bluuebunny/crossref_metadata_2025 huggingface dataset:
Deformation Behavior of the Percolating Intermetallic Microstructure of High Pressure Die Cast AZ91 Alloy
Authors: Zhang Bao , Nagasekhar Anumalasetty V. , Sivarupan Tharmalingam , Caceres Carlos H.
Published: September 2013

The intermetallic microstructure in two representative regions of the cross section, the corner and the core, of a cast‐to‐shape tensile specimen was studied. Available 3D data of the intermetallic, obtained with focused dual ion beam tomography, were incorporated into a finite element code to simulate the deformation behavior. The modeling reveals a high structural compliance at both the corner and the core, akin to the bending‐dominated behavior of cellular foams. The high compliance suggests that the percolating microstructure should keep most of its structural integrity, reinforcing the alloy without compromising the ductility, for strains above 1%. Scanning electron microscope observations of the damage by cracking of the intermetallic along the gauge of a tensile specimen deformed to fracture supported this prediction.
Filefish‐Inspired Surface Design for Anisotropic Underwater Oleophobicity
Authors: Cai Yue , Lin Ling , Xue Zhongxin , Liu Mingjie , Wang Shutao , Jiang Lei
Published: September 2013

Surfaces with anisotropic wettability, widely found in nature, have inspired the development of one‐dimensional water control on surfaces relying on the well‐arranged surface features. Controlling the wetting behavior of organic liquids, especially the motion of oil fluid on surfaces, is of great importance for a broad range of applications including oil transportation, oil‐repellent coatings, and water/oil separation. However, anisotropic oil‐wetting surfaces remain unexplored. Here, the unique skin of a filefish Navodon septentrionalis shows anisotropic oleophobicity under water. On the rough skin of N. septentrionalis, oil droplets tend to roll off in a head‐to‐tail direction, but pin in the opposite direction. This pronounced wetting anisotropy results from the oriented hook‐like spines arrayed on the fish skin. It inspires further exploration of the artificial anisotropic underwater oleophobic surfaces: By mimicking the oriented hook‐like microstructure on a polydimethylsiloxane layer via soft lithography and subsequent oxygen‐plasma treatment to make the PDMS hydrophilic, artificial fish skin is fabricated which has similar anisotropic underwater oleophobicity. Drawn from the processing of artificial fish skin, a simple principle is proposed to achieve anisotropic underwater oleophobicity by adjusting the hydrophilicity of surface composition and the anisotropic microtextures. This principle can guide the simple mass manufacturing of various inexpensive high surface‐energy materials, and the principle is demonstrated on commercial cloth corduroy. This study will profit broad applications involving low‐energy, low‐expense oil transportation, underwater oil collection, and oil‐repellant coatings on ship hulls and oil pipelines.
Stereotyped subset #1 chronic lymphocytic leukemia: a direct link between B‐cell receptor structure, function, and patients' prognosis
Authors: Del Giudice Ilaria , Chiaretti Sabina , Santangelo Simona , Tavolaro Simona , Peragine Nadia , Marinelli Marilisa , Ilari Caterina , Raponi Sara , Messina Monica , Nanni Mauro , Mauro Francesca Romana , Piciocchi Alfonso , Bontempi Katia , Rossi Davide , Gaidano Gianluca , Guarini Anna , Foà Robin
Published: September 2013

Chronic lymphocytic leukemia (CLL) with stereotyped B‐cell receptor (BCR) belonging to subset #1 (IGHV1‐5‐7/IGKV1‐39) display a poor outcome. To characterize their genetic and genomic features and BCR function, we selected 20 subset #1 CLL from a series of 579 cases. Subset #1 CLL, all showing unmutated IGHV, were associated with the presence of del(11q) (50%) in comparison with unmutated CLL, unmutated stereotyped CLL other than subset #1 and with cases using the same IGHV genes but a heterogeneous VH CDR3 (non‐subset #1 CLL). There were no distinctive features regarding CD38, ZAP‐70, and TP53 disruption. NOTCH1, SF3B1, and BIRC3 were mutated in 15%, 0%, and 5% of cases, respectively, while BIRC3 was deleted in 22% of cases. Microarray unsupervised analysis on 80 unmutated/mutated/stereotyped/non‐stereotyped CLL showed a tight clustering of subset #1 cases. Their genomic signature exhibited several differentially expressed transcripts involved in BCR signal transduction, apoptosis regulation, cell proliferation, and oxidative processes, regardless of del(11q). Accordingly, BCR ligation with anti‐IgM revealed a significant higher proliferation of subset #1 versus unmutated non‐subset #1 CLL, both at baseline and after 24–48 hr stimulation. Subset #1 CLL represent a paradigmatic example of the direct link between BCR structure, function, and patients prognosis. Am. J. Hematol. 89:74–82, 2014. © 2013 Wiley Periodicals, Inc.
Epigenetic studies in Alzheimer's disease: Current findings, caveats, and considerations for future studies
Authors: Lunnon Katie , Mill Jonathan
Published: September 2013

Alzheimer's disease (AD) is a sporadic, chronic neurodegenerative disease, usually occurring late in life. The last decade has witnessed tremendous advances in our understanding about the genetic basis of AD, but a large amount of the variance in disease risk remains to be explained. Epigenetic mechanisms, which developmentally regulate gene expression via modifications to DNA, histone proteins, and chromatin, have been hypothesized to play a role in other complex neurobiological diseases, and studies to identify genome‐wide epigenetic changes in AD are currently under way. However, the simple brute‐force approach that has been successfully employed in genome‐wide association studies is unlikely to be successful in epigenome‐wide association studies of neurodegeneration. A more academic approach to understanding the role of epigenetic variation in AD is required, with careful consideration of study design, methodological approaches, tissue‐specificity, and causal inference. In this article, we review the empirical literature supporting a role for epigenetic processes in AD, and discuss important considerations and future directions for this new and emerging field of research. © 2013 Wiley Periodicals, Inc.
Signaling context modulates social function of silent bared‐teeth displays in rhesus macaques (Macaca mulatta)
Authors: Beisner Brianne A. , McCowan Brenda
Published: September 2013

