐trifluoromethyl ketone to its corresponding 1,3‐diol. The gene encoding PPADH was cloned and heterologously expressed in Escherichia coli BL21(DE3). To determine the influence of an N‐ or C‐terminal His‐tag fusion, three different recombinant plasmids were constructed. Interestingly, the variant with the N‐terminal His‐tag showed the highest activity; consequently, this variant was purified and characterized. Kinetic parameters and the dependency of activity on pH and temperature were determined. PPADH shows a substrate preference for the reduction of linear and branched aliphatic aldehydes. Surprisingly, the enzyme shows no comparable activity towards ketones other than the β‐hydroxy‐β‐trifluoromethyl ketone.
Reduction‐Responsive Guanine Incorporated into G‐Quadruplex‐Forming DNA
Authors: Ikeda Masato , Kamimura Masahiro , Hayakawa Yukiko , Shibata Aya , Kitade Yukio 
Published: April 2016

AbstractStimulus‐responsive biomolecules are attractive targets to understand biomolecule behaviour as well as to explore their therapeutic and diagnostic applications. We demonstrate that a reduction‐responsive cleavable group (chemically caged unit) introduced into the guanine ring enables modulation of the secondary structure transition of an oligonucleotide in a reduction‐responsive and traceless manner leaving the unmodified oligonucleotide of interest. This simple but robust strategy could yield a variety of stimuli‐responsive oligonucleotides.
A Disassembly Strategy for Imaging Endogenous Pyrophosphate in Mitochondria by Using an FeIII–salen Complex
Authors: Kumari Namita , Huang Huaiyi , Chao Hui , Gasser Gilles , Zelder Felix 
Published: April 2016

AbstractInorganic pyrophosphate (PPi) is produced from nucleoside triphosphates in important biosynthetic reactions and is considered a diagnostic marker for various diseases, such as cancer, crystal deposition disease, and arthritis. Traditional methods for biological PPi detection rely on off‐line analytics after sample destruction. Molecular probes for imaging this biologically important analyte with temporal and spatial control in living cells are currently in demand. Herein, we report an FeIII–salen complex as the first small reaction‐based probe for endogenous mitochondrial PPi following a disassembly approach. Significantly, we successfully applied this complex for the detection of increased cellular PPi levels, and its performance was not affected by the presence of mitochondrial ATP in living cells.
Substrate‐Determined Diastereoselectivity in an Enzymatic Carboligation
Authors: Lehwald Patrizia , Fuchs Olga , Nafie Laurence A. , Müller Michael , Lüdeke Steffen 
Published: April 2016

AbstractThiamine diphosphate‐dependent enzymes catalyze the formation of C−C bonds, thereby generating chiral secondary or tertiary alcohols. By the use of vibrational circular dichroism (VCD) spectroscopy we studied the stereoselectivity of carboligations catalyzed by YerE, a carbohydrate‐modifying enzyme from Yersinia pseudotuberculosis. Conversion of the non‐physiological substrate (R)‐3‐methylcyclohexanone led to an R,R‐configured tertiary alcohol (diastereomeric ratio (dr) >99:1), whereas the corresponding reaction with the S enantiomer gave the S,S‐configured product (dr>99:1). This suggests that YerE‐catalyzed carboligations can undergo either an R‐ or an S‐specific pathway. We show that, in this case, the high stereoselectivity of the YerE‐catalyzed reaction depends on the substrate's preference to acquire a low‐energy conformation.
Enabling Better Electrochemical Activity Studies of H2O‐Soluble Au Clusters by Phase Transfer and a Case Study of Lipoic‐Acid‐Stabilized Au22
Authors: Padelford Jonathan W. , Wang Tanyu , Wang Gangli 
Published: April 2016

