bluuebunny/crossref_metadata_2025_split huggingface dataset:
Acoustic Propulsion of Nanorod Motors Inside Living Cells
Authors: Wang Wei , Li Sixing , Mair Lamar , Ahmed Suzanne , Huang Tony Jun , Mallouk Thomas E. 
Published: February 2014

AbstractThe ultrasonic propulsion of rod‐shaped nanomotors inside living HeLa cells is demonstrated. These nanomotors (gold rods about 300 nm in diameter and about 3 μm long) attach strongly to the external surface of the cells, and are readily internalized by incubation with the cells for periods longer than 24 h. Once inside the cells, the nanorod motors can be activated by resonant ultrasound operating at 4 MHz, and show axial propulsion as well as spinning. The intracellular propulsion does not involve chemical fuels or high‐power ultrasound and the HeLa cells remain viable. Ultrasonic propulsion of nanomotors may thus provide a new tool for probing the response of living cells to internal mechanical excitation, for controllably manipulating intracellular organelles, and for biomedical applications.
Palladium‐Catalyzed Chain‐Growth Polycondensation of AB‐type Monomers: High Catalyst Turnover and Polymerization Rates
Authors: Tkachov Roman , Senkovskyy Volodymyr , Beryozkina Tetyana , Boyko Kseniya , Bakulev Vasiliy , Lederer Albena , Sahre Karin , Voit Brigitte , Kiriy Anton 
Published: February 2014

AbstractChain‐growth catalyst‐transfer polycondensations of AB‐type monomers is a new and rapidly developing tool for the preparation of well‐defined π‐conjugated (semiconducting) polymers for various optoelectronic applications. Herein, we report the Pd/PtBu3‐catalyzed Negishi chain‐growth polycondensation of AB‐type monomers, which proceeds with unprecedented TONs of above 100 000 and TOFs of up to 280 s−1. In contrast, related AA/BB‐type step‐growth polycondensation proceeds with two orders of magnitude lower TONs and TOFs. A similar trend was observed in Suzuki‐type polycondensation. The key impact of the intramolecular (vs. intermolecular) catalyst‐transfer process on both polymerization kinetics and catalyst lifetime has been revealed.
Heterologe Rekonstitution der Ikarugamycin‐Biosynthese in E. coli
Authors: Antosch Janine , Schaefers Françoise , Gulder Tobias A. M. 
Published: February 2014

AbstractPolycyclische Tetramat‐Makrolactame (PTM) bilden eine Familie biomedizinisch vielversprechender Naturstoffe mit anspruchsvollen Molekülstrukturen. Trotz dieser interessanten Eigenschaften der PTMs ist bislang relativ wenig über ihren biosynthetischen Ursprung bekannt, insbesondere bezüglich der Mechanismen der Ausbildung der Ringsysteme. Hier liefern wir erste Einblicke in diese Prozesse am Beispiel der Biosynthese des Ikarugamycins. Dies gelingt durch erstmalige heterologe Expression eines PTM‐Biosynthesegenclusters in Escherichia coli. Mit diesem Verfahren wird es in Zukunft nicht nur möglich sein, bereits bekannte PTM‐Biosynthesegencluster mechanistisch genauer zu untersuchen, sondern auch durch Genom‐Mining identifizierte, chemisch bislang unerschlossene PTM‐Biosynthesewege chemisch und biochemisch eingehend zu beschreiben.
Two‐Orbital Three‐Electron Stabilizing Interaction for Direct Co2+As3+ Bonds involving Square‐Planar CoO4 in BaCoAs2O5
Authors: David Rénald , Kabbour Houria , Pautrat Alain , Touati Nadia , Whangbo Myung‐Hwan , Mentré Olivier 
Published: February 2014

