bluuebunny/crossref_metadata_2025_split huggingface dataset:
Die Polymorphe von L‐Phenylalanin
Authors: Ihlefeldt Franziska Stefanie , Pettersen Fredrik Bjarte , von Bonin Aidan , Zawadzka Malgorzata , Görbitz Carl Henrik 
Published: October 2014

AbstractDie Festkörperstruktur der Aminosäure Phenylalanin (Phe) bietet einen möglichen Schlüssel, um das Verhalten einer großen Klasse von wichtigen aromatischen Verbindungen zu verstehen. Gute Einkristalle zu erhalten ist bekanntermaßen dennoch schwierig. Die Struktur des üblichen Polymorphs von Phe, Form I, wurde zuerst von Weiss et al. (als D‐Phe) im Jahr 1990 beschrieben. Die Richtigkeit der veröffentlichten C2‐Elementarzelle mit zwei fehlgeordneten Molekülen in der asymmetrischen Einheit wurde jedoch später hinterfragt. Hier wird gezeigt, dass die Identität der Form I von L‐Phe P21 mit Z′=4 ist, basierend auf Daten aus einem gut beugenden Einkristall, der aus einer essigsauren Lösung der Aminosäure gezüchtet wurde. Ein zweiter neuer Polymorph, Form IV, bietet zusammen mit den beiden kürzlich beschriebenen Formen II und III präzedenzlose Informationen über die strukturelle Komplexität dieser essenziellen Aminosäure. Es ist weiterhin dokumentiert, dass das Racemat dl‐Phe nicht in ordnungsgemäßen Einkristallen wächst.
Sequence and Chiral Selectivity of Drug–DNA Interactions Revealed by Force Spectroscopy
Authors: Hu Qiongzheng , Xu Shoujun 
Published: October 2014

AbstractDifferential binding force has been used to precisely characterize the mechanical effect of a drug molecule binding to a DNA duplex. The high‐resolution binding forces measured by the force‐induced remnant magnetization spectroscopy (FIRMS) enable the binding behavior of drug molecules with different chirality and DNA of various sequences to be distinguished. The sequence specificity of Hg2+ and daunomycin was revealed by force spectroscopy for the first time, and the results are consistent with those obtained by other techniques. Furthermore, the two isomers of d,l‐tetrahydropalmatine showed selectivity for two different DNA sequences. One particular useful feature of this approach is that the small molecules under study do not require any labels.
Excellent Stability of a Lithium‐Ion‐Conducting Solid Electrolyte upon Reversible Li+/H+ Exchange in Aqueous Solutions
Authors: Ma Cheng , Rangasamy Ezhiylmurugan , Liang Chengdu , Sakamoto Jeffrey , More Karren L. , Chi Miaofang 
Published: October 2014

AbstractBatteries with an aqueous catholyte and a Li metal anode have attracted interest owing to their exceptional energy density and high charge/discharge rate. The long‐term operation of such batteries requires that the solid electrolyte separator between the anode and aqueous solutions must be compatible with Li and stable over a wide pH range. Unfortunately, no such compound has yet been reported. In this study, an excellent stability in neutral and strongly basic solutions was observed when using the cubic Li7La3Zr2O12 garnet as a Li‐stable solid electrolyte. The material underwent a Li+/H+ exchange in aqueous solutions. Nevertheless, its structure remained unchanged even under a high exchange rate of 63.6 %. When treated with a 2 M LiOH solution, the Li+/H+ exchange was reversed without any structural change. These observations suggest that cubic Li7La3Zr2O12 is a promising candidate for the separator in aqueous lithium batteries.
ZIF‐8 Derived Graphene‐Based Nitrogen‐Doped Porous Carbon Sheets as Highly Efficient and Durable Oxygen Reduction Electrocatalysts
Authors: Zhong Hai‐xia , Wang Jun , Zhang Yu‐wei , Xu Wei‐lin , Xing Wei , Xu Dan , Zhang Yue‐fei , Zhang Xin‐bo 
Published: October 2014

