bluuebunny/crossref_metadata_2025_split huggingface dataset:
Secondary‐Structure‐Driven Self‐Assembly of Reactive Polypept(o)ides: Controlling Size, Shape, and Function of Core Cross‐Linked Nanostructures
Authors: Klinker Kristina , Schäfer Olga , Huesmann David , Bauer Tobias , Capelôa Leon , Braun Lydia , Stergiou Natascha , Schinnerer Meike , Dirisala Anjaneyulu , Miyata Kanjiro , Osada Kensuke , Cabral Horacio , Kataoka Kazunori , Barz Matthias 
Published: May 2017

AbstractAchieving precise control over the morphology and function of polymeric nanostructures during self‐assembly remains a challenge in materials as well as biomedical science, especially when independent control over particle properties is desired. Herein, we report on nanostructures derived from amphiphilic block copolypept(o)ides by secondary‐structure‐directed self‐assembly, presenting a strategy to adjust core polarity and function separately from particle preparation in a bioreversible manner. The peptide‐inherent process of secondary‐structure formation allows for the synthesis of spherical and worm‐like core‐cross‐linked architectures from the same block copolymer, introducing a simple yet powerful approach to versatile peptide‐based core–shell nanostructures.
Sensitization‐Initiated Electron Transfer for Photoredox Catalysis
Authors: Ghosh Indrajit , Shaikh Rizwan S. , König Burkhard 
Published: May 2017

AbstractPhotosynthetic organisms exploit antenna chromophores to absorb light and transfer excitation energy to the reaction center where redox reactions occur. In contrast, in visible‐light chemical photoredox catalysis, a single species (i.e., the photoredox catalyst) absorbs light and performs the redox chemistry. Mimicking the energy flow of the biological model, we report a two‐center photoredox catalytic approach in which the tasks of light energy collection and electron transfer (i.e., redox reactions) are assigned to two different molecules. Ru(bpy)3Cl2 absorbs the visible light and transfers the energy to polycyclic aromatic hydrocarbons that enable the redox reactions. This operationally simple sensitization‐initiated electron transfer enables the use of arenes that do not absorb visible light, such as anthracene or pyrene, for photoredox applications. We demonstrate the merits of this approach by the reductive activation of chemical bonds with high reduction potentials for carbon–carbon and carbon–heteroatom bond formations.
Strain Stiffening Hydrogels through Self‐Assembly and Covalent Fixation of Semi‐Flexible Fibers
Authors: Fernandez‐Castano Romera Marcos , Lafleur René P. M. , Guibert Clément , Voets Ilja K. , Storm Cornelis , Sijbesma Rint P. 
Published: May 2017

AbstractBiomimetic, strain‐stiffening materials are reported, made through self‐assembly and covalent fixation of small building blocks to form fibrous hydrogels that are able to stiffen by an order of magnitude in response to applied stress. The gels consist of semi‐flexible rodlike micelles of bisurea bolaamphiphiles with oligo(ethylene oxide) (EO) outer blocks and a polydiacetylene (PDA) backbone. The micelles are fibers, composed of 9–10 ribbons. A gelation method based on Cu‐catalyzed azide–alkyne cycloaddition (CuAAC), was developed and shown to lead to strain‐stiffening hydrogels with unusual, yet universal, linear and nonlinear stress–strain response. Upon gelation, the X‐ray scattering profile is unchanged, suggesting that crosslinks are formed at random positions along the fiber contour without fiber bundling. The work expands current knowledge about the design principles and chemistries needed to achieve fully synthetic, biomimetic soft matter with on‐demand, targeted mechanical properties.
Polyelectrolytes with sulfonate groups obtained by chemical modification of chitosan useful in green synthesis of Au and Ag nanoparticles
Authors: Caldera‐Villalobos M. , García‐Serrano J. , Peláez‐Cid A. A. , Herrera‐González Ana M. 
Published: May 2017