AbstractThe quest for new oxides with cations containing active lone‐pair electrons (E) covers a broad field of targeted specificities owing to asymmetric electronic distribution and their particular band structure. Herein, we show that the novel compound BaCoAs2O5, with lone‐pair As3+ ions, is built from rare square‐planar Co2+O4 involved in direct bonding between As3+E and Co2+ dz2 orbitals (CoAs=2.51 Å). By means of DFT and Hückel calculations, we show that this σ‐type overlapping is stabilized by a two‐orbital three‐electron interaction allowed by the high‐spin character of the Co2+ ions. The negligible experimental spin‐orbit coupling is expected from the resulting molecular orbital scheme in O3AsE–CoO4 clusters.
Total Syntheses of Secalonic Acids A and D
Authors: Qin Tian , Porco John A. 
Published: February 2014

AbstractTotal syntheses of the dimeric tetrahydroxanthone natural products secalonic acids A and D are described. Key steps involve kinetic resolution of the tetrahydroxanthone core structure using homobenzotetramisole catalysis and late‐stage copper(I)‐mediated homodimerization of complex aryl stannane monomers.
Iron(II) Spin‐Crossover Complexes in Ultrathin Films: Electronic Structure and Spin‐State Switching by Visible and Vacuum‐UV Light
Authors: Ludwig E. , Naggert H. , Kalläne M. , Rohlf S. , Kröger E. , Bannwarth A. , Quer A. , Rossnagel K. , Kipp L. , Tuczek F. 
Published: February 2014

AbstractThe electronic structure of the iron(II) spin crossover complex [Fe(H2bpz)2(phen)] deposited as an ultrathin film on Au(111) is determined by means of UV‐photoelectron spectroscopy (UPS) in the high‐spin and in the low‐spin state. This also allows monitoring the thermal as well as photoinduced spin transition in this system. Moreover, the complex is excited to the metastable high‐spin state by irradiation with vacuum‐UV light. Relaxation rates after photoexcitation are determined as a function of temperature. They exhibit a transition from thermally activated to tunneling behavior and are two orders of magnitude higher than in the bulk material.
Surfactant‐Free Nonaqueous Synthesis of Plasmonic Molybdenum Oxide Nanosheets with Enhanced Catalytic Activity for Hydrogen Generation from Ammonia Borane under Visible Light
Authors: Cheng Hefeng , Kamegawa Takashi , Mori Kohsuke , Yamashita Hiromi 
Published: February 2014

AbstractPlasmonic materials have drawn emerging interest, especially in nontraditional semiconductor nanostructures with earth‐abundant elements and low resistive loss. However, the actualization of highly efficient catalysis in plasmonic semiconductor nanostructures is still a challenge, owing to the presence of surface‐capping agents in their synthetic procedures. To fulfill this, a facile non‐aqueous procedure was employed to prepare well‐defined molybdenum oxide nanosheets in the absence of surfactants. The obtained MoO3‐x nanosheets display intense absorption in a wide range attributed to the localized surface plasmon resonances, which can be tuned from the visible to the near‐infrared region. Herein, we demonstrate that such plasmonic semiconductor nanostructures could be used as highly efficient catalysts that dramatically enhance the hydrogen‐generation activity of ammonia borane under visible light irradiation.
Total Synthesis of the Isodon Diterpene Sculponeatin N
Authors: Moritz Benjamin J. , Mack Daniel J. , Tong Liuchuan , Thomson Regan J. 
Published: February 2014

AbstractThe total synthesis of sculponeatin N, a bioactive polycyclic diterpene isolated from Isodon sculponeatus, is reported. Key features of the synthesis include diastereoselective Nazarov and ring‐closing metathesis reactions, and a highly efficient formation of the bicyclo[3.2.1]octane ring system by a reductive radical cyclization.
Boron Clusters as Highly Stable Magnesium‐Battery Electrolytes
Authors: Carter Tyler J. , Mohtadi Rana , Arthur Timothy S. , Mizuno Fuminori , Zhang Ruigang , Shirai Soichi , Kampf Jeff W. 
Published: February 2014