AbstractNitrogen‐doped carbon (NC) materials have been proposed as next‐generation oxygen reduction reaction (ORR) catalysts to significantly improve scalability and reduce costs, but these alternatives usually exhibit low activity and/or gradual deactivation during use. Here, we develop new 2D sandwich‐like zeolitic imidazolate framework (ZIF) derived graphene‐based nitrogen‐doped porous carbon sheets (GNPCSs) obtained by in situ growing ZIF on graphene oxide (GO). Compared to commercial Pt/C catalyst, the GNPCSs show comparable onset potential, higher current density, and especially an excellent tolerance to methanol and superior durability in the ORR. Those properties might be attributed to a synergistic effect between NC and graphene with regard to structure and composition. Furthermore, higher open‐circuit voltage and power density are obtained in direct methanol fuel cells.
Preparation and properties of β‐phase graphene oxide/PVDF composite films
Authors: An Ningli , Liu Shaolong , Fang Changqing , Yu Ruien , Zhou Xing , Cheng Youliang 
Published: October 2014

ABSTRACTWe report preparation of graphene oxide (GO) from expanded graphite (EG) via a modified Hummers method. GO/PVDF composites films were obtained using solvent N, N‐Dimethylformamide (DMF) and cosolvent comprising deionized water/DMF combination. X‐ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) analyses revealed that the main crystal structure of the composite films is β‐phase, and use cosolvent method tends to favor the formation of β‐phase. Scanning electron microscopy (SEM) was used to investigate the microstructure of composite films. Storage modulus and loss modulus were measured by Dynamic mechanical analysis (DMA). Broadband dielectric spectrum tests showed an increase in the dielectric constant of the GO/PVDF composite films with the rising content of GO, and by cosolvent method could improve the dielectric constant while reducing the dielectric loss. Our method that uses GO as an additive and deionized water/DMF as the cosolvent provides a promising and low‐cost pathway to obtain high dielectric materials. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41577.
Amphoteric hydrolyzed poly(acrylamide/dimethyl diallyl ammonium chloride) as a filtration reducer under high temperatures and high salinities
Authors: Lin Ling , Luo Pingya 
Published: October 2014

ABSTRACTPoly(acrylamide/dimethyl diallyl ammonium chloride) (PAD) samples were synthesized via solution polymerization. Hydrolyzed poly(acrylamide/dimethyl diallyl ammonium chloride) (HPAD) was prepared with NaOH as a hydrolyzation agent. Both PAD and HPAD were characterized by IR and NMR spectroscopy. Na2SO3 was added to slow down the decomposition of HPAD under elevated temperatures. The rheological and filtrate properties of the drilling fluids were investigated in saltwater mud. We found that 30 wt % NaCl hampered those properties. Increasing HPAD's percentage in the clay suspensions reduced the filtrate volumes and whereas increased the viscosities. A greater amount of HPAD added to the saltwater mud resulted in a smaller particle medium size and caused the ζ potential to move toward a less negative value. The hydrolysis degree of HPAD needed to be controlled in a proper range to optimize the reduction in filtration. Scanning electron microscopy photos showed that HPAD was distributed in the surface of the high‐temperature and high‐pressure filter cake as bridges. The drilling fluids with 3.5 wt % HPAD had an excellent tolerance to 30 wt % NaCl and a temperature of 200°C. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41581.
Regioselective CH Imidation of Five‐Membered Heterocyclic Compounds through a Metal Catalytic or Organocatalytic Approach
Authors: Wang Xin , Sun Kai , Lv Yunhe , Ma Fengji , Li Gang , Li Donghui , Zhu Zhonghong , Jiang Yongqing , Zhao Feng 
Published: October 2014