The signaling context has been found to change the meaning of the silent bared‐teeth display (SBT) in pigtail macaques (Macaca nemestrina) such that the SBT in apparently peaceful contexts communicates subordination, a long‐term pattern of behavior, whereas in conflict contexts it communicates immediate submission (PNAS, 104: 1581–1586). However, the context dependent nature of the SBT has not yet been explored in other species. We investigated SBT usage with respect to grooming, severe aggression, and signaler‐receiver sex, rank difference, and body size in seven captive groups of rhesus macaques. Peaceful SBTs were given most often to male receivers by male and female signalers whereas conflict SBTs were given to both male and female receivers primarily by female signalers. Male signalers rarely gave SBTs (peaceful or conflict) to female receivers. Unlike pigtail macaques, peaceful SBTs in rhesus were often accompanied by withdrawal behavior (referred to as peaceful SBT‐leave), which influenced grooming, but not aggression, at the dyadic level. Severe aggression was less frequent among dyads using peaceful SBTs (regardless of withdrawal behavior) than those using conflict SBTs. In contrast, grooming was more frequent among dyads using peaceful SBT‐stay signals than those using peaceful SBT‐leave signals or conflict SBTs. In total, our results indicate that peaceful SBTs are a functionally different signal from conflict SBTs in rhesus macaques. Am. J. Primatol. 76:111–121, 2014. © 2013 Wiley Periodicals, Inc.
Thermal decomposition kinetics of rigid polyurethane foam and ignition risk by a hot particle
Authors: Wang Supan , Chen Haixiang , Zhang Linhe
Published: September 2013

Rigid polyurethane foam, one kind of building insulation material used in China, is prone to being ignited by hot particles from fireworks or welding processes and has been the fuel for some catastrophic fire accidents. Thermal decomposition has long been recognized to play an important role in the ignition and fire‐spreading processes of materials, and thus, it is important to understand the behavior and kinetics of material decomposition. In this study, the characteristics of the thermal decomposition of polyurethane foam were investigated in an air atmosphere with nonisothermal thermogravimetry and differential scanning calorimetry (DSC). Model‐free (isoconversional) methods and model‐fitting methods were used to study the decomposition kinetics. The results reveal that the decomposition process of polyurethane foam in air presented three main stages: the loss of low‐stability organic compounds (bond fission of the weakest link in the chain), oxidative degradation of organic components, and oxidative degradation of residue material. A scheme containing three consecutive reactions was proposed to describe the decomposition process, and good agreement was found between the experimental and simulated curves. The heat during decomposition was calculated from DSC measurement. On the basis of the kinetics and heat of decomposition, the critical conditions for a hot particle to ignite polyurethane foam was evaluated, and this was helpful for the understanding the ignition risk of polyurethane foam. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 39359.
Composite films of N,O‐carboxymethyl chitosan and bamboo fiber
Authors: Zheng Xue , Zhang Hao , She Ying , Pu Junwen
Published: September 2013

To obtain an antibacterial chitosan derivative, composite films of N,O‐Carboxymethyl Chitosan (N,O‐CMCS) and bamboo fiber were prepared. A water‐soluble chitosan derivative‐N,O‐CMCS was synthesized from chitosan with chloroacetic acid in alkaline solution. Composite films with 1–5 wt % N,O‐CMCS content were prepared in NaOH/urea/thiourea solution. The DS of N,O‐CMCS reached 1.70 and the water solubility increased with the increasing of DS. The carboxymethyl group was introduced into chitosan, which led to the decrease of thermal stability and crystallinity. The structural characterization confirmed that N,O‐CMCS was adsorbed on the surface of bamboo fiber. The antibacterial performance of the composite films were enhanced with the increasing of N,O‐CMCS content. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 39851.
Production of polyamic acid in supercritical carbon dioxide with N,N‐dimethylformamide
Authors: Haruki Masashi , Hasegawa Yumi , Fukui Naoya , Kihara Shin‐ichi , Takishima Shigeki
Published: September 2013

To develop a microscale processing technique for aromatic polyimides (APIs) in supercritical carbon dioxide (scCO2), the relationships between the polymerization condition, the phase behavior during polymerization and the molecular weight of polyamic acid (PAA)—an intermediate in the production of polyimides—were investigated in scCO2 at 50°C. 4,4′‐Diaminodiphenyl ether (ODA) and pyromellitic dianhydride (PMDA) were used as monomers of aromatic diamine and tetracarboxylic dianhydride, respectively, and 19 mol % of N,N‐Dimethylformamide (DMF) was added to scCO2 as a cosolvent. The cloudy phase appeared immediately when ODA and PMDA were mixed under any experimental conditions. However, the appearances of the phase behaviors during polymerization differed depending on the polymerization pressure and the initial monomer concentration. The number average molecular weight of PAA increased as the monomer concentration was increased in scCO2, as was the case with polymerization in pure DMF at atmospheric pressure, despite differences in the phase behavior. On the other hand, the weight average molecular weight of PAA depended on the phase behaviors during polymerization along with the monomer concentration. Moreover, API obtained from the PAA synthesized in scCO2 was analyzed using a Fourier transform infrared spectrophotometer and thermogravimetric analyzer, and the results were compared with those of APIs obtained by the solution polymerization. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 39878.
Optimization of extracellular truncated staphylococcal protein A expression in Escherichia coliBL21 (DE3)
Authors: Rigi Garshasb , Mohammadi Samira Ghaed , Arjomand Maryam Rezaei , Ahmadian Gholamreza , Noghabi Kambiz Akbari
Published: September 2013