AbstractBoron clusters are proposed as a new concept for the design of magnesium‐battery electrolytes that are magnesium‐battery‐compatible, highly stable, and noncorrosive. A novel carborane‐based electrolyte incorporating an unprecedented magnesium‐centered complex anion is reported and shown to perform well as a magnesium‐battery electrolyte. This finding opens a new approach towards the design of electrolytes whose likelihood of meeting the challenging design targets for magnesium‐battery electrolytes is very high.
Mechanical and thermal properties of thermoplastic random copolyesters made from lipid‐derived Medium and long chain poly(ω‐hydroxyfatty acid)s
Authors: Jose Jesmy , Li Shaojun , Bouzidi Laziz , Leao Alcides Lopes , Narine Suresh S. 
Published: February 2014

ABSTRACTThe physical properties of novel thermoplastic random copolyesters [‐(CH2)n‐COO‐/‐(CH2)n‐COO‐]x made of long (n = 12) and medium (n = 8) chain length ω‐hydroxyfatty esters [HO‐(CH2)n‐COOCH3] derived from bio‐based vegetable oil feedstock are described. Poly(ω‐hydroxy tridecanoate/ω‐hydroxy nonanoate) P(−Me13−/−Me9−) random copolyesters (Mn = 11,000–18,500 g/mol) with varying molar ratios were examined by TGA, DSC, DMA and tensile analysis, and WAXD. For the whole range of P(−Me13−/−Me9−) compositions, the WAXD data indicated an orthorhombic polyethylene‐like crystal packing. Their melting characteristics, determined by DSC, varied with composition suggesting an isomorphic cocrystallization behavior. TGA of the P(−Me13−/−Me9−)s indicated improved thermal stability determined by their molar compositions. The glass transition temperature, investigated by DMA, was also found to vary with composition. The crystallinities of P(−Me13−/−Me9−)s however, were unaffected by the composition. The stiffness (Young's modulus) of these materials was found to be related to their degrees of crystallinity. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40492.
Impact of impeller type on methyl methacrylate emulsion polymerization in a batch reactor
Authors: Fathi Roudsari Shideh , Dhib Ramdhane , Ein‐Mozaffari Farhad 
Published: February 2014

AbstractThe emulsion polymerization of methyl methacrylate (MMA) was carried out in a lab‐scale reactor, which was equipped with a top‐entry agitator, four wall baffles, a U‐shaped cooling coil, and a temperature controller. Potassium per sulfate and sodium dodecyl sulfate as were used as the initiator and the surfactant, respectively. The experimental investigation demonstrated the impact of the impeller type (45° six pitched‐blade turbine and Rushton impeller), number of impellers (single and double impellers), and impeller speed (100–350 rpm) on the monomer conversion, polymer particles size, molecular weight, and glass transition temperature. The results revealed that the effect of the impeller speed on the characteristics of the polymer attained using the pitched‐blade turbine was more prominent than that for the Rushton turbine. It was also found that the impact of the impeller speed on the polymer characteristics was much more pronounced for the double pitched‐blade turbines rather than for the double Rushton turbines. However, more uniform size distribution was achieved with the Rushton turbine. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40496.
Deposition of nonfouling plasma polymers to a thermoplastic silicone elastomer for microfluidic and biomedical applications
Authors: Gross‐Kosche Petra , Low Suet P. , Guo Rui , Steele David A. , Michelmore Andrew 
Published: February 2014