ABSTRACTUsually the metal nanoparticles are obtained by different chemical reactions that are not environmentally friendly. This paper describes the synthesis of two polyelectrolytes with sulfonate groups in ortho‐position and in ortho‐ and para‐positions, which were obtained by chemical modification of chitosan. They were used in the green synthesis of Au and Ag nanoparticles by colloidal method in aqueous solution. Polyelectrolytes were used as reducing agents of Au3+ and Ag+ ions and as stabilizing agents of Ag and Au nanoparticles. The hydroxyl and imine groups in the polyelectrolytes are reducing agents of Au3+ and Ag+ ions while the sulfonate groups and the polymer backbone stabilized Au and Ag nanoparticles. Polyelectrolyte 1, which has sulfonate group in ortho‐position, favors the obtaining of anisotropic Au nanoparticles with an average size of 19 nm. While the polyelectrolyte 2, with two sulfonate groups in the ortho‐ and para‐positions, yielded quasi‐spherical Au nanoparticles with an average size of 14 nm. In general, Ag nanoparticles stabilized with both polyelectrolytes, show quasi‐spherical forms with good control in size. Finally, both polyelectrolytes have the ability to protect the Au and Ag nanoparticles allowing obtaining colloidal solutions that are stable for several months. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 45240.
Synthesis of elastin‐based polymer and evaluation of its intermolecular interactions with hydroxypropyl methylcellulose
Authors: Mahesh B. , Nanjundaswamy G. S. , Channe Gowda D. , Siddaramaiah B. 
Published: May 2017

ABSTRACTThe parent repeating sequence of elastin, poly(GVGVP), was synthesized using solution phase method and characterized by 13C‐ and 1H‐NMR spectroscopy. In order to study the polymer–polymer interactions between poly(GVGVP) and hydroxyl propyl methyl cellulose (HPMC), the blends were prepared both in aqueous and solid phase and examined using various analytical techniques. The viscometric measurements have been carried out at 24 °C and the interaction parameters such as α, β, µ, and Δ[η]m revealed the miscible nature of the poly(GVGVP)/HPMC blend systems. In addition, Fourier‐transform infrared spectroscopy showed the formation of strong intermolecular hydrogen bond between poly(GVGVP) and HPMC networks. This result was further supported by glass transition temperature (Tg), scanning electron microscopic, and X‐ray diffraction studies. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 45283.
Molecular design for silane‐terminated polyurethane applied to moisture‐curable pressure‐sensitive adhesive
Authors: Yuan Ye , Zhang Yanyan , Fu Xiaowei , Kong Weibo , Liu Zhimeng , Hu Kai , Jiang Liang , Lei Jingxin 
Published: May 2017

ABSTRACTMoisture‐curable silane‐terminated polyurethanes (SPUs) served as pressure‐sensitive adhesive (PSA) were synthesized based on different soft‐segment materials, silanes and silane end‐capping ratios. Depending on peel strength, tack, and holding power, the characteristic properties for PSA, a proper scheme for the design of the PSA molecular structure could be selected. Completely end‐capped by silane and assembled by poly(propylene glycol), SPU films presented better properties. On the basis of comprehensive considerations, the anilinomethyltriethoxysilane was an excellent silane‐end capper for PSA. Otherwise, the obtained PSAs did not degrade below 250 °C. The glass transition temperature and hydrophobicity of SPU samples with different formulas were also investigated. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 45292.
Preparation and characterization of polymer‐Ti3C2Tx (MXene) composite nanofibers produced via electrospinning
Authors: Mayerberger Elisa A. , Urbanek Olga , McDaniel Riki M. , Street Reva M. , Barsoum Michel W. , Schauer Caroline L. 
Published: May 2017