Staphylococcal protein A (SpA) plays an important role in Staphylococcus aureus pathogenesis. The recombinant SpA is also widely used in biotechnology to purify polyclonal and monoclonal immunoglobulin G antibodies. In this study, expression and secretion of a truncated form of SpA containing five immunoglobulin‐binding domains using its own native signal sequence were optimized in Escherichia coli. Optimization was carried out using response surface method (RSM), making use of the interaction between five variables. The initial results revealed that the signal peptide from S. aureus was recognized in E. coli and the resulting SpA was expressed and secreted into the medium. Compounds, such as glycine, affected the secretion of SpA into the culture medium. The central composite design experiment showed that the optimum conditions for the maximum expression of recombinant truncated SpA in E. coli included 10% (w/v) lactose, 1.77% (w/v) glycine, induction time of 11 H, an optical density (600) of 1.1, and a temperature of 33 °C. Optimization using RSM resulted in a fivefold increase in the secretion of SpA. To date, this is the first study of its kind regarding the definite influence of glycine concentration and duration of the cultivation period on the secretion of SpA.
AUTISM TREATMENTS IN PRINT: MEDIA'S COVERAGE OF SCIENTIFICALLY SUPPORTED AND ALTERNATIVE TREATMENTS
Authors: Schreck Kimberly A. , Russell Melissa , Vargas Luis A.
Published: September 2013

Professionals, celebrities, and media frequently suggest to parents the possible treatment options for their children with autism. Some treatment recommendations advocate for scientifically supported treatments whereas others suggest novel, untested interventions, or potentially ineffective or harmful treatments. The current study examined the print media's coverage of applied behavior analysis (ABA) and non‐scientifically supported autism treatments. Over the last 10 years, print media have increasingly published articles referring to autism treatments with little scientific support and a decreased coverage of ABA. Print media's positive statements about non‐scientifically supported treatments also increased over the last decade, whereas positive statements about ABA decreased. ABA received two times as many positive comments as negative; however, non‐scientifically supported treatments as a group received four times as many positive comments as negative. These results could contribute to parents' decisions to implement treatments for their children with autism. To contribute to future positive perception of ABA, we provided suggestions for the dissemination of information to increase positive reporting of ABA in print media. Copyright © 2013 John Wiley & Sons, Ltd.
Prognostic value of quantitative fluorodeoxyglucose measurements in newly diagnosed metastatic breast cancer
Authors: Ulaner Gary A. , Eaton Anne , Morris Patrick G. , Lilienstein Joshua , Jhaveri Komal , Patil Sujata , Fazio Maurizio , Larson Steven , Hudis Clifford A. , Jochelson Maxine S.
Published: September 2013

The aim of this study was to determine the prognostic value of quantitative fluorodeoxyglucose (FDG) measurements (maximum standardized uptake value [SUVmax], metabolic tumor volume [MTV], and total lesion glycolysis [TLG]) in patients with newly diagnosed metastatic breast cancer (MBC). An IRB‐approved retrospective review was performed of patients who underwent FDG positron emission tomography (PET)/computed tomography (CT) from 1/02 to 12/08 within 60 days of diagnosis MBC. Patients with FDG‐avid lesions without receiving chemotherapy in the prior 30 days were included. Target lesions in bone, lymph node (LN), liver, and lung were analyzed for SUVmax, MTV, and TLG. Medical records were reviewed for patient characteristics and overall survival (OS). Cox regression was used to test associations between quantitative FDG measurements and OS. A total of 253 patients were identified with disease in bone (n = 150), LN (n = 162), liver (n = 48), and lung (n = 66) at the time of metastatic diagnosis. Higher SUVmax tertile was associated with worse OS in bone metastases (highest vs. lowest tertile hazard ratio [HR] = 3.1, P < 0.01), but not in LN, liver or lung (all P > 0.1). Higher MTV tertile was associated with worse OS in LN (HR = 2.4, P < 0.01) and liver (HR = 3.0, P = 0.02) metastases, but not in bone (P = 0.22) or lung (P = 0.14). Higher TLG tertile was associated with worse OS in bone (HR = 2.2, P = 0.02), LN (HR = 2.3, P < 0.01), and liver (HR = 4.9, P < 0.01) metastases, but not in lung (P = 0.19). We conclude measures of FDG avidity are prognostic biomarkers in newly diagnosed MBC. SUVmax and TLG were both predictors of survival in breast cancer patients with bone metastases. TLG may be a more informative biomarker of OS than SUVmax for patients with LN and liver metastases.
Apoptotic effect of methanol extract of Picrasma quassioides by regulating specificity protein 1 in human cervical cancer cells
Authors: Lee Hang‐Eun , Choi Eun‐Sun , Shin Ji‐Ae , Kim Lee‐Han , Cho Nam‐Pyo , Cho Sung‐Dae
Published: September 2013