ABSTRACTPlasma polymerization is used for the modification and control of surface properties of a highly transparent, thermoplastic elastomeric silicone copolymer, GENIOMER® 80 (G80). PEG‐like diglyme plasma polymer films were deposited with ether retentions varying between 20% and 70% as measured by X‐ray photoelectron spectroscopy analysis which did not affect the transparency of the substrate. Films with ether retentions of greater than 70% inhibit protein binding (bovine serum albumin and fibrinogen) and cell proliferation. A short oxygen plasma pretreatment enhances the adhesion and stability of the film as shown by protein binding and cell adhesion experiments. The transparency of the material and the stability of the coating makes this material a versatile bulk material for technical (e.g., lab‐on‐a‐chip) and biomedical (e.g., intraocular lens) applications. The G80/plasma polymer composite is stable against vigorous washing and storage over 5 months and, therefore, offers an attractive alternative to poly(dimethylsiloxane). © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40500.
Enhanced film forming ability of benzoxazine–urethane hybrid polymer network by sequential cure method
Authors: Rimdusit Sarawut , Sudjidjune Manop , Jubsilp Chanchira , Tiptipakorn Sunan 
Published: February 2014

ABSTRACTUniform copolymer films of benzoxazine resin (BA‐a) and urethane prepolymer (PU) were prepared at various BA‐a/PU mass ratios (100/0, 80/20, 60/40, 40/60, 20/80, and 0/100) via sequential cure method comprising of moisture cure and thermal cure steps. In the moisture cure step, Fourier Transform Infrared (FT‐IR) spectra revealed the network formation between NCO‐terminated group and moisture to firstly produce PU solid film. Then in the thermal cure step, the change of tri‐substituted benzene ring to tetra‐substituted benzene ring was observed suggesting polybenzoxazine network formation in this step. Moreover, the spectra reveal that isocyanate groups in polyurethane structure could react with phenolic hydroxyl groups of BA‐a to form biuret and allophanate groups. Dynamic mechanical analysis (DMA) confirms a synergistic behavior in glass transition temperature (Tg) of the alloys with the highest Tg value of 275°C which is uniquely observed in these alloys obtained from traditionally thermal cure method. The proposed sequential cure method above is found to be highly useful for uniform coating or film casting process which lacks in traditional, low A‐stage viscosity, benzoxazine resin. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40502.
Poly(vinylidene fluoride) membrane with piezoelectric β‐form prepared by immersion precipitation from mixed solvents containing an ionic liquid
Authors: Li Chun , Zhu Yun , Lv Ruihua , Na Bing , Chen Bibo 
Published: February 2014

ABSTRACTPoly(vinylidene fluoride) (PVDF) membranes with exclusive β‐form have been directly obtained by immersion precipitation from the mixed solvents containing an ionic liquid (IL). In contrast, without the IL only the α‐form is generated. The ion–dipole interactions between the IL and PVDF chains should account for the formation of the β‐form with TTTT conformation. In addition, the presence of the IL accelerates the crystallization and gelation of PVDF, responsible for the particulate morphology and high water flux in the membranes. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40505.
Adhesion failure of antiscratch coatings on polycarbonate under UV irradiation
Authors: Zhang Xuan , Zhong Yan‐Li , Li Lei , Yan Yue 
Published: February 2014

ABSTRACTThe adhesion failure of antiscratch (AS) coatings on unmodified and plasma‐modified polycarbonate (PC) substrate was studied using both chemical and physical methods while considering the surface and interface changes between coatings and PC under ultraviolet (UV) irradiation. The differences in the wettability and surface elemental compositions of the PC surface (PCs) and AS coatings after UV ageing were evaluated by contact angle and Fourier transform infrared (FTIR) measurements. The nanoindentation technique was employed for the quantitative assessment of the changes in the nanomechanical properties of both PCs and AS coatings under UV irradiation. The adhesion of coating on plasma‐modified PC was found to be significantly better than that of unmodified substrates. The hydrophilicity and polarity of PCs covered by AS coatings were significantly increased because of the photodegradation of PCs, whereas silicon coatings remained invariant. Nanoindentation tests revealed an obvious enhancement in stiffness of the coating and exposed PC after ageing. Based on these experiments, we proposed that adhesion failure under UV irradiation may be caused by two reasons: first, the photodegradation that occurred at the PCs covered by AS coatings; and second, the stress induced by the changes in stiffness of both AS and PCs under UV ageing. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40507.
Preparation of Zn porphyrin‐functionalized polystyrene and the fluorescence quenching of it by terbuthylazine
Authors: Wang Ruixin , Gao Baojiao , Jiao Weizhou , Yu Long , Pan Wen 
Published: February 2014