ABSTRACTMXene, a recently‐discovered family of two‐dimensional (2D) transition metal carbides and/or nitrides, have attracted much interest because of their unique electrical, thermal, and mechanical properties. In this study, poly(acrylic acid), poly(ethylene oxide) (PEO), poly(vinyl alcohol) (PVA), and alginate/PEO were electrospun with delaminated Ti3C2 (MXene) flakes. The effect of small additions of delaminated Ti3C2 (1% w/w) on the structure and properties of the nanofibers were investigated and compared with those of the neat polymer nanofibers using scanning electron microscopy, transmission electron microscopy, X‐ray diffraction, and Fourier transform infrared spectroscopy. Ti3C2 had an effect on the solution properties of the polymer and a greater effect on the average fiber diameter. The Ti3C2Tx/PEO solution exhibited the largest change in viscosity and conductivity with an 11% and 73.6% increase over the base polymer, respectively. X‐ray diffractograms demonstrated a high degree of crystallization for Ti3C2/PEO and a slight decrease in crystallinity for Ti3C2/PVA. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 45295.
Systematic review of the influence of chemotherapy-associated liver injury on outcome after partial hepatectomy for colorectal liver metastases
Authors: Zhao J , van Mierlo K M C , Gómez-Ramírez J , Kim H , Pilgrim C H C , Pessaux P , Rensen S S , van der Stok E P , Schaap F G , Soubrane O , Takamoto T , Viganò L , Winkens B , Dejong C H C , Olde Damink S W M ,   the Chemotherapy-Associated Liver Injury (CALI) consortium, García Sanz I , Martín Pérez E , Cho J Y , Choi Y R , Phillips W , Michael M , Panaro F , Chenard M-P , Verhoef C , Grünhagen D J , Vara J , Scatton O , Hashimoto T , Makuuchi M , De Rosa G , Ravarino N 
Published: May 2017

Abstract

Background
The impact of chemotherapy-associated liver injury (CALI) on postoperative outcome in patients undergoing partial hepatectomy for colorectal liver metastases (CRLM) remains controversial. The objective of this study was to clarify the effect of CALI (sinusoidal dilatation (SD), steatosis and steatohepatitis) on postoperative morbidity and mortality by investigating a large data set from multiple international centres.

Methods
PubMed and Embase were searched for studies published between 1 January 2004 and 31 December 2013 with keywords ‘chemotherapy’, ‘liver resection’, ‘outcome’ and ‘colorectal metastases’ to identify potential collaborating centres. Univariable and multivariable analyses were performed using binary logistic regression models, with results presented as odds ratios (ORs) with 95 per cent confidence intervals.

Results
A consolidated database comprising 788 patients who underwent hepatectomy for CRLM in eight centres was obtained. In multivariable analyses, severe SD was associated with increased major morbidity (Dindo–Clavien grade III–V; OR 1·73, 95 per cent c.i. 1·02 to 2·95; P = 0·043). Severe steatosis was associated with decreased liver surgery-specific complications (OR 0·52, 95 per cent c.i. 0·27 to 1·00; P = 0·049), whereas steatohepatitis was linked to an increase in these complications (OR 2·08, 1·18 to 3·66; P = 0·012). Subgroup analysis showed that lobular inflammation was the sole component associated with increased overall morbidity (OR 2·22, 1·48 to 3·34; P = 0·001) and liver surgery-specific complications (OR 3·35, 2·11 to 5·32; P &lt; 0·001). Finally, oxaliplatin treatment was linked to severe SD (OR 2·74, 1·67 to 4·49; P &lt; 0·001).