In the present study, we examined the effects of methanol extracts of Picrasma quassioides (MEPQ) on apoptosis in human cervical cancer cells. The results showed that MEPQ decreased the viability and induced caspase‐dependent apoptosis in HEp‐2 cells. MEPQ decreased specificity protein 1 (Sp1) in HEp‐2 cells, whereas Sp1 mRNA was not changed. We found that MEPQ reduced Sp1 protein through proteasome‐dependent protein degradation, but not the inhibition of protein synthesis. Also, MEPQ increased the expressions of Bad and truncated Bid (t‐Bid) but did not alter other Bcl‐2 family members. The knock‐down of Sp1 by both Sp1 interfering RNA and Mithramycin A, Sp1 specific inhibitor clearly increased Bad and t‐Bid expression to decrease cell viability and induce apoptosis. In addition, MEPQ inhibited cell viability and induced apoptotic cell death through the modulation of Sp1 in KB cells. These results suggest that MEPQ may be a potential anticancer agent for human cervical cancer. Copyright © 2013 John Wiley & Sons, Ltd.
Functionalisation and surface modification of electrospun polylactic acid scaffold for tissue engineering
Authors: Hoveizi Elham , Nabiuni Mohammad , Parivar Kazem , Rajabi‐Zeleti Sareh , Tavakol Shima
Published: September 2013

Repair or replacement of damaged tissues using tissue engineering technology is considered to be a fine solution for enhanced treatment of different diseases such as skin diseases. Although the nanofibers made of synthetic degradable polymers, such as polylactic acid (PLA), have been widely used in the medical field, they do not favour cellular adhesion and proliferation. To enhance cell adherence on scaffold and improve biocompatibility, the surface of PLA scaffold was modified by gelatin in our experiments. For electrospinning, PLA and gelatin were dissolved in hexafluoroisopropanol (HFIP) solvent at varying compositions (PLA:gelatin at 3:7 and 7:3). The properties of the blending nanofiber scaffold were investigated by Fourier transform infrared (FT‐IR) spectroscopy and scanning electron microscopy (SEM). Modified PLA/gelatin 7/3 scaffold is more suitable for fibroblasts attachment and viability than the PLA or gelatin nanofiber alone. Thus fibroblast cultured on PLA/gelatin scaffold could be an alternative way to improve skin wound healing.
Ocelot catheter for the treatment of long SFA occlusion
Authors: Cawich Ian , Marmagkiolis Konstantinos , Cilingiroglu Mehmet
Published: September 2013

Long saphenous femoral artery (SFA) chronic total occlusions (CTOs) are considered the “Achilles heel” of the lower extremity percutaneous interventions. Antegrade, retrograde, or transcollateral approaches, intraluminal or subintimal techniques with re‐entry and specialized CTO devices using microdissection, vibrational energy, and laser have all been tried for the management of such challenging lesions with various success rates. Ocelot is the first CTO crossing device using real‐time OCT technology. Its crossing catheter utilizes spiral wedges to corkscrew the CTO cap, while real‐time OCT offers direct visualization to facilitate intravascular true‐lumen orientation. The recently presented results of the CONNECT‐II study demonstrated crossing success of 97% and freedom from major adverse events of 98%. We present one of the most challenging SFA CTOs with ambiguous proximal cap in the ostium of the SFA, heavy calcification and involving almost the entire length of the SFA. The Ocelot catheter assisted to the successful true‐lumen recanalization of that complex lesion. © 2013 Wiley Periodicals, Inc.
Percutaneous transluminal pulmonary valvuloplasty in a child with tricuspid atresia, ventricular septal defect, and severe pulmonary valve stenosis
Authors: Torigoe Tsukasa , Sato Seiichi , Kanazawa Hiroshi
Published: September 2013

Percutaneous transluminal pulmonary valvuloplasty may be indicated in not only isolated pulmonary valve stenosis, but also complex congenital heart diseases. Because palliative surgery for increasing pulmonary blood flow entails a risk of scar formation and immediate postoperative complications, catheter intervention is preferred, if possible. However, an acute‐angled, twisted, or tortuous access route or a small valve orifice occasionally makes it difficult for the catheter to reach or cross the target. We succeeded in performing this intervention for such a complex stenosis effectively and safely in a patient with tricuspid atresia, ventricular septal defect (VSD), and severe pulmonary valve stenosis, thereby evading surgery. In previous reports, the catheter for this cardiac anomaly was accessed via the femoral vein. In the present case, the catheter was advanced through the femoral artery via the aorta, left ventricle, VSD, and right ventricle to the pulmonary valve, using a micro‐catheter in a telescopic manner, in combination with a coronary balloon dilatation catheter. This maneuver, which has not been reported previously, made it much easier to perform the procedure as compared to the femoral vein approach, despite the acute turn and the pinhole orifice. Moreover, reported complications of the femoral vein approach, including bradycardia, hypotension, and valve regurgitation, were not observed in this case. We conclude that the femoral artery approach can be a safe and effective alternative in patients for whom a more conventional procedure has been unsuccessful. © 2013 Wiley Periodicals, Inc.
A perspective on the growth of chemometrics in Iran: a glance into activities between 2005 and 2012
Authors: Naseri Abdolhossein , Bahram Morteza
Published: September 2013

Although the first publications in the field of chemometrics by Iranian researchers go back nearly 23 years, Iran's chemometrics has experienced significant growth after the year 2000. More than 1500 papers have been published by Iranian chemometricians between 2005 and 2012 which is about seven times more than those published before 2005. The aim of this review is to present a perspective about Iran's chemometrics developments. The role of enthusiastic students, motivated professors, annual workshops, and international collaborations is discussed in this work. After introducing the first papers in each field of chememotrics, the papers published during 2005–2012 were screened, and some of them were introduced. Copyright © 2013 John Wiley & Sons, Ltd.
Chemical Inhomogeneity, Short‐Range Order, and Magnetism in the LiNiO2‐NiO Solid Solution
Authors: Barton Phillip T. , Premchand Y. Daniel , Chater Philip A. , Seshadri Ram , Rosseinsky Matthew J.
Published: September 2013