ABSTRACTZinc tetraphenylporphyrin (ZnPP) was bond on the side chains of linear chloromethylated polystyrene (CMPS) through Friedel–Crafts alkylation reaction, and the metalloporphyrin‐functionalized polystyrene (ZnPP/PS) was obtained successfully. Its chemical structure was characterized with FTIR. And the effects of various factors on the bonding reaction of ZnPP had been investigated in detail. In addition, the photophysical properties of ZnPP/PS were studied by means of UV‐Vis spectroscopy and fluorescence spectroscopy. The research results show that ZnPP/PS could be prepared favorably through Friedel–Crafts alkylation reaction between ZnPP and CMPS, and the most bonding degree of ZnPP on PS is up to 7% under the condition of the temperature 25°C and 0.1 mL of SnCl4 lasting 8 h. Moreover, ZnPP/PS show the characteristic photophysical behavior similar to ZnPP. ZnPP moieties in ZnPP/PS interact with terbuthylazine (TBA) and form a complex with a red‐shift of Q‐band of absorbance peak from 559 to 565 nm. Especially TBA quenches ZnPP/PS emission intensity at 610 and 662 nm when excites at 423 nm. The TBA‐ZnPP/PS complex is formed in the ground state and TBA is bonded to the excited state of ZnPP/PS simultaneously on the basis of a non‐linear Stern–Volmer plot indicative of the combined dynamic and static quenching. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40516.
Synthesis of Pyridine N‐Oxide–BF2CF3 Complexes and Their Fluorescence Properties
Authors: Nishida Tomoaki , Fukazawa Aiko , Yamaguchi Eriko , Oshima Hiroya , Yamaguchi Shigehiro , Kanai Motomu , Kuninobu Yoichiro 
Published: February 2014

AbstractPyridine N‐oxide–BF2CF3 and –BF2C2F5 complexes and their derivatives were synthesized. Most of the complexes show fluorescence both in solution and in the solid state. By expanding the π‐conjugated skeleton, the color of the fluorescence could be changed dramatically. A fluorophore with a high solvent dependency could also be produced. Since such compounds can be synthesized on a gram scale in high yield, and are stable to oxygen, water, and heat, the complexes hold great potential as organic functional materials.
Silicon‐Based Bulky Group‐Induced Remote Control and Conformational Preference in the Synthesis and Application of Isolable Atropisomeric Amides with Secondary Alcohol or Amine Moieties
Authors: Bai Xing‐Feng , Deng Wen‐Hui , Xu Zheng , Li Fu‐Wei , Deng Yuan , Xia Chun‐Gu , Xu Li‐Wen 
Published: February 2014

AbstractRemote stereocontrol through conformational transmission along a carbon chain is highly important in synthetic systems and molecular architectures. In this work, the interactional reactivity between a remote silicon‐based bulky group and an O‐/N‐containing functional group has been revealed and determined by lateral lithiation–substitution, desilylation, as well as desilylation–olefination with benzaldehyde. The results suggest considerable information transmission and steric hindrance that can be exploited for the controllable synthesis of atropisomeric molecules. Based on the remote steric effect of a functional group across the aromatic ring of an amide, the construction of isolable atropisomeric amides with functional groups, such as alcohol, amine, and olefin was successfully achieved. All these new atropisomers were obtained in reasonable yield in pure diastereomeric form, and the specific configuration of representative products was confirmed by X‐ray crystallography.
Prenatal diagnosis of proximal partial trisomy 1q confirmed by comparative genomic hybridization array: Molecular cytogenetic analysis, fetal pathology and review of the literature
Authors: Sifakis Stavros , Eleftheriades Makarios , Kappou Dimitra , Murru Roberta , Konstantinidou Anastasia , Orru Sandro , Ziegler Monika , Liehr Thomas , Manolakos Emmanouil , Papoulidis Ioannis 
Published: February 2014