AbstractAn efficient method for the synthesis of 2‐amino and β‐amino five‐membered heterocyclic derivatives that are closely related to a variety of biologically active natural products is described. Regioselectivity was achieved through a metal catalytic or organocatalytic approach. Preliminary studies on the reaction mechanism suggest a radical imidation pathway; however, further studies are needed to verify the mechanism.
Effects of warm ischaemia combined with cold preservation on the hypoxia-inducible factor 1α pathway in an experimental renal autotransplantation model
Authors: Delpech P O , Thuillier R , Le Pape S , Rossard L , Jayle C , Billault C , Goujon J M , Hauet T 
Published: October 2014

AbstractBackgroundThe increased use of marginal donors highlights the importance of organ quality in transplantation and the identification of prognostic biomarkers. This experimental study investigated modulation of the hypoxia-inducible factor (HIF) 1α pathway in kidney grafts in relation to different degrees of ischaemia.MethodsIn a porcine autotransplantation model, two different kidney graft protocols were compared: standard 24-h cold storage (CS) and 24-h CS preceded by 1 h warm ischaemia (WI + CS). The renal HIF-1α pathway and tubular dedifferentiation were analysed in the early phase of reperfusion and at 3 months.ResultsThere was a relationship between the degree of ischaemic injury and the outcome of the kidney graft. During the first week of reperfusion, WI + CS grafts showed a higher degree of injury. The observed tubular dedifferentiation was associated with delayed HIF-1α expression, and with loss of its role in transcription. In highly injured kidneys, deregulation of the HIF-1α pathway was also observed in the chronic phase, with reduced production of vascular endothelial growth factor (VEGF) A, and upregulation of VEGF receptor 1 (Flt-1) and thrombospondin 1. In addition, these kidneys displayed altered kidney histology and decreased function.ConclusionThe HIF-1α pathway appears to be abolished early in response to severe ischaemia. A high degree of ischaemic injury also results in chronic activation of the HIF-1α pathway, diverting it away from the beneficial activation of angiogenesis. Further studies on the finely tuned balance of signals in this pathway may provide diagnostic biomarkers that can determine organ quality during kidney transplantation. Surgical relevanceThe increased use of marginal donors has highlighted the importance of organ quality in transplantation. Renal ischaemia–reperfusion injury following transplantation induces graft dysfunction.In a porcine model of renal autotransplantation, the induction of regenerative processes, in response to graded degrees of ischaemia, was studied in the post-transplantation phase. There was early abrogation of the hypoxia-inducible factor (HIF) 1α pathway in response to severe ischaemia. High degrees of ischaemic injury induced chronic activation of the HIF-1α pathway, diverting it from the beneficial activation of angiogenesis.Identification of the mechanisms involved in renal regeneration, such as those related to the HIF-1α pathway, are important as these mechanisms can be used to identify novel therapeutic targets or develop diagnostic biomarkers to determine organ quality early in the transplantation process.
The Search for New Amber Ingredients
Authors: Narula Anubhav P. S. 
Published: October 2014

AbstractThere is a constant need for developing new fragrance ingredients in the flavor and fragrance industry, as it allows perfumers to create unique and differentiating perfumes for fine as well as functional products. Among all the categories of notes used in perfume creation, amber notes are indispensible and ubiquitous in their presence in all perfumes. Not only amber notes impart high performance and substantivity to fragrances, but they are paramount in the development of classic and legendary fragrances. This article is based on the plenary lecture delivered at the flavor & fragrance 2013 conference of the German Chemical Society in Leipzig, Germany. The strategy, rationale, and the various synthetic approaches that led to the discovery of two new very powerful, woody, amber materials, Amber Xtreme® (1) and Trisamber® (2), are delineated.
4Fr in 5Fr sheathless technique with standard catheters for transradial coronary interventions: Technical challenges and persisting issues
Authors: Abdelaal Eltigani , Rimac Goran , Plourde Guillaume , MacHaalany Jimmy , Roy Louis , Tardif Marc‐Antoine , Costerousse Olivier , Pancholy Samir B. , Bertrand Olivier F. 
Published: October 2014