NiO:Li is an early exemplar for which hole‐doping of a correlated insulator gives rise to rich and varied magnetic behavior. It is also an important system from the viewpoint of p‐type transparent conducting oxides, and is representative of a large class of materials that have been used in lithium ion batteries, since the end‐member compound, LiNiO2, belongs to the class of layered cathode materials. Despite the deceptive structural and compositional simplicity of this system, a complete understanding of its complex magnetic properties has remained elusive. Here a comprehensive investigation of the solid solution LixNi2−xO2, examining samples of precise stoichiometry using a combination of high‐resolution synchrotron X‐ray powder diffraction and SQUID magnetometry, is provided. The focus is on the interesting region between 0.40<x<1.00 in which the magnetic ordering temperature changes drastically with composition. The magnetism evolves from strong G‐type antiferromagnetism of x=0.40 with TN=327 K to robust uncompensated magnetic order at TN=240 K when x is close to 0.7, and to glassy A‐type antiferromagnetism of x=1.00 at TN=9 K. This study demonstrates this magnetic behavior is linked to the Li–Ni chemical order that develops from short‐ to long‐range. The interfaces between ordered domains give rise to magnetic exchange bias, which manifests as a shift in the magnetization‐field loop for samples with nanoscale coherence lengths (0.54<x<0.66).
An Amino‐Acid‐Based Self‐Healing Hydrogel: Modulation of the Self‐Healing Properties by Incorporating Carbon‐Based Nanomaterials
Authors: Roy Subhasish , Baral Abhishek , Banerjee Arindam
Published: September 2013

An amino‐acid‐based (11‐(4‐(pyrene‐1‐yl)butanamido)undecanoic acid) self‐repairing hydrogel is reported. The native hydrogel, as well as hybrid hydrogels, have been thoroughly characterized by using various microscopic techniques, including transmission electron microscopy (TEM), atomic force microscopy (AFM), Raman spectroscopy, fluorescence spectroscopy, FTIR spectroscopy, X‐ray diffraction, and by using rheological experiments. The native hydrogel exhibited interesting fluorescence properties, as well as a self‐healing property. Interestingly, the self‐healing, thixotropy, and stiffness of the native hydrogel can be successfully modulated by incorporating carbon‐based nanomaterials, including graphene, pristine single‐walled carbon nanotubes (Pr‐SWCNTs), and both graphene and Pr‐SWCNTs, within the native gel system. The self‐recovery time of the gel was shortened by the inclusion of reduced graphene oxide (RGO), Pr‐SWCNTs, or both RGO and Pr‐SWCNTs. Moreover, hybrid gels that contained RGO and/or Pr‐SWCNTs exhibited interesting semiconducting behavior.
Exploring Supramolecular Self‐Assembly of Tetraarylporphyrins by Halogen Bonding: Crystal Engineering with Diversely Functionalized Six‐Coordinate Tin(L)2–Porphyrin Tectons
Authors: Titi Hatem M. , Patra Ranjan , Goldberg Israel
Published: September 2013

This study targets the construction of porphyrin assemblies directed by halogen bonds, by utilizing a series of purposely synthesized Sn(axial ligand)2–(5,10,15,20‐tetraarylporphyrin) [Sn(L)2‐TArP] complexes as building units. The porphyrin moiety and the axial ligands in these compounds contain different combinations of complimentary molecular recognition functions. The former bears p‐iodophenyl, p‐bromophenyl, 4′‐pyridyl, or 3′‐pyridyl substituents at the meso positions of the porphyrin ring. The latter comprises either a carboxylate or hydroxy anchor for attachment to the porphyrin‐inserted tin ion and a pyridyl‐, benzotriazole‐, or halophenyl‐type aromatic residue as the potential binding site. The various complexes were structurally analyzed by single‐crystal X‐ray diffraction, accompanied by computational modeling evaluations. Halogen‐bonding interactions between the lateral aryl substituents of one unit of the porphyrin complex and the axial ligands of neighboring moieties was successfully expressed in several of the resulting samples. Their occurrence is affected by structural (for example, specific geometry of the six‐coordinate complexes) and electronic effects (for example, charge densities and electrostatic potentials). The shortest intermolecular I⋅⋅⋅N halogen‐bonding distance of 2.991 Å was observed between iodophenyl (porphyrin) and benzotriazole (axial ligand) moieties. Manifestation of halogen bonds in these relatively bulky compounds without further activation of the halophenyl donor groups by electron‐withdrawing substituents is particularly remarkable.
Organocatalyzed Aldol Reaction between Pyridine‐2‐carbaldehydes and α‐Ketoacids: A Straightforward Route towards Indolizidines and Isotetronic Acids
Authors: Liautard Virginie , Jardel Damien , Davies Clotilde , Berlande Muriel , Buffeteau Thierry , Cavagnat Dominique , Robert Frédéric , Vincent Jean‐Marc , Landais Yannick
Published: September 2013

Enantioselective aldol reactions between substituted pyridine carbaldehydes and α‐ketoacids were shown to provide isotetronic acids or their corresponding pyridinium salts, depending on the nature of the substituents on the pyridine ring. The pyridinium salts were generated through nucleophilic attack of the pyridine nitrogen atom onto the reactive keto functional group. Moderate‐to‐good yields of both compounds were typically obtained and high levels of enantioselectivity were observed by using benzimidazole pyrrolidine I as a catalyst. Hydrogenation of the resulting pyridinium salts led to new indolizidines with high ee values and diastereocontrol. X‐ray diffraction studies allowed the determination of the relative configuration of the products. Finally, DFT calculations were performed to rationalize the divergent pathway as a function of the pyridine substituents.
RhIII‐Catalyzed CH Activation: A Versatile Route towards Various Polycyclic Pyridinium Salts
Authors: Luo Ching‐Zong , Gandeepan Parthasarathy , Jayakumar Jayachandran , Parthasarathy Kanniyappan , Chang Yu‐Wei , Cheng Chien‐Hong
Published: September 2013