Conclusion
An increase in postoperative major morbidity and liver surgery-specific complications was observed after partial hepatectomy in patients with severe SD and steatohepatitis. Postoperative liver failure occurred more often in patients with severe SD.
C‐X‐C motif chemokine receptor 4 promotes tumor angiogenesis in gastric cancer via activation of JAK2/STAT3
Authors: Zhang Qing , Xu Feng , Shi Yi , Chen Yi‐Wen , Wang Hai‐Ping , Yu Xue , Li Yong 
Published: May 2017

AbstractC‐X‐C motif chemokine receptor 4 (CXCR4) overexpression promotes gastric cancer growth and metastasis. In this study, we determined its role in regulating tumor angiogenesis. We overexpressed CXCR4 in gastric cancer cells and examined the effects of conditioned medium on endothelial cell proliferation, migration, and tube formation. The effects of CXCR4 overexpression on vascular endothelial growth factor (VEGF) expression and signal transducer and activator of transcription 3 (STAT3) activation were analyzed. In vivo xenograft studies were done to confirm the role of CXCR4 in tumor angiogenesis. Conditioned medium from CXCR4‐overexpressing gastric cancer cells stimulated endothelial cell proliferation, migration, and tube formation. Such effects were blocked by addition of a neutralizing anti‐VEGF antibody. CXCR4 induced VEGF production and JAK2/STAT3 activation and enhanced STAT3 binding to VEGF promoter in gastric cancer cells. Delivery of a dominant negative variant of STAT3 significantly impaired CXCR4‐induced upregulation of VEGF. Overexpression of CXCR4 facilitated tumor growth and angiogenesis in SGC7901 xenograft tumors, which was associated with increased levels of phospho‐STAT3. CXCR4 contributes to tumor angiogenesis in gastric cancer by inducing STAT3‐dependent VEGF expression and represents a promising therapeutic target for this malignancy.
Covalently Modified Graphenes in Catalysis, Electrocatalysis and Photoresponsive Materials
Authors: Navalón Sergio , Herance José Raúl , Álvaro Mercedes , García Hermenegildo 
Published: May 2017

AbstractThe ideal graphene is a one‐atom thick single layer of carbon atoms having sp2 hybridation in hexagonal arrangement. Due to their large surface area and good dispersability in common solvents, graphenes are suitable platforms to anchor covalently units. The appended unit can introduce additional functionality to graphene. Although the field of covalently modified graphene is still starting compared to the development of other carbon nanoforms, there is already many examples describing the use of modified graphenes as recoverable photo‐, electrocatalysts as well as in non‐linear optics and to improve mechanical resistance and solubility of graphenes. In this Review, the state of the art of covalently modified graphenes for these applications is reviewed. After some general sections describing properties and characterization techniques of graphenes relevant to their use as supports and those general reactions and starting substrates to obtain the modified graphene conjugates, the main body of the review describes the preparation and properties of covalently modified graphene depending on their use as catalyst, photocatalyst, photoresponsive material, non‐linear optics, electrocatalyst and other uses. The last section of the review summarizes the main achievements of the field and what should be according to our view the future developments.
The Role of Co‐Activation and Ligand Functionalization in Neutral Methallyl Nickel(II) Catalysts for Ethylene Oligomerization and Polymerization
Authors: Ortega Daniela E. , Cortés‐Arriagada Diego , Trofymchuk Oleksandra S. , Yepes Diana , Gutiérrez‐Oliva Soledad , Rojas René S. , Toro‐Labbé Alejandro 
Published: May 2017

AbstractA detailed quantum chemical study that analyzed the mechanism of ethylene oligomerization and polymerization by means of a family of four neutral methallyl NiII catalysts is presented. The role of the boron co‐activators, BF3 and B(C6F5)3, and the position of ligand functionalization (ortho or para position of the N‐arylcyano moiety of the catalysts) were investigated to explain the chain length of the obtained polymers. The chain initialization proceeded with higher activation barriers for the ortho‐functionalized complexes (≈19 kcal mol−1) than the para‐substituted isomers (17–18 kcal mol−1). Two main pathways were revealed for the chain propagation: The first pathway was favored when using the B(C6F5)3 co‐activated catalyst, and it produced long‐chain polymers. A second pathway led to the β‐hydrogen complexes, which resulted in chain oligomerization; this pathway was preferred when the BF3 co‐activated catalysts were used. Otherwise, the termination of longer chains occurred via a stable hydride intermediate, which was formed with an energy barrier of about 14 kcal mol−1 for the B(C6F5)3 co‐activated catalysts. Significant new insights were made into the reaction mechanism, whereby neutral methallyl NiII catalysts act in oligomerization and polymerization processes. Specifically, the role of co‐activation and ligand functionalization, which are key information for the further design of related catalysts, were revealed.
Preparation and Characterization of Group 13 Cyanides
Authors: Haiges Ralf , Deokar Piyush , Vasiliu Monica , Stein Trent H. , Dixon David A. , Christe Karl O. 
Published: May 2017