ObjectivesTo evaluate the feasibility and potential benefits of performing sheathless 5Fr transradial percutaneous coronary interventions (PCI) using 4Fr diagnostic catheters as dilators.BackgroundThere is a direct association between artery–catheter mismatch and risk of radial artery occlusion.MethodsWe recruited 130 patients who underwent 4Fr sheathless diagnostic angiography with super torque (Cordis Corporation, USA) catheters followed by ad hoc PCI. To facilitate skin and vessel penetration, the Judkins right catheter (110 cm) was inserted inside the 5Fr guiding catheter (100 cm) as dilator.ResultsThe mean age of patients was 63 ± 12 years with 74% of males. Unfractionated heparin monotherapy was used in 84%, bivalirudin in 12%, and platelet glycoprotein 2b/3a inhibitors in 13%. Right radial artery was used in 99%. In three cases, no PCI was performed (FFR) and in two (1.5%) cases, a sheath was required after guiding catheter insertion due to local bleeding. In six cases (4.6%), upscale to 6Fr sheathed approach was required. No spasm occurred. Overall procedural success was achieved in 114/119 (96%) cases, including left main PCI, bifurcation PCI in 10 (8%) cases, CTO in 5 (4%) and IVUS use in 6 (5%) cases. Immediately after hemostasis completion, duplex ultrasound showed normal flow in 76%, occlusive thrombus in 13%, pseudo‐aneurysmal dilatation in 11% and local hematoma surrounding puncture site in 20%. Hemoglobin dropped from 138 ± 19 g/l to 131 ± 16 g/l 4–6 hours after PCI.ConclusionUsing 4Fr diagnostic catheters as dilators, simple and complex PCI can be performed with standard 5Fr guiding catheters as sheathless techniques. However, suboptimal transition between diagnostic and guiding catheters likely creates radial artery trauma leading to frequent occlusive thrombus and hematoma surrounding the radial artery. © 2014 Wiley Periodicals, Inc.
Efficacy and safety of novel multi‐lumen catheter for chronic total occlusions
Authors: Mitsutake Yoshiaki , Ebner Adrian , Yeung Alan C. , Taber Mark D. , Davidson Charles J. , Ikeno Fumiaki 
Published: October 2014

ObjectiveTo report our initial animal and human experience with a new multi‐lumen catheter called MultiCross™ (Roxwood Medical, Inc.) in a porcine coronary model and patients with a chronic total occlusion (CTO).MethodsPreclinical safety study was done in the coronary vasculature of a porcine model. In a clinical setting, patients with a CTO of a coronary artery (n = 5) were enrolled. After an initial unsuccessful attempt using a conventional guidewire, operators could use the MultiCross system. The primary efficacy endpoint was successful recanalization (technical success) and the primary safety endpoint was serious adverse events through 30 days post‐procedure.ResultsThe MultiCross catheter was used for all patients after failure of the initial attempt with a guidewire. Successful recanalization was achieved in all CTOs attempted (100%). No patients reported any adverse events at 30 days post‐procedure.ConclusionIn this first‐in‐man experience, the MultiCross catheter has the potential to enhance crossing of CTOs. © 2014 Wiley Periodicals, Inc.
An Isomer of C60Cl10 Free of Skew‐Pentagonal‐Pyramidal C60Cl6 Substructure
Authors: Liang Hua , Dai Ke , Peng Ru‐Fang , Chu Shi‐Jin 
Published: October 2014