An efficient and convenient method for the synthesis of highly substituted polycyclic pyridinium salts from the reaction of various 2‐aryl‐pyridines and 2‐aryl‐sp2‐nitrogen‐atom‐containing heterocycles with alkynes through rhodium(III)‐catalyzed CH activation and annulation under an O2 atmosphere is described. A possible mechanism that involves the chelation‐assisted CH activation of the 2‐aryl‐pyridine substrate, insertion of the alkyne, and reductive elimination is proposed. This mechanism was supported by the isolation of a five‐membered rhodacycle (I′). In addition, kinetic isotope studies were performed to understand the intimate reaction mechanism.
Effect of Cyanide Ligands on the Electronic Structure of [FeFe] Hydrogenase Active‐Site Model Complexes with an Azadithiolate Cofactor
Authors: Erdem Özlen F. , Stein Matthias , Kaur‐Ghumaan Sandeep , Reijerse Edward J. , Ott Sascha , Lubitz Wolfgang
Published: September 2013

A detailed characterization of a close synthetic model of the [2 Fe]H subcluster in the [FeFe] hydrogenase active site is presented. It contains the full primary coordination sphere of the CO‐inhibited oxidized state of the enzyme including the CN− ligands and the azadithiolate (adt) bridge, [((μ‐SCH2)2NR)Fe2(CO)4(CN)2]2−, R=CH2CH2SCH3. The electronic structure of the model complex in its FeIFeII state was investigated by means of density functional theory (DFT) calculations and Fourier transform infrared (FTIR) spectroscopy. By using a combination of continuous‐wave (CW) electron paramagnetic resonance (EPR) and hyperfine sublevel correlation (HYSCORE) experiments as well as DFT calculations, it is shown that, for this complex, the spin density is delocalized over both iron atoms. Interestingly, we found that the nitrogen hyperfine coupling, which represents the interaction between the unpaired electron and the nitrogen at the dithiolate bridge, is slightly larger than that in the analogous complex in which the CN− ligands are replaced with PMe3 ligands. This reveals, first, that the CN−/PMe3 ligands coordinated to the iron core are electronically coupled to the amine in the adt bridge. Second, the CN− ligands in this complex are somewhat stronger σ‐donor ligands than the PMe3 ligand, and thereby enable more spin density to be transferred from the Fe core to the adt unit, which might in turn affect the reactivity of the bridging amine.
Facile Synthesis and Enhanced Nonlinear Optical Properties of Porphyrin‐Functionalized Multi‐Walled Carbon Nanotubes
Authors: Wang Aijian , Fang Yu , Long Lingliang , Song Yinglin , Yu Wang , Zhao Wei , Cifuentes Marie P. , Humphrey Mark G. , Zhang Chi
Published: September 2013

Two multi‐walled carbon nanotube (MWCNT)‐based nanohybrids, MWCNT–ZnTPP and MWCNT–TPP (TPP=5‐[4‐{2‐(4‐formylphenoxy)‐ ethyloxy}phenyl]‐10,15,20‐triphenylporphyrin, ZnTPP=5‐[4‐{(4‐formylphenyl)ethynyl}phenyl]‐10,15,20‐triphenylporphinatozinc(II)), were prepared directly from pristine MWCNTs through 1,3‐dipolar cycloaddition reactions. Covalent attachment of the porphyrins to the surfaces of the MWCNTs was confirmed by Fourier transform infrared spectroscopy, ultraviolet/visible absorption, fluorescence, Raman, and X‐ray photoelectron spectroscopy, elemental analysis, transmission electron microscopy, and thermogravimetric analysis. Attachment of the porphyrin moieties to the surface of the MWCNTs significantly improves the solubility and ease of processing of these MWCNT–porphyrin composite materials. Z‐scan studies reveal that these MWCNT–porphyrin nanohybrids exhibit enhanced nonlinear optical properties under both nanosecond and picosecond laser pulses at λ=532 nm in comparison with free MWCNTs and the free porphyrin chromophores, whereas superior optical limiting performance was displayed by MWCNT–porphyrin composite materials rather than MWCNTs/ZnTPP and MWCNTs/TPP blends, which is consistent with a remarkable accumulation effect as a result of the covalent linkage between the porphyrin and the MWCNTs.
An overview on the recent advances in computational fluid dynamics simulation of spouted beds
Authors: Bao Xiaojun , Du Wei , Xu Jian
Published: September 2013