AbstractIn stark contrast to organic systems, insight of the electrochemical properties is rather limited in aqueous solution for Au clusters, which have received extensive research attention recently. We demonstrate phase transfer as an efficient strategy to shuttle the Au nanoclusters between aqueous and organic solvents cyclically. The ability to phase transfer the Au clusters circumvents the limitations of potential window and high dielectric constant of water for electrochemistry studies. Two types of ligand molecular structures were employed with different hydrophilicity/hydrophobicity: mercaptosuccinic acid and lipoic acid, the latter featuring a longer hydrophobic portion and disulfide group (for Au bonding). The transfer efficiency was evaluated at different pHs. Additional redox activities from the Au22LA12 cluster that could not be seen from aqueous measurements were successfully resolved. Reversible and controllable transfer between aqueous and organic phases is believed to be a generalizable approach that could enable broader applications.
Effective Inhibition of Cellular ROS Production by MXCXXC‐Type Peptides: Potential Therapeutic Applications in Copper‐Homeostasis Disorders
Authors: Shoshan Michal S. , Tshuva Edit Y. 
Published: April 2016

AbstractCyclic and acyclic peptides with sequences derived from metallochaperone binding sites, but differing at position 2, were analyzed for their inhibitory reactivity towards cellular ROS (reactive oxygen species) formation and catalytic activity towards oxidation with H2O2, in comparison with three commercial drugs clinically employed in chelation therapy for Wilson's disease. Acyclic peptides were more effective inhibitors than the cyclic ones, with one leading peptide with threonine at position 2 systematically showing the highest efficiency in reducing cellular ROS levels and in inhibiting Cu oxidation. This peptide was more effective than all commercial drugs in all aspects analyzed, and showed no toxicity towards human colon HT‐29 cancer cells at concentrations 10–100 times higher than the IC50 of the commercial drugs, corroborating its high medicinal potential.
Zn or O? An Atomic Level Comparison on Antibacterial Activities of Zinc Oxides
Authors: Yu Fen , Fang Xuan , Jia Huimin , Liu Miaoxing , Shi Xiaotong , Xue Chaowen , Chen Tingtao , Wei Zhipeng , Fang Fang , Zhu Hui , Xin Hongbo , Feng Jing , Wang Xiaolei 
Published: April 2016

AbstractFor the first time, the influence of different types of atoms (Zn and O) on the antibacterial activities of nanosized ZnO was quantitatively evaluated with the aid of a 3D‐printing‐manufactured evaluation system. Two different outermost atomic layers were manufactured separately by using an ALD (atomic layer deposition) method. Interestingly, we found that each outermost atomic layer exhibited certain differences against gram‐positive or gram‐negative bacterial species. Zinc atoms as outermost layer (ZnO−Zn) showed a more pronounced antibacterial effect towards gram‐negative E. coli (Escherichia coli), whereas oxygen atoms (ZnO−O) showed a stronger antibacterial activity against gram‐positive S. aureus (Staphylococcus aureus). A possible antibacterial mechanism has been comprehensively discussed from different perspectives, including Zn2+ concentrations, oxygen vacancies, photocatalytic activities and the DNA structural characteristics of different bacterial species.
Suppression of Photocyclization: Stabilization of an Aggregation‐Induced Tetraaryldistyrylbenzene Emitter
Authors: Freudenberg Jan , Rominger Frank , Bunz Uwe H. F. 
Published: April 2016

AbstractThe synthesis of 2,3,5,6‐tetrakis(2,6‐difluorophenyl)di(styryl)benzene by using a conventional synthetic sequence, including Diels–Alder and Horner reactions is reported. The target is an effective aggregation‐induced emitter. It is photostable with respect to electrocyclization, due to the presence of the fluorine substituents. This compound undergoes photochemical trans/cis isomerization of its styryl double bonds.
A Rapid and Sensitive Strip‐Based Quick Test for Nerve Agents Tabun, Sarin, and Soman Using BODIPY‐Modified Silica Materials
Authors: Climent Estela , Biyikal Mustafa , Gawlitza Kornelia , Dropa Tomáš , Urban Martin , Costero Ana M. , Martínez‐Máñez Ramón , Rurack Knut 
Published: April 2016