AbstractInvited for the cover of this issue is the group of Ralf Haiges at the University of Southern California. The image depicts characters from the popular web comic “Cyanide & Happiness” alongside some of the cyanide complexes synthesized. Read the full text of the article at 10.1002/chem.201700611.
Relationship between carotid atherosclerosis and coronary artery calcification in asymptomatic diabetic patients: A prospective multicenter study
Authors: Jeevarethinam Anand , Venuraju Shreenidhi , Dumo Alain , Ruano Sherezade , Mehta Vishal S. , Rosenthal Miranda , Nair Devaki , Cohen Mark , Darko Daniel , Lahiri Avijit , Rakhit Roby 
Published: May 2017

BackgroundThe value of screening sub‐clinical atherosclerosis in asymptomatic patients with type 2 diabetes mellitus (T2DM) remains controversial.HypothesisAn integrated model incorporating carotid intima‐media thickness (CIMT) and carotid plaque with traditional risk factors can be used to predict prevalence and severity of coronary artery calcification in asymptomatic T2DM patients.MethodsA cohort of 262 asymptomatic T2DM patients were prospectively studied with carotid ultrasound to evaluate CIMT and carotid plaque and also a computed tomography coronary artery calcium (CT‐CAC) scan.ResultsCarotid plaque was detected in 124 (47%) patients and mean CIMT was 0.75±0.14 mm. Two hundred (76%) patients had a CAC score >0, of whom 57 (22%) had severe coronary atherosclerosis (>400 Au). In this group, carotid plaque was present in 40 (70%) patients (p<0.001).Univariable analysis revealed significant associations between non‐zero CAC score and age (p<0.001), hypertension (p=0.01), gender (p=0.003) and duration of diabetes (p=0.004). Carotid plaque and mean CIMT were also significantly associated with non‐zero CAC score (odds ratios [95% CI], 3.12 [1.66 ‐5.85] and 2.98 [0.24 ‐7.17], respectively). After adjusting for traditional risk factors, carotid plaque continued to be predictive of non‐zero CAC score (2.59 [1.17 ‐5.74]) and CIMT was borderline significant (p=0.05). When analysed with binary logistical regression, the prevalence of carotid plaque significantly predicted severe CAC burden (CAC >400 Au; 3.26 [2.05 ‐5.19]). Upper CIMT quartiles showed a similar association (2.55 [1.33 ‐4.87]).ConclusionCarotid plaque is more predictive of underlying silent coronary atherosclerosis prevalence, severity and extent in asymptomatic T2DM patients.
Thiazole‐Based σ1 Receptor Ligands: Diversity by Late‐Stage C−H Arylation of Thiazoles, Structure–Affinity and Selectivity Relationships, and Molecular Interactions
Authors: Kokornaczyk Artur K. , Schepmann Dirk , Yamaguchi Junichiro , Itami Kenichiro , Laurini Erik , Fermeglia Maurizio , Pricl Sabrina , Wünsch Bernhard 
Published: May 2017