BACKGROUNDPartial trisomy of the long arm of chromosome 1 (1q) is an exceptionally rare chromosomal abnormality and most of the prenatally diagnosed cases are associated with either complete (q11‐qter) or large (q21‐qter) duplications with pre‐ or perinatal demise of all reported cases. The most common sonographic findings associated with this karyotype abnormality include ventriculomegaly, increased nuchal translucency or nuchal fold, renal and cardiac abnormalities, craniofacial dysmorphism, and limb deformities. However, there is a wide spectrum of clinical manifestations due to the great variability in the extent of the duplication size and the possible contribution of additional genetic rearrangements in the final phenotype.CASE REPORTWe report on a female fetus with sole partial trisomy 1q presenting with multiple structural malformations in the second trimester scan. Standard karyotyping demonstrated a large duplication on the proximal end of chromosome 1 [46,XX,dup(1)(pter→q31::q31→q12::q31→qter)] and further application of comparative genomic hybridization array confirmed the diagnosis and offered a precise characterization of the genetic defect.CONCLUSIONA fetus with nonmosaic partial trisomy 1q that was prenatally diagnosed upon multiple abnormal ultrasound findings is presented. A detailed review of the currently available literature on the prenatal diagnostic approach of partial trisomy 1q in terms of fetal sonographic assessment and molecular cytogenetic investigation is also provided. The use of novel molecular techniques such comparative genomic hybridization array could shed further light on the correlation between the genes identified in the chromosomal region of interest and the resultant phenotype. Birth Defects Research (Part A) 100:284–293, 2014. © 2014 Wiley Periodicals, Inc.
Engineering articular cartilage‐like grafts by self‐assembly of infrapatellar fat pad‐derived stem cells
Authors: Mesallati Tariq , Buckley Conor T. , Kelly Daniel J. 
Published: February 2014

ABSTRACTWell documented limitations associated with primary chondrocytes for cartilage tissue engineering applications have led to increased interest in the use of multi‐potent stem/progenitor cells. The objective of this study was to firstly investigate if infrapatellar fat pad‐derived stem cells (FPSCs) could be used to engineer cartilage‐like tissues through a self‐assembly (SA) process, and secondly to compare the properties of such grafts to those engineered by agarose hydrogel encapsulation (AE). Self‐assembled cartilaginous tissues were first engineered by geometrically confining FPSCs on tissue culture plastic, and then either continuously or transiently supplementing these constructs with transforming growth factor‐β3 (TGF‐β3). Transient supplementation with TGF‐β3 (for the first 21 days of culture) enhanced the development of self‐assembled grafts, with sGAG accumulation reaching levels of 8.4 ± 1.5% w/w after 6 weeks of culture. While overall levels of matrix synthesis were higher with AE compared to SA, when normalized to tissue wet weight, ECM accumulation was significantly greater in the lighter SA constructs. A potential drawback with the SA approach on tissue culture plastic was that it often led to the development of contracted, geometrically inconsistent tissues. We therefore next explored if SA on polyethylene terephthalate (PET) transwell membranes would lead to the development of more morphologically stable and homogenous tissues. At high seeding densities, SA on such transwell membranes led to the formation of geometrically uniform constructs that underwent minimal contraction during culture. In conclusion, the results of this study demonstrate the potential of SA using FPSCs for cartilage tissue engineering, with grafts attaining relatively high levels of sGAG content within clinically relevant timeframes. Such an approach is easily scalable and may lend itself to treating large, full thickness cartilage defects. Biotechnol. Bioeng. 2014;111: 1686–1698. © 2014 Wiley Periodicals, Inc.