AbstractTest strips that in combination with a portable fluorescence reader or digital camera can rapidly and selectively detect chemical warfare agents (CWAs) such as Tabun (GA), Sarin (GB), and Soman (GD) and their simulants in the gas phase have been developed. The strips contain spots of a hybrid indicator material consisting of a fluorescent BODIPY indicator covalently anchored into the channels of mesoporous SBA silica microparticles. The fluorescence quenching response allows the sensitive detection of CWAs in the μg m−3 range in a few seconds.
Sophisticated Design of Covalent Organic Frameworks with Controllable Bimetallic Docking for a Cascade Reaction
Authors: Leng Wenguang , Peng Yongsheng , Zhang Jianqiang , Lu Hui , Feng Xiao , Ge Rile , Dong Bin , Wang Bo , Hu Xiangping , Gao Yanan 
Published: April 2016

AbstractPrecise control of the number and position of the catalytic metal ions in heterogeneous catalysts remains a big challenge. Here we synthesized a series of two‐dimensional (2D) covalent organic frameworks (COFs) containing two different types of nitrogen ligands, namely imine and bipyridine, with controllable contents. For the first time, the selective coordination of the two nitrogen ligands of the 2D COFs to two different metal complexes, chloro(1,5‐cyclooctadiene)rhodium(I) (Rh(COD)Cl) and palladium(II) acetate (Pd(OAc)2), has been realized using a programmed synthetic procedure. The bimetallically docked COFs showed excellent catalytic activity in a one‐pot addition–oxidation cascade reaction. The high surface area, controllable metal‐loading content, and predesigned active sites make them ideal candidates for their use as heterogeneous catalysts in a wide range of chemical reactions.
Triflic Acid‐Catalyzed Enynes Cyclization: A New Strategy beyond Electrophilic π‐Activation
Authors: Yu Zhunzhun , Liu Lu , Zhang Junliang 
Published: April 2016

AbstractThe cyclization of enynes, catalyzed by a transition metal, represents a powerful tool to construct an array of cyclic compounds through electrophilic π‐activation. In this paper, we disclose a new and efficient strategy for enynes cyclization catalyzed by triflic acid. The salient features of this transformation includes a broad substrate scope, metal free synthesis, open flask and mild conditions, good yields, ease of operation, low catalyst loading, and easy scale‐up to gram scale. A preliminary mechanism study demonstrated that the activation model of the reaction was σ‐activation, which is different from the transition‐metal‐catalyzed enynes cyclization. Our strategy affords a complementary method to the traditional strategies, which use transition‐metal catalysts.
A Capped Octahedral MHC6 Compound of a Platinum Group Metal
Authors: Eguillor Beatriz , Esteruelas Miguel A. , Lezáun Virginia , Oliván Montserrat , Oñate Enrique , Tsai Jui‐Yi , Xia Chuanjun 
Published: April 2016

AbstractA MHC6 complex of a platinum group metal with a capped octahedral arrangement of donor atoms around the metal center has been characterized. This osmium compound OsH{κ2‐C,C‐(PhBIm‐C6H4)}3, which reacts with HBF4 to afford the 14 e− species [Os{κ2‐C,C‐(PhBIm‐C6H4)}(Ph2BIm)2]BF4 stabilized by two agostic interactions, has been obtained by reaction of OsH6(PiPr3)2 with N,N′‐diphenylbenzimidazolium chloride ([Ph2BImH]Cl) in the presence of NEt3. Its formation takes place through the C,C,C‐pincer compound OsH2{κ3‐C,C,C‐(C6H4‐BIm‐C6H4)}(PiPr3)2, the dihydrogen derivative OsCl{κ2‐C,C‐(PhBIm‐C6H4)}(η2‐H2)(PiPr3)2, and the five‐coordinate osmium(II) species OsCl{κ2‐C,C‐(PhBIm‐C6H4)}(PiPr3)2.
Weak O‐Assistance Outcompeting Strong N,N‐Bidentate Directing Groups in Copper‐Catalyzed C−H Chalcogenation
Authors: Cera Gianpiero , Ackermann Lutz 
Published: April 2016