AbstractSpirocyclic thiophene derivatives represent promising σ1 ligands with high σ1 affinity and selectivity over the σ2 subtype. To increase ligand efficiency, the thiophene ring was replaced bioisosterically by a thiazole ring, and the pyran ring was opened. Late‐stage diversification by regioselective C−H arylation of thiazoles 9 a–c resulted in a set of 53 compounds with high diversity. This set of compounds was analyzed with respect to σ1 affinity, σ1/σ2 selectivity, lipophilicity (logD7.4), lipophilicity‐corrected ligand efficiency (LELP), and molecular target interactions. The most promising candidates were pyridyl‐substituted thiazole derivatives 33 c (2‐(1‐benzyl‐4‐ethoxypiperidin‐4‐yl)‐5‐(pyridin‐3‐yl)thiazole) and 34 c (2‐(1‐benzyl‐4‐ethoxypiperidin‐4‐yl)‐5‐(pyridin‐4‐yl)thiazole), possessing low‐nanomolar σ1 affinity (Ki=1.3 and 1.9 nm), high σ1/σ2 selectivity (>1500‐fold), low lipophilicity (logD7.4=1.8) and very good ligand efficiency (LELP=5.5), indicating promising pharmacodynamics and pharmacokinetics. Molecular simulation studies, including docking and deconvolution of the free binding energy into its major components, led to decreased hydrophobic stabilization of pyridyl derivatives 33 c and 34 c, which was compensated by lower desolvation energy.
Chemoproteomics‐Aided Medicinal Chemistry for the Discovery of EPHA2 Inhibitors
Authors: Heinzlmeir Stephanie , Lohse Jonas , Treiber Tobias , Kudlinzki Denis , Linhard Verena , Gande Santosh Lakshmi , Sreeramulu Sridhar , Saxena Krishna , Liu Xiaofeng , Wilhelm Mathias , Schwalbe Harald , Kuster Bernhard , Médard Guillaume 
Published: May 2017

AbstractThe receptor tyrosine kinase EPHA2 has gained attention as a therapeutic drug target for cancer and infectious diseases. However, EPHA2 research and EPHA2‐based therapies have been hampered by the lack of selective small‐molecule inhibitors. Herein we report the synthesis and evaluation of dedicated EPHA2 inhibitors based on the clinical BCR‐ABL/SRC inhibitor dasatinib as a lead structure. We designed hybrid structures of dasatinib and the previously known EPHA2 binders CHEMBL249097, PD‐173955, and a known EPHB4 inhibitor in order to exploit both the ATP pocket entrance as well as the ribose pocket as binding epitopes in the kinase EPHA2. Medicinal chemistry and inhibitor design were guided by a chemical proteomics approach, allowing early selectivity profiling of the newly synthesized inhibitor candidates. Concomitant protein crystallography of 17 inhibitor co‐crystals delivered detailed insight into the atomic interactions that underlie the structure–affinity relationship. Finally, the anti‐proliferative effect of the inhibitor candidates was confirmed in the glioblastoma cell line SF‐268. In this work, we thus discovered a novel EPHA2 inhibitor candidate that features an improved selectivity profile while maintaining potency against EPHA2 and anticancer activity in SF‐268 cells.
Synthesis, ADMET Properties, and Biological Evaluation of Benzothiazole Compounds Targeting Chemokine Receptor 2 (CXCR2)
Authors: Mehanna Wesam E. , Lu Tiangong , Debnath Bikash , Lasheen Deena S. , Serya Rabah A. T. , Abouzid Khaled A. , Neamati Nouri 
Published: May 2017

AbstractHerein we describe the synthesis and biological evaluation of a series of novel benzothiazoles based on a diaryl urea scaffold previously reported in some allosteric chemokine receptor 2 (CXCR2) inhibitors. From a library of 41 new compounds, 17 showed significant inhibition of CXCR2, with IC50 values less than 10 μm and selectivity over CXCR4. Our ADMET simulations suggest favorable drug‐like properties for the active compounds. Importantly, we developed a predictive model that can distinguish active from inactive compounds; this will serve as a valuable tool to guide the design of optimized compounds to be evaluated in preclinical models.