AbstractChlorination is an effective approach for understanding the feature of multiple additions on fullerene cages. The chlorofullerenes obtained are versatile synthons for further derivatization. However, chlorofullerenes used for chemical reaction studies are mainly based on the skew‐pentagonal‐pyramidal (SPP) C60Cl6. In this work, a new isomer of C60Cl10 that does not contain an SPP‐C60Cl6 substructure was identified. Its electrochemical properties give it unexpected cyclic voltammetric behavior at more negative potentials relative to other chlorofullerenes. Friedel–Crafts arylation shows good reactivity of this compound. These new findings challenge opinions of fullerene addition patterns and will break the monopoly of C60Cl6 as a precursor for fullerene modifications.
Chiral N‐Heterocyclic Carbene Ligands Bearing a Pyridine Moiety for the Copper‐Catalyzed Alkylation of N‐Sulfonylimines with Dialkylzinc Reagents
Authors: Soeta Takahiro , Ishizaka Tomohiro , Tabatake Yuta , Ukaji Yutaka 
Published: October 2014

AbstractAmino acid‐derived chiral imidazolium salts, each bearing a pyridine ring, were developed as N‐heterocyclic carbene ligands. The copper‐catalyzed asymmetric alkylation of various N‐sulfonylimines with dialkylzinc reagents in the presence of these chiral imidazolium salts afforded the corresponding alkylated products with high enantioselectivity (up to 99 % ee). The addition of HMPA to the reaction mixture as a co‐solvent is critical in terms of chemical yield and enantioselectivity. A wide range of N‐sulfonylimines and dialkylzinc reagents were found to be applicable to this reaction.
An “Ingredients” Approach to Functional Self‐Synthesizing Materials: A Metal‐Ion‐Selective, Multi‐Responsive, Self‐Assembled Hydrogel
Authors: Li Jianwei , Cvrtila Ivica , Colomb‐Delsuc Mathieu , Otten Edwin , Otto Sijbren 
Published: October 2014

AbstractNew methodology for making novel materials is highly desirable. Here, an “ingredients” approach to functional self‐assembled hydrogels was developed. By designing a building block to contain the right ingredients, a multi‐responsive, self‐assembled hydrogel was obtained through a process of template‐induced self‐synthesis in a dynamic combinatorial library. The system can be switched between gel and solution by light, redox reactions, pH, temperature, mechanical energy and sequestration or addition of MgII salt.
Molecular‐Target‐Based Anticancer Photosensitizer: Synthesis and in vitro Photodynamic Activity of Erlotinib–Zinc(II) Phthalocyanine Conjugates
Authors: Zhang Feng‐Ling , Huang Qi , Liu Jian‐Yong , Huang Ming‐Dong , Xue Jin‐Ping 
Published: October 2014

AbstractTargeted photodynamic therapy is a new promising therapeutic strategy to overcome growing problems in contemporary medicine, such as drug toxicity and drug resistance. A series of erlotinib–zinc(II) phthalocyanine conjugates were designed and synthesized. Compared with unsubstituted zinc(II) phthalocyanine, these conjugates can successfully target EGFR‐overexpressing cancer cells owing to the presence of the small molecular‐target‐based anticancer agent erlotinib. All conjugates were found to be essentially non‐cytotoxic in the absence of light (up to 50 μM), but upon illumination, they show significantly high photo‐cytotoxicity toward HepG2 cells, with IC50 values as low as 9.61–91.77 nM under a rather low light dose (λ=670 nm, 1.5 J cm−2). Structure–activity relationships for these conjugates were assessed by determining their photophysical/photochemical properties, cellular uptake, and in vitro photodynamic activities. The results show that these conjugates are highly promising antitumor agents for molecular‐target‐based photodynamic therapy.
A Roundabout Approach to Control Morphological Orientation and Solar‐Cell Performance by Modulating Side‐Chain Branching Position in Benzodithiophene‐Based Polymers
Authors: Lee Kyu Cheol , Song Seyeong , Lee Junghoon , Kim Dong Suk , Kim Jin Young , Yang Changduk 
Published: October 2014