AbstractA copper‐mediated C−H chalcogenation of triazoles has been achieved by weak coordination. The user‐friendly protocol showed high functional‐group tolerance and ample substrate scope, yielding fully substituted 1,2,3‐triazoles with complete positional site‐selectivity. The C−H selenylation could likewise be achieved by means of copper catalysis. Our findings highlight for the first time that weak O‐coordination can outcompete the strong N,N‐bidentate coordination mode in C−H functionalization technology.
Catalyst‐Driven Scaffold Diversity: Selective Synthesis of Spirocycles, Carbazoles and Quinolines from Indolyl Ynones
Authors: Liddon John T. R. , James Michael J. , Clarke Aimee K. , O'Brien Peter , Taylor Richard J. K. , Unsworth William P. 
Published: April 2016

AbstractMedicinally relevant spirocyclic indolenines, carbazoles and quinolines can each be directly synthesised selectively from common indolyl ynone starting materials by catalyst variation. The high yielding, divergent reactions all proceed by an initial dearomatising spirocyclisation reaction to generate an intermediate vinyl–metal species, which then rearranges selectively by careful choice of catalyst and reaction conditions.
Multicomponent Double Diels–Alder/Nazarov Tandem Cyclization of Symmetric Cross‐Conjugated Diynones to Generate [6‐5‐6] Tricyclic Products
Authors: Carmichael Rachael A. , Chalifoux Wesley A. 
Published: April 2016

AbstractThe construction of complex polycyclic terpenoid products in an efficient and step‐economical manner using multicomponent and tandem processes is highly valuable. Herein, we report a tandem cyclization sequence that initiates with a multicomponent double Diels–Alder reaction of cross‐conjugated diynones, followed by a Nazarov cyclization to efficiently produce [6‐5‐6] tricyclic products with excellent regio‐ and diastereoselectivity. This methodology generates five new carbon–carbon bonds, three rings, quaternary or vicinal quaternary carbons, and stereogenic centers in a one‐pot reaction.
ChemInform Abstract: A THEORETICAL ANALYSIS OF THE OXIDATION OF IRON‐SILICON ALLOYS
Authors: ATKINSON A. 
Published: April 2016

AbstractDie Analyse der Oxidation von Fe‐Si‐Legierungen in CO2 + 1 Vol‐% CO bei 500°C mit Hilfe einer phänomenologischen Theorie der Legierungsoxidation gestattet eine detaillierte Voraussage zur Mikrostruktur der gebildeten Oxidzunder.
ChemInform Abstract: CYCLOADDITION OF N‐PHENYLTRIAZOLINEDIONE AND 1,5‐DIALKYL SUBSTITUTED SEMIBULLVALENE
Authors: ASKANI R. , KIRSTEN R. , DUGALL B. 
Published: April 2016

AbstractDas Bicyclooctadion (I) wird u.a. mit MeMgI bzw. LiAlH4 zu den Diolen (IIIa) bzw. (IIIb) umgesetzt, wobei bei der Darstellung von (IIIa) dieses zuerst isoliert und der Rest des Reaktionsgemisches mit I2 thermisch zu dem Bicyclooctenon (II) sowie den Bicyclodienen (IVa) und (Va) dehydratisiert wird.
ChemInform Abstract: REACTIONS OF KETONES WITH HYDROXYLAMINE‐O‐SULFONIC ACID
Authors: NOVOSELOV E. F. , ISAEV S. D. , YURCHENKO A. G. , VODICHKA L. , TRSHISKA YA. 
Published: April 2016

AbstractDie alicyclischen Ketone bzw. Acetophenon (I) reagieren mit I‐Iydroxylamin‐O‐schwefelsäure zu den instabilen Sulfoketoximen, die mit NH3 in Form ihrer stabilen Ammoniumsalze (II) isoliert werden.