Spouted beds are now widely applied in various physical operations and chemical reaction systems due to their unique structural and flow characteristics. Now there are growing interests to use computational fluid dynamics (CFD) to understand dense gas–solid two‐phase flows in spouted beds. Both Eulerian–Eulerian (two‐fluid model, TFM) and Eulerian–Lagrangian (discrete element method, DEM) approaches can be applied to the CFD modelling of spouted beds and spouted‐fluidised beds, and numerous verification studies have shown their reliabilities. This overview summarises the recent advances of the TFM and DEM approaches in the CFD modelling of spouted beds. The typical flow patterns of spouted beds can be well reproduced by both the TFM and the DEM approaches, and the simulated characteristic properties such as spout diameter, minimum spouting velocity and voidage profile are in good agreement with experimental data, indicating that CFD modelling based on the TFM and DEM approaches can serve as an important tool for predicting gas and solids behaviour in spouted beds. The TFM approach has been widely used in phenomenological studies that are mainly towards the understanding of the flow behaviour of the whole system. Although more computational capacity is required, the DEM approach offers a more natural way to simulate gas–solid flows, with each individual particle tracked in the simulation and can be applied readily for particle tracking, collision, mixing, circulation and mass transfer studies that are aimed at obtaining the profound particle‐scale understanding in fluid–solid multiple‐phase systems. However, each approach has its own limitations and defects. The complex nature of the TFM‐based simulation framework requires both proper descriptions of pseudo‐fluid properties like solid pressure, solid viscosity, solid friction stresses, etc. and suitable choice of drag models, and the boundary conditions also have effects on the simulation results. Moreover, the effects of these factors often interact with each other, which require even more subtle skills in conducting a simulation. In the DEM approach, the high computing source requirement limits its application of no more than several million particles. Furthermore, more insight investigation should be given to the acting mechanism of several forces on particles. One common challenge for these two approaches is to properly describe the inherent turbulence for both the solid and gas phases, especially for the spout region. Further fundamental and experimental studies on the kinematic properties of the two phases are needed to improve the accuracy of the CFD models.
Response to Improvement of Arterial Stiffness in the Transition From Acute Decompensated Heart Failure to Chronic Compensated Heart Failure
Authors: Demirkol Sait , Balta Sevket , Kucuk Ugur , Unlu Murat , Cakar Mustafa , Dinc Mustafa
Published: September 2013

Kim DB et al. Clin Cardiol. 2013;36:358–362.
Single‐crystal X‐ray diffraction investigation of the reversible order‐disorder phase transition in iron‐deficient TlFe2–xSe2
Authors: Ahrens E. , Nitsche F. , Doert Th. , Ruck M.
Published: September 2013

A reversible phase transition was found for iron‐deficient TlFe2–xSe2 (x ≈ 0.4) and investigated on single crystals using high temperature synchrotron radiation X‐ray diffraction. Full data sets have been collected at room temperature and at 200 °C to evaluate the structures. The high‐temperature form (space group I4/mmm, lattice parameters a = 3.8919(3) Å, c = 14.027(3) Å) shows complete statistical disorder of iron positions and vacancies in a ThCr2Si2 type structure. The low‐temperature form corresponds to a √5 × √5 superstructure of the ThCr2Si2 type (I4/m, a = 8.6966(2) Å, c = 14.009(9) Å) and shows partial ordering of iron positions and vacancies. A group‐subgroup relation can be compiled between both structures.
Site‐Specific Carbon Deposition for Hierarchically Ordered Core/Shell‐Structured Graphitic Carbon with Remarkable Electrochemical Performance
Authors: Lv Yingying , Wu Zhangxiong , Qian Xufang , Fang Yin , Feng Dan , Xia Yongyao , Tu Bo , Zhao Dongyuan
Published: September 2013

A fascinating core–shell‐structured graphitic carbon material composed of ordered microporous core and uniform mesoporous shell is fabricated for the first time through a site‐specific chemical vapor deposition process by using a nanozeolite@mesostructured silica composite molecular sieve as the template. The mesostructure‐directing agent cetyltrimethylammonium bromide in the shell of the template can be either burned off or carbonized so that it is successfully utilized as a pore switch to turn the shell of the template “on” or “off” to allow selective carbon deposition. The preferred carbon deposition process can be performed only in the inner microporous zeolite cores or just within the outer mesoporous shells, resulting in a zeolite‐like ordered microporous carbon or a hollow mesoporous carbon. Full carbon deposition in the template leads to the new core–shell‐structured microporous@mesoporous carbon with a nanographene‐constructed framework for fast electron transport, a microporous nanocore with large surface area for high‐capacity storage of lithium ions, a mesoporous shell with highly opened mesopores as a transport layer for lithium ions and electron channels to access inner cores. The ordered micropores are protected by the mesoporous shell, avoiding pore blockage as the formation of solid electrolyte interphase layers. Such a unique core–shell‐structured microporous@mesoporous carbon material represents a newly established lithium ion storage model, demonstrating high reversible energy storage, excellent rate capability, and long cyclic stability.
Efficient Organic Dye‐Sensitized Solar Cells: Molecular Engineering of Donor–Acceptor–Acceptor cationic dyes
Authors: Cheng Ming , Yang Xichuan , Zhao Jianghua , Chen Cheng , Tan Qin , Zhang Fuguo , Sun Licheng
Published: September 2013

Three metal‐free donor–acceptor–acceptor sensitizers with ionized pyridine and a reference dye were synthesized, and a detailed investigation of the relationship between the dye structure and the photophysical and photoelectrochemical properties and the performance of dye‐sensitized solar cells (DSSCs) is described. The ionization of pyridine results in a red shift of the absorption spectrum in comparison to that of the reference dye. This is mainly attributable to the ionization of pyridine increasing the electron‐withdrawing ability of the total acceptor part. Incorporation of the strong electron‐withdrawing units of pyridinium and cyano acrylic acid gives rise to optimized energy levels, resulting in a large response range of wavelengths. When attached to TiO2 film, the conduction band of TiO2 is negatively shifted to a different extent depending on the dye. This is attributed to the electron recombination rate between the TiO2 film and the electrolyte being efficiently suppressed by the introduction of long alkyl chains and thiophene units. DSSCs assembled using these dyes show efficiencies as high as 8.8 %.
A novel media independent handover‐based approach for vertical handover over heterogeneous wireless networks
Authors: Omheni N. , Zarai F. , Obaidat M. S. , Hsiao K.‐F. , Kamoun L.
Published: September 2013