AbstractTo be meaningful to guide the rational design of novel high‐performance conjugated semiconductors, we prepared three benzo[1,2‐b:4,5‐b′]dithiophene (BDT)‐based polymers by systematically moving the branching point of the alkyl chain. The effect of side‐chain engineering was thoroughly investigated by a range of techniques. We demonstrate that a subtle change in the branching position in the BDT core can have a critical impact on polymer packing and preferential backbone orientation in thin films; copolymers made from BDT and thieno[3,4‐c]pyrrole‐4,6‐dione units (TPD) adopt more of a face‐on orientation as the branching point is shifted closer to the backbone, which can be correlated with a dramatic difference in solar‐cells performance. The high short‐circuit current density (11.6 mA cm−2) for the copolymer with one carbon atom between the alkoxylated oxygen atom and the branching point results from its predominantly face‐on orientation and smoother surface in thin films, which results in power conversion efficiencies as high as 4.56 %.
A New Stereoselective Total Synthesis of Phomonol
Authors: Subba Reddy Basi V. , Srinivas Lavudia , Sivaramakrishna Reddy Pathuri , Phaneendra Reddy Bhemavarapu , Prasad Attaluri R. , Yadav Jhillu S. 
Published: October 2014

AbstractA stereoselective total synthesis of phomonol, following organocatalytic enantioselective epoxidation and intramolecular oxa‐Michael reaction as key steps, is described. The use of readily available D‐tartaric acid as a chiral source renders this approach quite simple and attractive.
New Cytotoxic Laurene‐, Cuparene‐, and Laurokamurene‐Type Sesquiterpenes from the Red Alga Laurencia obtusa
Authors: Angawi Rihab F. , Alarif Walied M. , Hamza Rehab I. , Badria Farid A. , Ayyad Seif‐Eldin N. 
Published: October 2014

AbstractThree new sesquiterpene alcohols, laur‐2‐ene‐3,12‐diol (1), cuparene‐3,12‐diol (2), and 8,11‐dihydro‐1‐methoxylaurokamuren‐12‐ol (3), along with one known diterpene, kahukuen‐10‐ol (4) have been isolated from the organic extract of the red alga Laurencia obtusa. The chemical structures were elucidated on the basis of spectroscopic analysis. The cytotoxicity of the isolated compounds were evaluated against three cancer cell lines, i.e., KB, HepG2, and MCF‐7. Compound 4 exhibited a wide range of cytotoxic activity against KB, HepG2, and MCF‐7 cell lines with IC50 of 0.100, 0.057, and 0.054 μm, respectively. In addition, 1 showed moderate activities towards KB and MCF‐7 cell lines with IC50 values of 0.171 and 0.184 μM, respectively and 2 exhibited a moderate activity against KB cell line at a concentration of 0.213 μg/ml. On the other hand, compound 3 exhibited no cytotoxic activity against any of the three cell lines.
Synthesis of New C2‐Symmetric Chiral Bisamides from (1S,2S)‐Cyclohexane‐1,2‐dicarboxylic Acid
Authors: Zhou Chan , Xu Jiaxi 
Published: October 2014

AbstractA series of new C2‐symmetric (1S,2S)‐cyclohexane‐1,2‐dicarboxamides was synthesized from (1S,2S)‐cyclohexane‐1,2‐dicarbonyl dichloride and N‐benzyl‐substituted aromatic amines, which were prepared from 2‐aminopyridine, 2‐chloroaniline, and 2‐aminophenol via imine formation with benzaldehyde and subsequent reduction with NaBH4. (1S,2S)‐N,N′‐Dibenzyl‐N,N′‐bis[2‐(benzyloxy)phenyl]cyclohexane‐1,2‐dicarboxamide was converted to (1S,2S)‐N,N′‐dibenzyl‐N,N′‐bis(2‐hydroxyphenyl)cyclohexane‐1,2‐dicarboxamide via hydrogenolysis in the presence of Pd(OH)2 on active carbon powder.