The key purpose for seamless mobility and service continuity between heterogeneous wireless networks is the handover. Vertical handover management is one of key challenges in such environment. To deal with some of these challenges, an IEEE 802.21 media independent handover (MIH) framework has been standardized. The main purpose of this standard is to offer a general interface for the handover by abstracting the link layer intelligence to higher layers. However, there still exist a number of limitations in MIH architecture. In this paper, a new architecture of improved MIH is presented to perform vertical handover between wireless heterogeneous networks. We focused on interworking architecture between wireless local area network and long term evolution advanced network with the use of MIH signaling to define an efficient vertical handover. A performance analysis model for the proposed MIH‐based vertical handover is derived. Analysis results show that the proposed method can be easily deployed in present multimedia service networks. Copyright © 2013 John Wiley & Sons, Ltd.
A Facile Route to Flowerlike Bi2S3 Constructed by Polycrystalline Nanoplates with Enhanced Electrochemical Properties
Authors: Jin Rencheng , Li Guihua , Liu Junshen , Yang Lixia
Published: September 2013

In this work, hierarchical flowerlike Bi2S3 structures constructed by polycrystalline nanoplates combined with urchinlike and wirelike Bi2S3 were synthesized by using a thioglycolic acid assisted solvothermal method. On the basis of the time‐dependent experimental results, an anion exchange process and a self‐assembly mechanism were proposed to account for the growth mechanism of the synthesized flowerlike Bi2S3. In addition, the morphology and the crystalline nature of the products can be easily tuned by changing the reaction temperature. Moreover, the electrochemical properties (electrochemical hydrogen‐storage and lithium‐intercalation performance) of the products were studied. The flowerlike Bi2S3 possesses both higher electrochemical properties and better cycle stabilities compared to urchinlike and wirelike Bi2S3.
Lipid damage inhibition by previous high pressure processing in white muscle of frozen horse mackerel
Authors: Torres J. Antonio , Vázquez Manuel , Saraiva Jorge A. , Gallardo José M. , Aubourg Santiago P.
Published: September 2013

This work focuses on the effect of a previous high pressure processing (HPP) on the lipid damage development occurring during the frozen storage (−10°C; up to 3 months) of Atlantic horse mackerel (Trachurus trachurus). HPP conditions included different pressure (150, 300, 450 MPa) and pressure holding time (0.0, 2.5, 5.0 min) values. During frozen storage, horse mackerel muscle was analyzed for lipid hydrolysis (free fatty acid assessment; FFA) and oxidation (formation of peroxides, thiobarbituric acid reactive substances, and fluorescent compounds), and polyene content. An inhibition of lipid hydrolysis development was observed; thus, both an increasing pressure level and pressure holding time led to a marked inhibition of FFA content throughout the frozen storage. Concerning the lipid oxidation development, a partial inhibition was also obtained during the frozen storage (months 1 and 3) by increasing the pressure level applied (namely, fluorescent and peroxide compound formation); however, pressure holding time did not lead to a definite trend. No effect of HPP treatment was concluded on the polyene content of the fish muscle lipids. Present research provides novel information concerning the employment of HPP technology focused on the inhibition of lipid damage during a subsequent frozen storage.

Practical applications: Frozen storage of fatty and medium‐fat fish species is known to be strongly limited by lipid damage development, which is a drawback to its commercialization as such or to its subsequent employment as raw material in other kinds of processing (canneries, smoking, etc.). Present research provides valuable information concerning the employment of the high pressure technology to inhibit lipid damage development during the subsequent frozen storage of Atlantic horse mackerel (T. trachurus). Thus, both an increasing pressure level (from 150 to 450 MPa) and pressure holding time (from 0 to 5 min) led to a marked inhibition of lipid hydrolysis during frozen storage. Additionally, inhibition of lipid oxidation was produced by increasing the pressure level. Since the response to HPP of marine species has been reported to vary with species, a preliminary study is recommended to be carried out before applying the high pressure‐frozen storage combining strategy.
Thiol‐Ene Click Reactions – Versatile Tools for the Modification of Unsaturated Amino Acids and Peptides
Authors: Karmann Lisa , Kazmaier Uli
Published: September 2013

Terminal γ,δ‐unsaturated amino acids, easily available by Claisen rearrangement or palladium‐catalysed allylic alkylation, are excellent substrates for radical thiol additions. These click reactions allow the introduction of highly functionalized side‐chains into a given amino acid or peptide. This protocol is suitable for the modification of all kinds of terminal alkenes, such as allyl protecting groups.
A Stereoselective Approach to Functionalized Cyclohexenones
Authors: Meister Anne C. , Sauter Paul F. , Bräse Stefan
Published: September 2013

A catalytic enantioselective approach to 4‐hydroxy‐6‐methylcyclohex‐2‐enones is presented herein. The stereogenic information is generated through a copper‐catalyzed 1,4‐addition to p‐benzoquinone monoketal using a chiral, BINOL‐based (BINOL = 1,1′‐bi‐2‐naphthol) phosphane ligand, according to the procedure of Feringa et al. A CBS (Corey–Bakshi–Shibata) reduction of the 1,4‐adducts gave the four possible isomers in two steps and 82–97 % ee (enantiomeric excess), starting from commercially available 4,4‐dimethoxycyclohexa‐2,5‐dien‐1‐one (7).
Expression of Concern: One‐Step Synthesis of Biaryls under Mild Conditions
Authors: Bhat Aparna P. I. , Inam Fawad , Bhat Badekai Ramachandra
Published: September 2013

A one‐step synthesis of symmetrical biaryls was developed and uses a nickel(III) complex containing a Schiff base and dithiolate ligands as a catalyst for the homocoupling of in situ generated Grignard reagents. The coupling reaction was performed at room temperature with molecular oxygen as the oxidant, which renders the reaction energy‐efficient and environmentally friendly. The catalytic methodology is compatible with diverse functionalities, including chlorido, nitro, nitrile, and heteroatoms, and provides biaryls in appreciable yields.